//! Create a standalone native executable for a given Wasm file.

use super::ObjectFormat;
use crate::store::CompilerOptions;
use anyhow::{Context, Result};
use clap::Parser;
use serde::{Deserialize, Serialize};
use std::collections::BTreeMap;
use std::env;
use std::path::{Path, PathBuf};
use std::process::Command;
use wasmer::*;
use wasmer_object::{emit_serialized, get_object_for_target};
use wasmer_types::ModuleInfo;

use webc::{ParseOptions, WebCMmap};

/// The `prefixer` returns the a String to prefix each of the
/// functions in the static object generated by the
/// so we can assure no collisions.
pub type PrefixerFn = Box<dyn Fn(&[u8]) -> String + Send>;

#[derive(Debug, Parser)]
/// The options for the `wasmer create-exe` subcommand
pub struct CreateExe {
    /// Input file
    #[clap(name = "FILE", parse(from_os_str))]
    path: PathBuf,

    /// Output file
    #[clap(name = "OUTPUT PATH", short = 'o', parse(from_os_str))]
    output: PathBuf,

    /// Optional directorey used for debugging: if present, will output the zig command
    /// for reproducing issues in a debug directory
    #[clap(long, name = "DEBUG PATH", parse(from_os_str))]
    debug_dir: Option<PathBuf>,

    /// Prefix for every input file, e.g. "wat2wasm:sha256abc123" would
    /// prefix every function in the wat2wasm input object with the "sha256abc123" hash
    ///
    /// If only a single value is given without containing a ":", this value is used for
    /// all input files. If no value is given, the prefix is always equal to
    /// the sha256 of the input .wasm file
    #[clap(
        long,
        use_value_delimiter = true,
        value_delimiter = ',',
        name = "FILE:PATH:PREFIX"
    )]
    precompiled_atom: Vec<String>,

    /// Compilation Target triple
    ///
    /// Accepted target triple values must follow the
    /// ['target_lexicon'](https://crates.io/crates/target-lexicon) crate format.
    ///
    /// The recommended targets we try to support are:
    ///
    /// - "x86_64-linux-gnu"
    /// - "aarch64-linux-gnu"
    /// - "x86_64-apple-darwin"
    /// - "arm64-apple-darwin"
    /// - "x86_64-windows-gnu"
    #[clap(long = "target")]
    target_triple: Option<Triple>,

    /// Object format options
    ///
    /// This flag accepts two options: `symbols` or `serialized`.
    /// - (default) `symbols` creates an object where all functions and metadata of the module are regular object symbols
    /// - `serialized` creates an object where the module is zero-copy serialized as raw data
    #[clap(long = "object-format", name = "OBJECT_FORMAT", verbatim_doc_comment)]
    object_format: Option<ObjectFormat>,

    #[clap(long, short = 'm', multiple = true, number_of_values = 1)]
    cpu_features: Vec<CpuFeature>,

    /// Additional libraries to link against.
    /// This is useful for fixing linker errors that may occur on some systems.
    #[clap(long, short = 'l')]
    libraries: Vec<String>,

    #[clap(flatten)]
    cross_compile: CrossCompile,

    #[clap(flatten)]
    compiler: CompilerOptions,
}

// Cross-compilation options with `zig`
#[derive(Debug, Clone, Default, Parser)]
pub(crate) struct CrossCompile {
    /// Use the system linker instead of zig instead of zig for linking
    #[clap(long)]
    use_system_linker: bool,

    /// Cross-compilation library path (path to libwasmer.a / wasmer.lib)
    #[clap(long = "library-path", requires = "target")]
    library_path: Option<PathBuf>,

    /// Cross-compilation tarball library path
    #[clap(long = "tarball", requires = "target")]
    tarball: Option<PathBuf>,

    /// Specify `zig` binary path (defaults to `zig` in $PATH if not present)
    #[clap(long = "zig-binary-path", requires = "target")]
    zig_binary_path: Option<PathBuf>,
}

#[derive(Debug)]
pub(crate) struct CrossCompileSetup {
    pub(crate) target: Triple,
    pub(crate) zig_binary_path: Option<PathBuf>,
    pub(crate) library: Option<PathBuf>,
}

/// Given a pirita file, determines whether the file has one
/// default command as an entrypoint or multiple (need to be specified via --command)
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct Entrypoint {
    /// Compiled atom files to link into the final binary
    pub atoms: Vec<CommandEntrypoint>,
    /// Volume objects (if any) to link into the final binary
    pub volumes: Vec<Volume>,
    /// Type of the object format the atoms were compiled with
    pub object_format: ObjectFormat,
}

/// Command entrypoint for multiple commands
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct CommandEntrypoint {
    /// Command name
    pub command: String,
    /// Atom name
    pub atom: String,
    /// Path to the object file, relative to the entrypoint.json parent dir
    pub path: PathBuf,
    /// Optional path to the static_defs.h header file, relative to the entrypoint.json parent dir
    pub header: Option<PathBuf>,
    /// Module info, set when the wasm file is compiled
    pub module_info: Option<ModuleInfo>,
}

/// Volume object file (name + path to object file)
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct Volume {
    /// Volume name
    pub name: String,
    /// Path to volume fileblock object file
    pub obj_file: PathBuf,
}

impl CreateExe {
    /// Runs logic for the `compile` subcommand
    pub fn execute(&self) -> Result<()> {
        let target_triple = self.target_triple.clone().unwrap_or_else(Triple::host);
        let mut cc = self.cross_compile.clone();
        let target = utils::target_triple_to_target(&target_triple, &self.cpu_features);

        let starting_cd = env::current_dir()?;
        let input_path = starting_cd.join(&self.path);
        let output_path = starting_cd.join(&self.output);
        let cross_compilation =
            utils::get_cross_compile_setup(&mut cc, &target_triple, &starting_cd)?;

        if input_path.is_dir() {
            return Err(anyhow::anyhow!("input path cannot be a directory"));
        } else if let Ok(pirita) = WebCMmap::parse(input_path.clone(), &ParseOptions::default()) {
            // pirita file
            let temp = tempdir::TempDir::new("pirita-compile")?;
            let tempdir = match self.debug_dir.as_ref() {
                Some(s) => s.clone(),
                None => temp.path().to_path_buf(),
            };
            std::fs::create_dir_all(&tempdir)?;
            let atoms = compile_pirita_into_directory(
                &pirita,
                &tempdir,
                &self.compiler,
                &self.cpu_features,
                &cross_compilation.target,
                self.object_format.unwrap_or_default(),
                &self.precompiled_atom,
                AllowMultiWasm::Allow,
            )?;
            get_module_infos(&tempdir, &atoms)?;
            let mut entrypoint = get_entrypoint(&tempdir)?;
            create_header_files_in_dir(&tempdir, &mut entrypoint, &atoms, &self.precompiled_atom)?;
            link_exe_from_dir(
                &tempdir,
                output_path,
                &cross_compilation,
                &self.libraries,
                self.debug_dir.is_some(),
                &atoms,
                &self.precompiled_atom,
            )?;
        } else {
            // wasm file
            let temp = tempdir::TempDir::new("pirita-compile")?;
            let tempdir = match self.debug_dir.as_ref() {
                Some(s) => s.clone(),
                None => temp.path().to_path_buf(),
            };
            std::fs::create_dir_all(&tempdir)?;
            let atoms = prepare_directory_from_single_wasm_file(
                &input_path,
                &tempdir,
                &self.compiler,
                &cross_compilation.target,
                &self.cpu_features,
                self.object_format.unwrap_or_default(),
                &self.precompiled_atom,
            )?;
            get_module_infos(&tempdir, &atoms)?;
            let mut entrypoint = get_entrypoint(&tempdir)?;
            create_header_files_in_dir(&tempdir, &mut entrypoint, &atoms, &self.precompiled_atom)?;
            link_exe_from_dir(
                &tempdir,
                output_path,
                &cross_compilation,
                &self.libraries,
                self.debug_dir.is_some(),
                &atoms,
                &self.precompiled_atom,
            )?;
        }

        if self.target_triple.is_some() {
            eprintln!(
                "✔ Cross-compiled executable for `{}` target compiled successfully to `{}`.",
                target.triple(),
                self.output.display(),
            );
        } else {
            eprintln!(
                "✔ Native executable compiled successfully to `{}`.",
                self.output.display(),
            );
        }

