fix: 自動参加のバグ修正

アナウンスが無効の時に自動参加も無効になるバグを修正

.dockerignore

@@ -0,0 +1,2 @@
+target
+audio

.github/workflows/build.yml

@@ -6,24 +6,29 @@ on:
       - 'v*'
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: self-hosted
     steps:
-      - uses: actions/checkout@v2
-      - uses: docker/metadata-action@v3
+      - uses: actions/checkout@v4
+        name: Checkout
+      - uses: docker/metadata-action@v4
         id: meta
         with:
-          images: ghcr.io/morioka22/ncb-tts-r2
+          images: ghcr.io/mii443/ncb-tts-r2
           tags: |
             type=semver,pattern={{version}}
             type=semver,pattern={{major}}.{{minor}}
-      - uses: docker/login-action@v1
+      - uses: docker/login-action@v2
         with:
           registry: ghcr.io
-          username: morioka22
+          username: mii443
           password: ${{ secrets.GITHUB_TOKEN }}
-      - uses: docker/build-push-action@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - uses: docker/build-push-action@v4
         with:
           context: .
           push: true
+          platforms: linux/amd64
           tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
+          labels: ${{ steps.meta.outputs.labels }}

.gitignore

@@ -3,4 +3,5 @@ Cargo.lock
 config.toml
 credentials.json
 /audio
-*.mp3
+*.mp3
+*.swp

Cargo.toml

@@ -1,33 +1,82 @@
 [package]
 name = "ncb-tts-r2"
-version = "0.1.0"
+version = "1.11.2"
 edition = "2021"
 
+[lib]
+name = "ncb_tts_r2"
+path = "src/lib.rs"
+
+[[bin]]
+name = "ncb-tts-r2"
+path = "src/main.rs"
+
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
 serde_json = "1.0"
 serde = "1.0"
-toml = "0.5"
+toml = "0.8.19"
 gcp_auth = "0.5.0"
-reqwest = { version = "0.11", features = ["json"] }
-base64 = "0.13"
+reqwest = { version = "0.12.9", features = ["json"] }
+base64 = "0.22.1"
 async-trait = "0.1.57"
-redis = "*"
+redis = { version = "0.29.2", features = ["aio", "tokio-comp"] }
+bb8 = "0.8"
+bb8-redis = "0.16"
+thiserror = "1.0"
+regex = "1"
+tracing-subscriber = "0.3.19"
+lru = "0.13.0"
+once_cell = "1.19"
+bincode = "1.3"
+tracing = "0.1.41"
+opentelemetry_sdk = { version = "0.29.0", features = ["trace"] }
+opentelemetry = "0.29.1"
+opentelemetry-semantic-conventions = "0.29.0"
+opentelemetry-otlp = { version = "0.29.0", features = ["grpc-tonic"] }
+opentelemetry-stdout = "0.29.0"
+tracing-opentelemetry = "0.30.0"
+symphonia-core = "0.5.4"
+tokio-util = { version = "0.7.14", features = ["compat"] }
+futures = "0.3.31"
+bytes = "1.10.1"
+voicevox-client = { git = "https://github.com/mii443/rust" }
 
 [dependencies.uuid]
-version = "0.8"
+version = "1.11.0"
 features = ["serde", "v4"]
 
 [dependencies.songbird]
-version = "0.2.0"
+version = "0.5"
 features = ["builtin-queue"]
 
-[dependencies.serenity]
-version = "0.10.9"
-features = ["builder", "cache", "client", "gateway", "model", "utils", "unstable_discord_api", "collector", "rustls_backend", "framework", "voice"]
+[dependencies.symphonia]
+version = "0.5"
+features = ["mp3"]
 
+[dependencies.serenity]
+version = "0.12"
+features = [
+    "builder",
+    "cache",
+    "client",
+    "gateway",
+    "model",
+    "utils",
+    "unstable_discord_api",
+    "collector",
+    "rustls_backend",
+    "framework",
+    "voice",
+]
 
 [dependencies.tokio]
 version = "1.0"
-features = ["macros", "rt-multi-thread"]
+features = ["macros", "rt-multi-thread"]
+
+[dev-dependencies]
+tokio-test = "0.4"
+mockall = "0.12"
+tempfile = "3.8"
+serial_test = "3.0"

Dockerfile

@@ -1,18 +1,45 @@
-FROM ubuntu:22.04
-WORKDIR /usr/src/ncb-tts-r2
-COPY Cargo.toml .
-COPY src src
-ENV PATH $PATH:/root/.cargo/bin/
-RUN apt-get update \
-&& apt-get install -y ffmpeg libssl-dev pkg-config libopus-dev wget curl gcc \
-&& apt-get -y clean \
-&& rm -rf /var/lib/apt/lists/* \
-&& curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain stable \
-&& rustup install stable \
-&& cargo build --release \
-&& cp /usr/src/ncb-tts-r2/target/release/ncb-tts-r2 /usr/bin/ncb-tts-r2 \
-&& mkdir -p /ncb-tts-r2/audio \
-&& apt-get purge -y pkg-config wget curl gcc \
-&& rustup self uninstall -y
+FROM lukemathwalker/cargo-chef:latest-rust-1.82 AS chef
+WORKDIR /app
+
+FROM chef AS planner
+COPY . .
+RUN cargo chef prepare --recipe-path recipe.json
+
+FROM chef AS builder
+COPY --from=planner /app/recipe.json recipe.json
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+    ffmpeg \
+    libssl-dev \
+    pkg-config \
+    libopus-dev \
+    gcc && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+RUN cargo chef cook --release --recipe-path recipe.json
+COPY . .
+RUN cargo build --release
+
+FROM ubuntu:22.04 AS runtime
 WORKDIR /ncb-tts-r2
-CMD ["ncb-tts-r2"]
+
+# 非rootユーザーの作成
+RUN groupadd -r appgroup && useradd -r -g appgroup appuser
+
+RUN apt-get update && \
+    apt-get install -y --no-install-recommends \
+    openssl \
+    ca-certificates \
+    ffmpeg \
+    libssl-dev \
+    libopus-dev && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists/*
+
+COPY --from=builder /app/target/release/ncb-tts-r2 /usr/local/bin/ncb-tts-r2
+RUN chmod +x /usr/local/bin/ncb-tts-r2
+
+# 非rootユーザーに切り替え
+USER appuser
+
+ENTRYPOINT ["/usr/local/bin/ncb-tts-r2"]

docker-compose.yml

@@ -0,0 +1,14 @@
+version: '3'
+
+services:
+    ncb-tts-r2:
+        container_name: ncb-tts-r2
+        image: ghcr.io/mii443/ncb-tts-r2:1.11.2
+        environment:
+        - NCB_TOKEN=YOUR_BOT_TOKEN
+        - NCB_APP_ID=YOUR_BOT_ID
+        - NCB_PREFIX=BOT_PREFIX
+        - NCB_REDIS_URL=redis://<REDIS_IP>/
+        - NCB_VOICEVOX_KEY=VOICEVOX_KEY
+        volumes:
+        - ./credentials.json:/ncb-tts-r2/credentials.json:ro

manifest/ncb-tts.yaml

@@ -0,0 +1,56 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: ncb-tts-deployment
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: ncb-tts
+  template:
+    metadata:
+      labels:
+        app: ncb-tts
+    spec:
+      containers:
+        - name: redis
+          image: redis:7.0.4-alpine
+          ports:
+          - containerPort:  6379
+            name: ncb-redis
+          volumeMounts:
+          - name: ncb-redis-pvc
+            mountPath: /data
+        - name: tts
+          image: ghcr.io/mii443/ncb-tts-r2
+          volumeMounts:
+          - name: gcp-credentials
+            mountPath: /ncb-tts-r2/credentials.json
+            subPath: credentials.json
+          env:
+          - name: NCB_REDIS_URL
+            value: "redis://localhost:6379/"
+          - name: NCB_PREFIX
+            value: "t2!"
+          - name: NCB_TOKEN
+            valueFrom:
+              secretKeyRef:
+                name: ncb-secret
+                key: BOT_TOKEN
+          - name: NCB_VOICEVOX_KEY
+            valueFrom:
+              secretKeyRef:
+                name: ncb-secret
+                key: VOICEVOX_KEY
+          - name: NCB_APP_ID
+            valueFrom:
+              secretKeyRef:
+                name: ncb-secret
+                key: APP_ID
+      volumes:
+      - name: ncb-redis-pvc
+        persistentVolumeClaim:
+          claimName: ncb-redis-pvc
+      - name: gcp-credentials
+        secret:
+          secretName: gcp-credentials

manifest/pvc.yaml

@@ -0,0 +1,12 @@
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: ncb-redis-pvc
+  labels:
+    app: ncb-redis
+spec:
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 3Gi

src/commands/config.rs

@@ -0,0 +1,107 @@
+use serenity::{
+    all::{
+        ButtonStyle, CommandInteraction, CreateActionRow, CreateButton, CreateInteractionResponse,
+        CreateInteractionResponseMessage, CreateSelectMenu, CreateSelectMenuKind,
+        CreateSelectMenuOption,
+    },
+    prelude::Context,
+};
+
+use crate::{
+    data::{DatabaseClientData, TTSClientData},
+    tts::tts_type::TTSType,
+};
+
+#[tracing::instrument]
+pub async fn config_command(
+    ctx: &Context,
+    command: &CommandInteraction,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let data_read = ctx.data.read().await;
+
+    let config = {
+        let database = data_read
+            .get::<DatabaseClientData>()
+            .expect("Cannot get DatabaseClientData")
+            .clone();
+        database
+            .get_user_config_or_default(command.user.id.get())
+            .await
+            .unwrap()
+            .unwrap()
+    };
+
+    let tts_client = data_read
+        .get::<TTSClientData>()
+        .expect("Cannot get TTSClientData");
+    let voicevox_speakers = tts_client
+        .voicevox_client
+        .get_styles()
+        .await
+        .unwrap_or_else(|e| {
+            tracing::error!("Failed to get VOICEVOX styles: {}", e);
+            vec![("VOICEVOX API unavailable".to_string(), 1)]
+        });
+
+    let voicevox_speaker = config.voicevox_speaker.unwrap_or(1);
+    let tts_type = config.tts_type.unwrap_or(TTSType::GCP);
+
+    let engine_select = CreateActionRow::SelectMenu(
+        CreateSelectMenu::new(
+            "TTS_CONFIG_ENGINE",
+            CreateSelectMenuKind::String {
+                options: vec![
+                    CreateSelectMenuOption::new("Google TTS", "TTS_CONFIG_ENGINE_SELECTED_GOOGLE")
+                        .default_selection(tts_type == TTSType::GCP),
+                    CreateSelectMenuOption::new("VOICEVOX", "TTS_CONFIG_ENGINE_SELECTED_VOICEVOX")
+                        .default_selection(tts_type == TTSType::VOICEVOX),
+                ],
+            },
+        )
+        .placeholder("読み上げAPIを選択"),
+    );
+
+    let mut components = vec![engine_select];
+
+    for (index, speaker_chunk) in voicevox_speakers[0..24].chunks(25).enumerate() {
+        let mut options = Vec::new();
+
+        for (name, id) in speaker_chunk {
+            options.push(
+                CreateSelectMenuOption::new(
+                    name,
+                    format!("TTS_CONFIG_VOICEVOX_SPEAKER_SELECTED_{}", id),
+                )
+                .default_selection(*id == voicevox_speaker),
+            );
+        }
+
+        components.push(CreateActionRow::SelectMenu(
+            CreateSelectMenu::new(
+                format!("TTS_CONFIG_VOICEVOX_SPEAKER_{}", index),
+                CreateSelectMenuKind::String { options },
+            )
+            .placeholder("VOICEVOX Speakerを指定"),
+        ));
+    }
+
+    let server_button = CreateActionRow::Buttons(vec![CreateButton::new("TTS_CONFIG_SERVER")
+        .label("サーバー設定")
+        .style(ButtonStyle::Primary)]);
+
+    components.push(server_button);
+
+    command
+        .create_response(
+            &ctx.http,
+            CreateInteractionResponse::Message(
+                CreateInteractionResponseMessage::new()
+                    .content("読み上げ設定")
+                    .components(components)
+                    .ephemeral(true),
+            ),
+        )
+        .await?;
+
+    Ok(())
+}

src/commands/mod.rs

@@ -0,0 +1,4 @@
+pub mod config;
+pub mod setup;
+pub mod skip;
+pub mod stop;

src/commands/setup.rs

@@ -0,0 +1,186 @@
+use serenity::{
+    all::{
+        AutoArchiveDuration, CommandInteraction, CreateEmbed, CreateInteractionResponse, CreateInteractionResponseMessage, CreateMessage, CreateThread
+    },
+    model::prelude::UserId,
+    prelude::Context,
+};
+use tracing::info;
+
+use crate::{
+    data::{DatabaseClientData, TTSClientData, TTSData},
+    tts::instance::TTSInstance,
+};
+
+#[tracing::instrument]
+pub async fn setup_command(
+    ctx: &Context,
+    command: &CommandInteraction,
+) -> Result<(), Box<dyn std::error::Error>> {
+    info!("Received event");
+    
+    if command.guild_id.is_none() {
+        command
+            .create_response(&ctx.http, 
+                CreateInteractionResponse::Message(
+                    CreateInteractionResponseMessage::new()
+                        .content("このコマンドはサーバーでのみ使用可能です．")
+                        .ephemeral(true)
+                ))
+            .await?;
+        return Ok(());
+    }
+
+    info!("Fetching guild cache");
+    let guild_id = command.guild_id.unwrap();
+    let guild = guild_id.to_guild_cached(&ctx.cache).unwrap().clone();
+
+    let channel_id = guild
+        .voice_states
+        .get(&UserId::from(command.user.id.get()))
+        .and_then(|state| state.channel_id);
+
+    if channel_id.is_none() {
+        command
+            .create_response(&ctx.http, 
+                CreateInteractionResponse::Message(
+                    CreateInteractionResponseMessage::new()
+                        .content("ボイスチャンネルに参加してから実行してください．")
+                        .ephemeral(true)
+                ))
+            .await?;
+        return Ok(());
+    }
+
+    let channel_id = channel_id.unwrap();
+
+    let manager = songbird::get(ctx)
+        .await
+        .expect("Cannot get songbird client.")
+        .clone();
+
+    let storage_lock = {
+        let data_read = ctx.data.read().await;
+        data_read
+            .get::<TTSData>()
+            .expect("Cannot get TTSStorage")
+            .clone()
+    };
+
+    let text_channel_id = {
+        let mut storage = storage_lock.write().await;
+        if storage.contains_key(&guild.id) {
+            command
+                .create_response(&ctx.http, 
+                    CreateInteractionResponse::Message(
+                        CreateInteractionResponseMessage::new()
+                            .content("すでにセットアップしています．")
+                            .ephemeral(true)
+                    ))
+                .await?;
+            return Ok(());
+        }
+
+        let text_channel_ids = {
+            if let Some(mode) = command.data.options.get(0) {
+                match &mode.value {
+                    serenity::all::CommandDataOptionValue::String(value) => {
+                        match value.as_str() {
+                            "TEXT_CHANNEL" => vec![command.channel_id],
+                            "NEW_THREAD" => {
+                                vec![command
+                                .channel_id
+                                .create_thread(&ctx.http, CreateThread::new("TTS").auto_archive_duration(AutoArchiveDuration::OneHour).kind(serenity::all::ChannelType::PublicThread))
+                                .await
+                                .unwrap()
+                                .id]
+                            }
+                            "VOICE_CHANNEL" => vec![channel_id],
+                            _ => if channel_id != command.channel_id {
+                                vec![command.channel_id, channel_id]
+                            } else {
+                                vec![channel_id]
+                            },
+                        }
+                    },
+                    _ => if channel_id != command.channel_id {
+                        vec![command.channel_id, channel_id]
+                    } else {
+                        vec![channel_id]
+                    },
+                }
+            } else {
+                if channel_id != command.channel_id {
+                    vec![command.channel_id, channel_id]
+                } else {
+                    vec![channel_id]
+                }
+            }
+        };
+
+        let instance = TTSInstance::new(text_channel_ids.clone(), channel_id, guild.id);
+        storage.insert(guild.id, instance.clone());
+
+        // Save to database
+        let data_read = ctx.data.read().await;
+        let database = data_read
+            .get::<DatabaseClientData>()
+            .expect("Cannot get DatabaseClientData")
+            .clone();
+        drop(data_read);
+        
+        if let Err(e) = database.save_tts_instance(guild.id, &instance).await {
+            tracing::error!("Failed to save TTS instance to database: {}", e);
+        }
+
+        text_channel_ids[0]
+    };
+
+    command
+        .create_response(&ctx.http, 
+            CreateInteractionResponse::Message(
+                CreateInteractionResponseMessage::new()
+                    .content(format!(
+                        "TTS Channel: <#{}>{}", 
+                        text_channel_id, 
+                        if text_channel_id == channel_id { 
+                            "\nボイスチャンネルを右クリックし `チャットを開く` を押して開くことが出来ます。" 
+                        } else { 
+                            "" 
+                        }
+                    ))
+            ))
+        .await?;
+
+    let _handler = manager.join(guild.id, channel_id).await;
+
+    let data = ctx
+        .data
+        .read()
+        .await;
+    let tts_client = data
+        .get::<TTSClientData>()
+        .expect("Cannot get TTSClientData");
+    let voicevox_speakers = tts_client.voicevox_client.get_speakers().await
+        .unwrap_or_else(|e| {
+            tracing::error!("Failed to get VOICEVOX speakers: {}", e);
+            vec!["VOICEVOX API unavailable".to_string()]
+        });
+
+    text_channel_id
+        .send_message(&ctx.http, CreateMessage::new()
+            .embed(
+                CreateEmbed::new()
+                    .title("読み上げ (Serenity)")
+                    .field(
+                        "VOICEVOXクレジット",
+                        format!("```\n{}\n```", voicevox_speakers.join("\n")),
+                        false,
+                    )
+                    .field("設定コマンド", "`/config`", false)
+                    .field("フィードバック", "https://feedback.mii.codes/", false)
+            ))
+        .await?;
+
+    Ok(())
+}

src/commands/skip.rs

@@ -0,0 +1,81 @@
+use serenity::{
+    all::{
+        CommandInteraction, CreateInteractionResponse, CreateInteractionResponseMessage
+    },
+    model::prelude::UserId,
+    prelude::Context,
+};
+
+use crate::data::TTSData;
+
+pub async fn skip_command(
+    ctx: &Context,
+    command: &CommandInteraction,
+) -> Result<(), Box<dyn std::error::Error>> {
+    if command.guild_id.is_none() {
+        command
+            .create_response(&ctx.http, 
+                CreateInteractionResponse::Message(
+                    CreateInteractionResponseMessage::new()
+                        .content("このコマンドはサーバーでのみ使用可能です．")
+                        .ephemeral(true)
+                ))
+            .await?;
+        return Ok(());
+    }
+
+    let guild_id = command.guild_id.unwrap();
+    let guild = guild_id.to_guild_cached(&ctx.cache).unwrap().clone();
+
+    let channel_id = guild
+        .voice_states
+        .get(&UserId::from(command.user.id.get()))
+        .and_then(|state| state.channel_id);
+
+    if channel_id.is_none() {
+        command
+            .create_response(&ctx.http, 
+                CreateInteractionResponse::Message(
+                    CreateInteractionResponseMessage::new()
+                        .content("ボイスチャンネルに参加してから実行してください．")
+                        .ephemeral(true)
+                ))
+            .await?;
+        return Ok(());
+    }
+
+    let storage_lock = {
+        let data_read = ctx.data.read().await;
+        data_read
+            .get::<TTSData>()
+            .expect("Cannot get TTSStorage")
+            .clone()
+    };
+
+    {
+        let mut storage = storage_lock.write().await;
+        if !storage.contains_key(&guild.id) {
+            command
+                .create_response(&ctx.http, 
+                    CreateInteractionResponse::Message(
+                        CreateInteractionResponseMessage::new()
+                            .content("読み上げしていません")
+                            .ephemeral(true)
+                    ))
+                .await?;
+            return Ok(());
+        }
+
+        storage.get_mut(&guild.id).unwrap().skip(ctx).await;
+    }
+
+    command
+        .create_response(&ctx.http, 
+            CreateInteractionResponse::Message(
+                CreateInteractionResponseMessage::new()
+                    .content("スキップしました")
+            ))
+        .await?;
+
+    Ok(())
+}

src/commands/stop.rs

@@ -0,0 +1,115 @@
+use serenity::{
+    all::{
+        CommandInteraction, CreateInteractionResponse, CreateInteractionResponseMessage, EditThread,
+    },
+    model::prelude::UserId,
+    prelude::Context,
+};
+
+use crate::data::{DatabaseClientData, TTSData};
+
+pub async fn stop_command(
+    ctx: &Context,
+    command: &CommandInteraction,
+) -> Result<(), Box<dyn std::error::Error>> {
+    if command.guild_id.is_none() {
+        command
+            .create_response(
+                &ctx.http,
+                CreateInteractionResponse::Message(
+                    CreateInteractionResponseMessage::new()
+                        .content("このコマンドはサーバーでのみ使用可能です．")
+                        .ephemeral(true),
+                ),
+            )
+            .await?;
+        return Ok(());
+    }
+
+    let guild_id = command.guild_id.unwrap();
+    let guild = guild_id.to_guild_cached(&ctx.cache).unwrap().clone();
+
+    let channel_id = guild
+        .voice_states
+        .get(&UserId::from(command.user.id.get()))
+        .and_then(|state| state.channel_id);
+
+    if channel_id.is_none() {
+        command
+            .create_response(
+                &ctx.http,
+                CreateInteractionResponse::Message(
+                    CreateInteractionResponseMessage::new()
+                        .content("ボイスチャンネルに参加してから実行してください．")
+                        .ephemeral(true),
+                ),
+            )
+            .await?;
+        return Ok(());
+    }
+
+    let manager = songbird::get(ctx)
+        .await
+        .expect("Cannot get songbird client.")
+        .clone();
+
+    let storage_lock = {
+        let data_read = ctx.data.read().await;
+        data_read
+            .get::<TTSData>()
+            .expect("Cannot get TTSStorage")
+            .clone()
+    };
+
+    let text_channel_id = {
+        let mut storage = storage_lock.write().await;
+
+        if !storage.contains_key(&guild.id) {
+            command
+                .create_response(
+                    &ctx.http,
+                    CreateInteractionResponse::Message(
+                        CreateInteractionResponseMessage::new()
+                            .content("すでに停止しています")
+                            .ephemeral(true),
+                    ),
+                )
+                .await?;
+            return Ok(());
+        }
+
+        let text_channel_id = storage.get(&guild.id).unwrap().text_channels[0];
+        storage.remove(&guild.id);
+
+        // Remove from database
+        let data_read = ctx.data.read().await;
+        let database = data_read
+            .get::<DatabaseClientData>()
+            .expect("Cannot get DatabaseClientData")
+            .clone();
+        drop(data_read);
+
+        if let Err(e) = database.remove_tts_instance(guild.id).await {
+            tracing::error!("Failed to remove TTS instance from database: {}", e);
+        }
+
+        text_channel_id
+    };
+
+    let _handler = manager.remove(guild.id).await;
+
+    command
+        .create_response(
+            &ctx.http,
+            CreateInteractionResponse::Message(
+                CreateInteractionResponseMessage::new().content("停止しました"),
+            ),
+        )
+        .await?;
+
+    let _ = text_channel_id
+        .edit_thread(&ctx.http, EditThread::new().archived(true))
+        .await;
+
+    Ok(())
+}

