diff --git a/Cargo.lock b/Cargo.lock
index 07f5c4e..263642d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -35,6 +35,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.96"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b964d184e89d9b6b67dd2715bc8e74cf3107fb2b529990c90cf517326150bf4"
+
 [[package]]
 name = "autocfg"
 version = "1.4.0"
@@ -109,6 +115,7 @@ dependencies = [
 name = "iatjc-rs"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "tracing",
  "tracing-subscriber",
  "windows",
diff --git a/Cargo.toml b/Cargo.toml
index 84790ed..655cc32 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2024"
 windows-core = "0.56.0"
 tracing = "0.1"
 tracing-subscriber = "0.1"
+anyhow = "1.0.86"
 
 [dependencies.windows]
 version = "0.56.0"
diff --git a/src/lib.rs b/src/lib.rs
index 765669c..8cb1f80 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,17 +1,4 @@
 mod edit_session;
+mod thread_mgr;
 pub mod tsf;
-
-pub fn add(left: u64, right: u64) -> u64 {
-    left + right
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
-}
+mod text_store;
\ No newline at end of file
diff --git a/src/text_store.rs b/src/text_store.rs
new file mode 100644
index 0000000..a8654e4
--- /dev/null
+++ b/src/text_store.rs
@@ -0,0 +1,375 @@
+use std::sync::{atomic::{AtomicI32, Ordering}, Mutex, RwLock};
+
+use windows::{Win32::{Foundation::{HWND, POINT, RECT, E_INVALIDARG, E_NOINTERFACE, E_NOTIMPL, E_UNEXPECTED, S_OK, BOOL}, System::{Com::{IDataObject, FORMATETC}, Ole::CONNECT_E_ADVISELIMIT}, UI::TextServices::{ITextStoreACP, ITextStoreACPSink, ITextStoreACP_Impl, TEXT_STORE_LOCK_FLAGS, TEXT_STORE_TEXT_CHANGE_FLAGS, TS_AS_TEXT_CHANGE, TS_ATTRVAL, TS_E_NOLOCK, TS_E_SYNCHRONOUS, TS_LF_READ, TS_LF_READWRITE, TS_LF_SYNC, TS_RT_PLAIN, TS_SD_LOADING, TS_SD_READONLY, TS_SELECTION_ACP, TS_SS_REGIONS, TS_STATUS, TS_ST_NONE, TS_TEXTCHANGE}}};
+use windows_core::{IUnknown, IUnknownImpl, Interface, HRESULT};
+
+fn flag_check(value: u32, flag: u32) -> bool {
+    (value & flag) == flag
+}
+
+struct AdviceSink {
+    text_store_sink: Option<ITextStoreACPSink>,
+    mask: u32
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+enum LockType {
+    None,
+    Read,
+    ReadWrite,
+}
+
+impl From<u32> for LockType {
+    fn from(flags: u32) -> Self {
+        if flag_check(flags, TS_LF_READWRITE.0) {
+            LockType::ReadWrite
+        } else if flag_check(flags, TS_LF_READ.0) {
+            LockType::Read
+        } else {
+            LockType::None
+        }
+    }
+}
+
+pub struct TfTextStore {
+    ref_count: AtomicI32,
+    advice_sink: Mutex<AdviceSink>,
+    input_text: RwLock<String>,
+    lock_state: RwLock<(LockType, u32)>
+}
+
+impl TfTextStore {
+    pub fn new() -> Self {
+        Self {
+            ref_count: AtomicI32::new(1),
+            advice_sink: Mutex::new(AdviceSink {
+                text_store_sink: None,
+                mask: 0
+            }),
+            input_text: RwLock::new(String::new()),
+            lock_state: RwLock::new((LockType::None, 0))
+        }
+    }
+
+    pub fn is_locked(&self, flags: u32) -> bool {
+        let lock_state = self.lock_state.read().unwrap();
+        lock_state.0 != LockType::None && flag_check(lock_state.1, flags)
+    }
+
+    pub fn try_lock(&self, flags: u32) -> Result<LockGuard, ()> {
+        let mut lock_state = self.lock_state.write().unwrap();
+
+        if lock_state.0 == LockType::None {
+            let lock_type = LockType::from(flags);
+            *lock_state = (lock_type, flags);
+
+            Ok(LockGuard { text_store: self })
+        } else {
+            Err(())
+        }
+    }
+
+    pub fn set_string(&self, text: &str) -> bool {
+        if let Ok(_lock) = self.try_lock(TS_LF_READWRITE.0) {
+            let old_len = self.input_text.read().unwrap().len() as i32;
+
+            let mut input_text = self.input_text.write().unwrap();
+            *input_text = text.to_string();
+            let new_len = input_text.len() as i32;
+
+            let text_change = TS_TEXTCHANGE {
