use std::path::PathBuf;
use std::process::Command;

/// Extract audio from a video file to a WAV file using ffmpeg.
/// Returns the path to the extracted audio file.
#[tauri::command]
pub fn extract_audio(file_path: String) -> Result<String, String> {
    let input = PathBuf::from(&file_path);
    if !input.exists() {
        return Err(format!("File not found: {}", file_path));
    }

    // Output to a temp WAV file next to the original or in temp dir
    let stem = input.file_stem().unwrap_or_default().to_string_lossy();
    let output = std::env::temp_dir().join(format!("{stem}_audio.wav"));

    eprintln!(
        "[media] Extracting audio: {} -> {}",
        input.display(),
        output.display()
    );

    // Find ffmpeg — check sidecar extract dir first, then system PATH
    let ffmpeg = find_ffmpeg().ok_or("ffmpeg not found. Install ffmpeg or ensure it's in PATH.")?;

    let status = Command::new(&ffmpeg)
        .args([
            "-y",             // Overwrite output
            "-i",
            &file_path,
            "-vn",            // No video
            "-acodec",
            "pcm_s16le",      // WAV PCM 16-bit
            "-ar",
            "16000",          // 16kHz (optimal for whisper)
            "-ac",
            "1",              // Mono
        ])
        .arg(output.to_str().unwrap())
        .stdout(std::process::Stdio::null())
        .stderr(std::process::Stdio::piped())
        .status()
        .map_err(|e| format!("Failed to run ffmpeg: {e}"))?;

    if !status.success() {
        return Err(format!("ffmpeg exited with status {status}"));
    }

    if !output.exists() {
        return Err("ffmpeg completed but output file not found".to_string());
    }

    eprintln!("[media] Audio extracted successfully");
    Ok(output.to_string_lossy().to_string())
}

/// Find ffmpeg binary — check sidecar directory first, then system PATH.
fn find_ffmpeg() -> Option<String> {
    // Check sidecar extract dir (ffmpeg is bundled with the sidecar)
    if let Some(data_dir) = crate::sidecar::DATA_DIR.get() {
        // Read sidecar version to find the right directory
        let version_file = data_dir.join("sidecar-version.txt");
        if let Ok(version) = std::fs::read_to_string(&version_file) {
            let version = version.trim();
            let sidecar_dir = data_dir.join(format!("sidecar-{version}"));
            let ffmpeg_name = if cfg!(target_os = "windows") {
                "ffmpeg.exe"
            } else {
                "ffmpeg"
            };
            let ffmpeg_path = sidecar_dir.join(ffmpeg_name);
            if ffmpeg_path.exists() {
                return Some(ffmpeg_path.to_string_lossy().to_string());
            }
        }
    }

    // Fall back to system PATH
    let ffmpeg_name = if cfg!(target_os = "windows") {
        "ffmpeg.exe"
    } else {
        "ffmpeg"
    };
    if Command::new(ffmpeg_name)
        .arg("-version")
        .stdout(std::process::Stdio::null())
        .stderr(std::process::Stdio::null())
        .status()
        .is_ok()
    {
        return Some(ffmpeg_name.to_string());
    }

    None
}