src/config.rs

@@ -6,5 +6,7 @@ pub struct Config {
     pub token: String,
     pub application_id: u64,
     pub redis_url: String,
-    pub voicevox_key: String
-}
+    pub voicevox_key: Option<String>,
+    pub voicevox_original_api_url: Option<String>,
+    pub otel_http_url: Option<String>,
+}

src/connection_monitor.rs

@@ -0,0 +1,273 @@
+use serenity::{
+    all::{CreateEmbed, CreateMessage},
+    prelude::Context,
+};
+use std::time::Duration;
+use tokio::time;
+use tracing::{error, info, instrument, warn};
+
+use crate::data::{DatabaseClientData, TTSData};
+
+/// Constants for connection monitoring
+const CONNECTION_CHECK_INTERVAL_SECS: u64 = 5;
+const MAX_RECONNECTION_ATTEMPTS: u32 = 3;
+const RECONNECTION_BACKOFF_SECS: u64 = 2;
+
+/// Errors that can occur during connection monitoring
+#[derive(Debug, thiserror::Error)]
+pub enum ConnectionMonitorError {
+    #[error("Failed to get songbird manager")]
+    SongbirdManagerNotFound,
+    #[error("Failed to check voice channel users: {0}")]
+    VoiceChannelCheck(String),
+    #[error("Failed to reconnect after {attempts} attempts")]
+    ReconnectionFailed { attempts: u32 },
+    #[error("Database operation failed: {0}")]
+    Database(#[from] redis::RedisError),
+}
+
+type Result<T> = std::result::Result<T, ConnectionMonitorError>;
+
+/// Connection monitor that periodically checks voice channel connections
+pub struct ConnectionMonitor {
+    reconnection_attempts: std::collections::HashMap<serenity::model::id::GuildId, u32>,
+}
+
+impl Default for ConnectionMonitor {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl ConnectionMonitor {
+    pub fn new() -> Self {
+        Self {
+            reconnection_attempts: std::collections::HashMap::new(),
+        }
+    }
+
+    /// Start the connection monitoring task
+    pub fn start(ctx: Context) {
+        tokio::spawn(async move {
+            let mut monitor = ConnectionMonitor::new();
+            info!(
+                interval_secs = CONNECTION_CHECK_INTERVAL_SECS,
+                "Starting connection monitor"
+            );
+            let mut interval = time::interval(Duration::from_secs(CONNECTION_CHECK_INTERVAL_SECS));
+
+            loop {
+                interval.tick().await;
+                if let Err(e) = monitor.check_connections(&ctx).await {
+                    error!(error = %e, "Connection monitoring failed");
+                }
+            }
+        });
+    }
+
+    /// Check all active TTS instances and their voice channel connections
+    #[instrument(skip(self, ctx))]
+    async fn check_connections(&mut self, ctx: &Context) -> Result<()> {
+        let storage_lock = {
+            let data_read = ctx.data.read().await;
+            data_read
+                .get::<TTSData>()
+                .ok_or_else(|| {
+                    ConnectionMonitorError::VoiceChannelCheck("Cannot get TTSStorage".to_string())
+                })?
+                .clone()
+        };
+
+        let database = {
+            let data_read = ctx.data.read().await;
+            data_read
+                .get::<DatabaseClientData>()
+                .ok_or_else(|| {
+                    ConnectionMonitorError::VoiceChannelCheck(
+                        "Cannot get DatabaseClientData".to_string(),
+                    )
+                })?
+                .clone()
+        };
+
+        let mut storage = storage_lock.write().await;
+        let mut guilds_to_remove = Vec::new();
+
+        for (guild_id, instance) in storage.iter() {
+            // Check if bot is still connected to voice channel
+            let manager = songbird::get(ctx)
+                .await
+                .ok_or(ConnectionMonitorError::SongbirdManagerNotFound)?;
+
+            let call = manager.get(*guild_id);
+            let is_connected = if let Some(call) = call {
+                if let Some(connection) = call.lock().await.current_connection() {
+                    connection.channel_id.is_some()
+                } else {
+                    false
+                }
+            } else {
+                false
+            };
+
+            if !is_connected {
+                warn!(guild_id = %guild_id, "Bot disconnected from voice channel");
+
+                // Check if there are users in the voice channel
+                let should_reconnect = match self.check_voice_channel_users(ctx, instance).await {
+                    Ok(has_users) => has_users,
+                    Err(e) => {
+                        warn!(guild_id = %guild_id, error = %e, "Failed to check voice channel users, skipping reconnection");
+                        false
+                    }
+                };
+
+                if should_reconnect {
+                    // Try to reconnect with retry logic
+                    let attempts = self
+                        .reconnection_attempts
+                        .get(guild_id)
+                        .copied()
+                        .unwrap_or(0);
+
+                    if attempts >= MAX_RECONNECTION_ATTEMPTS {
+                        error!(
+                            guild_id = %guild_id,
+                            attempts = attempts,
+                            "Maximum reconnection attempts reached, removing instance"
+                        );
+                        guilds_to_remove.push(*guild_id);
+                        self.reconnection_attempts.remove(guild_id);
+                        continue;
+                    }
+
+                    // Apply exponential backoff
+                    if attempts > 0 {
+                        let backoff_duration =
+                            Duration::from_secs(RECONNECTION_BACKOFF_SECS * (2_u64.pow(attempts)));
+                        warn!(
+                            guild_id = %guild_id,
+                            attempt = attempts + 1,
+                            backoff_secs = backoff_duration.as_secs(),
+                            "Applying backoff before reconnection attempt"
+                        );
+                        tokio::time::sleep(backoff_duration).await;
+                    }
+
+                    match instance.reconnect(ctx, true).await {
+                        Ok(_) => {
+                            info!(
+                                guild_id = %guild_id,
+                                attempts = attempts + 1,
+                                "Successfully reconnected to voice channel"
+                            );
+
+                            // Reset reconnection attempts on success
+                            self.reconnection_attempts.remove(guild_id);
+
+                            // Send notification message to text channel with embed
+                            let embed = CreateEmbed::new()
+                                .title("🔄 自動再接続しました")
+                                .description("読み上げを停止したい場合は `/stop` コマンドを使用してください。")
+                                .color(0x00ff00);
+
+                            // Send message to the first text channel
+                            if let Some(&text_channel) = instance.text_channels.first() {
+                                if let Err(e) = text_channel
+                                    .send_message(&ctx.http, CreateMessage::new().embed(embed))
+                                    .await
+                                {
+                                    error!(guild_id = %guild_id, error = %e, "Failed to send reconnection message");
+                                }
+                            }
+                        }
+                        Err(e) => {
+                            let new_attempts = attempts + 1;
+                            self.reconnection_attempts.insert(*guild_id, new_attempts);
+                            error!(
+                                guild_id = %guild_id,
+                                attempt = new_attempts,
+                                error = %e,
+                                "Failed to reconnect to voice channel"
+                            );
+
+                            if new_attempts >= MAX_RECONNECTION_ATTEMPTS {
+                                guilds_to_remove.push(*guild_id);
+                                self.reconnection_attempts.remove(guild_id);
+                            }
+                        }
+                    }
+                } else {
+                    info!(
+                        guild_id = %guild_id,
+                        "No users in voice channel, removing instance"
+                    );
+                    guilds_to_remove.push(*guild_id);
+                    self.reconnection_attempts.remove(guild_id);
+                }
+            }
+        }
+
+        // Remove disconnected instances
+        for guild_id in guilds_to_remove {
+            storage.remove(&guild_id);
+
+            // Remove from database
+            if let Err(e) = database.remove_tts_instance(guild_id).await {
+                error!(guild_id = %guild_id, error = %e, "Failed to remove TTS instance from database");
+            }
+
+            // Ensure bot leaves voice channel
+            if let Some(manager) = songbird::get(ctx).await {
+                if let Err(e) = manager.remove(guild_id).await {
+                    error!(guild_id = %guild_id, error = %e, "Failed to remove bot from voice channel");
+                }
+            }
+
+            info!(guild_id = %guild_id, "Removed disconnected TTS instance");
+        }
+
+        Ok(())
+    }
+
+    /// Check if there are users in the voice channel
+    #[instrument(skip(self, ctx, instance))]
+    async fn check_voice_channel_users(
+        &self,
+        ctx: &Context,
+        instance: &crate::tts::instance::TTSInstance,
+    ) -> Result<bool> {
+        let channels = instance.guild.channels(&ctx.http).await.map_err(|e| {
+            ConnectionMonitorError::VoiceChannelCheck(format!(
+                "Failed to get guild channels: {}",
+                e
+            ))
+        })?;
+
+        if let Some(channel) = channels.get(&instance.voice_channel) {
+            let members = channel.members(&ctx.cache).map_err(|e| {
+                ConnectionMonitorError::VoiceChannelCheck(format!(
+                    "Failed to get channel members: {}",
+                    e
+                ))
+            })?;
+            let user_count = members.iter().filter(|member| !member.user.bot).count();
+
+            info!(
+                guild_id = %instance.guild,
+                channel_id = %instance.voice_channel,
+                user_count = user_count,
+                "Checked voice channel users"
+            );
+
+            Ok(user_count > 0)
+        } else {
+            warn!(
+                guild_id = %instance.guild,
+                channel_id = %instance.voice_channel,
+                "Voice channel no longer exists"
+            );
+            Ok(false)
+        }
+    }
+}

src/data.rs

@@ -1,8 +1,11 @@
-use crate::{tts::{gcp_tts::gcp_tts::TTS, voicevox::voicevox::VOICEVOX}, database::database::Database};
-use serenity::{prelude::{TypeMapKey, RwLock}, model::id::GuildId, futures::lock::Mutex};
+use crate::{database::database::Database, tts::tts::TTS};
+use serenity::{
+    model::id::GuildId,
+    prelude::{RwLock, TypeMapKey},
+};
 
 use crate::tts::instance::TTSInstance;
-use std::{sync::Arc, collections::HashMap};
+use std::{collections::HashMap, sync::Arc};
 
 /// TTSInstance data
 pub struct TTSData;
@@ -15,12 +18,12 @@ impl TypeMapKey for TTSData {
 pub struct TTSClientData;
 
 impl TypeMapKey for TTSClientData {
-    type Value = Arc<Mutex<(TTS, VOICEVOX)>>;
+    type Value = Arc<TTS>;
 }
 
 /// Database client data
 pub struct DatabaseClientData;
 
 impl TypeMapKey for DatabaseClientData {
-    type Value = Arc<Mutex<Database>>;
+    type Value = Arc<Database>;
 }

src/database/database.rs

@@ -1,60 +1,480 @@
-use crate::tts::{gcp_tts::structs::voice_selection_params::VoiceSelectionParams, tts_type::TTSType};
+use std::fmt::Debug;
 
-use super::user_config::UserConfig;
-use redis::Commands;
+use crate::{
+    errors::{constants::*, NCBError, Result},
+    tts::{
+        gcp_tts::structs::voice_selection_params::VoiceSelectionParams, instance::TTSInstance,
+        tts_type::TTSType,
+    },
+};
+use bb8_redis::{bb8::Pool, redis::AsyncCommands, RedisConnectionManager};
+use serenity::model::id::{ChannelId, GuildId, UserId};
+use std::collections::HashMap;
 
+use super::{dictionary::Dictionary, server_config::ServerConfig, user_config::UserConfig};
+
+#[derive(Debug, Clone)]
 pub struct Database {
-    pub connection: redis::Connection
+    pub pool: Pool<RedisConnectionManager>,
 }
 
 impl Database {
-    pub fn new(connection: redis::Connection) -> Self {
-        Self { connection }
+    pub fn new(pool: Pool<RedisConnectionManager>) -> Self {
+        Self { pool }
     }
 
-    pub async fn get_user_config(&mut self, user_id: u64) -> redis::RedisResult<Option<UserConfig>> {
-        let config: String = self.connection.get(format!("discord_user:{}", user_id)).unwrap_or_default();
+    pub async fn new_with_url(redis_url: String) -> Result<Self> {
+        let manager = RedisConnectionManager::new(redis_url)?;
+        let pool = Pool::builder()
+            .max_size(15)
+            .build(manager)
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool creation failed: {}", e)))?;
+        Ok(Self { pool })
+    }
+
+    fn server_key(server_id: u64) -> String {
+        format!("{}{}", DISCORD_SERVER_PREFIX, server_id)
+    }
+
+    fn user_key(user_id: u64) -> String {
+        format!("{}{}", DISCORD_USER_PREFIX, user_id)
+    }
+
+    fn tts_instance_key(guild_id: u64) -> String {
+        format!("{}{}", TTS_INSTANCE_PREFIX, guild_id)
+    }
+
+    fn tts_instances_list_key() -> String {
+        TTS_INSTANCES_LIST_KEY.to_string()
+    }
+
+    fn user_config_key(guild_id: u64, user_id: u64) -> String {
+        format!("user:config:{}:{}", guild_id, user_id)
+    }
+
+    fn server_config_key(guild_id: u64) -> String {
+        format!("server:config:{}", guild_id)
+    }
+
+    fn dictionary_key(guild_id: u64) -> String {
+        format!("dictionary:{}", guild_id)
+    }
+
+    #[tracing::instrument]
+    async fn get_config<T: serde::de::DeserializeOwned>(&self, key: &str) -> Result<Option<T>> {
+        let mut connection = self
+            .pool
+            .get()
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool connection failed: {}", e)))?;
+
+        let config: String = connection.get(key).await.unwrap_or_default();
+
+        if config.is_empty() {
+            return Ok(None);
+        }
 
         match serde_json::from_str(&config) {
             Ok(config) => Ok(Some(config)),
-            Err(_) => Ok(None)
+            Err(e) => {
+                tracing::warn!(key = key, error = %e, "Failed to deserialize config");
+                Ok(None)
+            }
         }
     }
 
-    pub async fn set_user_config(&mut self, user_id: u64, config: UserConfig) -> redis::RedisResult<()> {
-        let config = serde_json::to_string(&config).unwrap();
-        self.connection.set::<String, String, ()>(format!("discord_user:{}", user_id), config).unwrap();
+    #[tracing::instrument]
+    async fn set_config<T: serde::Serialize + Debug>(&self, key: &str, config: &T) -> Result<()> {
+        let mut connection = self
+            .pool
+            .get()
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool connection failed: {}", e)))?;
+
+        let config_str = serde_json::to_string(config)?;
+        connection.set::<_, _, ()>(key, config_str).await?;
         Ok(())
     }
 
-    pub async fn set_default_user_config(&mut self, user_id: u64) -> redis::RedisResult<()> {
+    #[tracing::instrument]
+    pub async fn get_server_config(&self, server_id: u64) -> Result<Option<ServerConfig>> {
+        self.get_config(&Self::server_key(server_id)).await
+    }
+
+    #[tracing::instrument]
+    pub async fn get_user_config(&self, user_id: u64) -> Result<Option<UserConfig>> {
+        self.get_config(&Self::user_key(user_id)).await
+    }
+
+    #[tracing::instrument]
+    pub async fn set_server_config(&self, server_id: u64, config: ServerConfig) -> Result<()> {
+        self.set_config(&Self::server_key(server_id), &config).await
+    }
+
+    #[tracing::instrument]
+    pub async fn set_user_config(&self, user_id: u64, config: UserConfig) -> Result<()> {
+        self.set_config(&Self::user_key(user_id), &config).await
+    }
+
+    #[tracing::instrument]
+    pub async fn set_default_server_config(&self, server_id: u64) -> Result<()> {
+        let config = ServerConfig {
+            dictionary: Dictionary::new(),
+            autostart_channel_id: None,
+            autostart_text_channel_id: None,
+            voice_state_announce: Some(false),
+            read_username: Some(false),
+        };
+
+        self.set_server_config(server_id, config).await
+    }
+
+    #[tracing::instrument]
+    pub async fn set_default_user_config(&self, user_id: u64) -> Result<()> {
         let voice_selection = VoiceSelectionParams {
             languageCode: String::from("ja-JP"),
             name: String::from("ja-JP-Wavenet-B"),
-            ssmlGender: String::from("neutral")
+            ssmlGender: String::from("neutral"),
         };
 
-        let voice_type = TTSType::GCP;
-
         let config = UserConfig {
-            tts_type: Some(voice_type),
+            tts_type: Some(TTSType::GCP),
             gcp_tts_voice: Some(voice_selection),
-            voicevox_speaker: Some(1)
+            voicevox_speaker: Some(DEFAULT_VOICEVOX_SPEAKER),
         };
 
-        self.connection.set(format!("discord_user:{}", user_id), serde_json::to_string(&config).unwrap())?;
-
-        Ok(())
+        self.set_user_config(user_id, config).await
     }
 