        Ok(())
    }
}

fn write_entrypoint(directory: &Path, entrypoint: &Entrypoint) -> Result<(), anyhow::Error> {
    std::fs::write(
        directory.join("entrypoint.json"),
        serde_json::to_string_pretty(&entrypoint).unwrap(),
    )
    .map_err(|e| {
        anyhow::anyhow!(
            "cannot create entrypoint.json dir in {}: {e}",
            directory.display()
        )
    })
}

fn get_entrypoint(directory: &Path) -> Result<Entrypoint, anyhow::Error> {
    let entrypoint_json =
        std::fs::read_to_string(directory.join("entrypoint.json")).map_err(|e| {
            anyhow::anyhow!(
                "could not read entrypoint.json in {}: {e}",
                directory.display()
            )
        })?;

    let entrypoint: Entrypoint = serde_json::from_str(&entrypoint_json).map_err(|e| {
        anyhow::anyhow!(
            "could not parse entrypoint.json in {}: {e}",
            directory.display()
        )
    })?;

    if entrypoint.atoms.is_empty() {
        return Err(anyhow::anyhow!("file has no atoms to compile"));
    }

    Ok(entrypoint)
}

/// In pirita mode, specifies whether multi-atom
/// pirita files should be allowed or rejected
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum AllowMultiWasm {
    /// allow
    Allow,
    /// reject
    Reject(Option<String>),
}

/// Given a pirita file, compiles the .wasm files into the target directory
pub(super) fn compile_pirita_into_directory(
    pirita: &WebCMmap,
    target_dir: &Path,
    compiler: &CompilerOptions,
    cpu_features: &[CpuFeature],
    triple: &Triple,
    object_format: ObjectFormat,
    prefixes: &[String],
    allow_multi_wasm: AllowMultiWasm,
) -> anyhow::Result<Vec<(String, Vec<u8>)>> {
    let all_atoms = match &allow_multi_wasm {
        AllowMultiWasm::Allow | AllowMultiWasm::Reject(None) => {
            pirita.get_all_atoms().into_iter().collect::<Vec<_>>()
        }
        AllowMultiWasm::Reject(Some(s)) => {
            vec![(
                s.to_string(),
                pirita
                    .get_atom(&pirita.get_package_name(), s)
                    .with_context(|| {
                        anyhow::anyhow!(
                            "could not find atom {s} in package {}",
                            pirita.get_package_name()
                        )
                    })?,
            )]
        }
    };

    if allow_multi_wasm == AllowMultiWasm::Reject(None) && all_atoms.len() > 1 {
        let keys = all_atoms
            .iter()
            .map(|(name, _)| name.clone())
            .collect::<Vec<_>>();
        return Err(anyhow::anyhow!(
            "where <ATOM> is one of: {}",
            keys.join(", ")
        ))
        .context(anyhow::anyhow!(
            "note: use --atom <ATOM> to specify which atom to compile"
        ))
        .context(anyhow::anyhow!(
            "cannot compile more than one atom at a time"
        ));
    }

    std::fs::create_dir_all(target_dir)
        .map_err(|e| anyhow::anyhow!("cannot create / dir in {}: {e}", target_dir.display()))?;

    let target_dir = target_dir.canonicalize()?;
    let target = &utils::target_triple_to_target(triple, cpu_features);

    std::fs::create_dir_all(target_dir.join("volumes")).map_err(|e| {
        anyhow::anyhow!(
            "cannot create /volumes dir in {}: {e}",
            target_dir.display()
        )
    })?;

    let volume_bytes = pirita.get_volumes_as_fileblock();
    let volume_name = "VOLUMES";
    let volume_path = target_dir.join("volumes").join("volume.o");
    write_volume_obj(&volume_bytes, volume_name, &volume_path, target)?;
    let volume_path = volume_path.canonicalize()?;
    let volume_path = pathdiff::diff_paths(&volume_path, &target_dir).unwrap();

    std::fs::create_dir_all(target_dir.join("atoms")).map_err(|e| {
        anyhow::anyhow!("cannot create /atoms dir in {}: {e}", target_dir.display())
    })?;

    let mut atoms_from_file = Vec::new();
    let mut target_paths = Vec::new();

    for (atom_name, atom_bytes) in all_atoms {
        atoms_from_file.push((utils::normalize_atom_name(&atom_name), atom_bytes.to_vec()));
        let atom_path = target_dir
            .join("atoms")
            .join(format!("{}.o", utils::normalize_atom_name(&atom_name)));
        let header_path = match object_format {
            ObjectFormat::Symbols => {
                std::fs::create_dir_all(target_dir.join("include")).map_err(|e| {
                    anyhow::anyhow!(
                        "cannot create /include dir in {}: {e}",
                        target_dir.display()
                    )
                })?;

                Some(target_dir.join("include").join(format!(
                    "static_defs_{}.h",
                    utils::normalize_atom_name(&atom_name)
                )))
            }
            ObjectFormat::Serialized => None,
        };
        target_paths.push((
            atom_name.clone(),
            utils::normalize_atom_name(&atom_name),
            atom_path,
            header_path,
        ));
    }

    let prefix_map = PrefixMapCompilation::from_input(&atoms_from_file, prefixes, false)?;
    let module_infos = conpile_atoms(
        &atoms_from_file,
        &target_dir.join("atoms"),
        compiler,
        target,
        object_format,
        &prefix_map,
    )?;

    // target_dir
    let mut atoms = Vec::new();
    for (command_name, atom_name, a, opt_header_path) in target_paths {
        let mut atom_path = a;
        let mut header_path = opt_header_path;
        if let Ok(a) = atom_path.canonicalize() {
            let opt_header_path = header_path.and_then(|p| p.canonicalize().ok());
            atom_path = pathdiff::diff_paths(&a, &target_dir).unwrap_or_else(|| a.clone());
            header_path = opt_header_path.and_then(|h| pathdiff::diff_paths(&h, &target_dir));
        }
        atoms.push(CommandEntrypoint {
            // TODO: improve, "--command pip" should be able to invoke atom "python" with args "-m pip"
            command: command_name,
            atom: atom_name.clone(),
            path: atom_path,
            header: header_path,
            module_info: module_infos.get(&atom_name).cloned(),
        });
    }

    let entrypoint = Entrypoint {
        atoms,
        volumes: vec![Volume {
            name: volume_name.to_string(),
            obj_file: volume_path,
        }],
        object_format,
    };

    write_entrypoint(&target_dir, &entrypoint)?;

    Ok(atoms_from_file)
}

/// Prefix map used during compilation of object files
#[derive(Debug, Default)]
struct PrefixMapCompilation {
    /// Sha256 hashes for the input files
    input_hashes: BTreeMap<String, String>,
    /// Manual prefixes for input files (file:prefix)
    manual_prefixes: BTreeMap<String, String>,
    /// Cached compilation objects for files on disk
    #[allow(dead_code)]
    compilation_objects: BTreeMap<String, Vec<u8>>,
}

impl PrefixMapCompilation {
    /// Sets up the prefix map from a collection like "sha123123" or "wasmfile:sha123123" or "wasmfile:/tmp/filepath/:sha123123"
    fn from_input(
        atoms: &[(String, Vec<u8>)],
        prefixes: &[String],
        compilation_object_mode: bool,
    ) -> Result<Self, anyhow::Error> {
        if atoms.is_empty() {
            return Ok(Self::default());
        }

        if prefixes.is_empty() {
            return Ok(Self {
                input_hashes: atoms
                    .iter()
                    .map(|(name, bytes)| (name.clone(), Self::hash_for_bytes(bytes)))
                    .collect(),
                manual_prefixes: BTreeMap::new(),
                compilation_objects: BTreeMap::new(),
            });
        }

        if prefixes.len() != atoms.len() {
            return Err(anyhow::anyhow!(
                "invalid mapping of prefix and atoms: expected prefixes for {} atoms, got {} prefixes", 
                atoms.len(), prefixes.len()
            ));
        }

