fn main() {
    // Ensure MinGW tools are on PATH for build scripts (windres, dlltool, etc.)
    let mingw_bin = "C:/Users/lashman/mingw-w64/mingw64/bin";
    if let Ok(current_path) = std::env::var("PATH") {
        std::env::set_var("PATH", format!("{};{}", mingw_bin, current_path));
    } else {
        std::env::set_var("PATH", mingw_bin);
    }

    // On GNU targets, replace the WebView2Loader import library with the static
    // library so the loader is baked into the exe — no DLL to ship.
    if std::env::var("CARGO_CFG_TARGET_ENV").as_deref() == Ok("gnu") {
        swap_webview2_to_static();
    }

    tauri_build::build();

    // When targeting GNU, embed-resource may find MSVC's rc.exe (via Windows
    // SDK) and produce a .res file instead of COFF .o. GNU ld can't link .res
    // files. Fix: re-compile with windres if needed.
    // Note: cfg() in build scripts checks the HOST, not target. Use env var.
    if std::env::var("CARGO_CFG_TARGET_ENV").as_deref() == Ok("gnu") {
        fix_resource_lib();
    }
}

/// If resource.lib is in .res format (produced by MSVC rc.exe), re-compile
/// the .rc source with MinGW windres to produce a COFF object that GNU ld
/// can link.
fn fix_resource_lib() {
    use std::path::PathBuf;
    use std::process::Command;

    let out_dir = std::env::var("OUT_DIR").unwrap_or_default();
    let out_path = PathBuf::from(&out_dir);
    let rc_file = out_path.join("resource.rc");
    let lib_file = out_path.join("resource.lib");

    if !rc_file.exists() || !lib_file.exists() {
        return;
    }

    // Check if the file is already COFF (starts with COFF machine type or
    // archive signature). A .res file starts with 0x00000000.
    if let Ok(header) = std::fs::read(&lib_file) {
        if header.len() >= 4 && header[0..4] == [0, 0, 0, 0] {
            // This is a .res file, not COFF — re-compile with windres
            let windres = "C:/Users/lashman/mingw-w64/mingw64/bin/windres.exe";
            let status = Command::new(windres)
                .args([
                    "-i", &rc_file.to_string_lossy(),
                    "-o", &lib_file.to_string_lossy(),
                    "--output-format=coff",
                ])
                .status();

            match status {
                Ok(s) if s.success() => {
                    println!("cargo:warning=Re-compiled resource.rc with windres (COFF output)");
                }
                Ok(s) => {
                    println!("cargo:warning=windres failed with exit code: {}", s);
                }
                Err(e) => {
                    println!("cargo:warning=Failed to run windres: {}", e);
                }
            }
        }
    }
}

/// Replace `WebView2Loader.dll.lib` (dynamic import lib) with the contents of
/// `WebView2LoaderStatic.lib` (static archive) in the webview2-com-sys build
/// output. The linker then statically links the WebView2 loader code, removing
/// the runtime dependency on WebView2Loader.dll.
fn swap_webview2_to_static() {
    use std::fs;
    use std::path::PathBuf;

    let out_dir = std::env::var("OUT_DIR").unwrap_or_default();
    // OUT_DIR = target/.../build/core-cooldown-HASH/out
    // We need:  target/.../build/  (two levels up)
    let build_dir = PathBuf::from(&out_dir)
        .parent()   // core-cooldown-HASH
        .and_then(|p| p.parent()) // build/
        .map(|p| p.to_path_buf());

    let build_dir = match build_dir {
        Some(d) => d,
        None => return,
    };

    let target_arch = match std::env::var("CARGO_CFG_TARGET_ARCH")
        .unwrap_or_default()
        .as_str()
    {
        "x86_64" => "x64",
        "x86" => "x86",
        "aarch64" => "arm64",
        _ => return,
    };

    let entries = match fs::read_dir(&build_dir) {
        Ok(e) => e,
        Err(_) => return,
    };

    for entry in entries.flatten() {
        let name = entry.file_name();
        let name = name.to_string_lossy();
        if !name.starts_with("webview2-com-sys-") {
            continue;
        }

        let lib_dir = entry.path().join("out").join(target_arch);
        let import_lib = lib_dir.join("WebView2Loader.dll.lib");
        let static_lib = lib_dir.join("WebView2LoaderStatic.lib");

        if static_lib.exists() && import_lib.exists() {
            if let Ok(static_bytes) = fs::read(&static_lib) {
                match fs::write(&import_lib, &static_bytes) {
                    Ok(_) => println!(
                        "cargo:warning=Swapped WebView2Loader to static linking ({})",
                        lib_dir.display()
                    ),
                    Err(e) => println!(
                        "cargo:warning=Failed to swap WebView2Loader lib: {}",
                        e
                    ),
                }
            }
        }
    }
}