-    pub async fn get_user_config_or_default(&mut self, user_id: u64) -> redis::RedisResult<Option<UserConfig>> {
-        let config = self.get_user_config(user_id).await?;
-        match config {
-            Some(_) => Ok(config),
+    #[tracing::instrument]
+    pub async fn get_server_config_or_default(
+        &self,
+        server_id: u64,
+    ) -> Result<Option<ServerConfig>> {
+        match self.get_server_config(server_id).await? {
+            Some(config) => Ok(Some(config)),
+            None => {
+                self.set_default_server_config(server_id).await?;
+                self.get_server_config(server_id).await
+            }
+        }
+    }
+
+    #[tracing::instrument]
+    pub async fn get_user_config_or_default(&self, user_id: u64) -> Result<Option<UserConfig>> {
+        match self.get_user_config(user_id).await? {
+            Some(config) => Ok(Some(config)),
             None => {
                 self.set_default_user_config(user_id).await?;
                 self.get_user_config(user_id).await
             }
         }
     }
+
+    /// Save TTS instance to database
+    pub async fn save_tts_instance(&self, guild_id: GuildId, instance: &TTSInstance) -> Result<()> {
+        let key = Self::tts_instance_key(guild_id.get());
+        let list_key = Self::tts_instances_list_key();
+
+        // Save the instance
+        self.set_config(&key, instance).await?;
+
+        // Add guild_id to the list of active instances
+        let mut connection = self
+            .pool
+            .get()
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool connection failed: {}", e)))?;
+
+        connection
+            .sadd::<_, _, ()>(&list_key, guild_id.get())
+            .await?;
+        Ok(())
+    }
+
+    /// Load TTS instance from database
+    #[tracing::instrument]
+    pub async fn load_tts_instance(&self, guild_id: GuildId) -> Result<Option<TTSInstance>> {
+        let key = Self::tts_instance_key(guild_id.get());
+        self.get_config(&key).await
+    }
+
+    /// Remove TTS instance from database
+    #[tracing::instrument]
+    pub async fn remove_tts_instance(&self, guild_id: GuildId) -> Result<()> {
+        let key = Self::tts_instance_key(guild_id.get());
+        let list_key = Self::tts_instances_list_key();
+
+        let mut connection = self
+            .pool
+            .get()
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool connection failed: {}", e)))?;
+
+        let _: std::result::Result<(), bb8_redis::redis::RedisError> = connection.del(&key).await;
+        let _: std::result::Result<(), bb8_redis::redis::RedisError> =
+            connection.srem(&list_key, guild_id.get()).await;
+
+        Ok(())
+    }
+
+    /// Get all active TTS instances
+    #[tracing::instrument]
+    pub async fn get_all_tts_instances(&self) -> Result<Vec<(GuildId, TTSInstance)>> {
+        let list_key = Self::tts_instances_list_key();
+
+        let mut connection = self
+            .pool
+            .get()
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool connection failed: {}", e)))?;
+
+        let guild_ids: Vec<u64> = connection.smembers(&list_key).await.unwrap_or_default();
+        let mut instances = Vec::new();
+
+        for guild_id in guild_ids {
+            let guild_id = GuildId::new(guild_id);
+            if let Ok(Some(instance)) = self.load_tts_instance(guild_id).await {
+                instances.push((guild_id, instance));
+            } else {
+                tracing::warn!(guild_id = %guild_id, "Failed to load TTS instance");
+            }
+        }
+
+        Ok(instances)
+    }
+
+    // Additional user config methods
+    pub async fn save_user_config(
+        &self,
+        guild_id: GuildId,
+        user_id: UserId,
+        config: &UserConfig,
+    ) -> Result<()> {
+        let key = Self::user_config_key(guild_id.get(), user_id.get());
+        self.set_config(&key, config).await
+    }
+
+    pub async fn load_user_config(
+        &self,
+        guild_id: GuildId,
+        user_id: UserId,
+    ) -> Result<Option<UserConfig>> {
+        let key = Self::user_config_key(guild_id.get(), user_id.get());
+        self.get_config(&key).await
+    }
+
+    pub async fn delete_user_config(&self, guild_id: GuildId, user_id: UserId) -> Result<()> {
+        let key = Self::user_config_key(guild_id.get(), user_id.get());
+        let mut connection = self
+            .pool
+            .get()
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool connection failed: {}", e)))?;
+        let _: std::result::Result<(), bb8_redis::redis::RedisError> = connection.del(&key).await;
+        Ok(())
+    }
+
+    // Additional server config methods
+    pub async fn save_server_config(&self, guild_id: GuildId, config: &ServerConfig) -> Result<()> {
+        let key = Self::server_config_key(guild_id.get());
+        self.set_config(&key, config).await
+    }
+
+    pub async fn load_server_config(&self, guild_id: GuildId) -> Result<Option<ServerConfig>> {
+        let key = Self::server_config_key(guild_id.get());
+        self.get_config(&key).await
+    }
+
+    pub async fn delete_server_config(&self, guild_id: GuildId) -> Result<()> {
+        let key = Self::server_config_key(guild_id.get());
+        let mut connection = self
+            .pool
+            .get()
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool connection failed: {}", e)))?;
+        let _: std::result::Result<(), bb8_redis::redis::RedisError> = connection.del(&key).await;
+        Ok(())
+    }
+
+    // Dictionary methods
+    pub async fn save_dictionary(
+        &self,
+        guild_id: GuildId,
+        dictionary: &HashMap<String, String>,
+    ) -> Result<()> {
+        let key = Self::dictionary_key(guild_id.get());
+        self.set_config(&key, dictionary).await
+    }
+
+    pub async fn load_dictionary(&self, guild_id: GuildId) -> Result<HashMap<String, String>> {
+        let key = Self::dictionary_key(guild_id.get());
+        let dict: Option<HashMap<String, String>> = self.get_config(&key).await?;
+        Ok(dict.unwrap_or_default())
+    }
+
+    pub async fn delete_dictionary(&self, guild_id: GuildId) -> Result<()> {
+        let key = Self::dictionary_key(guild_id.get());
+        let mut connection = self
+            .pool
+            .get()
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool connection failed: {}", e)))?;
+        let _: std::result::Result<(), bb8_redis::redis::RedisError> = connection.del(&key).await;
+        Ok(())
+    }
+
+    pub async fn delete_tts_instance(&self, guild_id: GuildId) -> Result<()> {
+        self.remove_tts_instance(guild_id).await
+    }
+
+    pub async fn list_active_instances(&self) -> Result<Vec<u64>> {
+        let list_key = Self::tts_instances_list_key();
+        let mut connection = self
+            .pool
+            .get()
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool connection failed: {}", e)))?;
+        let guild_ids: Vec<u64> = connection.smembers(&list_key).await.unwrap_or_default();
+        Ok(guild_ids)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::errors::constants;
+    use bb8_redis::redis::AsyncCommands;
+    use serial_test::serial;
+
+    // Helper function to create test database (requires Redis running)
+    async fn create_test_database() -> Result<Database> {
+        let manager = RedisConnectionManager::new("redis://127.0.0.1:6379/15")?; // Use test DB
+        let pool = bb8::Pool::builder()
+            .max_size(1)
+            .build(manager)
+            .await
+            .map_err(|e| NCBError::Database(format!("Pool creation failed: {}", e)))?;
+
+        Ok(Database { pool })
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_database_creation() {
+        // This test requires Redis to be running
+        match create_test_database().await {
+            Ok(_db) => {
+                // Test successful creation
+                assert!(true);
+            }
+            Err(_) => {
+                // Skip test if Redis is not available
+                return;
+            }
+        }
+    }
+
+    #[test]
+    fn test_key_generation() {
+        let guild_id = 123456789u64;
+        let user_id = 987654321u64;
+
+        // Test TTS instance key
+        let tts_key = Database::tts_instance_key(guild_id);
+        assert!(tts_key.contains(&guild_id.to_string()));
+
+        // Test TTS instances list key
+        let list_key = Database::tts_instances_list_key();
+        assert!(!list_key.is_empty());
+
+        // Test user config key
+        let user_key = Database::user_config_key(guild_id, user_id);
+        assert_eq!(user_key, "user:config:123456789:987654321");
+
+        // Test server config key
+        let server_key = Database::server_config_key(guild_id);
+        assert_eq!(server_key, "server:config:123456789");
+
+        // Test dictionary key
+        let dict_key = Database::dictionary_key(guild_id);
+        assert_eq!(dict_key, "dictionary:123456789");
+    }
+
+    #[tokio::test]
+    #[serial]
+    async fn test_tts_instance_operations() {
+        let db = match create_test_database().await {
+            Ok(db) => db,
+            Err(_) => return, // Skip if Redis not available
+        };
+
+        let guild_id = GuildId::new(12345);
+        let test_instance =
+            TTSInstance::new_single(ChannelId::new(123), ChannelId::new(456), guild_id);
+
+        // Clear any existing data
+        if let Ok(mut conn) = db.pool.get().await {
+            let _: () = conn
+                .del(Database::tts_instance_key(guild_id.get()))
+                .await
+                .unwrap_or_default();
+            let _: () = conn
+                .srem(Database::tts_instances_list_key(), guild_id.get())
+                .await
+                .unwrap_or_default();
+        } else {
+            return; // Skip if can't get connection
+        }
+
+        // Test saving TTS instance
+        let save_result = db.save_tts_instance(guild_id, &test_instance).await;
+        if save_result.is_err() {
+            // Skip test if Redis operations fail
+            return;
+        }
+
+        // Test loading TTS instance
+        let load_result = db.load_tts_instance(guild_id).await;
+        if load_result.is_err() {
+            return; // Skip if Redis operations fail
+        }
+
+        let loaded_instance = load_result.unwrap();
+        if let Some(instance) = loaded_instance {
+            assert_eq!(instance.guild, test_instance.guild);
+            assert_eq!(instance.text_channels, test_instance.text_channels);
+            assert_eq!(instance.voice_channel, test_instance.voice_channel);
+        }
+
+        // Test listing active instances
+        let list_result = db.list_active_instances().await;
+        if list_result.is_err() {
+            return; // Skip if Redis operations fail
+        }
+        let instances = list_result.unwrap();
+        assert!(instances.contains(&guild_id.get()));
+
+        // Test deleting TTS instance
+        let delete_result = db.delete_tts_instance(guild_id).await;
+        if delete_result.is_err() {
+            return; // Skip if Redis operations fail
+        }
+
+        // Verify deletion
+        let load_after_delete = db.load_tts_instance(guild_id).await;
+        if load_after_delete.is_err() {
+            return; // Skip if Redis operations fail
+        }
+        assert!(load_after_delete.unwrap().is_none());
+    }
+
+    #[test]
+    fn test_database_constants() {
+        // Test that constants are reasonable
+        assert!(constants::REDIS_CONNECTION_TIMEOUT_SECS > 0);
+        assert!(constants::REDIS_MAX_CONNECTIONS > 0);
+        assert!(constants::REDIS_MIN_IDLE_CONNECTIONS <= constants::REDIS_MAX_CONNECTIONS);
+    }
 }

src/database/dictionary.rs

@@ -0,0 +1,34 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct Rule {
+    pub id: String,
+    pub is_regex: bool,
+    pub rule: String,
+    pub to: String,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct Dictionary {
+    pub rules: Vec<Rule>,
+}
+
+impl Dictionary {
+    pub fn new() -> Self {
+        let rules = vec![
+            Rule {
+                id: String::from("url"),
+                is_regex: true,
+                rule: String::from(r"(http://|https://){1}[\w\.\-/:\#\?=\&;%\~\+]+"),
+                to: String::from("URL"),
+            },
+            Rule {
+                id: String::from("code"),
+                is_regex: true,
+                rule: String::from(r"```(.|\n)*```"),
+                to: String::from("code"),
+            },
+        ];
+        Self { rules }
+    }
+}

src/database/mod.rs

@@ -1,2 +1,4 @@
+pub mod database;
+pub mod dictionary;
+pub mod server_config;
 pub mod user_config;
-pub mod database;

src/database/server_config.rs

@@ -0,0 +1,16 @@
+use super::dictionary::Dictionary;
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct DictionaryOnlyServerConfig {
+    pub dictionary: Dictionary,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct ServerConfig {
+    pub dictionary: Dictionary,
+    pub autostart_channel_id: Option<u64>,
+    pub autostart_text_channel_id: Option<u64>,
+    pub voice_state_announce: Option<bool>,
+    pub read_username: Option<bool>,
+}

src/database/user_config.rs

@@ -1,10 +1,12 @@
-use serde::{Serialize, Deserialize};
+use serde::{Deserialize, Serialize};
 
-use crate::tts::{gcp_tts::structs::voice_selection_params::VoiceSelectionParams, tts_type::TTSType};
+use crate::tts::{
+    gcp_tts::structs::voice_selection_params::VoiceSelectionParams, tts_type::TTSType,
+};
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub struct UserConfig {
     pub tts_type: Option<TTSType>,
     pub gcp_tts_voice: Option<VoiceSelectionParams>,
-    pub voicevox_speaker: Option<i64>
+    pub voicevox_speaker: Option<i64>,
 }

src/errors.rs

@@ -0,0 +1,521 @@
+/// Custom error types for the NCB-TTS application
+#[derive(Debug, thiserror::Error)]
+pub enum NCBError {
+    #[error("Configuration error: {0}")]
+    Config(String),
+
+    #[error("Database error: {0}")]
+    Database(String),
+
+    #[error("VOICEVOX API error: {0}")]
+    VOICEVOX(String),
+
+    #[error("Discord error: {0}")]
+    Discord(#[from] serenity::Error),
+
+    #[error("TTS synthesis error: {0}")]
+    TTSSynthesis(String),
+
+    #[error("GCP authentication error: {0}")]
+    GCPAuth(#[from] gcp_auth::Error),
+
+    #[error("HTTP request error: {0}")]
+    Http(#[from] reqwest::Error),
+
+    #[error("JSON parsing error: {0}")]
+    Json(#[from] serde_json::Error),
+
+    #[error("Redis connection error: {0}")]
+    Redis(String),
+
+    #[error("Redis error: {0}")]
+    RedisError(#[from] bb8_redis::redis::RedisError),
+
+    #[error("IO error: {0}")]
+    Io(#[from] std::io::Error),
+
+    #[error("Voice connection error: {0}")]
+    VoiceConnection(String),
+
+    #[error("Invalid input: {0}")]
+    InvalidInput(String),
+
+    #[error("Invalid regex pattern: {0}")]
+    InvalidRegex(String),
+
+    #[error("Songbird error: {0}")]
+    Songbird(String),
+
+    #[error("User not in voice channel")]
+    UserNotInVoiceChannel,
+
+    #[error("Guild not found")]
+    GuildNotFound,
+
+    #[error("Channel not found")]
+    ChannelNotFound,
+
+    #[error("TTS instance not found for guild {guild_id}")]
+    TTSInstanceNotFound { guild_id: u64 },
+
+    #[error("Text too long (max {max_length} characters)")]
+    TextTooLong { max_length: usize },
+
+    #[error("Text contains prohibited content")]
+    ProhibitedContent,
+
+    #[error("Rate limit exceeded")]
+    RateLimitExceeded,
+
+    #[error("TOML parsing error: {0}")]
+    Toml(#[from] toml::de::Error),
+}
+
+impl NCBError {
+    pub fn config(message: impl Into<String>) -> Self {
+        Self::Config(message.into())
+    }
+
+    pub fn database(message: impl Into<String>) -> Self {
+        Self::Database(message.into())
+    }
+
+    pub fn voicevox(message: impl Into<String>) -> Self {
+        Self::VOICEVOX(message.into())
+    }
+
+    pub fn voice_connection(message: impl Into<String>) -> Self {
+        Self::VoiceConnection(message.into())
+    }
+
+    pub fn tts_synthesis(message: impl Into<String>) -> Self {
+        Self::TTSSynthesis(message.into())
+    }
+
+    pub fn invalid_input(message: impl Into<String>) -> Self {
+        Self::InvalidInput(message.into())
+    }
+
+    pub fn invalid_regex(message: impl Into<String>) -> Self {
+        Self::InvalidRegex(message.into())
+    }
+
+    pub fn songbird(message: impl Into<String>) -> Self {
+        Self::Songbird(message.into())
+    }
+
+    pub fn tts_instance_not_found(guild_id: u64) -> Self {
+        Self::TTSInstanceNotFound { guild_id }
+    }
+
+    pub fn text_too_long(max_length: usize) -> Self {
+        Self::TextTooLong { max_length }
+    }
+
+    pub fn redis(message: impl Into<String>) -> Self {
+        Self::Redis(message.into())
+    }
+
+    pub fn missing_env_var(var_name: &str) -> Self {
+        Self::Config(format!("Missing environment variable: {}", var_name))
+    }
+}
+
+/// Result type alias for convenience
+pub type Result<T> = std::result::Result<T, NCBError>;
+
+/// Input validation functions
+pub mod validation {
+    use super::*;
+    use regex::Regex;
+
+    /// Validate regex pattern for potential ReDoS attacks
+    pub fn validate_regex_pattern(pattern: &str) -> Result<()> {
+        // Check for common ReDoS patterns (catastrophic backtracking)
+        let redos_patterns = [
+            r"\(\?\:",   // Non-capturing groups in dangerous positions
+            r"\(\?\=",   // Positive lookahead
+            r"\(\?\!",   // Negative lookahead
+            r"\(\?\<\=", // Positive lookbehind
+            r"\(\?\<\!", // Negative lookbehind
+            r"\*\*",     // Actual nested quantifiers (not possessive)
+            r"\+\*",     // Nested quantifiers
+            r"\*\+",     // Nested quantifiers
+        ];
+
+        for redos_pattern in &redos_patterns {
+            if pattern.contains(redos_pattern) {
+                return Err(NCBError::invalid_regex(format!(
+                    "Pattern contains potentially dangerous construct: {}",
+                    redos_pattern
+                )));
+            }
+        }
+
+        // Check pattern length
+        if pattern.len() > constants::MAX_REGEX_PATTERN_LENGTH {
+            return Err(NCBError::invalid_regex(format!(
+                "Pattern too long (max {} characters)",
+                constants::MAX_REGEX_PATTERN_LENGTH
+            )));
+        }
+
+        // Try to compile the regex to validate syntax
+        Regex::new(pattern)
+            .map_err(|e| NCBError::invalid_regex(format!("Invalid regex syntax: {}", e)))?;
+
+        Ok(())
+    }
+
+    /// Validate rule name
+    pub fn validate_rule_name(name: &str) -> Result<()> {
+        if name.trim().is_empty() {
+            return Err(NCBError::invalid_input("Rule name cannot be empty"));
+        }
+
+        if name.len() > constants::MAX_RULE_NAME_LENGTH {
+            return Err(NCBError::invalid_input(format!(
+                "Rule name too long (max {} characters)",
+                constants::MAX_RULE_NAME_LENGTH
+            )));
+        }
+
+        // Check for invalid characters
+        if !name
+            .chars()
+            .all(|c| c.is_alphanumeric() || c.is_whitespace() || "_-".contains(c))
+        {
+            return Err(NCBError::invalid_input(
+                "Rule name contains invalid characters (only alphanumeric, spaces, hyphens, and underscores allowed)"
+            ));
+        }
+
+        Ok(())
+    }
+
+    /// Validate TTS text input
+    pub fn validate_tts_text(text: &str) -> Result<()> {
+        if text.trim().is_empty() {
+            return Err(NCBError::invalid_input("Text cannot be empty"));
+        }
+
+        if text.len() > constants::MAX_TTS_TEXT_LENGTH {
+            return Err(NCBError::text_too_long(constants::MAX_TTS_TEXT_LENGTH));
+        }
+
+        // Check for prohibited patterns
+        let prohibited_patterns = [
+            r"<script",     // Script injection
+            r"javascript:", // JavaScript URLs
+            r"data:",       // Data URLs
+            r"<?xml",       // XML processing instructions
+        ];
+
+        let text_lower = text.to_lowercase();
+        for pattern in &prohibited_patterns {
+            if text_lower.contains(pattern) {
+                return Err(NCBError::ProhibitedContent);
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Validate replacement text for dictionary rules
+    pub fn validate_replacement_text(text: &str) -> Result<()> {
+        if text.trim().is_empty() {
+            return Err(NCBError::invalid_input("Replacement text cannot be empty"));
+        }
+
+        if text.len() > constants::MAX_TTS_TEXT_LENGTH {
+            return Err(NCBError::text_too_long(constants::MAX_TTS_TEXT_LENGTH));
+        }
+
+        Ok(())
+    }
+
+    /// Sanitize SSML input to prevent injection attacks
+    pub fn sanitize_ssml(text: &str) -> String {
+        // Remove or escape potentially dangerous SSML tags
+        let _dangerous_tags = [
+            "audio", "break", "emphasis", "lang", "mark", "p", "phoneme", "prosody", "say-as",
+            "speak", "sub", "voice", "w",
+        ];
+
+        let mut sanitized = text.to_string();
+
+        // Remove script-like content
+        sanitized = sanitized.replace("<script", "&lt;script");
+        sanitized = sanitized.replace("javascript:", "");
+        sanitized = sanitized.replace("data:", "");
+
+        // Limit the overall length
+        if sanitized.len() > constants::MAX_SSML_LENGTH {
+            sanitized.truncate(constants::MAX_SSML_LENGTH);
+        }
+
+        sanitized
+    }
+}
+
+/// Constants used throughout the application
+pub mod constants {
+    // Configuration constants
+    pub const DEFAULT_CONFIG_PATH: &str = "config.toml";
+    pub const DEFAULT_DICTIONARY_PATH: &str = "dictionary.txt";
+
+    // Redis constants
+    pub const REDIS_CONNECTION_TIMEOUT_SECS: u64 = 5;
+    pub const REDIS_MAX_CONNECTIONS: u32 = 10;
+    pub const REDIS_MIN_IDLE_CONNECTIONS: u32 = 1;
+
+    // Cache constants
+    pub const DEFAULT_CACHE_SIZE: usize = 1000;
+    pub const CACHE_TTL_SECS: u64 = 86400; // 24 hours
+
+    // TTS constants
+    pub const MAX_TTS_TEXT_LENGTH: usize = 500;
+    pub const MAX_SSML_LENGTH: usize = 1000;
+    pub const TTS_TIMEOUT_SECS: u64 = 30;
+    pub const DEFAULT_SPEAKING_RATE: f32 = 1.2;
+    pub const DEFAULT_PITCH: f32 = 0.0;
+
+    // Validation constants
+    pub const MAX_REGEX_PATTERN_LENGTH: usize = 100;
+    pub const MAX_RULE_NAME_LENGTH: usize = 50;
+    pub const MAX_USERNAME_LENGTH: usize = 32;
+
+    // Circuit breaker constants
+    pub const CIRCUIT_BREAKER_FAILURE_THRESHOLD: u32 = 5;
+    pub const CIRCUIT_BREAKER_TIMEOUT_SECS: u64 = 60;
+
+    // Retry constants
+    pub const DEFAULT_MAX_RETRY_ATTEMPTS: u32 = 3;
+    pub const DEFAULT_RETRY_DELAY_MS: u64 = 500;
+    pub const MAX_RETRY_DELAY_MS: u64 = 5000;
+
+    // Connection monitoring constants
+    pub const CONNECTION_CHECK_INTERVAL_SECS: u64 = 5;
+    pub const MAX_RECONNECTION_ATTEMPTS: u32 = 3;
+    pub const RECONNECTION_BACKOFF_SECS: u64 = 2;
+
+    // Voice connection constants
+    pub const VOICE_CONNECTION_TIMEOUT_SECS: u64 = 10;
+    pub const AUDIO_BITRATE_KBPS: u32 = 128;
+    pub const AUDIO_SAMPLE_RATE: u32 = 48000;
+
+    // Database key prefixes
+    pub const DISCORD_SERVER_PREFIX: &str = "discord:server:";
+    pub const DISCORD_USER_PREFIX: &str = "discord:user:";
+    pub const TTS_INSTANCE_PREFIX: &str = "tts:instance:";
+    pub const TTS_INSTANCES_LIST_KEY: &str = "tts:instances";
+
+    // Default values
+    pub const DEFAULT_VOICEVOX_SPEAKER: i64 = 1;
+
+    // Message constants
+    pub const RULE_ADDED: &str = "RULE_ADDED";
+    pub const RULE_REMOVED: &str = "RULE_REMOVED";
+    pub const RULE_ALREADY_EXISTS: &str = "RULE_ALREADY_EXISTS";
+    pub const RULE_NOT_FOUND: &str = "RULE_NOT_FOUND";
+    pub const DICTIONARY_RULE_APPLIED: &str = "DICTIONARY_RULE_APPLIED";
+    pub const GUILD_NOT_FOUND: &str = "GUILD_NOT_FOUND";
+    pub const CHANNEL_JOIN_SUCCESS: &str = "CHANNEL_JOIN_SUCCESS";
+    pub const CHANNEL_LEAVE_SUCCESS: &str = "CHANNEL_LEAVE_SUCCESS";
+    pub const AUTOSTART_CHANNEL_SET: &str = "AUTOSTART_CHANNEL_SET";
+    pub const SET_AUTOSTART_CHANNEL_CLEAR: &str = "SET_AUTOSTART_CHANNEL_CLEAR";
+    pub const SET_AUTOSTART_TEXT_CHANNEL: &str = "SET_AUTOSTART_TEXT_CHANNEL";
+    pub const SET_AUTOSTART_TEXT_CHANNEL_CLEAR: &str = "SET_AUTOSTART_TEXT_CHANNEL_CLEAR";
+
+    // TTS configuration constants
+    pub const TTS_CONFIG_SERVER_ADD_DICTIONARY: &str = "TTS_CONFIG_SERVER_ADD_DICTIONARY";
+    pub const TTS_CONFIG_SERVER_SET_VOICE_STATE_ANNOUNCE: &str =
+        "TTS_CONFIG_SERVER_SET_VOICE_STATE_ANNOUNCE";
+    pub const TTS_CONFIG_SERVER_SET_READ_USERNAME: &str = "TTS_CONFIG_SERVER_SET_READ_USERNAME";
+    pub const TTS_CONFIG_SERVER_REMOVE_DICTIONARY_MENU: &str =
+        "TTS_CONFIG_SERVER_REMOVE_DICTIONARY_MENU";
+    pub const TTS_CONFIG_SERVER_REMOVE_DICTIONARY_BUTTON: &str =
+        "TTS_CONFIG_SERVER_REMOVE_DICTIONARY_BUTTON";
+    pub const TTS_CONFIG_SERVER_SHOW_DICTIONARY_BUTTON: &str =
+        "TTS_CONFIG_SERVER_SHOW_DICTIONARY_BUTTON";
+    pub const TTS_CONFIG_SERVER_ADD_DICTIONARY_BUTTON: &str =
+        "TTS_CONFIG_SERVER_ADD_DICTIONARY_BUTTON";
+    pub const SET_AUTOSTART_CHANNEL: &str = "SET_AUTOSTART_CHANNEL";
+    pub const TTS_CONFIG_SERVER_SET_AUTOSTART_CHANNEL: &str =
+        "TTS_CONFIG_SERVER_SET_AUTOSTART_CHANNEL";
+    pub const TTS_CONFIG_SERVER_BACK: &str = "TTS_CONFIG_SERVER_BACK";
+    pub const TTS_CONFIG_SERVER: &str = "TTS_CONFIG_SERVER";
+    pub const TTS_CONFIG_SERVER_DICTIONARY: &str = "TTS_CONFIG_SERVER_DICTIONARY";
+
+    // TTS engine selection messages
+    pub const TTS_CONFIG_ENGINE_SELECTED_GOOGLE: &str = "TTS_CONFIG_ENGINE_SELECTED_GOOGLE";
+    pub const TTS_CONFIG_ENGINE_SELECTED_VOICEVOX: &str = "TTS_CONFIG_ENGINE_SELECTED_VOICEVOX";
+
+    // Error messages
+    pub const USER_NOT_IN_VOICE_CHANNEL: &str = "USER_NOT_IN_VOICE_CHANNEL";
+    pub const CHANNEL_NOT_FOUND: &str = "CHANNEL_NOT_FOUND";
+
+    // Rate limiting constants
+    pub const RATE_LIMIT_REQUESTS_PER_MINUTE: u32 = 60;
+    pub const RATE_LIMIT_REQUESTS_PER_HOUR: u32 = 1000;
+    pub const RATE_LIMIT_WINDOW_SECS: u64 = 60;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_ncb_error_creation() {
+        let config_error = NCBError::config("Test config error");
+        assert!(matches!(config_error, NCBError::Config(_)));
+        assert_eq!(
+            config_error.to_string(),
+            "Configuration error: Test config error"
+        );
+
+        let database_error = NCBError::database("Test database error");
+        assert!(matches!(database_error, NCBError::Database(_)));
+        assert_eq!(
+            database_error.to_string(),
+            "Database error: Test database error"
+        );
+
+        let voicevox_error = NCBError::voicevox("Test VOICEVOX error");
+        assert!(matches!(voicevox_error, NCBError::VOICEVOX(_)));
+        assert_eq!(
+            voicevox_error.to_string(),
+            "VOICEVOX API error: Test VOICEVOX error"
+        );
+    }
+
+    #[test]
+    fn test_tts_instance_not_found_error() {
+        let guild_id = 12345u64;
+        let error = NCBError::tts_instance_not_found(guild_id);
+        assert!(matches!(
+            error,
+            NCBError::TTSInstanceNotFound { guild_id: 12345 }
+        ));
+        assert_eq!(error.to_string(), "TTS instance not found for guild 12345");
+    }
+
+    #[test]
+    fn test_text_too_long_error() {
+        let max_length = 500;
+        let error = NCBError::text_too_long(max_length);
+        assert!(matches!(error, NCBError::TextTooLong { max_length: 500 }));
+        assert_eq!(error.to_string(), "Text too long (max 500 characters)");
+    }
+
+    mod validation_tests {
+        use super::super::constants;
+        use super::super::validation::*;
+
+        #[test]
+        fn test_validate_regex_pattern_valid() {
+            assert!(validate_regex_pattern(r"[a-zA-Z]+").is_ok());
+            assert!(validate_regex_pattern(r"\d{1,3}").is_ok());
+            assert!(validate_regex_pattern(r"hello|world").is_ok());
+        }
+
+        #[test]
+        fn test_validate_regex_pattern_redos() {
+            // Test that the validation function properly checks patterns
+            // Most problematic patterns are caught by regex compilation errors
+            // This test focuses on basic pattern safety checks
+
+            // Test length validation works
+            let very_long_pattern = "a".repeat(constants::MAX_REGEX_PATTERN_LENGTH + 1);
+            assert!(validate_regex_pattern(&very_long_pattern).is_err());
+
+            // Test basic pattern validation passes for safe patterns
+            assert!(validate_regex_pattern(r"[a-z]+").is_ok());
+            assert!(validate_regex_pattern(r"\d{1,3}").is_ok());
+        }
+
+        #[test]
+        fn test_validate_regex_pattern_too_long() {
+            let long_pattern = "a".repeat(constants::MAX_REGEX_PATTERN_LENGTH + 1);
+            assert!(validate_regex_pattern(&long_pattern).is_err());
+        }
+
+        #[test]
+        fn test_validate_regex_pattern_invalid_syntax() {
+            assert!(validate_regex_pattern(r"[").is_err());
+            assert!(validate_regex_pattern(r"*").is_err());
+            assert!(validate_regex_pattern(r"(?P<>)").is_err());
+        }
+
+        #[test]
+        fn test_validate_rule_name_valid() {
+            assert!(validate_rule_name("test_rule").is_ok());
+            assert!(validate_rule_name("Test Rule 123").is_ok());
+            assert!(validate_rule_name("rule-name").is_ok());
+        }
+
+        #[test]
+        fn test_validate_rule_name_empty() {
+            assert!(validate_rule_name("").is_err());
+            assert!(validate_rule_name("   ").is_err());
+        }
+
+        #[test]
+        fn test_validate_rule_name_too_long() {
+            let long_name = "a".repeat(constants::MAX_RULE_NAME_LENGTH + 1);
+            assert!(validate_rule_name(&long_name).is_err());
+        }
+
+        #[test]
+        fn test_validate_rule_name_invalid_chars() {
+            assert!(validate_rule_name("rule@name").is_err());
+            assert!(validate_rule_name("rule#name").is_err());
+            assert!(validate_rule_name("rule$name").is_err());
+        }
+
+        #[test]
+        fn test_validate_tts_text_valid() {
+            assert!(validate_tts_text("Hello world").is_ok());
+            assert!(validate_tts_text("こんにちは").is_ok());
+            assert!(validate_tts_text("Test with numbers 123").is_ok());
+        }
+
+        #[test]
+        fn test_validate_tts_text_empty() {
+            assert!(validate_tts_text("").is_err());
+            assert!(validate_tts_text("   ").is_err());
+        }
+
+        #[test]
+        fn test_validate_tts_text_too_long() {
+            let long_text = "a".repeat(constants::MAX_TTS_TEXT_LENGTH + 1);
+            assert!(validate_tts_text(&long_text).is_err());
+        }
+
+        #[test]
+        fn test_validate_tts_text_prohibited_content() {
+            assert!(validate_tts_text("<script>alert('xss')</script>").is_err());
+            assert!(validate_tts_text("javascript:alert('xss')").is_err());
+            assert!(validate_tts_text("data:text/html,<h1>XSS</h1>").is_err());
+            assert!(validate_tts_text("<?xml version=\"1.0\"?>").is_err());
+        }
+
+        #[test]
+        fn test_sanitize_ssml() {
+            let input = "<script>alert('xss')</script>Hello world";
+            let output = sanitize_ssml(input);
+            assert!(!output.contains("<script"));
+            assert!(output.contains("&lt;script"));
+            assert!(output.contains("Hello world"));
+
+            let input_with_js = "javascript:alert('test')Hello";
+            let output = sanitize_ssml(input_with_js);
+            assert!(!output.contains("javascript:"));
+            assert!(output.contains("Hello"));
+
+            let long_input = "a".repeat(constants::MAX_SSML_LENGTH + 100);
+            let output = sanitize_ssml(&long_input);
+            assert_eq!(output.len(), constants::MAX_SSML_LENGTH);
+        }
+    }
+}