        // Only on single atom mapping is using a raw input allowed, all other prefix
        // have to carry something like "nameofatom:sha256hash" instead of just "sha256hash"
        if atoms.len() == 1 && !compilation_object_mode {
            let prefix = &prefixes[0];
            let (atom_name, _atom_bytes) = &atoms[0];
            let atom_prefix = format!("{atom_name}:");

            if prefix.contains(':') && !prefix.contains(&atom_prefix) {
                return Err(anyhow::anyhow!("invalid prefix in prefix {prefix}"));
            }

            let prefix_without_atom_name = prefix.replacen(&atom_prefix, "", 1);
            if !prefix_without_atom_name
                .chars()
                .all(|c| c.is_alphanumeric() || c == '_' || c == '-')
            {
                return Err(anyhow::anyhow!("invalid prefix {prefix}"));
            }
            return Ok(Self {
                input_hashes: BTreeMap::new(),
                manual_prefixes: IntoIterator::into_iter([(
                    atom_name.clone(),
                    prefix_without_atom_name,
                )])
                .collect(),
                compilation_objects: BTreeMap::new(),
            });
        }

        let mut manual_prefixes = BTreeMap::new();
        let mut compilation_objects = BTreeMap::new();
        for (atom_name, _atom_bytes) in atoms {
            let prefix_start_str = format!("{atom_name}:");
            let prefix = match prefixes.iter().find(|p| p.contains(&prefix_start_str)) {
                Some(s) => s,
                None => {
                    return Err(anyhow::anyhow!(
                        "could not find prefix for atom {atom_name:?}"
                    ))
                }
            };
            let prefix_without_atom_name = prefix.replacen(&prefix_start_str, "", 1);
            match prefix_without_atom_name
                .split(':')
                .collect::<Vec<_>>()
                .as_slice()
            {
                &[path, prefix] => {
                    let bytes = std::fs::read(path).map_err(|e| {
                        anyhow::anyhow!("could not read file for prefix {prefix} ({path}): {e}")
                    })?;
                    compilation_objects.insert(atom_name.clone(), bytes);
                }
                _ => {
                    if compilation_object_mode {
                        return Err(anyhow::anyhow!("invalid prefix format {prefix}"));
                    }
                }
            };
            if !prefix_without_atom_name
                .chars()
                .all(|c| c.is_alphanumeric() || c == '_' || c == '-')
            {
                return Err(anyhow::anyhow!("invalid prefix {prefix}"));
            }
            manual_prefixes.insert(atom_name.clone(), prefix_without_atom_name);
        }

        Ok(Self {
            input_hashes: BTreeMap::new(),
            manual_prefixes,
            compilation_objects,
        })
    }

    fn hash_for_bytes(bytes: &[u8]) -> String {
        use sha2::{Digest, Sha256};
        let mut hasher = Sha256::new();
        hasher.update(bytes);
        let result = hasher.finalize();
        let result = hex::encode(&result[..]);
        result
    }

    fn get_prefix_for_atom(&self, atom_name: &str) -> Option<String> {
        self.manual_prefixes
            .get(atom_name)
            .or_else(|| self.input_hashes.get(atom_name))
            .cloned()
    }

    #[allow(dead_code)]
    fn get_compilation_object_for_atom(&self, atom_name: &str) -> Option<&[u8]> {
        self.compilation_objects
            .get(atom_name)
            .map(|s| s.as_slice())
    }
}

fn conpile_atoms(
    atoms: &[(String, Vec<u8>)],
    output_dir: &Path,
    compiler: &CompilerOptions,
    target: &Target,
    object_format: ObjectFormat,
    prefixes: &PrefixMapCompilation,
) -> Result<BTreeMap<String, ModuleInfo>, anyhow::Error> {
    use std::fs::File;
    use std::io::BufWriter;
    use std::io::Write;

    let mut module_infos = BTreeMap::new();
    for (a, data) in atoms {
        let prefix = prefixes
            .get_prefix_for_atom(a)
            .ok_or_else(|| anyhow::anyhow!("no prefix given for atom {a}"))?;
        let (store, _) = compiler.get_store_for_target(target.clone())?;
        let atom_name = utils::normalize_atom_name(a);
        let output_object_path = output_dir.join(format!("{atom_name}.o"));
        let module_name = format!("WASMER_{}_METADATA", prefix.to_uppercase());
        match object_format {
            ObjectFormat::Symbols => {
                let engine = store.engine();
                let engine_inner = engine.inner();
                let compiler = engine_inner.compiler()?;
                let features = engine_inner.features();
                let tunables = store.tunables();
                let prefix_copy = prefix.to_string();
                let prefixer: Option<PrefixerFn> = Some(Box::new(move |_| prefix_copy.to_string()));
                let (module_info, obj, _, _) = Artifact::generate_object(
                    compiler,
                    data,
                    &module_name,
                    prefixer,
                    target,
                    tunables,
                    features,
                )?;
                module_infos.insert(atom_name, module_info);
                // Write object file with functions
                let mut writer = BufWriter::new(File::create(&output_object_path)?);
                obj.write_stream(&mut writer)
                    .map_err(|err| anyhow::anyhow!(err.to_string()))?;
                writer.flush()?;
            }
            ObjectFormat::Serialized => {
                let module = Module::from_binary(&store, data).context("failed to compile Wasm")?;
                let bytes = module.serialize()?;
                let mut obj = get_object_for_target(target.triple())?;
                emit_serialized(&mut obj, &bytes, target.triple(), &module_name)?;

                let mut writer = BufWriter::new(File::create(&output_object_path)?);
                obj.write_stream(&mut writer)
                    .map_err(|err| anyhow::anyhow!(err.to_string()))?;
                writer.flush()?;
            }
        }
    }

    Ok(module_infos)
}

/// Compile the C code.
fn run_c_compile(path_to_c_src: &Path, output_name: &Path, target: &Triple) -> anyhow::Result<()> {
    #[cfg(not(windows))]
    let c_compiler = "cc";
    // We must use a C++ compiler on Windows because wasm.h uses `static_assert`
    // which isn't available in `clang` on Windows.
    #[cfg(windows)]
    let c_compiler = "clang++";

    let mut command = Command::new(c_compiler);
    let command = command
        .arg("-Wall")
        .arg("-O2")
        .arg("-c")
        .arg(path_to_c_src)
        .arg("-I")
        .arg(utils::get_wasmer_include_directory()?)
        .arg("-target")
        .arg(format!("{}", target));

    let output = command.arg("-o").arg(output_name).output()?;
    eprintln!(
        "run_c_compile: stdout: {}\n\nstderr: {}",
        std::str::from_utf8(&output.stdout)
            .expect("stdout is not utf8! need to handle arbitrary bytes"),
        std::str::from_utf8(&output.stderr)
            .expect("stderr is not utf8! need to handle arbitrary bytes")
    );

    if !output.status.success() {
        bail!(
            "C code compile failed with: stdout: {}\n\nstderr: {}",
            std::str::from_utf8(&output.stdout)
                .expect("stdout is not utf8! need to handle arbitrary bytes"),
            std::str::from_utf8(&output.stderr)
                .expect("stderr is not utf8! need to handle arbitrary bytes")
        );
    }

    Ok(())
}

fn write_volume_obj(
    volume_bytes: &[u8],
    object_name: &str,
    output_path: &Path,
    target: &Target,
) -> anyhow::Result<()> {
    use std::fs::File;
    use std::io::BufWriter;
    use std::io::Write;

    let mut volumes_object = get_object_for_target(target.triple())?;
    emit_serialized(
        &mut volumes_object,
        volume_bytes,
        target.triple(),
        object_name,
    )?;

    let mut writer = BufWriter::new(File::create(&output_path)?);
    volumes_object
        .write_stream(&mut writer)
        .map_err(|err| anyhow::anyhow!(err.to_string()))?;
    writer.flush()?;
    drop(writer);