+                acpStart: 0,
+                acpOldEnd: old_len,
+                acpNewEnd: new_len
+            };
+
+            drop(input_text);
+
+            let advice_sink = self.advice_sink.lock().unwrap();
+            if flag_check(advice_sink.mask, TS_AS_TEXT_CHANGE) {
+                if let Some(sink) = &advice_sink.text_store_sink {
+                    unsafe {
+                        sink.OnTextChange(TS_ST_NONE, &text_change).ok();
+                    }
+                }
+            }
+
+            true
+        } else {
+            false
+        }
+    }
+}
+
+pub struct LockGuard<'a> {
+    text_store: &'a TfTextStore
+}
+
+impl <'a> Drop for LockGuard<'a> {
+    fn drop(&mut self) {
+        let mut lock_state = self.text_store.lock_state.write().unwrap();
+        *lock_state = (LockType::None, 0);
+    }
+}
+
+impl IUnknownImpl for TfTextStore {
+    type Impl = Self;
+
+    fn AddRef(&self) -> u32 {
+        self.ref_count.fetch_add(1, Ordering::SeqCst) as u32
+    }
+
+    unsafe fn Release(&self) -> u32 {
+        let count = self.ref_count.fetch_sub(1, Ordering::SeqCst) - 1;
+        count as u32
+    }
+
+    unsafe fn GetTrustLevel(&self, value: *mut i32) -> windows_core::HRESULT {
+        if !value.is_null() {
+            unsafe {
+                *value = 0;
+            }
+
+             S_OK
+        } else {
+            E_INVALIDARG
+        }
+    }
+
+    unsafe fn QueryInterface(&self, iid: *const windows_core::GUID, interface: *mut *mut std::ffi::c_void) -> HRESULT {
+        let iid = unsafe { &*iid };
+
+        if iid == &<IUnknown as Interface>::IID || iid == &<ITextStoreACP as Interface>::IID {
+            unsafe {
+                *interface = self as *const _ as *mut std::ffi::c_void;
+            }
+            self.AddRef();
+
+            S_OK
+        } else {
+            unsafe {
+                *interface = std::ptr::null_mut();
+            }
+
+            E_NOINTERFACE
+        }
+    }
+
+    fn get_impl(&self) -> &Self::Impl {
+        self
+    }
+}
+
+impl ITextStoreACP_Impl for TfTextStore {
+    fn AdviseSink(&self, riid: *const windows_core::GUID, punk: Option<&windows_core::IUnknown>, mask: u32) -> windows_core::Result<()> {
+        let punk = match punk {
+            Some(punk) => punk,
+            None => return Err(E_INVALIDARG.into())
+        };
+
+        let mut advice_sink = self.advice_sink.lock().unwrap();
+
+        if let Some(existing_sink) = &advice_sink.text_store_sink {
+            advice_sink.mask = mask;
+            
+            Ok(())
+        } else if advice_sink.text_store_sink.is_some() {
+            Err(CONNECT_E_ADVISELIMIT.into())
+        } else {
+            let mut sink: Option<ITextStoreACPSink> = None;
+            let hr = unsafe { punk.query(&<ITextStoreACPSink as Interface>::IID, &mut sink as *mut _ as *mut _) };
+
+            if hr.is_ok() {
+                advice_sink.text_store_sink = sink;
+                advice_sink.mask = mask;
+
+                return Ok(());
+            }
+
+            Err(hr.into())
+        }
+    }
+
+    fn UnadviseSink(&self, punk: Option<&windows_core::IUnknown>) -> windows_core::Result<()> {
+        let mut advice_sink = self.advice_sink.lock().unwrap();
+
+        if let Some(_existing_sink) = &advice_sink.text_store_sink {
+            advice_sink.text_store_sink = None;
+            advice_sink.mask = 0;
+
+            Ok(())
+        } else {
+            Err(E_INVALIDARG.into())
+        }
+    }
+
+    fn RequestLock(&self, dwlockflags: u32) -> windows_core::Result<windows_core::HRESULT> {
+        let advice_sink = self.advice_sink.lock().unwrap();
+
+        if advice_sink.text_store_sink.is_none() {
+            return Ok(E_UNEXPECTED);
+        }
+
+        let is_currently_locked = {
+            let lock_state = self.lock_state.read().unwrap();
+            lock_state.0 != LockType::None
+        };
+
+        if is_currently_locked {