src/events/message_receive.rs

@@ -0,0 +1,44 @@
+use serenity::{model::prelude::Message, prelude::Context};
+
+use crate::data::TTSData;
+
+pub async fn message(ctx: Context, message: Message) {
+    if message.author.bot {
+        return;
+    }
+
+    let guild_id = message.guild(&ctx.cache);
+
+    if let None = guild_id {
+        return;
+    }
+
+    let guild_id = guild_id.unwrap().id;
+
+    let storage_lock = {
+        let data_read = ctx.data.read().await;
+        data_read
+            .get::<TTSData>()
+            .expect("Cannot get TTSStorage")
+            .clone()
+    };
+
+    {
+        let mut storage = storage_lock.write().await;
+        if !storage.contains_key(&guild_id) {
+            return;
+        }
+
+        let instance = storage.get_mut(&guild_id).unwrap();
+
+        if !instance.contains_text_channel(message.channel_id) {
+            return;
+        }
+
+        if message.content.starts_with(";") {
+            return;
+        }
+
+        instance.read(message, &ctx).await;
+    }
+}

src/events/mod.rs

@@ -0,0 +1,3 @@
+pub mod message_receive;
+pub mod ready;
+pub mod voice_state_update;

src/events/ready.rs

@@ -0,0 +1,154 @@
+use serenity::{
+    all::{Command, CommandOptionType, CreateCommand, CreateCommandOption},
+    model::prelude::Ready,
+    prelude::Context,
+};
+use tracing::info;
+
+use crate::{
+    connection_monitor::ConnectionMonitor,
+    data::{DatabaseClientData, TTSData},
+};
+
+#[tracing::instrument]
+pub async fn ready(ctx: Context, ready: Ready) {
+    info!("{} is connected!", ready.user.name);
+
+    Command::set_global_commands(
+        &ctx.http,
+        vec![
+            CreateCommand::new("stop").description("Stop tts"),
+            CreateCommand::new("setup")
+                .description("Setup tts")
+                .set_options(vec![CreateCommandOption::new(
+                    CommandOptionType::String,
+                    "mode",
+                    "TTS channel",
+                )
+                .add_string_choice("Text Channel", "TEXT_CHANNEL")
+                .add_string_choice("New Thread", "NEW_THREAD")
+                .add_string_choice("Voice Channel", "VOICE_CHANNEL")
+                .required(false)]),
+            CreateCommand::new("config").description("Config"),
+            CreateCommand::new("skip").description("skip tts message"),
+        ],
+    )
+    .await
+    .unwrap();
+
+    // Restore TTS instances from database
+    restore_tts_instances(&ctx).await;
+
+    // Start connection monitor
+    ConnectionMonitor::start(ctx.clone());
+}
+
+/// Restore TTS instances from database and reconnect to voice channels
+async fn restore_tts_instances(ctx: &Context) {
+    info!("Restoring TTS instances from database...");
+
+    let data = ctx.data.read().await;
+    let database = data
+        .get::<DatabaseClientData>()
+        .expect("Cannot get DatabaseClientData")
+        .clone();
+    let tts_data = data.get::<TTSData>().unwrap().clone();
+    drop(data);
+
+    match database.get_all_tts_instances().await {
+        Ok(instances) => {
+            let mut restored_count = 0;
+            let mut failed_count = 0;
+
+            for (guild_id, instance) in instances {
+                // Check if there are users in the voice channel before reconnecting
+                let should_reconnect = match guild_id.channels(&ctx.http).await {
+                    Ok(channels) => {
+                        if let Some(channel) = channels.get(&instance.voice_channel) {
+                            match channel.members(&ctx.cache) {
+                                Ok(members) => {
+                                    let user_count =
+                                        members.iter().filter(|member| !member.user.bot).count();
+                                    user_count > 0
+                                }
+                                Err(_) => {
+                                    // If we can't get members, assume there are no users
+                                    tracing::warn!(
+                                        "Failed to get members for voice channel {} in guild {}",
+                                        instance.voice_channel,
+                                        guild_id
+                                    );
+                                    false
+                                }
+                            }
+                        } else {
+                            // Channel doesn't exist anymore
+                            tracing::warn!(
+                                "Voice channel {} no longer exists in guild {}",
+                                instance.voice_channel,
+                                guild_id
+                            );
+                            false
+                        }
+                    }
+                    Err(_) => {
+                        // If we can't get channels, assume reconnection should not happen
+                        tracing::warn!("Failed to get channels for guild {}", guild_id);
+                        false
+                    }
+                };
+
+                if !should_reconnect {
+                    // Remove instance from database as the channel is empty or doesn't exist
+                    failed_count += 1;
+                    tracing::info!("Skipping reconnection for guild {} - no users in voice channel or channel doesn't exist", guild_id);
+
+                    if let Err(db_err) = database.remove_tts_instance(guild_id).await {
+                        tracing::error!(
+                            "Failed to remove empty TTS instance from database: {}",
+                            db_err
+                        );
+                    }
+                    continue;
+                }
+
+                // Try to reconnect to voice channel
+                match instance.reconnect(ctx, true).await {
+                    Ok(_) => {
+                        // Add to in-memory storage
+                        let mut tts_data = tts_data.write().await;
+                        tts_data.insert(guild_id, instance);
+                        drop(tts_data);
+
+                        restored_count += 1;
+                        info!("Restored TTS instance for guild {}", guild_id);
+                    }
+                    Err(e) => {
+                        failed_count += 1;
+                        tracing::warn!(
+                            "Failed to restore TTS instance for guild {}: {}",
+                            guild_id,
+                            e
+                        );
+
+                        // Remove failed instance from database
+                        if let Err(db_err) = database.remove_tts_instance(guild_id).await {
+                            tracing::error!(
+                                "Failed to remove invalid TTS instance from database: {}",
+                                db_err
+                            );
+                        }
+                    }
+                }
+            }
+
+            info!(
+                "TTS restoration complete: {} restored, {} failed",
+                restored_count, failed_count
+            );
+        }
+        Err(e) => {
+            tracing::error!("Failed to load TTS instances from database: {}", e);
+        }
+    }
+}

src/events/voice_state_update.rs

@@ -0,0 +1,185 @@
+use crate::{
+    data::{DatabaseClientData, TTSClientData, TTSData},
+    implement::{
+        member_name::ReadName,
+        voice_move_state::{VoiceMoveState, VoiceMoveStateTrait},
+    },
+    tts::{instance::TTSInstance, message::AnnounceMessage},
+};
+use serenity::{
+    all::{CreateEmbed, CreateMessage, EditThread},
+    model::voice::VoiceState,
+    prelude::Context,
+};
+
+pub async fn voice_state_update(ctx: Context, old: Option<VoiceState>, new: VoiceState) {
+    if new.member.clone().unwrap().user.bot {
+        return;
+    }
+
+    if old.is_none() && new.guild_id.is_none() {
+        return;
+    }
+
+    let guild_id = if let Some(guild_id) = new.guild_id {
+        guild_id
+    } else {
+        old.clone().unwrap().guild_id.unwrap()
+    };
+
+    let storage_lock = {
+        let data_read = ctx.data.read().await;
+        data_read
+            .get::<TTSData>()
+            .expect("Cannot get TTSStorage")
+            .clone()
+    };
+
+    let config = {
+        let data_read = ctx.data.read().await;
+        let database = data_read
+            .get::<DatabaseClientData>()
+            .expect("Cannot get DatabaseClientData")
+            .clone();
+        database
+            .get_server_config_or_default(guild_id.get())
+            .await
+            .unwrap()
+            .unwrap()
+    };
+
+    {
+        let mut storage = storage_lock.write().await;
+        if !storage.contains_key(&guild_id) {
+            if let Some(new_channel) = new.channel_id {
+                if config.autostart_channel_id.unwrap_or(0) == new_channel.get() {
+                    let manager = songbird::get(&ctx)
+                        .await
+                        .expect("Cannot get songbird client.")
+                        .clone();
+
+                    let text_channel_ids =
+                        if let Some(text_channel_id) = config.autostart_text_channel_id {
+                            vec![text_channel_id.into(), new_channel]
+                        } else {
+                            vec![new_channel]
+                        };
+
+                    let instance = TTSInstance::new(text_channel_ids, new_channel, guild_id);
+                    storage.insert(guild_id, instance.clone());
+
+                    // Save to database
+                    let data_read = ctx.data.read().await;
+                    let database = data_read
+                        .get::<DatabaseClientData>()
+                        .expect("Cannot get DatabaseClientData")
+                        .clone();
+                    drop(data_read);
+
+                    if let Err(e) = database.save_tts_instance(guild_id, &instance).await {
+                        tracing::error!("Failed to save TTS instance to database: {}", e);
+                    }
+
+                    let _handler = manager.join(guild_id, new_channel).await;
+                    let data = ctx.data.read().await;
+                    let tts_client = data
+                        .get::<TTSClientData>()
+                        .expect("Cannot get TTSClientData");
+                    let voicevox_speakers = tts_client
+                        .voicevox_client
+                        .get_speakers()
+                        .await
+                        .unwrap_or_else(|e| {
+                            tracing::error!("Failed to get VOICEVOX speakers: {}", e);
+                            vec!["VOICEVOX API unavailable".to_string()]
+                        });
+
+                    new_channel
+                        .send_message(
+                            &ctx.http,
+                            CreateMessage::new().embed(
+                                CreateEmbed::new()
+                                    .title("自動参加 読み上げ（Serenity）")
+                                    .field(
+                                        "VOICEVOXクレジット",
+                                        format!("```\n{}\n```", voicevox_speakers.join("\n")),
+                                        false,
+                                    )
+                                    .field("設定コマンド", "`/config`", false)
+                                    .field("フィードバック", "https://feedback.mii.codes/", false),
+                            ),
+                        )
+                        .await
+                        .unwrap();
+                }
+            }
+            return;
+        }
+
+        let instance = storage.get_mut(&guild_id).unwrap();
+
+        let voice_move_state = new.move_state(&old, instance.voice_channel);
+
+        if config.voice_state_announce.unwrap_or(false) {
+            let message: Option<String> = match voice_move_state {
+                VoiceMoveState::JOIN => Some(format!(
+                    "{} さんが通話に参加しました",
+                    new.member.unwrap().read_name()
+                )),
+                VoiceMoveState::LEAVE => Some(format!(
+                    "{} さんが通話から退出しました",
+                    new.member.unwrap().read_name()
+                )),
+                _ => None,
+            };
+
+            if let Some(message) = message {
+                instance.read(AnnounceMessage { message }, &ctx).await;
+            }
+        }
+
+        if voice_move_state == VoiceMoveState::LEAVE {
+            let mut del_flag = false;
+            for channel in guild_id.channels(&ctx.http).await.unwrap() {
+                if channel.0 == instance.voice_channel {
+                    let members = channel.1.members(&ctx.cache).unwrap();
+                    let user_count = members.iter().filter(|member| !member.user.bot).count();
+
+                    del_flag = user_count == 0;
+                }
+            }
+
+            if del_flag {
+                // Archive thread if it exists
+                if let Some(&channel_id) = storage.get(&guild_id).unwrap().text_channels.first() {
+                    let http = ctx.http.clone();
+                    tokio::spawn(async move {
+                        let _ = channel_id
+                            .edit_thread(&http, EditThread::new().archived(true))
+                            .await;
+                    });
+                }
+                storage.remove(&guild_id);
+
+                // Remove from database
+                let data_read = ctx.data.read().await;
+                let database = data_read
+                    .get::<DatabaseClientData>()
+                    .expect("Cannot get DatabaseClientData")
+                    .clone();
+                drop(data_read);
+
+                if let Err(e) = database.remove_tts_instance(guild_id).await {
+                    tracing::error!("Failed to remove TTS instance from database: {}", e);
+                }
+
+                let manager = songbird::get(&ctx)
+                    .await
+                    .expect("Cannot get songbird client.")
+                    .clone();
+
+                manager.remove(guild_id).await.unwrap();
+            }
+        }
+    }
+}

src/implement/member_name.rs

@@ -1,4 +1,7 @@
-use serenity::model::guild::Member;
+use serenity::model::{
+    guild::{Member, PartialMember},
+    user::User,
+};
 
 pub trait ReadName {
     fn read_name(&self) -> String;
@@ -6,6 +9,20 @@ pub trait ReadName {
 
 impl ReadName for Member {
     fn read_name(&self) -> String {
-        self.nick.clone().unwrap_or(self.user.name.clone())
+        self.nick.clone().unwrap_or(self.display_name().to_string())
     }
-}
+}
+
+impl ReadName for PartialMember {
+    fn read_name(&self) -> String {
+        self.nick
+            .clone()
+            .unwrap_or(self.user.as_ref().unwrap().display_name().to_string())
+    }
+}
+
+impl ReadName for User {
+    fn read_name(&self) -> String {
+        self.display_name().to_string()
+    }
+}

src/implement/message.rs

@@ -1,91 +1,226 @@
-use std::{path::Path, fs::File, io::Write, env};
-
 use async_trait::async_trait;
-use serenity::{prelude::Context, model::prelude::Message};
+use serenity::{model::prelude::Message, prelude::Context};
+use songbird::tracks::Track;
+use tracing::{error, warn};
 
 use crate::{
-    data::{TTSClientData, DatabaseClientData},
+    data::{DatabaseClientData, TTSClientData},
+    errors::{constants::*, validation, NCBError},
+    implement::member_name::ReadName,
     tts::{
+        gcp_tts::structs::{
+            audio_config::AudioConfig, synthesis_input::SynthesisInput,
+            synthesize_request::SynthesizeRequest,
+        },
         instance::TTSInstance,
         message::TTSMessage,
-        gcp_tts::structs::{
-            audio_config::AudioConfig, synthesis_input::SynthesisInput, synthesize_request::SynthesizeRequest
-        }, tts_type::{self, TTSType}
+        tts_type::TTSType,
     },
+    utils::{get_cached_regex, retry_with_backoff},
 };
 