    Ok(())
}

/// Given a .wasm file, compiles the .wasm file into the target directory and creates the entrypoint.json
pub(super) fn prepare_directory_from_single_wasm_file(
    wasm_file: &Path,
    target_dir: &Path,
    compiler: &CompilerOptions,
    triple: &Triple,
    cpu_features: &[CpuFeature],
    object_format: ObjectFormat,
    prefix: &[String],
) -> anyhow::Result<Vec<(String, Vec<u8>)>, anyhow::Error> {
    let bytes = std::fs::read(wasm_file)?;
    let target = &utils::target_triple_to_target(triple, cpu_features);

    std::fs::create_dir_all(target_dir)
        .map_err(|e| anyhow::anyhow!("cannot create / dir in {}: {e}", target_dir.display()))?;

    let target_dir = target_dir.canonicalize()?;

    std::fs::create_dir_all(target_dir.join("atoms")).map_err(|e| {
        anyhow::anyhow!("cannot create /atoms dir in {}: {e}", target_dir.display())
    })?;

    let mut atoms_from_file = Vec::new();
    let mut target_paths = Vec::new();

    let all_files = vec![(
        wasm_file
            .file_stem()
            .and_then(|f| f.to_str())
            .unwrap_or("main")
            .to_string(),
        bytes,
    )];

    for (atom_name, atom_bytes) in all_files.iter() {
        atoms_from_file.push((atom_name.clone(), atom_bytes.to_vec()));
        let atom_path = target_dir.join("atoms").join(format!("{atom_name}.o"));
        target_paths.push((atom_name, atom_path));
    }

    let prefix_map = PrefixMapCompilation::from_input(&atoms_from_file, prefix, false)?;
    let module_infos = conpile_atoms(
        &atoms_from_file,
        &target_dir.join("atoms"),
        compiler,
        target,
        object_format,
        &prefix_map,
    )?;

    let mut atoms = Vec::new();
    for (atom_name, atom_path) in target_paths {
        atoms.push(CommandEntrypoint {
            // TODO: improve, "--command pip" should be able to invoke atom "python" with args "-m pip"
            command: atom_name.clone(),
            atom: atom_name.clone(),
            path: atom_path,
            header: None,
            module_info: module_infos.get(atom_name).cloned(),
        });
    }

    let entrypoint = Entrypoint {
        atoms,
        volumes: Vec::new(),
        object_format,
    };

    write_entrypoint(&target_dir, &entrypoint)?;

    Ok(all_files)
}

// Given the input file paths, correctly resolves the .wasm files,
// reads the module info from the wasm module and writes the ModuleInfo for each file
// into the entrypoint.json file
fn get_module_infos(
    directory: &Path,
    atoms: &[(String, Vec<u8>)],
) -> Result<BTreeMap<String, ModuleInfo>, anyhow::Error> {
    let mut entrypoint =
        get_entrypoint(directory).with_context(|| anyhow::anyhow!("get module infos"))?;

    let mut module_infos = BTreeMap::new();
    for (atom_name, atom_bytes) in atoms {
        let store = Store::default();
        let module = Module::from_binary(&store, atom_bytes.as_slice())
            .map_err(|e| anyhow::anyhow!("could not deserialize module {atom_name}: {e}"))?;
        if let Some(s) = entrypoint
            .atoms
            .iter_mut()
            .find(|a| a.atom.as_str() == atom_name.as_str())
        {
            s.module_info = Some(module.info().clone());
            module_infos.insert(atom_name.clone(), module.info().clone());
        }
    }

    write_entrypoint(directory, &entrypoint)?;

    Ok(module_infos)
}

/// Create the static_defs.h header files in the /include directory
fn create_header_files_in_dir(
    directory: &Path,
    entrypoint: &mut Entrypoint,
    atoms: &[(String, Vec<u8>)],
    prefixes: &[String],
) -> anyhow::Result<()> {
    use object::{Object, ObjectSection};
    use wasmer_types::compilation::symbols::ModuleMetadataSymbolRegistry;

    if entrypoint.object_format == ObjectFormat::Serialized {
        write_entrypoint(&directory, &entrypoint)?;
        return Ok(());
    }

    std::fs::create_dir_all(directory.join("include")).map_err(|e| {
        anyhow::anyhow!("cannot create /include dir in {}: {e}", directory.display())
    })?;

    let prefixes = PrefixMapCompilation::from_input(atoms, prefixes, false)?;

    for atom in entrypoint.atoms.iter_mut() {
        let atom_name = &atom.atom;
        let prefix = prefixes
            .get_prefix_for_atom(atom_name)
            .ok_or_else(|| anyhow::anyhow!("cannot get prefix for atom {atom_name}"))?;

        let object_file_src = directory.join(&atom.path);
        let object_file = std::fs::read(&object_file_src)
            .map_err(|e| anyhow::anyhow!("could not read {}: {e}", object_file_src.display()))?;
        let module_name = format!("WASMER_{}_METADATA", prefix.to_uppercase());
        let obj_file = object::File::parse(&*object_file)?;
        let sections = obj_file
            .sections()
            .filter_map(|s| s.name().ok().map(|s| s.to_string()))
            .collect::<Vec<_>>();
        let section = obj_file
            .section_by_name(".data")
            .unwrap()
            .data()
            .map_err(|_| {
                anyhow::anyhow!(
                    "missing section {module_name} in object file {} (sections = {:#?}",
                    object_file_src.display(),
                    sections
                )
            })?;
        let metadata_length = section.len();

        let module_info = atom
            .module_info
            .as_ref()
            .ok_or_else(|| anyhow::anyhow!("no module info for atom {atom_name:?}"))?;

        let base_path = Path::new("include").join(format!("static_defs_{prefix}.h"));
        let header_file_path = directory.join(&base_path);

        let header_file_src = crate::c_gen::staticlib_header::generate_header_file(
            &prefix,
            &format!("WASMER_{}_METADATA", prefix.to_uppercase()),
            module_info,
            &ModuleMetadataSymbolRegistry {
                prefix: prefix.clone(),
            },
            metadata_length as usize,
        );

        std::fs::write(&header_file_path, &header_file_src).map_err(|e| {
            anyhow::anyhow!(
                "could not write static_defs.h for atom {atom_name} in generate-header step: {e}"
            )
        })?;

        atom.header = Some(base_path);
    }

    write_entrypoint(&directory, &entrypoint)?;

    Ok(())
}

/// Given a directory, links all the objects from the directory appropriately
fn link_exe_from_dir(
    directory: &Path,
    output_path: PathBuf,
    cross_compilation: &CrossCompileSetup,
    additional_libraries: &[String],
    debug: bool,
    atoms: &[(String, Vec<u8>)],
    prefixes: &[String],
) -> anyhow::Result<()> {
    let entrypoint =
        get_entrypoint(directory).with_context(|| anyhow::anyhow!("link exe from dir"))?;

    let prefixes = PrefixMapCompilation::from_input(atoms, prefixes, true)?;
    let wasmer_main_c = generate_wasmer_main_c(&entrypoint, &prefixes).map_err(|e| {
        anyhow::anyhow!(
            "could not generate wasmer_main.c in dir {}: {e}",
            directory.display()
        )
    })?;

    std::fs::write(directory.join("wasmer_main.c"), wasmer_main_c.as_bytes()).map_err(|e| {
        anyhow::anyhow!(
            "could not write wasmer_main.c in dir {}: {e}",
            directory.display()
        )
    })?;

    let library_path = cross_compilation
        .library
        .as_ref()
        .ok_or_else(|| anyhow::anyhow!("libwasmer.a / wasmer.lib not found"))?;

    let mut object_paths = entrypoint
        .atoms
        .iter()
        .filter_map(|a| directory.join(&a.path).canonicalize().ok())
        .collect::<Vec<_>>();