+            if flag_check(dwlockflags, TS_LF_SYNC) {
+                return Ok(TS_E_SYNCHRONOUS)
+            } else {
+                return Ok(E_NOTIMPL)
+            }
+        } else {
+            if let Ok(_guard) = self.try_lock(dwlockflags) {
+                if let Some(sink) = &advice_sink.text_store_sink {
+                    let hr = unsafe { sink.OnLockGranted(TEXT_STORE_LOCK_FLAGS(dwlockflags)) };
+
+                    return match hr {
+                        Ok(_) => Ok(S_OK),
+                        Err(e) => Err(e)
+                    };
+                }
+            }
+
+            Ok(S_OK)
+        }
+    }
+
+    fn GetStatus(&self) -> windows_core::Result<windows::Win32::UI::TextServices::TS_STATUS> {
+        let status = TS_STATUS {
+            dwDynamicFlags: TS_SD_READONLY | TS_SD_LOADING,
+            dwStaticFlags: TS_SS_REGIONS
+        };
+
+        Ok(status)
+    }
+
+    fn GetText(&self, acpstart: i32, acpend: i32, pchplain: windows_core::PWSTR, cchplainreq: u32, pcchplainret: *mut u32, prgruninfo: *mut windows::Win32::UI::TextServices::TS_RUNINFO, cruninforeq: u32, pcruninforet: *mut u32, pacpnext: *mut i32) -> windows_core::Result<()> {
+        if !self.is_locked(TS_LF_READ.0) {
+            return Err(TS_E_NOLOCK.into());
+        }
+
+        let input_text = self.input_text.read().unwrap();
+        let text_len = input_text.len();
+        let copy_len = std::cmp::min(text_len as u32, cchplainreq);
+
+        if copy_len > 0 && !pchplain.is_null() {
+            let src_slice = input_text.as_bytes();
+            let dest_slice = unsafe { std::slice::from_raw_parts_mut(pchplain.0 as *mut u8, copy_len as usize) };
+            dest_slice.copy_from_slice(&src_slice[0..copy_len as usize]);
+        }
+
+        if !pcchplainret.is_null() {
+            unsafe {
+                *pcchplainret = copy_len;
+            }
+        }
+
+        if !prgruninfo.is_null() && cruninforeq > 0 {
+            unsafe {
+                (*prgruninfo).r#type = TS_RT_PLAIN;
+                (*prgruninfo).uCount = text_len as u32;
+            }
+        }
+
+        if !pcruninforet.is_null() {
+            unsafe {
+                *pcruninforet = 1;
+            }
+        }
+
+        if !pacpnext.is_null() {
+            unsafe {
+                *pacpnext = acpstart + text_len as i32;
+            }
+        }
+
+        Ok(())
+    }
+
+    fn QueryInsert(&self, _acpteststart: i32, _acptestend: i32, _cch: u32, _pacpresultstart: *mut i32, _pacpresultend: *mut i32) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn GetSelection(&self, _ulindex: u32, _ulcount: u32, _pselection: *mut TS_SELECTION_ACP, _pcfetched: *mut u32) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn SetSelection(&self, _ulcount: u32, _pselection: *const TS_SELECTION_ACP) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn SetText(&self, _dwflags: u32, _acpstart: i32, _acpend: i32, _pchtext: &windows_core::PCWSTR, _cch: u32) -> windows_core::Result<TS_TEXTCHANGE> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn GetFormattedText(&self, _acpstart: i32, _acpend: i32) -> windows_core::Result<IDataObject> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn GetEmbedded(&self, _acppos: i32, _rguidservice: *const windows_core::GUID, _riid: *const windows_core::GUID) -> windows_core::Result<windows_core::IUnknown> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn QueryInsertEmbedded(&self, _pguidservice: *const windows_core::GUID, _pformatetc: *const FORMATETC) -> windows_core::Result<BOOL> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn InsertEmbedded(&self, _dwflags: u32, _acpstart: i32, _acpend: i32, _pdataobject: Option<&IDataObject>) -> windows_core::Result<TS_TEXTCHANGE> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn InsertTextAtSelection(&self, _dwflags: u32, _pchtext: &windows_core::PCWSTR, _cch: u32, _pacpstart: *mut i32, _pacpend: *mut i32, _pchange: *mut TS_TEXTCHANGE) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn InsertEmbeddedAtSelection(&self, _dwflags: u32, _pdataobject: Option<&IDataObject>, _pacpstart: *mut i32, _pacpend: *mut i32, _pchange: *mut TS_TEXTCHANGE) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn RequestSupportedAttrs(&self, _dwflags: u32, _cfilterattrs: u32, _pafilterattrs: *const windows_core::GUID) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn RequestAttrsAtPosition(&self, _acppos: i32, _cfilterattrs: u32, _pafilterattrs: *const windows_core::GUID, _dwflags: u32) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn RequestAttrsTransitioningAtPosition(&self, _acppos: i32, _cfilterattrs: u32, _pafilterattrs: *const windows_core::GUID, _dwflags: u32) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn FindNextAttrTransition(&self, _acpstart: i32, _acphalt: i32, _cfilterattrs: u32, _pafilterattrs: *const windows_core::GUID, _dwflags: u32, _pacpnext: *mut i32, _pffound: *mut BOOL, _plfoundoffset: *mut i32) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn RetrieveRequestedAttrs(&self, _ulcount: u32, _paattrvals: *mut TS_ATTRVAL, _pcfetched: *mut u32) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn GetEndACP(&self) -> windows_core::Result<i32> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn GetActiveView(&self) -> windows_core::Result<u32> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn GetACPFromPoint(&self, _vcview: u32, _ptscreen: *const POINT, _dwflags: u32) -> windows_core::Result<i32> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn GetTextExt(&self, _vcview: u32, _acpstart: i32, _acpend: i32, _prc: *mut RECT, _pfclipped: *mut BOOL) -> windows_core::Result<()> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn GetScreenExt(&self, _vcview: u32) -> windows_core::Result<RECT> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+    
+    fn GetWnd(&self, _vcview: u32) -> windows_core::Result<HWND> {
+        Err(windows_core::Error::from(E_NOTIMPL))
+    }
+}
diff --git a/src/thread_mgr.rs b/src/thread_mgr.rs
new file mode 100644
index 0000000..b8e2aca
--- /dev/null
+++ b/src/thread_mgr.rs
@@ -0,0 +1,57 @@
+use anyhow::Result;
+use tracing::{debug, error, info};
+use windows::Win32::{
+    System::Com::{CoCreateInstance, CLSCTX_INPROC_SERVER},
+    UI::TextServices::{CLSID_TF_ThreadMgr, ITfDocumentMgr, ITfFunctionProvider, ITfThreadMgr2},
+};
+
+pub struct ThreadMgr {
+    pub thread_mgr: ITfThreadMgr2,
+}
+
+impl ThreadMgr {
+    pub fn new() -> Result<Self> {
+        debug!("Creating new ThreadMgr");
+        let thread_mgr =
+            unsafe { CoCreateInstance(&CLSID_TF_ThreadMgr, None, CLSCTX_INPROC_SERVER)? };
+        info!("ThreadMgr created successfully");
+        Ok(ThreadMgr { thread_mgr })
+    }
+
+    pub fn activate_ex(&self, flags: u32) -> Result<u32> {
+        debug!("Activating ThreadMgr with flags: {}", flags);
+        let mut client_id = 0;
+        unsafe {
+            self.thread_mgr
+                .ActivateEx(&mut client_id as *mut _ as *const _ as *mut _, flags)?
+        };
+        info!("ThreadMgr activated with client_id: {}", client_id);
+        Ok(client_id)
+    }
+
+    pub fn get_function_provider(&self, clsid: &windows_core::GUID) -> Result<ITfFunctionProvider> {
+        debug!("Getting function provider for CLSID: {:?}", clsid);
+        match unsafe { self.thread_mgr.GetFunctionProvider(clsid) } {
+            Ok(provider) => {
+                info!("Function provider obtained successfully");
+                Ok(provider)
+            }
+            Err(e) => {
+                error!("Failed to get function provider: {:?}", e);
+                Err(e.into())
+            }
+        }
+    }
+
+    pub fn activate(&self) -> Result<u32> {
+        let client_id = unsafe { self.thread_mgr.Activate()? };
+
+        Ok(client_id)
+    }
+
+    pub fn create_document_manager(&self) -> Result<ITfDocumentMgr> {
+        let document_mgr = unsafe { self.thread_mgr.CreateDocumentMgr()? };
+
+        Ok(document_mgr)
+    }
+}