use std::{
    env::VarError,
    io::Write,
    net::{Ipv4Addr, SocketAddr},
};

use axum::{
    routing::{get, MethodRouter},
    Router,
};
use sqlx::sqlite::{SqliteConnectOptions, SqlitePool, SqlitePoolOptions};
use tokio::net::TcpListener;
use tower_http::services::ServeDir;

#[macro_use]
extern crate justerror;

#[macro_use]
extern crate lazy_static;

mod handlers;
mod templates;
mod user;

#[tokio::main]
async fn main() {
    use handlers::handlers::{get_signup, payment_success, post_signup};
    init();

    // for javascript and css
    // TODO: figure out how to intern these contents
    let assets_dir = std::env::current_dir().unwrap().join("assets");
    let assets_svc = ServeDir::new(assets_dir.as_path());

    let pool = db().await;

    sqlx::migrate!().run(&pool).await.unwrap();

    // the core application, defining the routes and handlers
    let app = Router::new()
        .nest_service("/assets", assets_svc)
        .stripped_clone("/signup/", get(get_signup).post(post_signup))
        .stripped_clone("/payment_success/", get(payment_success))
        .route("/payment_success/:receipt", get(payment_success))
        .with_state(pool.clone())
        .into_make_service();
    let listener = mklistener().await;
    axum::serve(listener, app)
        .with_graceful_shutdown(shutdown_signal())
        .await
        .unwrap();

    pool.close().await;
}

//-************************************************************************
// li'l helpers
//-************************************************************************
fn init() {
    dotenvy::dotenv().expect("Could not read .env file.");
    env_logger::builder()
        .format(|buf, record| {
            let ts = buf.timestamp();
            writeln!(buf, "{}: {}", ts, record.args())
        })
        .init();
}

async fn db() -> SqlitePool {
    //let dbfile = std::env::var("DATABASE_URL").unwrap();
    let opts = SqliteConnectOptions::new()
        .foreign_keys(true)
        .create_if_missing(true)
        .journal_mode(sqlx::sqlite::SqliteJournalMode::Wal)
        .optimize_on_close(true, None);
    SqlitePoolOptions::new().connect_with(opts).await.unwrap()
}

async fn mklistener() -> TcpListener {
    let ip =
        std::env::var("LISTENING_ADDR").expect("Could not find $LISTENING_ADDR in environment");
    let ip: Ipv4Addr = ip
        .parse()
        .unwrap_or_else(|_| panic!("Could not parse {ip} as an IP address"));
    let port: u16 = std::env::var("LISTENING_PORT")
        .and_then(|p| p.parse().map_err(|_| VarError::NotPresent))
        .unwrap_or_else(|_| {
            panic!("Could not find LISTENING_PORT in env or parse if present");
        });
    let addr = SocketAddr::from((ip, port));
    TcpListener::bind(&addr).await.unwrap()
}

/// Adds both routes, with and without a trailing slash.
trait RouterPathStrip<S>
where
    S: Clone + Send + Sync + 'static,
{
    fn stripped_clone(self, path: &str, method_router: MethodRouter<S>) -> Self;
}

impl<S> RouterPathStrip<S> for Router<S>
where
    S: Clone + Send + Sync + 'static,
{
    fn stripped_clone(self, path: &str, method_router: MethodRouter<S>) -> Self {
        assert!(path.ends_with('/'));
        self.route(path, method_router.clone())
            .route(path.trim_end_matches('/'), method_router)
    }
}

async fn shutdown_signal() {
    use tokio::signal;
    let ctrl_c = async {
        signal::ctrl_c()
            .await
            .expect("failed to install Ctrl+C handler");
    };

    #[cfg(unix)]
    let terminate = async {
        signal::unix::signal(signal::unix::SignalKind::terminate())
            .expect("failed to install signal handler")
            .recv()
            .await;
    };

    #[cfg(not(unix))]
    let terminate = std::future::pending::<()>();

    tokio::select! {
        _ = ctrl_c => {log::info!("shutting down")},
        _ = terminate => {},
    }
}