    object_paths.extend(
        entrypoint
            .volumes
            .iter()
            .filter_map(|v| directory.join(&v.obj_file).canonicalize().ok()),
    );

    let zig_triple = utils::triple_to_zig_triple(&cross_compilation.target);
    let include_dirs = entrypoint
        .atoms
        .iter()
        .filter_map(|a| {
            Some(
                directory
                    .join(a.header.as_deref()?)
                    .canonicalize()
                    .ok()?
                    .parent()?
                    .to_path_buf(),
            )
        })
        .collect::<Vec<_>>();

    match entrypoint.object_format {
        ObjectFormat::Serialized => {
            if cross_compilation.target == Triple::host() {
                run_c_compile(
                    &directory.join("wasmer_main.c"),
                    &directory.join("wasmer_main.o"),
                    &cross_compilation.target,
                )
                .map_err(|e| {
                    anyhow::anyhow!(
                        "could not write wasmer_main.c in dir {}: {e}",
                        directory.display()
                    )
                })?;
            } else {
                return Err(anyhow::anyhow!(
                    "ObjectFormat::Serialized + cross compilation not implemented"
                ));
            }
        }
        ObjectFormat::Symbols => {}
    }

    // compilation done, now link
    if cross_compilation.zig_binary_path.is_none() {
        #[cfg(not(windows))]
        let linker = "cc";
        #[cfg(windows)]
        let linker = "clang";
        let optimization_flag = "-O2";

        let object_path = match directory.join("wasmer_main.o").canonicalize() {
            Ok(s) => s,
            Err(_) => directory.join("wasmer_main.c"),
        };

        object_paths.push(object_path);

        return link_objects_system_linker(
            library_path,
            linker,
            optimization_flag,
            &object_paths,
            &cross_compilation.target,
            additional_libraries,
            &output_path,
            debug,
        );
    }

    let zig_binary_path = cross_compilation
        .zig_binary_path
        .as_ref()
        .ok_or_else(|| anyhow::anyhow!("could not find zig in $PATH {}", directory.display()))?;

    let mut cmd = Command::new(&zig_binary_path);
    cmd.arg("build-exe");
    cmd.arg("--verbose-cc");
    cmd.arg("--verbose-link");
    cmd.arg("-target");
    cmd.arg(&zig_triple);

    if zig_triple.contains("windows") {
        cmd.arg("-lc++");
    } else {
        cmd.arg("-lc");
    }

    let mut include_dirs = include_dirs
        .iter()
        .map(|i| format!("{}", i.display()))
        .collect::<Vec<_>>();
    include_dirs.sort();
    include_dirs.dedup();
    for include_dir in include_dirs {
        cmd.arg(format!("-I{include_dir}"));
    }

    let mut include_path = library_path.clone();
    include_path.pop();
    include_path.pop();
    include_path.push("include");
    cmd.arg(format!("-I{}", include_path.display()));

    cmd.arg("-lunwind");
    cmd.arg("-OReleaseSafe");
    cmd.arg("-fno-compiler-rt");
    cmd.arg("-fno-lto");
    #[cfg(target_os = "windows")]
    let out_path = directory.join("wasmer_main.exe");
    #[cfg(not(target_os = "windows"))]
    let out_path = directory.join("wasmer_main");
    cmd.arg(&format!("-femit-bin={}", out_path.display()));
    cmd.args(&object_paths);
    cmd.arg(&library_path);
    cmd.arg(
        directory
            .join(match entrypoint.object_format {
                ObjectFormat::Serialized => "wasmer_main.o",
                ObjectFormat::Symbols => "wasmer_main.c",
            })
            .canonicalize()
            .expect("could not find wasmer_main.c / wasmer_main.o"),
    );

    if zig_triple.contains("windows") {
        let mut winsdk_path = library_path.clone();
        winsdk_path.pop();
        winsdk_path.pop();
        winsdk_path.push("winsdk");

        let files_winsdk = std::fs::read_dir(winsdk_path)
            .ok()
            .map(|res| res.filter_map(|r| Some(r.ok()?.path())).collect::<Vec<_>>())
            .unwrap_or_default();

        cmd.args(files_winsdk);
    }

    if debug {
        println!("{cmd:?}");
    }
    let compilation = cmd
        .output()
        .context(anyhow!("Could not execute `zig`: {cmd:?}"))?;

    if !compilation.status.success() {
        return Err(anyhow::anyhow!(String::from_utf8_lossy(
            &compilation.stderr
        )
        .to_string()));
    }

    // remove file if it exists - if not done, can lead to errors on copy
    let _ = std::fs::remove_file(&output_path);
    std::fs::copy(&out_path, &output_path).map_err(|e| {
        anyhow::anyhow!(
            "could not copy from {} to {}: {e}",
            out_path.display(),
            output_path.display()
        )
    })?;

    Ok(())
}

/// Link compiled objects using the system linker
#[allow(clippy::too_many_arguments)]
fn link_objects_system_linker(
    libwasmer_path: &Path,
    linker_cmd: &str,
    optimization_flag: &str,
    object_paths: &[PathBuf],
    target: &Triple,
    additional_libraries: &[String],
    output_path: &Path,
    debug: bool,
) -> Result<(), anyhow::Error> {
    let libwasmer_path = libwasmer_path
        .canonicalize()
        .context("Failed to find libwasmer")?;
    println!(
        "Using path `{}` as libwasmer path.",
        libwasmer_path.display()
    );
    let mut command = Command::new(linker_cmd);
    let command = command
        .arg("-Wall")
        .arg(optimization_flag)
        .args(object_paths.iter().map(|path| path.canonicalize().unwrap()))
        .arg(&libwasmer_path)
        .arg("-target")
        .arg(format!("{}", target));

    // Add libraries required per platform.
    // We need userenv, sockets (Ws2_32), advapi32 for some system calls and bcrypt for random numbers.
    #[cfg(windows)]
    let command = command
        .arg("-luserenv")
        .arg("-lWs2_32")
        .arg("-ladvapi32")
        .arg("-lbcrypt");

    // On unix we need dlopen-related symbols, libmath for a few things, and pthreads.
    #[cfg(not(windows))]
    let command = command.arg("-ldl").arg("-lm").arg("-pthread");
    let link_against_extra_libs = additional_libraries.iter().map(|lib| format!("-l{}", lib));
    let command = command.args(link_against_extra_libs);
    let command = command.arg("-o").arg(output_path);
    if debug {
        println!("{:#?}", command);
    }
    let output = command.output()?;

    if !output.status.success() {
        bail!(
            "linking failed with: stdout: {}\n\nstderr: {}",
            std::str::from_utf8(&output.stdout)
                .expect("stdout is not utf8! need to handle arbitrary bytes"),
            std::str::from_utf8(&output.stderr)
                .expect("stderr is not utf8! need to handle arbitrary bytes")
        );
    }
    Ok(())
}

/// Generate the wasmer_main.c that links all object files together
/// (depending on the object format / atoms number)
fn generate_wasmer_main_c(
    entrypoint: &Entrypoint,
    prefixes: &PrefixMapCompilation,
) -> Result<String, anyhow::Error> {
    use std::fmt::Write;

    const WASMER_MAIN_C_SOURCE: &str = include_str!("wasmer_create_exe_main.c");

    let compile_static = entrypoint.object_format == ObjectFormat::Symbols;

