mod auth;
mod config;
mod db;
mod errors;
mod models;
mod routes;
mod webpush;

use axum::routing::{get, post, put};
use axum::Router;
use tower_http::cors::{Any, CorsLayer};
use tower_http::services::{ServeDir, ServeFile};

#[tokio::main]
async fn main() {
    // Load .env file (silently ignore if missing).
    let _ = dotenvy::dotenv();

    let database_url = config::database_url();
    let pool = db::init_pool(&database_url).await;
    db::run_migrations(&pool).await;

    let (vapid_pem, vapid_pub) = webpush::init_vapid_keys(&pool).await;
    let state = config::AppState::new(pool, config::jwt_secret(), vapid_pem, vapid_pub);
    let port = config::port();

    // Spawn background notification scheduler
    tokio::spawn(notification_scheduler(state.clone()));

    let cors = CorsLayer::new()
        .allow_origin(Any)
        .allow_methods([
            axum::http::Method::GET,
            axum::http::Method::POST,
            axum::http::Method::PUT,
            axum::http::Method::DELETE,
        ])
        .allow_headers([
            axum::http::header::AUTHORIZATION,
            axum::http::header::CONTENT_TYPE,
        ]);

    let mut app = Router::new()
        .route("/api/register", post(routes::auth::register))
        .route("/api/login", post(routes::auth::login))
        .route("/api/me", get(routes::auth::me))
        .route(
            "/api/progress",
            get(routes::progress::get_progress).put(routes::progress::update_progress),
        )
        .route(
            "/api/lesson-state",
            put(routes::lesson_state::save_lesson_state),
        )
        .route(
            "/api/lesson-state/{topic_id}/{lesson_id}",
            get(routes::lesson_state::get_lesson_state)
                .delete(routes::lesson_state::delete_lesson_state),
        )
        .route("/api/tts", get(routes::tts::synthesize))
        .route("/api/push/vapid-key", get(routes::push::vapid_key))
        .route(
            "/api/push/subscribe",
            post(routes::push::subscribe).delete(routes::push::unsubscribe),
        )
        .route(
            "/api/push/preferences",
            get(routes::push::get_preferences).put(routes::push::update_preferences),
        )
        .layer(cors)
        .with_state(state);

    // In production, serve the frontend build as static files with SPA fallback
    if let Some(static_dir) = config::static_dir() {
        let index = format!("{}/index.html", static_dir);
        app = app.fallback_service(ServeDir::new(&static_dir).fallback(ServeFile::new(index)));
        println!("Serving static files from {static_dir}");
    }

    let addr = format!("0.0.0.0:{port}");
    let listener = tokio::net::TcpListener::bind(&addr)
        .await
        .expect("Failed to bind");

    println!("Ayos API listening on http://{addr}");

    axum::serve(listener, app).await.expect("Server error");
}

async fn notification_scheduler(state: config::AppState) {
    let mut interval = tokio::time::interval(std::time::Duration::from_secs(60));
    loop {
        interval.tick().await;

        let now = chrono::Utc::now();
        let current_time = now.format("%H:%M").to_string();
        let today = now.format("%Y-%m-%d").to_string();

        // Find users who should receive a reminder now (haven't been notified today)
        let users: Vec<(String,)> = match sqlx::query_as(
            "SELECT user_id FROM user_stats
             WHERE reminder_enabled = 1 AND reminder_time = ?
             AND (last_notified_date IS NULL OR last_notified_date != ?)",
        )
        .bind(&current_time)
        .bind(&today)
        .fetch_all(&state.db)
        .await
        {
            Ok(users) => users,
            Err(e) => {
                eprintln!("Notification scheduler error: {e}");
                continue;
            }
        };

        for (user_id,) in &users {
            let subs: Vec<(String, String, String)> = match sqlx::query_as(
                "SELECT endpoint, p256dh, auth FROM push_subscriptions WHERE user_id = ?",
            )
            .bind(user_id)
            .fetch_all(&state.db)
            .await
            {
                Ok(s) => s,
                Err(_) => continue,
            };

            let payload = serde_json::json!({
                "title": "Time to practice Tagalog!",
                "body": "Keep your streak going!",
                "data": { "url": "/home" }
            });
            let payload_bytes = payload.to_string().into_bytes();

            for (endpoint, p256dh, auth) in &subs {
                match webpush::send_push(
                    &state.vapid_private_key_pem,
                    &state.vapid_public_key,
                    endpoint,
                    p256dh,
                    auth,
                    &payload_bytes,
                )
                .await
                {
                    Ok(()) => {}
                    Err(errors::AppError::NotFound(_)) => {
                        // Subscription expired, clean up
                        let _ = sqlx::query("DELETE FROM push_subscriptions WHERE endpoint = ?")
                            .bind(endpoint)
                            .execute(&state.db)
                            .await;
                    }
                    Err(e) => {
                        eprintln!("Failed to send push to {user_id}: {e}");
                    }
                }
            }

            // Mark as notified today
            let _ = sqlx::query("UPDATE user_stats SET last_notified_date = ? WHERE user_id = ?")
                .bind(&today)
                .bind(user_id)
                .execute(&state.db)
                .await;
        }
    }
}