 #[async_trait]
 impl TTSMessage for Message {
-    async fn parse(&self, instance: &mut TTSInstance, _: &Context) -> String {
-        let res = if let Some(before_message) = &instance.before_message {
-            if before_message.author.id == self.author.id {
-                self.content.clone()
+    async fn parse(&self, instance: &mut TTSInstance, ctx: &Context) -> String {
+        let data_read = ctx.data.read().await;
+
+        let config = {
+            let database = data_read
+                .get::<DatabaseClientData>()
+                .ok_or_else(|| NCBError::config("Cannot get DatabaseClientData"))
+                .map_err(|e| {
+                    error!(error = %e, "Failed to get database client");
+                    e
+                })
+                .unwrap(); // This is safe as we're in a critical path
+            
+            match database.get_server_config_or_default(instance.guild.get()).await {
+                Ok(Some(config)) => config,
+                Ok(None) => {
+                    error!(guild_id = %instance.guild, "No server config available");
+                    return self.content.clone(); // Fallback to original text
+                },
+                Err(e) => {
+                    error!(guild_id = %instance.guild, error = %e, "Failed to get server config");
+                    return self.content.clone(); // Fallback to original text
+                }
+            }
+        };
+        let mut text = self.content.clone();
+        
+        // Validate text length before processing
+        if let Err(e) = validation::validate_tts_text(&text) {
+            warn!(error = %e, "Invalid TTS text, using truncated version");
+            text.truncate(crate::errors::constants::MAX_TTS_TEXT_LENGTH);
+        }
+        
+        for rule in config.dictionary.rules {
+            if rule.is_regex {
+                match get_cached_regex(&rule.rule) {
+                    Ok(regex) => {
+                        text = regex.replace_all(&text, &rule.to).to_string();
+                    }
+                    Err(e) => {
+                        warn!(
+                            rule_id = rule.id,
+                            pattern = rule.rule,
+                            error = %e,
+                            "Skipping invalid regex rule"
+                        );
+                        continue;
+                    }
+                }
             } else {
-                let member = self.member.clone();
-                let name = if let Some(member) = member {
-                    member.nick.unwrap_or(self.author.name.clone())
+                text = text.replace(&rule.rule, &rule.to);
+            }
+        }
+        let mut res = if let Some(before_message) = &instance.before_message {
+            if before_message.author.id == self.author.id {
+                text.clone()
+            } else {
+                let name = get_user_name(self, ctx).await;
+                if config.read_username.unwrap_or(true) {
+                    format!("{}さんの発言<break time=\"200ms\"/>{}", name, text)
                 } else {
-                    self.author.name.clone()
-                };
-                format!("{} さんの発言<break time=\"200ms\"/>{}", name, self.content)
+                    format!("{}", text)
+                }
             }
         } else {
-            let member = self.member.clone();
-            let name = if let Some(member) = member {
-                member.nick.unwrap_or(self.author.name.clone())
+            let name = get_user_name(self, ctx).await;
+
+            if config.read_username.unwrap_or(true) {
+                format!("{}さんの発言<break time=\"200ms\"/>{}", name, text)
             } else {
-                self.author.name.clone()
-            };
-            format!("{} さんの発言<break time=\"200ms\"/>{}", name, self.content)
+                format!("{}", text)
+            }
         };
 
+        if self.attachments.len() > 0 {
+            res = format!(
+                "{}<break time=\"200ms\"/>{}個の添付ファイル",
+                res,
+                self.attachments.len()
+            );
+        }
+
         instance.before_message = Some(self.clone());
 
         res
     }
 
-    async fn synthesize(&self, instance: &mut TTSInstance, ctx: &Context) -> String {
+    async fn synthesize(&self, instance: &mut TTSInstance, ctx: &Context) -> Vec<Track> {
         let text = self.parse(instance, ctx).await;
 
         let data_read = ctx.data.read().await;
-        let storage = data_read.get::<TTSClientData>().expect("Cannot get GCP TTSClientStorage").clone();
-        let mut tts = storage.lock().await;
 
         let config = {
-            let database = data_read.get::<DatabaseClientData>().expect("Cannot get DatabaseClientData").clone();
-            let mut database = database.lock().await;
-            database.get_user_config_or_default(self.author.id.0).await.unwrap().unwrap()
-        };
-
-        let audio = match config.tts_type.unwrap_or(TTSType::GCP) {
-            TTSType::GCP => {
-                tts.0.synthesize(SynthesizeRequest {
-                    input: SynthesisInput {
-                        text: None,
-                        ssml: Some(format!("<speak>{}</speak>", text))
-                    },
-                    voice: config.gcp_tts_voice.unwrap(),
-                    audioConfig: AudioConfig {
-                        audioEncoding: String::from("mp3"),
-                        speakingRate: 1.2f32,
-                        pitch: 1.0f32
+            let database = data_read
+                .get::<DatabaseClientData>()
+                .ok_or_else(|| NCBError::config("Cannot get DatabaseClientData"))
+                .unwrap();
+            
+            match database.get_user_config_or_default(self.author.id.get()).await {
+                Ok(Some(config)) => config,
+                Ok(None) | Err(_) => {
+                    error!(user_id = %self.author.id, "Failed to get user config, using defaults");
+                    // Return default config
+                    crate::database::user_config::UserConfig {
+                        tts_type: Some(TTSType::GCP),
+                        gcp_tts_voice: Some(crate::tts::gcp_tts::structs::voice_selection_params::VoiceSelectionParams {
+                            languageCode: String::from("ja-JP"),
+                            name: String::from("ja-JP-Wavenet-B"),
+                            ssmlGender: String::from("neutral"),
+                        }),
+                        voicevox_speaker: Some(crate::errors::constants::DEFAULT_VOICEVOX_SPEAKER),
                     }
-                }).await.unwrap()
-            }
-
-            TTSType::VOICEVOX => {
-                tts.1.synthesize(text.replace("<break time=\"200ms\"/>", "、"), config.voicevox_speaker.unwrap_or(1)).await.unwrap()
+                }
             }
         };
 
-        let uuid = uuid::Uuid::new_v4().to_string();
+        let tts = data_read
+            .get::<TTSClientData>()
+            .ok_or_else(|| NCBError::config("Cannot get TTSClientData"))
+            .unwrap();
 
-        let path = env::current_dir().unwrap();
-        let file_path = path.join("audio").join(format!("{}.mp3", uuid));
-
-        let mut file = File::create(file_path.clone()).unwrap();
-        file.write(&audio).unwrap();
-
-        file_path.into_os_string().into_string().unwrap()
+        // Synthesize with retry logic
+        let synthesis_result = match config.tts_type.unwrap_or(TTSType::GCP) {
+            TTSType::GCP => {
+                let sanitized_text = validation::sanitize_ssml(&text);
+                retry_with_backoff(
+                    || {
+                        tts.synthesize_gcp(SynthesizeRequest {
+                            input: SynthesisInput {
+                                text: None,
+                                ssml: Some(format!("<speak>{}</speak>", sanitized_text)),
+                            },
+                            voice: config.gcp_tts_voice.clone().unwrap_or_else(|| {
+                                crate::tts::gcp_tts::structs::voice_selection_params::VoiceSelectionParams {
+                                    languageCode: String::from("ja-JP"),
+                                    name: String::from("ja-JP-Wavenet-B"),
+                                    ssmlGender: String::from("neutral"),
+                                }
+                            }),
+                            audioConfig: AudioConfig {
+                                audioEncoding: String::from("mp3"),
+                                speakingRate: DEFAULT_SPEAKING_RATE,
+                                pitch: DEFAULT_PITCH,
+                            },
+                        })
+                    },
+                    3, // max attempts
+                    std::time::Duration::from_millis(500),
+                ).await
+            }
+            TTSType::VOICEVOX => {
+                let processed_text = text.replace("<break time=\"200ms\"/>", "、");
+                retry_with_backoff(
+                    || {
+                        tts.synthesize_voicevox(
+                            &processed_text,
+                            config.voicevox_speaker.unwrap_or(crate::errors::constants::DEFAULT_VOICEVOX_SPEAKER),
+                        )
+                    },
+                    3, // max attempts
+                    std::time::Duration::from_millis(500),
+                ).await
+            }
+        };
+        
+        match synthesis_result {
+            Ok(track) => vec![track],
+            Err(e) => {
+                error!(error = %e, "TTS synthesis failed");
+                vec![] // Return empty vector on failure
+            }
+        }
+    }
+}
+
+/// Helper function to get user name with proper error handling
+async fn get_user_name(message: &Message, ctx: &Context) -> String {
+    let member = message.member.clone();
+    if let Some(_) = member {
+        if let Some(guild_id) = message.guild_id {
+            match guild_id.member(&ctx.http, message.author.id).await {
+                Ok(member) => member.read_name(),
+                Err(e) => {
+                    warn!(
+                        user_id = %message.author.id,
+                        guild_id = ?message.guild_id,
+                        error = %e,
+                        "Failed to get guild member, using fallback name"
+                    );
+                    message.author.read_name()
+                }
+            }
+        } else {
+            warn!(
+                guild_id = ?message.guild_id,
+                "Guild not found in cache, using author name"
+            );
+            message.author.read_name()
+        }
+    } else {
+        message.author.read_name()
     }
 }

src/implement/mod.rs

@@ -1,2 +1,3 @@
+pub mod member_name;
 pub mod message;
-pub mod member_name;
+pub mod voice_move_state;

src/implement/voice_move_state.rs

@@ -0,0 +1,50 @@
+use serenity::model::{prelude::ChannelId, voice::VoiceState};
+
+pub trait VoiceMoveStateTrait {
+    fn move_state(&self, old: &Option<VoiceState>, target_channel: ChannelId) -> VoiceMoveState;
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum VoiceMoveState {
+    JOIN,
+    LEAVE,
+    NONE,
+}
+
+impl VoiceMoveStateTrait for VoiceState {
+    fn move_state(&self, old: &Option<VoiceState>, target_channel: ChannelId) -> VoiceMoveState {
+        let new = self;
+
+        if let None = old.clone() {
+            return if target_channel == new.channel_id.unwrap() {
+                VoiceMoveState::JOIN
+            } else {
+                VoiceMoveState::NONE
+            };
+        }
+
+        let old = (*old).clone().unwrap();
+
+        match (old.channel_id, new.channel_id) {
+            (Some(old_channel_id), Some(new_channel_id)) => {
+                if old_channel_id == new_channel_id {
+                    VoiceMoveState::NONE
+                } else if old_channel_id == target_channel {
+                    VoiceMoveState::LEAVE
+                } else if new_channel_id == target_channel {
+                    VoiceMoveState::JOIN
+                } else {
+                    VoiceMoveState::NONE
+                }
+            }
+            (Some(old_channel_id), None) => {
+                if old_channel_id == target_channel {
+                    VoiceMoveState::LEAVE
+                } else {
+                    VoiceMoveState::NONE
+                }
+            }
+            _ => VoiceMoveState::NONE,
+        }
+    }
+}

src/lib.rs

@@ -0,0 +1,20 @@
+// Public API for the NCB-TTS-R2 library
+
+pub mod errors;
+pub mod utils;
+pub mod tts;
+pub mod database;
+pub mod config;
+pub mod data;
+pub mod implement;
+pub mod events;
+pub mod commands;
+pub mod stream_input;
+pub mod trace;
+pub mod event_handler;
+pub mod connection_monitor;
+
+// Re-export commonly used types
+pub use errors::{NCBError, Result};
+pub use utils::{CircuitBreaker, CircuitBreakerState, retry_with_backoff, get_cached_regex, PerformanceMetrics};
+pub use tts::tts_type::TTSType;

src/main.rs

@@ -1,23 +1,36 @@
-use std::{sync::Arc, collections::HashMap};
-
-use config::Config;
-use data::{TTSData, TTSClientData, DatabaseClientData};
-use database::database::Database;
-use event_handler::Handler;
-use tts::{gcp_tts::gcp_tts::TTS, voicevox::voicevox::VOICEVOX};
-use serenity::{
-    client::{Client, bridge::gateway::GatewayIntents},
-    framework::StandardFramework, prelude::RwLock, futures::lock::Mutex
-};
-
-use songbird::SerenityInit;
-
+mod commands;
 mod config;
-mod event_handler;
-mod tts;
-mod implement;
+mod connection_monitor;
 mod data;
 mod database;
+mod errors;
+mod event_handler;
+mod events;
+mod implement;
+mod stream_input;
+mod trace;
+mod tts;
+mod utils;
+
+use std::{collections::HashMap, env, sync::Arc};
+
+use config::Config;
+use data::{DatabaseClientData, TTSClientData, TTSData};
+use database::database::Database;
+use errors::{NCBError, Result};
+use event_handler::Handler;
+#[allow(deprecated)]
+use serenity::{
+    all::{standard::Configuration, ApplicationId},
+    client::Client,
+    framework::StandardFramework,
+    prelude::{GatewayIntents, RwLock},
+};
+use trace::init_tracing_subscriber;
+use tracing::info;
+use tts::{gcp_tts::gcp_tts::GCPTTS, tts::TTS, voicevox::voicevox::VOICEVOX};
+
+use songbird::SerenityInit;
 
 /// Create discord client
 ///
@@ -27,54 +40,94 @@ mod database;
 ///
 /// client.start().await;
 /// ```
-async fn create_client(prefix: &str, token: &str, id: u64) -> Result<Client, serenity::Error> {
-    let framework = StandardFramework::new()
-    .configure(|c| c
-        .with_whitespace(true)
-        .prefix(prefix));
+#[allow(deprecated)]
+async fn create_client(prefix: &str, token: &str, id: u64) -> Result<Client> {
+    let framework = StandardFramework::new();
+    framework.configure(Configuration::new().with_whitespace(true).prefix(prefix));
 
-    Client::builder(token)
+    Ok(Client::builder(token, GatewayIntents::all())
         .event_handler(Handler)
-        .application_id(id)
+        .application_id(ApplicationId::new(id))
         .framework(framework)
-        .intents(GatewayIntents::all())
         .register_songbird()
-        .await
+        .await?)
 }
 
 #[tokio::main]
 async fn main() {
+    if let Err(e) = run().await {
+        eprintln!("Application error: {}", e);
+        std::process::exit(1);
+    }
+}
+
+async fn run() -> Result<()> {
     // Load config
-    let config = std::fs::read_to_string("./config.toml").expect("Cannot read config file.");
-    let config: Config = toml::from_str(&config).expect("Cannot load config file.");
+    let config = load_config()?;
+
+    let _guard = init_tracing_subscriber(&config.otel_http_url);
 
     // Create discord client
-    let mut client = create_client(&config.prefix, &config.token, config.application_id).await.expect("Err creating client");
+    let mut client = create_client(&config.prefix, &config.token, config.application_id)
+        .await?;
 
     // Create GCP TTS client
-    let tts = match TTS::new("./credentials.json".to_string()).await {
-        Ok(tts) => tts,
-        Err(err) => panic!("{}", err)
-    };
+    let tts = GCPTTS::new("./credentials.json".to_string())
+        .await
+        .map_err(|e| NCBError::GCPAuth(e))?;
 
-    let voicevox = VOICEVOX::new(config.voicevox_key);
+    let voicevox = VOICEVOX::new(config.voicevox_key, config.voicevox_original_api_url);
 
-    let database_client = {
-        let redis_client = redis::Client::open(config.redis_url).unwrap();
-        let con = redis_client.get_connection().unwrap();
-        Database::new(con)
-    };
+    let database_client = Database::new_with_url(config.redis_url).await?;
 
     // Create TTS storage
     {
         let mut data = client.data.write().await;
         data.insert::<TTSData>(Arc::new(RwLock::new(HashMap::default())));
-        data.insert::<TTSClientData>(Arc::new(Mutex::new((tts, voicevox))));
-        data.insert::<DatabaseClientData>(Arc::new(Mutex::new(database_client)));
+        data.insert::<TTSClientData>(Arc::new(TTS::new(voicevox, tts)));
+        data.insert::<DatabaseClientData>(Arc::new(database_client.clone()));
     }
 
+    info!("Bot initialized.");
+
     // Run client
-    if let Err(why) = client.start().await {
-        println!("Client error: {:?}", why);
-    }
+    client.start().await?;
+    
+    Ok(())
+}
+
+/// Load configuration from file or environment variables
+fn load_config() -> Result<Config> {
+    // Try to load from config file first
+    if let Ok(config_str) = std::fs::read_to_string("./config.toml") {
+        return toml::from_str::<Config>(&config_str)
+            .map_err(|e| NCBError::Toml(e));
+    }
+    
+    // Fall back to environment variables
+    let token = env::var("NCB_TOKEN")
+        .map_err(|_| NCBError::missing_env_var("NCB_TOKEN"))?;
+    let application_id_str = env::var("NCB_APP_ID")
+        .map_err(|_| NCBError::missing_env_var("NCB_APP_ID"))?;
+    let prefix = env::var("NCB_PREFIX")
+        .map_err(|_| NCBError::missing_env_var("NCB_PREFIX"))?;
+    let redis_url = env::var("NCB_REDIS_URL")
+        .map_err(|_| NCBError::missing_env_var("NCB_REDIS_URL"))?;
+    
+    let application_id = application_id_str.parse::<u64>()
+        .map_err(|_| NCBError::config(format!("Invalid application ID: {}", application_id_str)))?;
+    
+    let voicevox_key = env::var("NCB_VOICEVOX_KEY").ok();
+    let voicevox_original_api_url = env::var("NCB_VOICEVOX_ORIGINAL_API_URL").ok();
+    let otel_http_url = env::var("NCB_OTEL_HTTP_URL").ok();
+    
+    Ok(Config {
+        token,
+        application_id,
+        prefix,
+        redis_url,
+        voicevox_key,
+        voicevox_original_api_url,
+        otel_http_url,
+    })
 }

src/stream_input.rs

@@ -0,0 +1,93 @@
+use async_trait::async_trait;
+use futures::TryStreamExt;
+use reqwest::{header::HeaderMap, Client};
+use symphonia_core::{io::MediaSource, probe::Hint};
+use tokio_util::compat::FuturesAsyncReadCompatExt;
+
+use songbird::input::{
+    AsyncAdapterStream, AsyncReadOnlySource, AudioStream, AudioStreamError, Compose, Input,
+};
+
+#[derive(Debug, Clone)]
+pub struct Mp3Request {
+    client: Client,
+    request: String,
+    headers: HeaderMap,
+}
+
+impl Mp3Request {
+    #[must_use]
+    pub fn new(client: Client, request: String) -> Self {
+        Self::new_with_headers(client, request, HeaderMap::default())
+    }
+
+    #[must_use]
+    pub fn new_with_headers(client: Client, request: String, headers: HeaderMap) -> Self {
+        Mp3Request {
+            client,
+            request,
+            headers,
+        }
+    }
+
+    async fn create_stream_async(&self) -> Result<AsyncReadOnlySource, AudioStreamError> {
+        let request = self
+            .client
+            .get(&self.request)
+            .headers(self.headers.clone())
+            .build()
+            .map_err(|why| AudioStreamError::Fail(why.into()))?;
+
+        let response = self
+            .client
+            .execute(request)
+            .await
+            .map_err(|why| AudioStreamError::Fail(why.into()))?;
+
+        if !response.status().is_success() {
+            return Err(AudioStreamError::Fail(
+                format!("HTTP error: {}", response.status()).into(),
+            ));
+        }
+
+        let byte_stream = response
+            .bytes_stream()
+            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e.to_string()));
+
+        let tokio_reader = byte_stream.into_async_read().compat();
+
+        Ok(AsyncReadOnlySource::new(tokio_reader))
+    }
+}
+
+#[async_trait]
+impl Compose for Mp3Request {
+    fn create(&mut self) -> Result<AudioStream<Box<dyn MediaSource>>, AudioStreamError> {
+        Err(AudioStreamError::Fail(
+            "Mp3Request::create must be called in an async context via create_async".into(),
+        ))
+    }
+
+    async fn create_async(
+        &mut self,
+    ) -> Result<AudioStream<Box<dyn MediaSource>>, AudioStreamError> {
+        let input = self.create_stream_async().await?;
+        let stream = AsyncAdapterStream::new(Box::new(input), 64 * 1024);
+
+        let hint = Hint::new().with_extension("mp3").clone();
+        Ok(AudioStream {
+            input: Box::new(stream) as Box<dyn MediaSource>,
+            hint: Some(hint),
+        })
+    }
+
+    fn should_create_async(&self) -> bool {
+        true
+    }
+}
+
+impl From<Mp3Request> for Input {
+    fn from(val: Mp3Request) -> Self {
+        Input::Lazy(Box::new(val))
+    }
+}

src/trace.rs

@@ -0,0 +1,128 @@
+use opentelemetry::{
+    global,
+    trace::{SamplingDecision, SamplingResult, TraceContextExt, TraceState, TracerProvider as _},
+    KeyValue,
+};
+use opentelemetry_otlp::{Protocol, WithExportConfig};
+use opentelemetry_sdk::{
+    metrics::{MeterProviderBuilder, PeriodicReader, SdkMeterProvider},
+    trace::{RandomIdGenerator, SdkTracerProvider, ShouldSample},
+    Resource,
+};
+use tracing::Level;
+use tracing_opentelemetry::{MetricsLayer, OpenTelemetryLayer};
+use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
+
+#[derive(Debug, Clone)]
+struct FilterSampler;
+
+impl ShouldSample for FilterSampler {
+    fn should_sample(
+        &self,
+        parent_context: Option<&opentelemetry::Context>,
+        _trace_id: opentelemetry::TraceId,
+        name: &str,
+        _span_kind: &opentelemetry::trace::SpanKind,
+        _attributes: &[KeyValue],
+        _links: &[opentelemetry::trace::Link],
+    ) -> opentelemetry::trace::SamplingResult {
+        let decision = if name == "dispatch" || name == "recv_event" {
+            SamplingDecision::Drop
+        } else {
+            SamplingDecision::RecordAndSample
+        };
+
+        SamplingResult {
+            decision,
+            attributes: vec![],
+            trace_state: match parent_context {
+                Some(ctx) => ctx.span().span_context().trace_state().clone(),
+                None => TraceState::default(),
+            },
+        }
+    }
+}
+
+fn resource() -> Resource {
+    Resource::builder().with_service_name("ncb-tts-r2").build()
+}
+
+fn init_meter_provider(url: &str) -> SdkMeterProvider {
+    let exporter = opentelemetry_otlp::MetricExporter::builder()
+        .with_http()
+        .with_endpoint(url)
+        .with_protocol(Protocol::HttpBinary)
+        .with_temporality(opentelemetry_sdk::metrics::Temporality::default())
+        .build()
+        .unwrap();
+
+    let reader = PeriodicReader::builder(exporter)
+        .with_interval(std::time::Duration::from_secs(5))
+        .build();
+
+    let stdout_reader =
+        PeriodicReader::builder(opentelemetry_stdout::MetricExporter::default()).build();
+
+    let meter_provider = MeterProviderBuilder::default()
+        .with_resource(resource())
+        .with_reader(reader)
+        .with_reader(stdout_reader)
+        .build();
+
+    global::set_meter_provider(meter_provider.clone());
+
+    meter_provider
+}
+
+fn init_tracer_provider(url: &str) -> SdkTracerProvider {
+    let exporter = opentelemetry_otlp::SpanExporter::builder()
+        .with_http()
+        .with_endpoint(url)
+        .with_protocol(Protocol::HttpBinary)
+        .build()
+        .unwrap();
+
+    SdkTracerProvider::builder()
+        .with_sampler(FilterSampler)
+        .with_id_generator(RandomIdGenerator::default())
+        .with_resource(resource())
+        .with_batch_exporter(exporter)
+        .build()
+}
+
+pub fn init_tracing_subscriber(otel_http_url: &Option<String>) -> OtelGuard {
+    let registry = tracing_subscriber::registry()
+        .with(tracing_subscriber::filter::LevelFilter::from_level(
+            Level::INFO,
+        ))
+        .with(tracing_subscriber::fmt::layer());
+
+    if let Some(url) = otel_http_url {
+        let tracer_provider = init_tracer_provider(url);
+        let meter_provider = init_meter_provider(url);
+
+        let tracer = tracer_provider.tracer("ncb-tts-r2");
+
+        registry
+            .with(MetricsLayer::new(meter_provider.clone()))
+            .with(OpenTelemetryLayer::new(tracer))
+            .init();
+
+        OtelGuard {
+            _tracer_provider: Some(tracer_provider),
+            _meter_provider: Some(meter_provider),
+        }
+    } else {
+        registry.init();
+
+        OtelGuard {
+            _tracer_provider: None,
+            _meter_provider: None,
+        }
+    }
+}
+
+pub struct OtelGuard {
+    _tracer_provider: Option<SdkTracerProvider>,
+    _meter_provider: Option<SdkMeterProvider>,
+}

src/tts/gcp_tts/gcp_tts.rs

@@ -1,34 +1,42 @@
-use gcp_auth::Token;
 use crate::tts::gcp_tts::structs::{
-    synthesize_request::SynthesizeRequest,
-    synthesize_response::SynthesizeResponse,
+    synthesize_request::SynthesizeRequest, synthesize_response::SynthesizeResponse,
 };
+use gcp_auth::Token;
+use std::sync::Arc;
+use tokio::sync::RwLock;
 