    // always with compile zig + static_defs.h
    let atom_names = entrypoint
        .atoms
        .iter()
        .map(|a| &a.command)
        .collect::<Vec<_>>();

    let mut c_code_to_add = String::new();
    let mut c_code_to_instantiate = String::new();
    let mut deallocate_module = String::new();
    let mut extra_headers = Vec::new();

    for a in atom_names.iter() {
        let prefix = prefixes
            .get_prefix_for_atom(&utils::normalize_atom_name(a))
            .ok_or_else(|| {
                anyhow::anyhow!(
                    "cannot find prefix for atom {a} when generating wasmer_main.c ({:#?})",
                    prefixes
                )
            })?;
        let atom_name = prefix.clone();
        let module_name = format!("WASMER_{}_METADATA", prefix.to_uppercase());

        if compile_static {
            extra_headers.push(format!("#include \"static_defs_{atom_name}.h\""));

            write!(c_code_to_instantiate, "
            wasm_module_t *atom_{atom_name} = wasmer_object_module_new_{atom_name}(store, \"{atom_name}\");
            if (!atom_{atom_name}) {{
                fprintf(stderr, \"Failed to create module from atom \\\"{a}\\\"\\n\");
                print_wasmer_error();
                return -1;
            }}
            ")?;
        } else {
            extra_headers.push(format!("const extern unsigned char {module_name}[];\r\n"));

            write!(
                c_code_to_add,
                "
                extern size_t {module_name}_LENGTH asm(\"{module_name}_LENGTH\");
                extern char {module_name}_DATA asm(\"{module_name}_DATA\");
                "
            )?;

            write!(c_code_to_instantiate, "
            wasm_byte_vec_t atom_{atom_name}_byte_vec = {{
                .size = {module_name}_LENGTH,
                .data = &{module_name}_DATA,
            }};
            wasm_module_t *atom_{atom_name} = wasm_module_deserialize(store, &atom_{atom_name}_byte_vec);
            if (!atom_{atom_name}) {{
                fprintf(stderr, \"Failed to create module from atom \\\"{atom_name}\\\"\\n\");
                print_wasmer_error();
                return -1;
            }}
            ")?;
        }

        write!(deallocate_module, "wasm_module_delete(atom_{atom_name});")?;
    }

    let volumes_str = entrypoint
        .volumes
        .iter()
        .map(|v| utils::normalize_atom_name(&v.name).to_uppercase())
        .map(|uppercase| {
            vec![
                format!("extern size_t {uppercase}_LENGTH asm(\"{uppercase}_LENGTH\");"),
                format!("extern char {uppercase}_DATA asm(\"{uppercase}_DATA\");"),
            ]
            .join("\r\n")
        })
        .collect::<Vec<_>>();

    let base_str = WASMER_MAIN_C_SOURCE;
    let volumes_str = volumes_str.join("\r\n");
    let return_str = base_str
        .replace(
            "#define WASI",
            if !volumes_str.trim().is_empty() {
                "#define WASI\r\n#define WASI_PIRITA"
            } else {
                "#define WASI"
            },
        )
        .replace("// DECLARE_MODULES", &c_code_to_add)
        .replace("// DECLARE_VOLUMES", &volumes_str)
        .replace("// EXTRA_HEADERS", &extra_headers.join("\r\n"))
        .replace("wasm_module_delete(module);", &deallocate_module);

    if atom_names.len() == 1 {
        let prefix = prefixes
            .get_prefix_for_atom(&utils::normalize_atom_name(&atom_names[0]))
            .ok_or_else(|| {
                anyhow::anyhow!(
                    "cannot find prefix for atom {} when generating wasmer_main.c ({:#?})",
                    &atom_names[0],
                    prefixes
                )
            })?;
        write!(c_code_to_instantiate, "module = atom_{prefix};")?;
    } else {
        for a in atom_names.iter() {
            let prefix = prefixes
                .get_prefix_for_atom(&utils::normalize_atom_name(a))
                .ok_or_else(|| {
                    anyhow::anyhow!(
                        "cannot find prefix for atom {a} when generating wasmer_main.c ({:#?})",
                        prefixes
                    )
                })?;
            writeln!(
                c_code_to_instantiate,
                "if (strcmp(selected_atom, \"{a}\") == 0) {{ module = atom_{}; }}",
                prefix
            )?;
        }
    }

    write!(
        c_code_to_instantiate,
        "
    if (!module) {{
        fprintf(stderr, \"No --command given, available commands are:\\n\");
        fprintf(stderr, \"\\n\");
        {commands}
        fprintf(stderr, \"\\n\");
        return -1;
    }}
    ",
        commands = atom_names
            .iter()
            .map(|a| format!("fprintf(stderr, \"    {a}\\n\");"))
            .collect::<Vec<_>>()
            .join("\n")
    )?;

    Ok(return_str.replace("// INSTANTIATE_MODULES", &c_code_to_instantiate))
}

#[allow(dead_code)]
pub(super) mod utils {

    use super::{CrossCompile, CrossCompileSetup};
    use anyhow::Context;
    use std::path::{Path, PathBuf};
    use target_lexicon::{Architecture, OperatingSystem, Triple};
    use wasmer_types::{CpuFeature, Target};

    pub(in crate::commands) fn target_triple_to_target(
        target_triple: &Triple,
        cpu_features: &[CpuFeature],
    ) -> Target {
        let mut features = cpu_features.iter().fold(CpuFeature::set(), |a, b| a | *b);
        // Cranelift requires SSE2, so we have this "hack" for now to facilitate
        // usage
        if target_triple.architecture == Architecture::X86_64 {
            features |= CpuFeature::SSE2;
        }
        Target::new(target_triple.clone(), features)
    }

    pub(in crate::commands) fn get_cross_compile_setup(
        cross_subc: &mut CrossCompile,
        target_triple: &Triple,
        starting_cd: &Path,
    ) -> Result<CrossCompileSetup, anyhow::Error> {
        let target = target_triple;

        if let Some(tarball_path) = cross_subc.tarball.as_mut() {
            if tarball_path.is_relative() {
                *tarball_path = starting_cd.join(&tarball_path);
                if !tarball_path.exists() {
                    return Err(anyhow!(
                        "Tarball path `{}` does not exist.",
                        tarball_path.display()
                    ));
                } else if tarball_path.is_dir() {
                    return Err(anyhow!(
                        "Tarball path `{}` is a directory.",
                        tarball_path.display()
                    ));
                }
            }
        }

        let zig_binary_path = if !cross_subc.use_system_linker {
            find_zig_binary(cross_subc.zig_binary_path.as_ref().and_then(|p| {
                if p.is_absolute() {
                    p.canonicalize().ok()
                } else {
                    starting_cd.join(p).canonicalize().ok()
                }
            }))
            .ok()
        } else {
            None
        };

        let library = if let Some(v) = cross_subc.library_path.clone() {
            Some(v.canonicalize().unwrap_or(v))
        } else {
            if let Some(local_tarball) = cross_subc.tarball.as_ref() {
                find_filename(local_tarball, target)
            } else {
                // check if the tarball for the target already exists locally
                let local_tarball = std::fs::read_dir(get_libwasmer_cache_path()?)?
                    .filter_map(|e| e.ok())
                    .filter_map(|e| {
                        let path = format!("{}", e.path().display());
                        if path.ends_with(".tar.gz") {
                            Some(e.path())
                        } else {
                            None
                        }
                    })
                    .filter_map(|p| filter_tarballs(&p, target))
                    .next();

                if let Some(local_tarball) = local_tarball.as_ref() {
                    find_filename(local_tarball, target)
                } else {
                    let release = super::http_fetch::get_latest_release()?;
                    let tarball = super::http_fetch::download_release(release, target.clone())?;
                    find_filename(&tarball, target)
                }
            }
            .ok()
            .map(|(filename, tarball_dir)| tarball_dir.join(&filename))
        };
        let ccs = CrossCompileSetup {
            target: target.clone(),
            zig_binary_path,
            library,
        };
        Ok(ccs)
    }

    pub(super) fn find_filename(
        local_tarball: &Path,
        target: &Triple,
    ) -> Result<(String, PathBuf), anyhow::Error> {
        let target_file_path = local_tarball
            .parent()
            .and_then(|parent| Some(parent.join(local_tarball.file_stem()?)))
            .unwrap_or_else(|| local_tarball.to_path_buf());

        let target_file_path = target_file_path
            .parent()
            .and_then(|parent| Some(parent.join(target_file_path.file_stem()?)))
            .unwrap_or_else(|| target_file_path.clone());

        std::fs::create_dir_all(&target_file_path)
            .map_err(|e| anyhow::anyhow!("{e}"))
            .with_context(|| anyhow::anyhow!("{}", target_file_path.display()))?;
        let files =
            super::http_fetch::untar(local_tarball.to_path_buf(), target_file_path.clone())?;
        let tarball_dir = target_file_path.canonicalize().unwrap_or(target_file_path);

        let file = files
        .iter()
        .find(|f| f.ends_with("libwasmer-headless.a") || f.ends_with("wasmer-headless.lib"))
        .or_else(|| {
            files
            .iter()
            .find(|f| f.ends_with("libwasmer.a") || f.ends_with("wasmer.lib"))
        })
        .cloned()
        .ok_or_else(|| {
            anyhow!("Could not find libwasmer.a for {} target in the provided tarball path (files = {files:#?})", target)
        })?;

