// --- Commands ---

mod transcription;

/// Returns the backend URL. Stubbed for now; will be replaced once the
/// Python/Rust backend is fully wired up.
#[tauri::command]
fn get_backend_url() -> String {
    // During development the Python backend still runs on 8642.
    // In production this will be replaced with a local Rust server or IPC.
    "http://localhost:8642".to_string()
}

/// Minimal encrypt: base64-encodes the string as a placeholder until a proper
/// OS keychain implementation is added (e.g. tauri-plugin-stronghold).
#[tauri::command]
fn encrypt_string(data: String) -> String {
    data
        .as_bytes()
        .iter()
        .fold(String::new(), |mut acc, b| {
            use std::fmt::Write as FmtWrite;
            let _ = write!(acc, "{:02x}", b);
            acc
        })
}

/// Companion decode for encrypt_string.
#[tauri::command]
fn decrypt_string(encrypted: String) -> Result<String, String> {
    (0..encrypted.len())
        .step_by(2)
        .map(|i| u8::from_str_radix(&encrypted[i..i + 2], 16))
        .collect::<Result<Vec<u8>, _>>()
        .map_err(|e| format!("decrypt error: {e}"))
        .and_then(|b| String::from_utf8(b).map_err(|e| format!("utf8 error: {e}")))
}

/// Ensure a Whisper model is downloaded, downloading it if not present.
#[tauri::command]
async fn ensure_model(model_name: String) -> Result<String, String> {
    tauri::async_runtime::spawn_blocking(move || {
        transcription::ensure_model_downloaded(&model_name)
    })
    .await
    .map_err(|e| format!("Task error: {:?}", e))?
}

/// Transcribe audio file using Whisper.cpp (runs on a background thread)
#[tauri::command]
async fn transcribe_audio(file_path: String, model_name: String, language: Option<String>) -> Result<transcription::TranscriptionResult, String> {
    tauri::async_runtime::spawn_blocking(move || {
        transcription::transcribe_audio(&file_path, &model_name, language.as_deref())
    })
    .await
    .map_err(|e| format!("Task error: {:?}", e))?
}

// --- App entry point ---

#[cfg_attr(mobile, tauri::mobile_entry_point)]
pub fn run() {
    tauri::Builder::default()
        .plugin(tauri_plugin_dialog::init())
        .plugin(tauri_plugin_fs::init())
        .setup(|app| {
            if cfg!(debug_assertions) {
                app.handle().plugin(
                    tauri_plugin_log::Builder::default()
                        .level(log::LevelFilter::Info)
                        .build(),
                )?;
            }
            Ok(())
        })
        .invoke_handler(tauri::generate_handler![
            get_backend_url,
            encrypt_string,
            decrypt_string,
            ensure_model,
            transcribe_audio,
        ])
        .run(tauri::generate_context!())
        .expect("error while running tauri application");
}