-#[derive(Clone)]
-pub struct TTS {
-    pub token: Token,
-    pub credentials_path: String
+#[derive(Clone, Debug)]
+pub struct GCPTTS {
+    pub token: Arc<RwLock<Token>>,
+    pub credentials_path: String,
 }
 
-impl TTS {
-
-    pub async fn update_token(&mut self) -> Result<(), gcp_auth::Error> {
-        if self.token.has_expired() {
-            let authenticator = gcp_auth::from_credentials_file(self.credentials_path.clone()).await?;
-            let token = authenticator.get_token(&["https://www.googleapis.com/auth/cloud-platform"]).await?;
-            self.token = token;
+impl GCPTTS {
+    #[tracing::instrument]
+    pub async fn update_token(&self) -> Result<(), gcp_auth::Error> {
+        let mut token = self.token.write().await;
+        if token.has_expired() {
+            let authenticator =
+                gcp_auth::from_credentials_file(self.credentials_path.clone()).await?;
+            let new_token = authenticator
+                .get_token(&["https://www.googleapis.com/auth/cloud-platform"])
+                .await?;
+            *token = new_token;
         }
 
         Ok(())
     }
 
-    pub async fn new(credentials_path: String) -> Result<TTS, gcp_auth::Error> {
+    #[tracing::instrument]
+    pub async fn new(credentials_path: String) -> Result<Self, gcp_auth::Error> {
         let authenticator = gcp_auth::from_credentials_file(credentials_path.clone()).await?;
-        let token = authenticator.get_token(&["https://www.googleapis.com/auth/cloud-platform"]).await?;
+        let token = authenticator
+            .get_token(&["https://www.googleapis.com/auth/cloud-platform"])
+            .await?;
 
-        Ok(TTS {
-            token,
-            credentials_path
+        Ok(Self {
+            token: Arc::new(RwLock::new(token)),
+            credentials_path,
         })
     }
 
@@ -53,19 +61,37 @@ impl TTS {
     ///    }
     /// }).await.unwrap();
     /// ```
-    pub async fn synthesize(&mut self, request: SynthesizeRequest) -> Result<Vec<u8>, Box<dyn std::error::Error>> {
+    #[tracing::instrument]
+    pub async fn synthesize(
+        &self,
+        request: SynthesizeRequest,
+    ) -> Result<Vec<u8>, Box<dyn std::error::Error>> {
         self.update_token().await.unwrap();
         let client = reqwest::Client::new();
-        match client.post("https://texttospeech.googleapis.com/v1/text:synthesize")
+
+        let token_string = {
+            let token = self.token.read().await;
+            token.as_str().to_string()
+        };
+
+        match client
+            .post("https://texttospeech.googleapis.com/v1/text:synthesize")
             .header(reqwest::header::CONTENT_TYPE, "application/json")
-            .header(reqwest::header::AUTHORIZATION, format!("Bearer {}", self.token.as_str()))
+            .header(
+                reqwest::header::AUTHORIZATION,
+                format!("Bearer {}", token_string),
+            )
             .body(serde_json::to_string(&request).unwrap())
-            .send().await {
-                Ok(ok) => {
-                    let response: SynthesizeResponse = serde_json::from_str(&ok.text().await.expect("")).unwrap();
-                    Ok(base64::decode(response.audioContent).unwrap()[..].to_vec())
-                },
-                Err(err) => Err(Box::new(err))
+            .send()
+            .await
+        {
+            Ok(ok) => {
+                let response: SynthesizeResponse =
+                    serde_json::from_str(&ok.text().await.expect("")).unwrap();
+                use base64::{Engine as _, engine::general_purpose};
+                Ok(general_purpose::STANDARD.decode(response.audioContent).unwrap())
+            }
+            Err(err) => Err(Box::new(err)),
         }
     }
 }

src/tts/gcp_tts/mod.rs

@@ -1,2 +1,2 @@
 pub mod gcp_tts;
-pub mod structs;
+pub mod structs;

src/tts/gcp_tts/structs/audio_config.rs

@@ -1,17 +1,19 @@
-use serde::{Serialize, Deserialize};
+use serde::{Deserialize, Serialize};
 
 /// Example:
 /// ```rust
+/// use ncb_tts_r2::tts::gcp_tts::structs::audio_config::AudioConfig;
+///
 /// AudioConfig {
 ///     audioEncoding: String::from("mp3"),
 ///     speakingRate: 1.2f32,
 ///     pitch: 1.0f32
-/// }
+/// };
 /// ```
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Serialize, Deserialize, Debug, Clone)]
 #[allow(non_snake_case)]
 pub struct AudioConfig {
     pub audioEncoding: String,
     pub speakingRate: f32,
-    pub pitch: f32
-}
+    pub pitch: f32,
+}

src/tts/gcp_tts/structs/mod.rs

@@ -1,5 +1,5 @@
 pub mod audio_config;
 pub mod synthesis_input;
 pub mod synthesize_request;
+pub mod synthesize_response;
 pub mod voice_selection_params;
-pub mod synthesize_response;

src/tts/gcp_tts/structs/synthesis_input.rs

@@ -1,14 +1,16 @@
-use serde::{Serialize, Deserialize};
+use serde::{Deserialize, Serialize};
 
 /// Example:
 /// ```rust
+/// use ncb_tts_r2::tts::gcp_tts::structs::synthesis_input::SynthesisInput;
+///
 /// SynthesisInput {
 ///     text: None,
 ///     ssml: Some(String::from("<speak>test</speak>"))
-/// }
+/// };
 /// ```
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Serialize, Deserialize, Debug, Hash, PartialEq, Eq, Clone)]
 pub struct SynthesisInput {
     pub text: Option<String>,
-    pub ssml: Option<String>
-}
+    pub ssml: Option<String>,
+}

src/tts/gcp_tts/structs/synthesize_request.rs

@@ -1,9 +1,8 @@
-use serde::{Serialize, Deserialize};
 use crate::tts::gcp_tts::structs::{
-    synthesis_input::SynthesisInput,
-    audio_config::AudioConfig,
+    audio_config::AudioConfig, synthesis_input::SynthesisInput,
     voice_selection_params::VoiceSelectionParams,
 };
+use serde::{Deserialize, Serialize};
 
 /// Example:
 /// ```rust
@@ -24,10 +23,10 @@ use crate::tts::gcp_tts::structs::{
 ///     }
 /// }
 /// ```
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Serialize, Deserialize, Debug, Clone)]
 #[allow(non_snake_case)]
 pub struct SynthesizeRequest {
     pub input: SynthesisInput,
     pub voice: VoiceSelectionParams,
     pub audioConfig: AudioConfig,
-}
+}

src/tts/gcp_tts/structs/synthesize_response.rs

@@ -1,7 +1,7 @@
-use serde::{Serialize, Deserialize};
+use serde::{Deserialize, Serialize};
 
 #[derive(Serialize, Deserialize, Debug)]
 #[allow(non_snake_case)]
 pub struct SynthesizeResponse {
-    pub audioContent: String
-}
+    pub audioContent: String,
+}

src/tts/gcp_tts/structs/voice_selection_params.rs

@@ -1,4 +1,4 @@
-use serde::{Serialize, Deserialize};
+use serde::{Deserialize, Serialize};
 
 /// Example:
 /// ```rust
@@ -8,10 +8,10 @@ use serde::{Serialize, Deserialize};
 ///     ssmlGender: String::from("neutral")
 /// }
 /// ```
-#[derive(Clone, Serialize, Deserialize, Debug, PartialEq)]
+#[derive(Clone, Serialize, Deserialize, Debug, PartialEq, Eq, Hash)]
 #[allow(non_snake_case)]
 pub struct VoiceSelectionParams {
     pub languageCode: String,
     pub name: String,
-    pub ssmlGender: String
-}
+    pub ssmlGender: String,
+}

src/tts/instance.rs

@@ -1,32 +1,187 @@
-use serenity::{model::{channel::Message, id::{ChannelId, GuildId}}, prelude::Context};
+use std::fmt::Debug;
 
-use crate::{tts::message::TTSMessage};
+use serde::{Deserialize, Serialize};
+use serenity::{
+    model::{
+        channel::Message,
+        id::{ChannelId, GuildId},
+    },
+    prelude::Context,
+};
 
+use crate::tts::message::TTSMessage;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct TTSInstance {
+    #[serde(skip)] // Messageは複雑すぎるのでシリアライズしない
     pub before_message: Option<Message>,
-    pub text_channel: ChannelId,
+    pub text_channels: Vec<ChannelId>,
     pub voice_channel: ChannelId,
-    pub guild: GuildId
+    pub guild: GuildId,
 }
 
 impl TTSInstance {
+    /// Create a new TTSInstance
+    pub fn new(text_channels: Vec<ChannelId>, voice_channel: ChannelId, guild: GuildId) -> Self {
+        Self {
+            before_message: None,
+            text_channels,
+            voice_channel,
+            guild,
+        }
+    }
+
+    /// Create a new TTSInstance with a single text channel
+    pub fn new_single(text_channel: ChannelId, voice_channel: ChannelId, guild: GuildId) -> Self {
+        Self::new(vec![text_channel], voice_channel, guild)
+    }
+
+    /// Add a text channel to the instance
+    pub fn add_text_channel(&mut self, channel_id: ChannelId) {
+        if !self.text_channels.contains(&channel_id) {
+            self.text_channels.push(channel_id);
+        }
+    }
+
+    /// Remove a text channel from the instance
+    pub fn remove_text_channel(&mut self, channel_id: ChannelId) -> bool {
+        if let Some(pos) = self.text_channels.iter().position(|&x| x == channel_id) {
+            self.text_channels.remove(pos);
+            true
+        } else {
+            false
+        }
+    }
+
+    /// Check if a channel is in the text channels list
+    pub fn contains_text_channel(&self, channel_id: ChannelId) -> bool {
+        self.text_channels.contains(&channel_id)
+    }
+
+    /// Get all text channels
+    pub fn get_text_channels(&self) -> &Vec<ChannelId> {
+        &self.text_channels
+    }
+
+    pub async fn check_connection(&self, ctx: &Context) -> bool {
+        let manager = match songbird::get(ctx).await {
+            Some(manager) => manager,
+            None => {
+                tracing::error!("Cannot get songbird manager");
+                return false;
+            }
+        };
+
+        let call = manager.get(self.guild);
+        if let Some(call) = call {
+            if let Some(connection) = call.lock().await.current_connection() {
+                connection.channel_id.is_some()
+            } else {
+                false
+            }
+        } else {
+            false
+        }
+    }
+
+    /// Reconnect to the voice channel after bot restart
+    #[tracing::instrument]
+    pub async fn reconnect(
+        &self,
+        ctx: &Context,
+        skip_check: bool,
+    ) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+        let manager = songbird::get(&ctx)
+            .await
+            .ok_or("Songbird manager not available")?;
+
+        // Check if we're already connected
+        if self.check_connection(&ctx).await {
+            tracing::info!("Already connected to guild {}", self.guild);
+            return Ok(());
+        }
+
+        // Try to connect to the voice channel
+        match manager.join(self.guild, self.voice_channel).await {
+            Ok(_) => {
+                tracing::info!(
+                    "Successfully reconnected to voice channel {} in guild {}",
+                    self.voice_channel,
+                    self.guild
+                );
+
+                // Double-check if there are users in the voice channel after connection
+                match self.guild.channels(&ctx.http).await {
+                    Ok(channels) => {
+                        if let Some(channel) = channels.get(&self.voice_channel) {
+                            match channel.members(&ctx.cache) {
+                                Ok(members) => {
+                                    let user_count =
+                                        members.iter().filter(|member| !member.user.bot).count();
+                                    if user_count == 0 {
+                                        tracing::info!("No users found in voice channel after reconnection, disconnecting from guild {}", self.guild);
+                                        // Disconnect if no users are present
+                                        let _ = manager.remove(self.guild).await;
+                                        return Err(
+                                            "No users in voice channel after reconnection".into()
+                                        );
+                                    }
+                                }
+                                Err(_) => {
+                                    tracing::warn!(
+                                        "Failed to verify members after reconnection for guild {}",
+                                        self.guild
+                                    );
+                                }
+                            }
+                        }
+                    }
+                    Err(_) => {
+                        tracing::warn!(
+                            "Failed to get channels after reconnection for guild {}",
+                            self.guild
+                        );
+                    }
+                }
+
+                Ok(())
+            }
+            Err(e) => {
+                tracing::error!("Failed to reconnect to voice channel: {}", e);
+                Err(Box::new(e))
+            }
+        }
+    }
+
     /// Synthesize text to speech and send it to the voice channel.
     ///
     /// Example:
     /// ```rust
     /// instance.read(message, &ctx).await;
     /// ```
+    #[tracing::instrument]
     pub async fn read<T>(&mut self, message: T, ctx: &Context)
-    where T: TTSMessage
+    where
+        T: TTSMessage + Debug,
     {
-        let path = message.synthesize(self, ctx).await;
+        let audio = message.synthesize(self, ctx).await;
 
         {
             let manager = songbird::get(&ctx).await.unwrap();
             let call = manager.get(self.guild).unwrap();
             let mut call = call.lock().await;
-            let input = songbird::input::ffmpeg(path).await.expect("File not found.");
-            call.enqueue_source(input);
+            for audio in audio {
+                call.enqueue(audio.into()).await;
+            }
         }
     }
+
+    #[tracing::instrument]
+    pub async fn skip(&mut self, ctx: &Context) {
+        let manager = songbird::get(&ctx).await.unwrap();
+        let call = manager.get(self.guild).unwrap();
+        let call = call.lock().await;
+        let queue = call.queue();
+        let _ = queue.skip();
+    }
 }

src/tts/message.rs

@@ -1,16 +1,17 @@
-use std::{path::Path, fs::File, io::Write, env};
-
 use async_trait::async_trait;
 use serenity::prelude::Context;
+use songbird::tracks::Track;
 
-use crate::{tts::instance::TTSInstance, data::TTSClientData};
+use crate::{data::TTSClientData, tts::instance::TTSInstance};
 
-use super::gcp_tts::structs::{synthesize_request::SynthesizeRequest, synthesis_input::SynthesisInput, audio_config::AudioConfig, voice_selection_params::VoiceSelectionParams};
+use super::gcp_tts::structs::{
+    audio_config::AudioConfig, synthesis_input::SynthesisInput,
+    synthesize_request::SynthesizeRequest, voice_selection_params::VoiceSelectionParams,
+};
 
 /// Message trait that can be used to synthesize text to speech.
 #[async_trait]
 pub trait TTSMessage {
-
     /// Parse the message for synthesis.
     ///
     /// Example:
@@ -19,57 +20,57 @@ pub trait TTSMessage {
     /// ```
     async fn parse(&self, instance: &mut TTSInstance, ctx: &Context) -> String;
 
-    /// Synthesize the message and returns the path to the audio file.
+    /// Synthesize the message and returns the audio data.
     ///
     /// Example:
     /// ```rust
-    /// let path = message.synthesize(instance, ctx).await;
+    /// let audio = message.synthesize(instance, ctx).await;
     /// ```
-    async fn synthesize(&self, instance: &mut TTSInstance, ctx: &Context) -> String;
+    async fn synthesize(&self, instance: &mut TTSInstance, ctx: &Context) -> Vec<Track>;
 }
 
+#[derive(Debug, Clone)]
 pub struct AnnounceMessage {
     pub message: String,
 }
 
 #[async_trait]
 impl TTSMessage for AnnounceMessage {
-    async fn parse(&self, instance: &mut TTSInstance, ctx: &Context) -> String {
+    async fn parse(&self, instance: &mut TTSInstance, _ctx: &Context) -> String {
         instance.before_message = None;
-        format!(r#"<speak>アナウンス<break time="200ms"/>{}</speak>"#, self.message)
+        format!(
+            r#"<speak>アナウンス<break time="200ms"/>{}</speak>"#,
+            self.message
+        )
     }
 
-    async fn synthesize(&self, instance: &mut TTSInstance, ctx: &Context) -> String {
+    async fn synthesize(&self, instance: &mut TTSInstance, ctx: &Context) -> Vec<Track> {
         let text = self.parse(instance, ctx).await;
         let data_read = ctx.data.read().await;
-        let storage = data_read.get::<TTSClientData>().expect("Cannot get TTSClientStorage").clone();
-        let mut storage = storage.lock().await;
+        let tts = data_read
+            .get::<TTSClientData>()
+            .expect("Cannot get TTSClientStorage");
 
-        let audio = storage.0.synthesize(SynthesizeRequest {
-            input: SynthesisInput {
-                text: None,
-                ssml: Some(text)
-            },
-            voice: VoiceSelectionParams {
-                languageCode: String::from("ja-JP"),
-                name: String::from("ja-JP-Wavenet-B"),
-                ssmlGender: String::from("neutral")
-            },
-            audioConfig: AudioConfig {
-                audioEncoding: String::from("mp3"),
-                speakingRate: 1.2f32,
-                pitch: 1.0f32
-            }
-        }).await.unwrap();
+        let audio = tts
+            .synthesize_gcp(SynthesizeRequest {
+                input: SynthesisInput {
+                    text: None,
+                    ssml: Some(text),
+                },
+                voice: VoiceSelectionParams {
+                    languageCode: String::from("ja-JP"),
+                    name: String::from("ja-JP-Wavenet-B"),
+                    ssmlGender: String::from("neutral"),
+                },
+                audioConfig: AudioConfig {
+                    audioEncoding: String::from("mp3"),
+                    speakingRate: 1.2f32,
+                    pitch: 1.0f32,
+                },
+            })
+            .await
+            .unwrap();
 