        Ok((file, tarball_dir))
    }

    pub(super) fn filter_tarballs(p: &Path, target: &Triple) -> Option<PathBuf> {
        if let Architecture::Aarch64(_) = target.architecture {
            if !(p.file_name()?.to_str()?.contains("aarch64")
                || p.file_name()?.to_str()?.contains("-arm"))
            {
                return None;
            }
        }

        if let Architecture::X86_64 = target.architecture {
            if !(p.file_name()?.to_str()?.contains("x86_64")
                || p.file_name()?.to_str()?.contains("-gnu64"))
            {
                return None;
            }
        }

        if let OperatingSystem::Windows = target.operating_system {
            if !p.file_name()?.to_str()?.contains("windows") {
                return None;
            }
        }

        if let OperatingSystem::Darwin = target.operating_system {
            if !(p.file_name()?.to_str()?.contains("apple")
                || p.file_name()?.to_str()?.contains("darwin"))
            {
                return None;
            }
        }

        if let OperatingSystem::Linux = target.operating_system {
            if !p.file_name()?.to_str()?.contains("linux") {
                return None;
            }
        }

        Some(p.to_path_buf())
    }

    pub(super) fn normalize_atom_name(s: &str) -> String {
        s.chars()
            .filter_map(|c| {
                if char::is_alphabetic(c) {
                    Some(c)
                } else if c == '-' || c == '_' {
                    Some('_')
                } else {
                    None
                }
            })
            .collect()
    }

    pub(super) fn triple_to_zig_triple(target_triple: &Triple) -> String {
        let arch = match target_triple.architecture {
            wasmer_types::Architecture::X86_64 => "x86_64".into(),
            wasmer_types::Architecture::Aarch64(wasmer_types::Aarch64Architecture::Aarch64) => {
                "aarch64".into()
            }
            v => v.to_string(),
        };
        let os = match target_triple.operating_system {
            wasmer_types::OperatingSystem::Linux => "linux".into(),
            wasmer_types::OperatingSystem::Darwin => "macos".into(),
            wasmer_types::OperatingSystem::Windows => "windows".into(),
            v => v.to_string(),
        };
        let env = match target_triple.environment {
            wasmer_types::Environment::Musl => "musl",
            wasmer_types::Environment::Gnu => "gnu",
            wasmer_types::Environment::Msvc => "msvc",
            _ => "none",
        };
        format!("{}-{}-{}", arch, os, env)
    }

    pub(super) fn get_wasmer_dir() -> anyhow::Result<PathBuf> {
        wasmer_registry::WasmerConfig::get_wasmer_dir().map_err(|e| anyhow::anyhow!("{e}"))
    }

    pub(super) fn get_wasmer_include_directory() -> anyhow::Result<PathBuf> {
        let mut path = get_wasmer_dir()?;
        if path.clone().join("wasmer.h").exists() {
            return Ok(path);
        }
        path.push("include");
        if !path.clone().join("wasmer.h").exists() {
            println!(
                "wasmer.h does not exist in {}, will probably default to the system path",
                path.canonicalize().unwrap().display()
            );
        }
        Ok(path)
    }

    /// path to the static libwasmer
    pub(super) fn get_libwasmer_path() -> anyhow::Result<PathBuf> {
        let path = get_wasmer_dir()?;

        // TODO: prefer headless Wasmer if/when it's a separate library.
        #[cfg(not(windows))]
        let libwasmer_static_name = "libwasmer.a";
        #[cfg(windows)]
        let libwasmer_static_name = "libwasmer.lib";

        if path.exists() && path.join(libwasmer_static_name).exists() {
            Ok(path.join(libwasmer_static_name))
        } else {
            Ok(path.join("lib").join(libwasmer_static_name))
        }
    }

    /// path to library tarball cache dir
    pub(super) fn get_libwasmer_cache_path() -> anyhow::Result<PathBuf> {
        let mut path = get_wasmer_dir()?;
        path.push("cache");
        let _ = std::fs::create_dir(&path);
        Ok(path)
    }

    pub(super) fn get_zig_exe_str() -> &'static str {
        #[cfg(target_os = "windows")]
        {
            "zig.exe"
        }
        #[cfg(not(target_os = "windows"))]
        {
            "zig"
        }
    }

    pub(super) fn find_zig_binary(path: Option<PathBuf>) -> Result<PathBuf, anyhow::Error> {
        use std::env::split_paths;
        use std::ffi::OsStr;
        #[cfg(unix)]
        use std::os::unix::ffi::OsStrExt;
        let path_var = std::env::var("PATH").unwrap_or_default();
        #[cfg(unix)]
        let system_path_var = std::process::Command::new("getconf")
            .args(&["PATH"])
            .output()
            .map(|output| output.stdout)
            .unwrap_or_default();
        let retval = if let Some(p) = path {
            if p.exists() {
                p
            } else {
                return Err(anyhow!("Could not find `zig` binary in {}.", p.display()));
            }
        } else {
            let mut retval = None;
            for mut p in split_paths(&path_var).chain(split_paths(
                #[cfg(unix)]
                {
                    &OsStr::from_bytes(&system_path_var[..])
                },
                #[cfg(not(unix))]
                {
                    OsStr::new("")
                },
            )) {
                p.push(get_zig_exe_str());
                if p.exists() {
                    retval = Some(p);
                    break;
                }
            }
            retval.ok_or_else(|| anyhow!("Could not find `zig` binary in PATH."))?
        };

        let version = std::process::Command::new(&retval)
            .arg("version")
            .output()
            .with_context(|| {
                format!(
                    "Could not execute `zig` binary at path `{}`",
                    retval.display()
                )
            })?
            .stdout;
        let version_slice = if let Some(pos) = version
            .iter()
            .position(|c| !(c.is_ascii_digit() || (*c == b'.')))
        {
            &version[..pos]
        } else {
            &version[..]
        };

        if version_slice < b"0.10.0".as_ref() {
            Err(anyhow!("`zig` binary in PATH (`{}`) is not a new enough version (`{}`): please use version `0.10.0` or newer.", retval.display(), String::from_utf8_lossy(version_slice)))
        } else {
            Ok(retval)
        }
    }

    #[test]
    fn test_normalize_atom_name() {
        assert_eq!(
            normalize_atom_name("atom-name-with-dash"),
            "atom_name_with_dash".to_string()
        );
    }
}

mod http_fetch {
    use anyhow::{anyhow, Context, Result};
    use http_req::{request::Request, response::StatusCode, uri::Uri};
    use std::convert::TryFrom;
    use target_lexicon::OperatingSystem;

    pub(super) fn get_latest_release() -> Result<serde_json::Value> {
        let mut writer = Vec::new();
        let uri = Uri::try_from("https://api.github.com/repos/wasmerio/wasmer/releases").unwrap();