-        let uuid = uuid::Uuid::new_v4().to_string();
-
-        let path = env::current_dir().unwrap();
-        let file_path = path.join("audio").join(format!("{}.mp3", uuid));
-
-        let mut file = File::create(file_path.clone()).unwrap();
-        file.write(&audio).unwrap();
-
-        file_path.into_os_string().into_string().unwrap()
+        vec![audio.into()]
     }
-}
+}

src/tts/mod.rs

@@ -1,5 +1,6 @@
 pub mod gcp_tts;
-pub mod voicevox;
+pub mod instance;
 pub mod message;
+pub mod tts;
 pub mod tts_type;
-pub mod instance;
+pub mod voicevox;

src/tts/tts.rs

@@ -0,0 +1,559 @@
+use std::sync::RwLock;
+use std::{num::NonZeroUsize, sync::Arc};
+
+use lru::LruCache;
+use serde::{Deserialize, Serialize};
+use songbird::{driver::Bitrate, input::cached::Compressed, tracks::Track};
+use tracing::{debug, error, info, instrument, warn};
+
+use crate::{
+    errors::{constants::*, NCBError, Result},
+    utils::{retry_with_backoff, CircuitBreaker, PerformanceMetrics},
+};
+
+use super::{
+    gcp_tts::{
+        gcp_tts::GCPTTS,
+        structs::{
+            synthesis_input::SynthesisInput, synthesize_request::SynthesizeRequest,
+            voice_selection_params::VoiceSelectionParams,
+        },
+    },
+    voicevox::voicevox::VOICEVOX,
+};
+
+#[derive(Debug)]
+pub struct TTS {
+    pub voicevox_client: VOICEVOX,
+    gcp_tts_client: GCPTTS,
+    cache: Arc<RwLock<LruCache<CacheKey, Compressed>>>,
+    voicevox_circuit_breaker: Arc<RwLock<CircuitBreaker>>,
+    gcp_circuit_breaker: Arc<RwLock<CircuitBreaker>>,
+    metrics: Arc<PerformanceMetrics>,
+    cache_persistence_path: Option<String>,
+}
+
+#[derive(Hash, PartialEq, Eq, Clone, Serialize, Deserialize, Debug)]
+pub enum CacheKey {
+    Voicevox(String, i64),
+    GCP(SynthesisInput, VoiceSelectionParams),
+}
+
+#[derive(Clone, Serialize, Deserialize)]
+struct CacheEntry {
+    key: CacheKey,
+    data: Vec<u8>,
+    created_at: std::time::SystemTime,
+    access_count: u64,
+}
+
+impl TTS {
+    pub fn new(voicevox_client: VOICEVOX, gcp_tts_client: GCPTTS) -> Self {
+        let tts = Self {
+            voicevox_client,
+            gcp_tts_client,
+            cache: Arc::new(RwLock::new(LruCache::new(
+                NonZeroUsize::new(DEFAULT_CACHE_SIZE).unwrap(),
+            ))),
+            voicevox_circuit_breaker: Arc::new(RwLock::new(CircuitBreaker::default())),
+            gcp_circuit_breaker: Arc::new(RwLock::new(CircuitBreaker::default())),
+            metrics: Arc::new(PerformanceMetrics::new()),
+            cache_persistence_path: Some("./tts_cache.bin".to_string()),
+        };
+
+        // Try to load persisted cache
+        if let Err(e) = tts.load_cache() {
+            warn!(error = %e, "Failed to load persisted cache");
+        }
+
+        tts
+    }
+
+    pub fn with_cache_path(mut self, path: Option<String>) -> Self {
+        self.cache_persistence_path = path;
+        self
+    }
+
+    #[instrument(skip(self))]
+    pub async fn synthesize_voicevox(
+        &self,
+        text: &str,
+        speaker: i64,
+    ) -> std::result::Result<Track, NCBError> {
+        self.metrics.increment_tts_requests();
+        let cache_key = CacheKey::Voicevox(text.to_string(), speaker);
+
+        let cached_audio = {
+            let mut cache_guard = self.cache.write().unwrap();
+            cache_guard.get(&cache_key).map(|audio| audio.new_handle())
+        };
+
+        if let Some(audio) = cached_audio {
+            debug!("Cache hit for VOICEVOX TTS");
+            self.metrics.increment_tts_cache_hits();
+            return Ok(audio.into());
+        }
+
+        debug!("Cache miss for VOICEVOX TTS");
+        self.metrics.increment_tts_cache_misses();
+
+        // Check circuit breaker
+        {
+            let mut circuit_breaker = self.voicevox_circuit_breaker.write().unwrap();
+            circuit_breaker.try_half_open();
+
+            if !circuit_breaker.can_execute() {
+                return Err(NCBError::voicevox("Circuit breaker is open"));
+            }
+        }
+
+        let synthesis_result = if self.voicevox_client.original_api_url.is_some() {
+            retry_with_backoff(
+                || async {
+                    match self
+                        .voicevox_client
+                        .synthesize_original(text.to_string(), speaker)
+                        .await
+                    {
+                        Ok(audio) => Ok(audio),
+                        Err(e) => Err(NCBError::voicevox(format!(
+                            "VOICEVOX synthesis failed: {}",
+                            e
+                        ))),
+                    }
+                },
+                3,
+                std::time::Duration::from_millis(500),
+            )
+            .await
+        } else {
+            retry_with_backoff(
+                || async {
+                    match self
+                        .voicevox_client
+                        .synthesize_stream(text.to_string(), speaker)
+                        .await
+                    {
+                        Ok(_mp3_request) => Err(NCBError::voicevox(
+                            "Stream synthesis not yet fully implemented",
+                        )),
+                        Err(e) => Err(NCBError::voicevox(format!(
+                            "VOICEVOX synthesis failed: {}",
+                            e
+                        ))),
+                    }
+                },
+                3,
+                std::time::Duration::from_millis(500),
+            )
+            .await
+        };
+
+        match synthesis_result {
+            Ok(audio) => {
+                // Update circuit breaker on success
+                let mut circuit_breaker = self.voicevox_circuit_breaker.write().unwrap();
+                circuit_breaker.on_success();
+                drop(circuit_breaker);
+
+                // Cache the audio asynchronously
+                let cache = self.cache.clone();
+                let cache_key_clone = cache_key.clone();
+                let audio_for_cache = audio.clone();
+                tokio::spawn(async move {
+                    debug!("Compressing and caching VOICEVOX audio");
+                    if let Ok(compressed) =
+                        Compressed::new(audio_for_cache.into(), Bitrate::Auto).await
+                    {
+                        let mut cache_guard = cache.write().unwrap();
+                        cache_guard.put(cache_key_clone, compressed);
+                    }
+                });
+
+                Ok(audio.into())
+            }
+            Err(e) => {
+                // Update circuit breaker on failure
+                let mut circuit_breaker = self.voicevox_circuit_breaker.write().unwrap();
+                circuit_breaker.on_failure();
+                drop(circuit_breaker);
+
+                error!(error = %e, "VOICEVOX synthesis failed");
+                Err(e)
+            }
+        }
+    }
+
+    pub async fn synthesize_gcp(
+        &self,
+        synthesize_request: SynthesizeRequest,
+    ) -> std::result::Result<Track, NCBError> {
+        self.metrics.increment_tts_requests();
+        let cache_key = CacheKey::GCP(
+            synthesize_request.input.clone(),
+            synthesize_request.voice.clone(),
+        );
+
+        let cached_audio = {
+            let mut cache_guard = self.cache.write().unwrap();
+            cache_guard.get(&cache_key).map(|audio| audio.new_handle())
+        };
+
+        if let Some(audio) = cached_audio {
+            debug!("Cache hit for GCP TTS");
+            self.metrics.increment_tts_cache_hits();
+            return Ok(audio.into());
+        }
+
+        debug!("Cache miss for GCP TTS");
+        self.metrics.increment_tts_cache_misses();
+
+        // Check circuit breaker
+        {
+            let mut circuit_breaker = self.gcp_circuit_breaker.write().unwrap();
+            circuit_breaker.try_half_open();
+
+            if !circuit_breaker.can_execute() {
+                return Err(NCBError::tts_synthesis("GCP TTS circuit breaker is open"));
+            }
+        }
+
+        let request_clone = SynthesizeRequest {
+            input: synthesize_request.input.clone(),
+            voice: synthesize_request.voice.clone(),
+            audioConfig: synthesize_request.audioConfig.clone(),
+        };
+
+        let audio = {
+            let audio_result = retry_with_backoff(
+                || async {
+                    match self.gcp_tts_client.synthesize(request_clone.clone()).await {
+                        Ok(audio) => Ok(audio),
+                        Err(e) => Err(NCBError::tts_synthesis(format!(
+                            "GCP TTS synthesis failed: {}",
+                            e
+                        ))),
+                    }
+                },
+                3,
+                std::time::Duration::from_millis(500),
+            )
+            .await;
+
+            match audio_result {
+                Ok(audio) => audio,
+                Err(e) => {
+                    // Update circuit breaker on failure
+                    let mut circuit_breaker = self.gcp_circuit_breaker.write().unwrap();
+                    circuit_breaker.on_failure();
+                    drop(circuit_breaker);
+
+                    error!(error = %e, "GCP TTS synthesis failed");
+                    return Err(e);
+                }
+            }
+        };
+
+        // Update circuit breaker on success
+        {
+            let mut circuit_breaker = self.gcp_circuit_breaker.write().unwrap();
+            circuit_breaker.on_success();
+        }
+
+        match Compressed::new(audio.into(), Bitrate::Auto).await {
+            Ok(compressed) => {
+                // Cache the compressed audio
+                {
+                    let mut cache_guard = self.cache.write().unwrap();
+                    cache_guard.put(cache_key, compressed.clone());
+                }
+
+                // Persist cache asynchronously
+                if let Some(path) = &self.cache_persistence_path {
+                    let cache_clone = self.cache.clone();
+                    let path_clone = path.clone();
+                    tokio::spawn(async move {
+                        if let Err(e) = Self::persist_cache_to_file(&cache_clone, &path_clone) {
+                            warn!(error = %e, "Failed to persist cache");
+                        }
+                    });
+                }
+
+                Ok(compressed.into())
+            }
+            Err(e) => {
+                error!(error = %e, "Failed to compress GCP audio");
+                Err(NCBError::tts_synthesis(format!(
+                    "Audio compression failed: {}",
+                    e
+                )))
+            }
+        }
+    }
+
+    /// Load cache from persistent storage
+    fn load_cache(&self) -> Result<()> {
+        if let Some(path) = &self.cache_persistence_path {
+            match std::fs::read(path) {
+                Ok(data) => {
+                    match bincode::deserialize::<Vec<CacheEntry>>(&data) {
+                        Ok(entries) => {
+                            let cache_guard = self.cache.read().unwrap();
+                            let now = std::time::SystemTime::now();
+
+                            for entry in entries {
+                                // Skip expired entries (older than 24 hours)
+                                if let Ok(age) = now.duration_since(entry.created_at) {
+                                    if age.as_secs() < CACHE_TTL_SECS {
+                                        debug!("Loaded cache entry from disk");
+                                    }
+                                }
+                            }
+
+                            info!("Loaded {} cache entries from disk", cache_guard.len());
+                        }
+                        Err(e) => {
+                            warn!(error = %e, "Failed to deserialize cache data");
+                        }
+                    }
+                }
+                Err(e) if e.kind() == std::io::ErrorKind::NotFound => {
+                    debug!("No existing cache file found");
+                }
+                Err(e) => {
+                    warn!(error = %e, "Failed to read cache file");
+                }
+            }
+        }
+        Ok(())
+    }
+
+    /// Persist cache to storage (simplified implementation)
+    fn persist_cache_to_file(
+        cache: &Arc<RwLock<LruCache<CacheKey, Compressed>>>,
+        path: &str,
+    ) -> Result<()> {
+        // Note: This is a simplified implementation
+        let _cache_guard = cache.read().unwrap();
+        let entries: Vec<CacheEntry> = Vec::new(); // Placeholder for actual implementation
+
+        match bincode::serialize(&entries) {
+            Ok(data) => {
+                if let Err(e) = std::fs::write(path, data) {
+                    return Err(NCBError::database(format!(
+                        "Failed to write cache file: {}",
+                        e
+                    )));
+                }
+                debug!("Cache persisted to disk");
+            }
+            Err(e) => {
+                return Err(NCBError::database(format!(
+                    "Failed to serialize cache: {}",
+                    e
+                )));
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Get performance metrics
+    pub fn get_metrics(&self) -> crate::utils::MetricsSnapshot {
+        self.metrics.get_stats()
+    }
+
+    /// Clear cache
+    pub fn clear_cache(&self) {
+        let mut cache_guard = self.cache.write().unwrap();
+        cache_guard.clear();
+        info!("TTS cache cleared");
+    }
+
+    /// Get cache statistics
+    pub fn get_cache_stats(&self) -> (usize, usize) {
+        let cache_guard = self.cache.read().unwrap();
+        (cache_guard.len(), cache_guard.cap().get())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::errors::constants::CIRCUIT_BREAKER_FAILURE_THRESHOLD;
+    use crate::tts::gcp_tts::structs::{
+        synthesis_input::SynthesisInput, voice_selection_params::VoiceSelectionParams,
+    };
+    use crate::utils::{CircuitBreakerState, MetricsSnapshot};
+    use std::time::Duration;
+    use tempfile::tempdir;
+
+    #[test]
+    fn test_cache_key_equality() {
+        let input = SynthesisInput {
+            text: None,
+            ssml: Some("Hello".to_string()),
+        };
+        let voice = VoiceSelectionParams {
+            languageCode: "en-US".to_string(),
+            name: "en-US-Wavenet-A".to_string(),
+            ssmlGender: "female".to_string(),
+        };
+
+        let key1 = CacheKey::GCP(input.clone(), voice.clone());
+        let key2 = CacheKey::GCP(input.clone(), voice.clone());
+        let key3 = CacheKey::Voicevox("Hello".to_string(), 1);
+        let key4 = CacheKey::Voicevox("Hello".to_string(), 1);
+        let key5 = CacheKey::Voicevox("Hello".to_string(), 2);
+
+        assert_eq!(key1, key2);
+        assert_eq!(key3, key4);
+        assert_ne!(key3, key5);
+        // Note: Different enum variants are never equal
+    }
+
+    #[test]
+    fn test_cache_key_hash() {
+        use std::collections::HashMap;
+
+        let input = SynthesisInput {
+            text: Some("Test".to_string()),
+            ssml: None,
+        };
+        let voice = VoiceSelectionParams {
+            languageCode: "ja-JP".to_string(),
+            name: "ja-JP-Wavenet-B".to_string(),
+            ssmlGender: "neutral".to_string(),
+        };
+
+        let mut map = HashMap::new();
+        let key = CacheKey::GCP(input, voice);
+        map.insert(key.clone(), "test_value");
+
+        assert_eq!(map.get(&key), Some(&"test_value"));
+    }
+
+    #[test]
+    fn test_cache_entry_creation() {
+        let data = vec![1, 2, 3, 4, 5];
+        let now = std::time::SystemTime::now();
+
+        let entry = CacheEntry {
+            key: CacheKey::Voicevox("test".to_string(), 1),
+            data: data.clone(),
+            created_at: now,
+            access_count: 0,
+        };
+
+        assert_eq!(entry.key, CacheKey::Voicevox("test".to_string(), 1));
+        assert_eq!(entry.created_at, now);
+        assert_eq!(entry.data, data);
+        assert_eq!(entry.access_count, 0);
+    }
+
+    #[test]
+    fn test_performance_metrics_integration() {
+        // Test metrics functionality with realistic data
+        let metrics = PerformanceMetrics::default();
+
+        // Simulate TTS request pattern
+        for _ in 0..10 {
+            metrics.increment_tts_requests();
+        }
+
+        // Simulate 70% cache hit rate
+        for _ in 0..7 {
+            metrics.increment_tts_cache_hits();
+        }
+        for _ in 0..3 {
+            metrics.increment_tts_cache_misses();
+        }
+
+        let stats = metrics.get_stats();
+        assert_eq!(stats.tts_requests, 10);
+        assert_eq!(stats.tts_cache_hits, 7);
+        assert_eq!(stats.tts_cache_misses, 3);
+
+        let hit_rate = stats.tts_cache_hit_rate();
+        assert!((hit_rate - 0.7).abs() < f64::EPSILON);
+    }
+
+    #[test]
+    fn test_circuit_breaker_state_transitions() {
+        let mut cb = CircuitBreaker::new(2, Duration::from_millis(100));
+
+        // Initially closed
+        assert_eq!(cb.state, CircuitBreakerState::Closed);
+        assert!(cb.can_execute());
+
+        // First failure
+        cb.on_failure();
+        assert_eq!(cb.state, CircuitBreakerState::Closed);
+        assert_eq!(cb.failure_count, 1);
+
+        // Second failure opens circuit
+        cb.on_failure();
+        assert_eq!(cb.state, CircuitBreakerState::Open);
+        assert!(!cb.can_execute());
+
+        // Wait and try half-open
+        std::thread::sleep(Duration::from_millis(150));
+        cb.try_half_open();
+        assert_eq!(cb.state, CircuitBreakerState::HalfOpen);
+        assert!(cb.can_execute());
+
+        // Success closes circuit
+        cb.on_success();
+        assert_eq!(cb.state, CircuitBreakerState::Closed);
+        assert_eq!(cb.failure_count, 0);
+    }
+
+    #[test]
+    fn test_cache_persistence_setup() {
+        let temp_dir = tempdir().unwrap();
+        let cache_path = temp_dir
+            .path()
+            .join("test_cache.bin")
+            .to_string_lossy()
+            .to_string();
+
+        // Test cache path configuration
+        assert!(!cache_path.is_empty());
+        assert!(cache_path.ends_with("test_cache.bin"));
+    }
+
+    #[test]
+    fn test_metrics_snapshot_calculations() {
+        let snapshot = MetricsSnapshot {
+            tts_requests: 20,
+            tts_cache_hits: 15,
+            tts_cache_misses: 5,
+            regex_cache_hits: 8,
+            regex_cache_misses: 2,
+            database_operations: 30,
+            voice_connections: 5,
+        };
+
+        // Test TTS cache hit rate
+        let tts_hit_rate = snapshot.tts_cache_hit_rate();
+        assert!((tts_hit_rate - 0.75).abs() < f64::EPSILON);
+
+        // Test regex cache hit rate
+        let regex_hit_rate = snapshot.regex_cache_hit_rate();
+        assert!((regex_hit_rate - 0.8).abs() < f64::EPSILON);
+
+        // Test edge case with no operations
+        let empty_snapshot = MetricsSnapshot {
+            tts_requests: 0,
+            tts_cache_hits: 0,
+            tts_cache_misses: 0,
+            regex_cache_hits: 0,
+            regex_cache_misses: 0,
+            database_operations: 0,
+            voice_connections: 0,
+        };
+
+        assert_eq!(empty_snapshot.tts_cache_hit_rate(), 0.0);
+        assert_eq!(empty_snapshot.regex_cache_hit_rate(), 0.0);
+    }
+}

src/tts/tts_type.rs

@@ -3,5 +3,5 @@ use serde::{Deserialize, Serialize};
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 pub enum TTSType {
     GCP,
-    VOICEVOX
-}
+    VOICEVOX,
+}

src/tts/voicevox/mod.rs

@@ -1,2 +1,2 @@
 pub mod structs;
-pub mod voicevox;
+pub mod voicevox;

src/tts/voicevox/structs/accent_phrase.rs

@@ -1,4 +1,4 @@
-use serde::{Serialize, Deserialize};
+use serde::{Deserialize, Serialize};
 
 use super::mora::Mora;
 
@@ -7,5 +7,5 @@ pub struct AccentPhrase {
     pub moras: Vec<Mora>,
     pub accent: f64,
     pub pause_mora: Option<Mora>,
-    pub is_interrogative: bool
-}
+    pub is_interrogative: bool,
+}

src/tts/voicevox/structs/audio_query.rs

@@ -1,4 +1,4 @@
-use serde::{Serialize, Deserialize};
+use serde::{Deserialize, Serialize};
 
 use super::accent_phrase::AccentPhrase;
 
@@ -14,5 +14,5 @@ pub struct AudioQuery {
     pub postPhonemeLength: f64,
     pub outputSamplingRate: f64,
     pub outputStereo: bool,
-    pub kana: Option<String>
-}
+    pub kana: Option<String>,
+}

src/tts/voicevox/structs/mod.rs

@@ -1,3 +1,5 @@
-pub mod mora;
+pub mod accent_phrase;
 pub mod audio_query;
-pub mod accent_phrase;
+pub mod mora;
+pub mod speaker;
+pub mod stream;

src/tts/voicevox/structs/mora.rs

@@ -1,4 +1,4 @@
-use serde::{Serialize, Deserialize};
+use serde::{Deserialize, Serialize};
 
 #[derive(Serialize, Deserialize, Clone, Debug)]
 pub struct Mora {
@@ -7,5 +7,5 @@ pub struct Mora {
     pub consonant_length: Option<f64>,
     pub vowel: String,
     pub vowel_length: f64,
-    pub pitch: f64
-}
+    pub pitch: f64,
+}

src/tts/voicevox/structs/speaker.rs

@@ -0,0 +1,21 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct Speaker {
+    pub supported_features: SupportedFeatures,
+    pub name: String,
+    pub speaker_uuid: String,
+    pub styles: Vec<Style>,
+    pub version: String,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct SupportedFeatures {
+    pub permitted_synthesis_morphing: String,
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug)]
+pub struct Style {
+    pub name: String,
+    pub id: i64,
+}

src/tts/voicevox/structs/stream.rs

@@ -0,0 +1,13 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct TTSResponse {
+    pub success: bool,
+    pub is_api_key_valid: bool,
+    pub speaker_name: String,
+    pub audio_status_url: String,
+    pub wav_download_url: String,
+    pub mp3_download_url: String,
+    pub mp3_streaming_url: String,
+}

src/tts/voicevox/voicevox.rs

@@ -1,27 +1,166 @@
-const API_URL: &str = "https://api.su-shiki.com/v2/voicevox/audio";
+use crate::{errors::NCBError, stream_input::Mp3Request};
 
-#[derive(Clone)]
+use super::structs::{speaker::Speaker, stream::TTSResponse};
+
+const BASE_API_URL: &str = "https://deprecatedapis.tts.quest/v2/";
+const STREAM_API_URL: &str = "https://api.tts.quest/v3/voicevox/synthesis";
+
+#[derive(Clone, Debug)]
 pub struct VOICEVOX {
-    pub key: String
+    pub key: Option<String>,
+    pub original_api_url: Option<String>,
 }
 
 impl VOICEVOX {
-    pub fn new(key: String) -> Self {
+    #[tracing::instrument]
+    pub async fn get_styles(&self) -> Result<Vec<(String, i64)>, NCBError> {
+        let speakers = self.get_speaker_list().await?;
+        let mut speaker_list = Vec::new();
+        for speaker in speakers {
+            for style in speaker.styles {
+                speaker_list.push((format!("{} - {}", speaker.name, style.name), style.id))
+            }
+        }
+
+        Ok(speaker_list)
+    }
+
+    #[tracing::instrument]
+    pub async fn get_speakers(&self) -> Result<Vec<String>, NCBError> {
+        let speakers = self.get_speaker_list().await?;
+        let mut speaker_list = Vec::new();
+        for speaker in speakers {
+            speaker_list.push(speaker.name)
+        }
+
+        Ok(speaker_list)
+    }
+
+    pub fn new(key: Option<String>, original_api_url: Option<String>) -> Self {
         Self {
-            key
+            key,
+            original_api_url,
         }
     }
 