        // Increases rate-limiting in GitHub CI
        let auth = std::env::var("GITHUB_TOKEN");
        let mut response = Request::new(&uri);

        if let Ok(token) = auth {
            response.header("Authorization", &format!("Bearer {token}"));
        }

        let response = response
            .header("User-Agent", "wasmerio")
            .header("Accept", "application/vnd.github.v3+json")
            .timeout(Some(std::time::Duration::new(30, 0)))
            .send(&mut writer)
            .map_err(anyhow::Error::new)
            .context("Could not lookup wasmer repository on Github.")?;

        if response.status_code() != StatusCode::new(200) {
            #[cfg(feature = "debug")]
            log::warn!(
                "Warning: Github API replied with non-200 status code: {}. Response: {}",
                response.status_code(),
                String::from_utf8_lossy(&writer),
            );
        }

        let v: std::result::Result<serde_json::Value, _> = serde_json::from_reader(&*writer);
        let mut response = v.map_err(anyhow::Error::new)?;

        if let Some(releases) = response.as_array_mut() {
            releases.retain(|r| {
                r["tag_name"].is_string() && !r["tag_name"].as_str().unwrap().is_empty()
            });
            releases.sort_by_cached_key(|r| r["tag_name"].as_str().unwrap_or_default().to_string());
            if let Some(latest) = releases.pop() {
                return Ok(latest);
            }
        }

        Err(anyhow!(
            "Could not get expected Github API response.\n\nReason: response format is not recognized:\n{response:#?}",
        ))
    }

    pub(super) fn download_release(
        mut release: serde_json::Value,
        target_triple: wasmer::Triple,
    ) -> Result<std::path::PathBuf> {
        let check_arch = |name: &str| -> bool {
            match target_triple.architecture {
                wasmer_types::Architecture::X86_64 => {
                    name.contains("x86_64") || name.contains("amd64")
                }
                wasmer_types::Architecture::Aarch64(wasmer_types::Aarch64Architecture::Aarch64) => {
                    name.contains("arm64") || name.contains("aarch64")
                }
                _ => false,
            }
        };

        let check_vendor = |name: &str| -> bool {
            match target_triple.vendor {
                wasmer_types::Vendor::Apple => {
                    name.contains("apple") || name.contains("macos") || name.contains("darwin")
                }
                wasmer_types::Vendor::Pc => name.contains("windows"),
                _ => true,
            }
        };
        let check_os = |name: &str| -> bool {
            match target_triple.operating_system {
                wasmer_types::OperatingSystem::Darwin => {
                    name.contains("apple") || name.contains("darwin") || name.contains("macos")
                }
                wasmer_types::OperatingSystem::Windows => name.contains("windows"),
                wasmer_types::OperatingSystem::Linux => name.contains("linux"),
                _ => false,
            }
        };
        let check_env = |name: &str| -> bool {
            match target_triple.environment {
                wasmer_types::Environment::Musl => name.contains("musl"),
                _ => !name.contains("musl"),
            }
        };

        // Test if file has been already downloaded
        if let Ok(mut cache_path) = super::utils::get_libwasmer_cache_path() {
            let paths = std::fs::read_dir(&cache_path).and_then(|r| {
                r.map(|res| res.map(|e| e.path()))
                    .collect::<Result<Vec<_>, std::io::Error>>()
            });

            if let Ok(mut entries) = paths {
                entries.retain(|p| p.to_str().map(|p| p.ends_with(".tar.gz")).unwrap_or(false));

                // create-exe on Windows is special: we use the windows-gnu64.tar.gz (GNU ABI)
                // to link, not the windows-amd64.tar.gz (MSVC ABI)
                if target_triple.operating_system == OperatingSystem::Windows {
                    entries.retain(|p| {
                        p.to_str()
                            .map(|p| p.contains("windows") && p.contains("gnu64"))
                            .unwrap_or(false)
                    });
                } else {
                    entries.retain(|p| p.to_str().map(|p| check_arch(p)).unwrap_or(true));
                    entries.retain(|p| p.to_str().map(|p| check_vendor(p)).unwrap_or(true));
                    entries.retain(|p| p.to_str().map(|p| check_os(p)).unwrap_or(true));
                    entries.retain(|p| p.to_str().map(|p| check_env(p)).unwrap_or(true));
                }

                if !entries.is_empty() {
                    cache_path.push(&entries[0]);
                    if cache_path.exists() {
                        eprintln!(
                            "Using cached tarball to cache path `{}`.",
                            cache_path.display()
                        );
                        return Ok(cache_path);
                    }
                }
            }
        }

        let assets = match release["assets"].as_array_mut() {
            Some(s) => s,
            None => {
                return Err(anyhow!(
                    "GitHub API: no [assets] array in JSON response for latest releases"
                ));
            }
        };

        // create-exe on Windows is special: we use the windows-gnu64.tar.gz (GNU ABI)
        // to link, not the windows-amd64.tar.gz (MSVC ABI)
        if target_triple.operating_system == OperatingSystem::Windows {
            assets.retain(|a| {
                if let Some(name) = a["name"].as_str() {
                    name.contains("windows") && name.contains("gnu64")
                } else {
                    false
                }
            });
        } else {
            assets.retain(|a| {
                if let Some(name) = a["name"].as_str() {
                    check_arch(name)
                } else {
                    false
                }
            });
            assets.retain(|a| {
                if let Some(name) = a["name"].as_str() {
                    check_vendor(name)
                } else {
                    false
                }
            });

            assets.retain(|a| {
                if let Some(name) = a["name"].as_str() {
                    check_os(name)
                } else {
                    false
                }
            });

            assets.retain(|a| {
                if let Some(name) = a["name"].as_str() {
                    check_env(name)
                } else {
                    false
                }
            });
        }

        if assets.len() != 1 {
            return Err(anyhow!(
                "GitHub API: more that one release selected for target {target_triple}: {assets:?}"
            ));
        }

        let browser_download_url = if let Some(url) = assets[0]["browser_download_url"].as_str() {
            url.to_string()
        } else {
            return Err(anyhow!(
                "Could not get download url from Github API response."
            ));
        };

        let filename = browser_download_url
            .split('/')
            .last()
            .unwrap_or("output")
            .to_string();

        let download_tempdir = tempdir::TempDir::new("wasmer-download")?;
        let download_path = download_tempdir.path().join(&filename);

        let mut file = std::fs::File::create(&download_path)?;
        #[cfg(feature = "debug")]
        log::debug!(
            "Downloading {} to {}",
            browser_download_url,
            download_path.display()
        );

        let mut response = reqwest::blocking::Client::builder()
            .redirect(reqwest::redirect::Policy::limited(10))
            .timeout(std::time::Duration::from_secs(10))
            .build()
            .map_err(anyhow::Error::new)
            .context("Could not lookup wasmer artifact on Github.")?
            .get(browser_download_url.as_str())
            .send()
            .map_err(anyhow::Error::new)
            .context("Could not lookup wasmer artifact on Github.")?;

        response
            .copy_to(&mut file)
            .map_err(|e| anyhow::anyhow!("{e}"))?;

        match super::utils::get_libwasmer_cache_path() {
            Ok(mut cache_path) => {
                cache_path.push(&filename);
                if let Err(err) = std::fs::copy(&download_path, &cache_path) {
                    eprintln!(
                        "Could not store tarball to cache path `{}`: {}",
                        cache_path.display(),
                        err
                    );
                    Err(anyhow!(
                        "Could not copy from {} to {}",
                        download_path.display(),
                        cache_path.display()
                    ))
                } else {
                    eprintln!("Cached tarball to cache path `{}`.", cache_path.display());
                    Ok(cache_path)
                }
            }
            Err(err) => {
                eprintln!(
                    "Could not determine cache path for downloaded binaries.: {}",
                    err
                );
                Err(anyhow!("Could not determine libwasmer cache path"))
            }
        }
    }

    pub(super) fn untar(
        tarball: std::path::PathBuf,
        target: std::path::PathBuf,
    ) -> Result<Vec<String>> {
        use walkdir::WalkDir;

        wasmer_registry::try_unpack_targz(&tarball, &target, false)?;

        Ok(WalkDir::new(&target)
            .into_iter()
            .filter_map(|e| e.ok())
            .map(|entry| format!("{}", entry.path().display()))
            .collect())
    }
}