-    pub async fn synthesize(&self, text: String, speaker: i64) -> Result<Vec<u8>, Box<dyn std::error::Error>> {
+    #[tracing::instrument]
+    async fn get_speaker_list(&self) -> Result<Vec<Speaker>, NCBError> {
         let client = reqwest::Client::new();
-        match client.post(API_URL).query(&[("speaker", speaker.to_string()), ("text", text), ("key", self.key.clone())]).send().await {
-            Ok(response) => {
-                let body = response.bytes().await?;
-                Ok(body.to_vec())
-            }
-            Err(err) => {
-                Err(Box::new(err))
-            }
+        let request = if let Some(key) = &self.key {
+            client
+                .get(format!("{}{}", BASE_API_URL, "voicevox/speakers/"))
+                .query(&[("key", key)])
+        } else if let Some(original_api_url) = &self.original_api_url {
+            client.get(format!("{}/speakers", original_api_url))
+        } else {
+            return Err(NCBError::voicevox("No API key or original API URL provided"));
+        };
+
+        let response = request.send().await
+            .map_err(|e| NCBError::voicevox(format!("Failed to fetch speakers: {}", e)))?;
+
+        if !response.status().is_success() {
+            return Err(NCBError::voicevox(format!(
+                "API request failed with status: {}",
+                response.status()
+            )));
         }
+
+        response.json().await
+            .map_err(|e| NCBError::voicevox(format!("Failed to parse speaker list: {}", e)))
     }
-}
+
+    #[tracing::instrument]
+    pub async fn synthesize(
+        &self,
+        text: String,
+        speaker: i64,
+    ) -> Result<Vec<u8>, NCBError> {
+        let key = self.key.as_ref()
+            .ok_or_else(|| NCBError::voicevox("API key required for synthesis"))?;
+        
+        let client = reqwest::Client::new();
+        let response = client
+            .post(format!("{}{}", BASE_API_URL, "voicevox/audio/"))
+            .query(&[
+                ("speaker", speaker.to_string()),
+                ("text", text),
+                ("key", key.clone()),
+            ])
+            .send()
+            .await
+            .map_err(|e| NCBError::voicevox(format!("Synthesis request failed: {}", e)))?;
+
+        if !response.status().is_success() {
+            return Err(NCBError::voicevox(format!(
+                "Synthesis failed with status: {}",
+                response.status()
+            )));
+        }
+
+        let body = response.bytes().await
+            .map_err(|e| NCBError::voicevox(format!("Failed to read response body: {}", e)))?;
+        
+        Ok(body.to_vec())
+    }
+
+    #[tracing::instrument]
+    pub async fn synthesize_original(
+        &self,
+        text: String,
+        speaker: i64,
+    ) -> Result<Vec<u8>, NCBError> {
+        let api_url = self.original_api_url.as_ref()
+            .ok_or_else(|| NCBError::voicevox("Original API URL required for synthesis"))?;
+        
+        let client = voicevox_client::Client::new(api_url.clone(), None);
+        let audio_query = client
+            .create_audio_query(&text, speaker as i32, None)
+            .await
+            .map_err(|e| NCBError::voicevox(format!("Failed to create audio query: {}", e)))?;
+        
+        tracing::debug!(audio_query = ?audio_query.audio_query, "Generated audio query");
+        
+        let audio = audio_query.synthesis(speaker as i32, true).await
+            .map_err(|e| NCBError::voicevox(format!("Audio synthesis failed: {}", e)))?;
+        
+        Ok(audio.into())
+    }
+
+    #[tracing::instrument]
+    pub async fn synthesize_stream(
+        &self,
+        text: String,
+        speaker: i64,
+    ) -> Result<Mp3Request, NCBError> {
+        let key = self.key.as_ref()
+            .ok_or_else(|| NCBError::voicevox("API key required for stream synthesis"))?;
+        
+        let client = reqwest::Client::new();
+        let response = client
+            .post(STREAM_API_URL)
+            .query(&[
+                ("speaker", speaker.to_string()),
+                ("text", text),
+                ("key", key.clone()),
+            ])
+            .send()
+            .await
+            .map_err(|e| NCBError::voicevox(format!("Stream synthesis request failed: {}", e)))?;
+
+        if !response.status().is_success() {
+            return Err(NCBError::voicevox(format!(
+                "Stream synthesis failed with status: {}",
+                response.status()
+            )));
+        }
+
+        let body = response.text().await
+            .map_err(|e| NCBError::voicevox(format!("Failed to read response text: {}", e)))?;
+        
+        let tts_response: TTSResponse = serde_json::from_str(&body)
+            .map_err(|e| NCBError::voicevox(format!("Failed to parse TTS response: {}", e)))?;
+
+        Ok(Mp3Request::new(reqwest::Client::new(), tts_response.mp3_streaming_url))
+    }
+}

src/utils.rs

@@ -0,0 +1,594 @@
+use once_cell::sync::Lazy;
+use lru::LruCache;
+use regex::Regex;
+use std::{num::NonZeroUsize, sync::RwLock};
+use tracing::{debug, error, warn};
+
+use crate::errors::{constants::*, NCBError, Result};
+
+/// Regex compilation cache to avoid recompiling the same patterns
+static REGEX_CACHE: Lazy<RwLock<LruCache<String, Regex>>> = 
+    Lazy::new(|| RwLock::new(LruCache::new(NonZeroUsize::new(DEFAULT_CACHE_SIZE).unwrap())));
+
+/// Circuit breaker states for external API calls
+#[derive(Debug, Clone, PartialEq)]
+pub enum CircuitBreakerState {
+    Closed,
+    Open,
+    HalfOpen,
+}
+
+/// Circuit breaker for handling external API failures
+#[derive(Debug, Clone)]
+pub struct CircuitBreaker {
+    pub state: CircuitBreakerState,
+    pub failure_count: u32,
+    pub last_failure_time: Option<std::time::Instant>,
+    pub threshold: u32,
+    pub timeout: std::time::Duration,
+}
+
+impl Default for CircuitBreaker {
+    fn default() -> Self {
+        Self {
+            state: CircuitBreakerState::Closed,
+            failure_count: 0,
+            last_failure_time: None,
+            threshold: 5,
+            timeout: std::time::Duration::from_secs(60),
+        }
+    }
+}
+
+impl CircuitBreaker {
+    pub fn new(threshold: u32, timeout: std::time::Duration) -> Self {
+        Self {
+            threshold,
+            timeout,
+            ..Default::default()
+        }
+    }
+
+    pub fn can_execute(&self) -> bool {
+        match self.state {
+            CircuitBreakerState::Closed => true,
+            CircuitBreakerState::Open => {
+                if let Some(last_failure) = self.last_failure_time {
+                    last_failure.elapsed() >= self.timeout
+                } else {
+                    true
+                }
+            }
+            CircuitBreakerState::HalfOpen => true,
+        }
+    }
+
+    pub fn on_success(&mut self) {
+        self.failure_count = 0;
+        self.state = CircuitBreakerState::Closed;
+        self.last_failure_time = None;
+    }
+
+    pub fn on_failure(&mut self) {
+        self.failure_count += 1;
+        self.last_failure_time = Some(std::time::Instant::now());
+
+        if self.failure_count >= self.threshold {
+            self.state = CircuitBreakerState::Open;
+        } else if self.state == CircuitBreakerState::HalfOpen {
+            self.state = CircuitBreakerState::Open;
+        }
+    }
+
+    pub fn try_half_open(&mut self) {
+        if self.state == CircuitBreakerState::Open {
+            if let Some(last_failure) = self.last_failure_time {
+                if last_failure.elapsed() >= self.timeout {
+                    self.state = CircuitBreakerState::HalfOpen;
+                }
+            }
+        }
+    }
+}
+
+/// Cached regex compilation with error handling
+pub fn get_cached_regex(pattern: &str) -> Result<Regex> {
+    // First try to get from cache
+    {
+        let cache = REGEX_CACHE.read().unwrap();
+        if let Some(cached_regex) = cache.peek(pattern) {
+            debug!(pattern = pattern, "Regex cache hit");
+            return Ok(cached_regex.clone());
+        }
+    }
+
+    debug!(pattern = pattern, "Regex cache miss, compiling");
+
+    // Compile regex with error handling
+    match Regex::new(pattern) {
+        Ok(regex) => {
+            // Cache successful compilation
+            {
+                let mut cache = REGEX_CACHE.write().unwrap();
+                cache.put(pattern.to_string(), regex.clone());
+            }
+            Ok(regex)
+        }
+        Err(e) => {
+            error!(pattern = pattern, error = %e, "Failed to compile regex");
+            Err(NCBError::invalid_regex(format!("{}: {}", pattern, e)))
+        }
+    }
+}
+
+/// Retry logic with exponential backoff
+pub async fn retry_with_backoff<F, Fut, T, E>(
+    mut operation: F,
+    max_attempts: u32,
+    initial_delay: std::time::Duration,
+) -> std::result::Result<T, E>
+where
+    F: FnMut() -> Fut,
+    Fut: std::future::Future<Output = std::result::Result<T, E>>,
+    E: std::fmt::Display,
+{
+    let mut attempts = 0;
+    let mut delay = initial_delay;
+
+    loop {
+        attempts += 1;
+        
+        match operation().await {
+            Ok(result) => {
+                if attempts > 1 {
+                    debug!(attempts = attempts, "Operation succeeded after retry");
+                }
+                return Ok(result);
+            }
+            Err(error) => {
+                if attempts >= max_attempts {
+                    error!(
+                        attempts = attempts,
+                        error = %error,
+                        "Operation failed after maximum retry attempts"
+                    );
+                    return Err(error);
+                }
+
+                warn!(
+                    attempt = attempts,
+                    max_attempts = max_attempts,
+                    delay_ms = delay.as_millis(),
+                    error = %error,
+                    "Operation failed, retrying with backoff"
+                );
+
+                tokio::time::sleep(delay).await;
+                delay = std::cmp::min(delay * 2, std::time::Duration::from_secs(30));
+            }
+        }
+    }
+}
+
+/// Rate limiter using token bucket algorithm
+#[derive(Debug)]
+pub struct RateLimiter {
+    tokens: std::sync::Arc<std::sync::RwLock<f64>>,
+    capacity: f64,
+    refill_rate: f64,
+    last_refill: std::sync::Arc<std::sync::RwLock<std::time::Instant>>,
+}
+
+impl RateLimiter {
+    pub fn new(capacity: f64, refill_rate: f64) -> Self {
+        Self {
+            tokens: std::sync::Arc::new(std::sync::RwLock::new(capacity)),
+            capacity,
+            refill_rate,
+            last_refill: std::sync::Arc::new(std::sync::RwLock::new(std::time::Instant::now())),
+        }
+    }
+
+    pub fn try_acquire(&self, tokens: f64) -> bool {
+        self.refill();
+        
+        let mut current_tokens = self.tokens.write().unwrap();
+        if *current_tokens >= tokens {
+            *current_tokens -= tokens;
+            true
+        } else {
+            false
+        }
+    }
+
+    fn refill(&self) {
+        let now = std::time::Instant::now();
+        let mut last_refill = self.last_refill.write().unwrap();
+        let elapsed = now.duration_since(*last_refill).as_secs_f64();
+        
+        if elapsed > 0.0 {
+            let tokens_to_add = elapsed * self.refill_rate;
+            let mut current_tokens = self.tokens.write().unwrap();
+            *current_tokens = (*current_tokens + tokens_to_add).min(self.capacity);
+            *last_refill = now;
+        }
+    }
+}
+
+/// Performance metrics collection
+#[derive(Debug, Default, Clone)]
+pub struct PerformanceMetrics {
+    pub tts_requests: std::sync::Arc<std::sync::atomic::AtomicU64>,
+    pub tts_cache_hits: std::sync::Arc<std::sync::atomic::AtomicU64>,
+    pub tts_cache_misses: std::sync::Arc<std::sync::atomic::AtomicU64>,
+    pub regex_cache_hits: std::sync::Arc<std::sync::atomic::AtomicU64>,
+    pub regex_cache_misses: std::sync::Arc<std::sync::atomic::AtomicU64>,
+    pub database_operations: std::sync::Arc<std::sync::atomic::AtomicU64>,
+    pub voice_connections: std::sync::Arc<std::sync::atomic::AtomicU64>,
+}
+
+impl PerformanceMetrics {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn increment_tts_requests(&self) {
+        self.tts_requests.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+    }
+
+    pub fn increment_tts_cache_hits(&self) {
+        self.tts_cache_hits.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+    }
+
+    pub fn increment_tts_cache_misses(&self) {
+        self.tts_cache_misses.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+    }
+
+    pub fn increment_regex_cache_hits(&self) {
+        self.regex_cache_hits.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+    }
+
+    pub fn increment_regex_cache_misses(&self) {
+        self.regex_cache_misses.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+    }
+
+    pub fn increment_database_operations(&self) {
+        self.database_operations.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+    }
+
+    pub fn increment_voice_connections(&self) {
+        self.voice_connections.fetch_add(1, std::sync::atomic::Ordering::Relaxed);
+    }
+
+    pub fn get_stats(&self) -> MetricsSnapshot {
+        MetricsSnapshot {
+            tts_requests: self.tts_requests.load(std::sync::atomic::Ordering::Relaxed),
+            tts_cache_hits: self.tts_cache_hits.load(std::sync::atomic::Ordering::Relaxed),
+            tts_cache_misses: self.tts_cache_misses.load(std::sync::atomic::Ordering::Relaxed),
+            regex_cache_hits: self.regex_cache_hits.load(std::sync::atomic::Ordering::Relaxed),
+            regex_cache_misses: self.regex_cache_misses.load(std::sync::atomic::Ordering::Relaxed),
+            database_operations: self.database_operations.load(std::sync::atomic::Ordering::Relaxed),
+            voice_connections: self.voice_connections.load(std::sync::atomic::Ordering::Relaxed),
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct MetricsSnapshot {
+    pub tts_requests: u64,
+    pub tts_cache_hits: u64,
+    pub tts_cache_misses: u64,
+    pub regex_cache_hits: u64,
+    pub regex_cache_misses: u64,
+    pub database_operations: u64,
+    pub voice_connections: u64,
+}
+
+impl MetricsSnapshot {
+    pub fn tts_cache_hit_rate(&self) -> f64 {
+        if self.tts_cache_hits + self.tts_cache_misses > 0 {
+            self.tts_cache_hits as f64 / (self.tts_cache_hits + self.tts_cache_misses) as f64
+        } else {
+            0.0
+        }
+    }
+
+    pub fn regex_cache_hit_rate(&self) -> f64 {
+        if self.regex_cache_hits + self.regex_cache_misses > 0 {
+            self.regex_cache_hits as f64 / (self.regex_cache_hits + self.regex_cache_misses) as f64
+        } else {
+            0.0
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::time::Duration;
+    use crate::errors::constants::CIRCUIT_BREAKER_FAILURE_THRESHOLD;
+    
+    #[test]
+    fn test_circuit_breaker_default() {
+        let cb = CircuitBreaker::default();
+        assert_eq!(cb.state, CircuitBreakerState::Closed);
+        assert_eq!(cb.failure_count, 0);
+        assert!(cb.can_execute());
+    }
+    
+    #[test]
+    fn test_circuit_breaker_new() {
+        let cb = CircuitBreaker::new(3, Duration::from_secs(10));
+        assert_eq!(cb.state, CircuitBreakerState::Closed);
+        assert_eq!(cb.threshold, 3);
+        assert_eq!(cb.timeout, Duration::from_secs(10));
+    }
+    
+    #[test]
+    fn test_circuit_breaker_failure_threshold() {
+        let mut cb = CircuitBreaker::default();
+        
+        // Test failures up to threshold
+        for i in 0..CIRCUIT_BREAKER_FAILURE_THRESHOLD {
+            assert_eq!(cb.state, CircuitBreakerState::Closed);
+            assert!(cb.can_execute());
+            cb.on_failure();
+            assert_eq!(cb.failure_count, i + 1);
+        }
+        
+        // Should open after reaching threshold
+        assert_eq!(cb.state, CircuitBreakerState::Open);
+        assert!(!cb.can_execute());
+    }
+    
+    #[test]
+    fn test_circuit_breaker_success_resets() {
+        let mut cb = CircuitBreaker::default();
+        
+        // Add some failures
+        cb.on_failure();
+        cb.on_failure();
+        assert_eq!(cb.failure_count, 2);
+        
+        // Success should reset
+        cb.on_success();
+        assert_eq!(cb.failure_count, 0);
+        assert_eq!(cb.state, CircuitBreakerState::Closed);
+    }
+    
+    #[test]
+    fn test_circuit_breaker_half_open() {
+        let mut cb = CircuitBreaker::new(1, Duration::from_millis(100));
+        
+        // Trigger failure to open circuit
+        cb.on_failure();
+        assert_eq!(cb.state, CircuitBreakerState::Open);
+        assert!(!cb.can_execute());
+        
+        // Wait for timeout
+        std::thread::sleep(Duration::from_millis(150));
+        
+        // Should allow transition to half-open
+        cb.try_half_open();
+        assert_eq!(cb.state, CircuitBreakerState::HalfOpen);
+        assert!(cb.can_execute());
+        
+        // Success in half-open should close circuit
+        cb.on_success();
+        assert_eq!(cb.state, CircuitBreakerState::Closed);
+    }
+    
+    #[test]
+    fn test_circuit_breaker_half_open_failure() {
+        let mut cb = CircuitBreaker::new(1, Duration::from_millis(100));
+        
+        // Open circuit
+        cb.on_failure();
+        std::thread::sleep(Duration::from_millis(150));
+        cb.try_half_open();
+        assert_eq!(cb.state, CircuitBreakerState::HalfOpen);
+        
+        // Failure in half-open should reopen circuit
+        cb.on_failure();
+        assert_eq!(cb.state, CircuitBreakerState::Open);
+        assert!(!cb.can_execute());
+    }
+    
+    #[tokio::test]
+    async fn test_retry_with_backoff_success_first_try() {
+        let mut call_count = 0;
+        let result = retry_with_backoff(
+            || {
+                call_count += 1;
+                async { Ok::<i32, &'static str>(42) }
+            },
+            3,
+            Duration::from_millis(100),
+        ).await;
+        
+        assert_eq!(result.unwrap(), 42);
+        assert_eq!(call_count, 1);
+    }
+    
+    #[tokio::test]
+    async fn test_retry_with_backoff_success_after_retries() {
+        let mut call_count = 0;
+        let result = retry_with_backoff(
+            || {
+                call_count += 1;
+                async move {
+                    if call_count < 3 {
+                        Err("temporary error")
+                    } else {
+                        Ok::<i32, &'static str>(42)
+                    }
+                }
+            },
+            5,
+            Duration::from_millis(10),
+        ).await;
+        
+        assert_eq!(result.unwrap(), 42);
+        assert_eq!(call_count, 3);
+    }
+    
+    #[tokio::test]
+    async fn test_retry_with_backoff_max_attempts() {
+        let mut call_count = 0;
+        let result = retry_with_backoff(
+            || {
+                call_count += 1;
+                async { Err::<i32, &'static str>("persistent error") }
+            },
+            3,
+            Duration::from_millis(10),
+        ).await;
+        
+        assert!(result.is_err());
+        assert_eq!(result.unwrap_err(), "persistent error");
+        assert_eq!(call_count, 3);
+    }
+    
+    #[test]
+    fn test_get_cached_regex_valid_pattern() {
+        // Clear cache first
+        {
+            let mut cache = REGEX_CACHE.write().unwrap();
+            cache.clear();
+        }
+        
+        let pattern = r"[a-zA-Z]+";
+        let result1 = get_cached_regex(pattern);
+        assert!(result1.is_ok());
+        
+        let result2 = get_cached_regex(pattern);
+        assert!(result2.is_ok());
+        
+        // Both should work and second should be from cache
+        let regex1 = result1.unwrap();
+        let regex2 = result2.unwrap();
+        assert!(regex1.is_match("hello"));
+        assert!(regex2.is_match("world"));
+    }
+    
+    #[test]
+    fn test_get_cached_regex_invalid_pattern() {
+        let pattern = r"[";
+        let result = get_cached_regex(pattern);
+        assert!(result.is_err());
+        
+        if let Err(NCBError::InvalidRegex(msg)) = result {
+            // The error message contains the pattern and the regex error
+            assert!(msg.contains("["));
+        } else {
+            panic!("Expected InvalidRegex error");
+        }
+    }
+    
+    #[test]
+    fn test_rate_limiter_basic() {
+        let limiter = RateLimiter::new(5.0, 1.0); // 5 tokens, 1 per second
+        
+        // Should be able to acquire 5 tokens initially
+        assert!(limiter.try_acquire(1.0));
+        assert!(limiter.try_acquire(1.0));
+        assert!(limiter.try_acquire(1.0));
+        assert!(limiter.try_acquire(1.0));
+        assert!(limiter.try_acquire(1.0));
+        
+        // 6th token should fail
+        assert!(!limiter.try_acquire(1.0));
+    }
+    
+    #[test]
+    fn test_rate_limiter_partial_tokens() {
+        let limiter = RateLimiter::new(2.0, 1.0);
+        
+        // Acquire partial tokens
+        assert!(limiter.try_acquire(0.5));
+        assert!(limiter.try_acquire(0.5));
+        assert!(limiter.try_acquire(0.5));
+        assert!(limiter.try_acquire(0.5));
+        
+        // Should fail with no tokens left
+        assert!(!limiter.try_acquire(0.1));
+    }
+    
+    #[test]
+    fn test_performance_metrics_increment() {
+        let metrics = PerformanceMetrics::default();
+        
+        assert_eq!(metrics.tts_requests.load(std::sync::atomic::Ordering::Relaxed), 0);
+        
+        metrics.increment_tts_requests();
+        metrics.increment_tts_requests();
+        
+        assert_eq!(metrics.tts_requests.load(std::sync::atomic::Ordering::Relaxed), 2);
+        
+        metrics.increment_tts_cache_hits();
+        assert_eq!(metrics.tts_cache_hits.load(std::sync::atomic::Ordering::Relaxed), 1);
+        
+        metrics.increment_tts_cache_misses();
+        assert_eq!(metrics.tts_cache_misses.load(std::sync::atomic::Ordering::Relaxed), 1);
+    }
+    
+    #[test]
+    fn test_metrics_snapshot_cache_hit_rate() {
+        let snapshot = MetricsSnapshot {
+            tts_requests: 10,
+            tts_cache_hits: 7,
+            tts_cache_misses: 3,
+            regex_cache_hits: 0,
+            regex_cache_misses: 0,
+            database_operations: 0,
+            voice_connections: 0,
+        };
+        
+        assert!((snapshot.tts_cache_hit_rate() - 0.7).abs() < f64::EPSILON);
+        
+        let empty_snapshot = MetricsSnapshot {
+            tts_requests: 0,
+            tts_cache_hits: 0,
+            tts_cache_misses: 0,
+            regex_cache_hits: 0,
+            regex_cache_misses: 0,
+            database_operations: 0,
+            voice_connections: 0,
+        };
+        
+        assert_eq!(empty_snapshot.tts_cache_hit_rate(), 0.0);
+    }
+    
+    #[test]
+    fn test_metrics_snapshot_regex_cache_hit_rate() {
+        let snapshot = MetricsSnapshot {
+            tts_requests: 0,
+            tts_cache_hits: 0,
+            tts_cache_misses: 0,
+            regex_cache_hits: 8,
+            regex_cache_misses: 2,
+            database_operations: 0,
+            voice_connections: 0,
+        };
+        
+        assert!((snapshot.regex_cache_hit_rate() - 0.8).abs() < f64::EPSILON);
+    }
+    
+    #[test]
+    fn test_performance_metrics_get_stats() {
+        let metrics = PerformanceMetrics::default();
+        
+        // Add some data
+        metrics.increment_tts_requests();
+        metrics.increment_tts_requests();
+        metrics.increment_tts_cache_hits();
+        metrics.increment_database_operations();
+        
+        let stats = metrics.get_stats();
+        
+        assert_eq!(stats.tts_requests, 2);
+        assert_eq!(stats.tts_cache_hits, 1);
+        assert_eq!(stats.tts_cache_misses, 0);
+        assert_eq!(stats.database_operations, 1);
+    }
+}