// Copyright 2022 Daniel Arbuckle
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Run with `cargo run --example axum --features examples`

use std::{net::TcpListener, sync::Arc};

use axum::{
    response::{Html, IntoResponse},
    routing::{get, post},
    Extension, Router, Server,
};
use tokio::sync::{
    oneshot::{channel, Sender},
    Mutex,
};

struct State {
    shutdown: Option<Sender<()>>,
}

async fn index() -> impl IntoResponse {
    Html(
        r#"Hello World. <form method="post" action="/shutdown"><input type="submit" value="Shut Down"></form>"#,
    )
}

async fn shutdown(Extension(state): Extension<Arc<Mutex<State>>>) -> impl IntoResponse {
    if let Some(shutdown) = state.lock().await.shutdown.take() {
        let _ = shutdown.send(());
        "Shutting down"
    } else {
        "Shutdown already initiated"
    }
}

fn main() {
    // Non-async set up. We can do any server configuration that
    // doesn't need an async context here, parse the command line,
    // etc.

    let (shutdown_tx, shutdown_rx) = channel::<()>();

    let state = Arc::new(Mutex::new(State {
        shutdown: Some(shutdown_tx),
    }));

    let app = Router::new()
        .route("/", get(index))
        .route("/shutdown", post(shutdown))
        .layer(Extension(state));

    // Pick a random available port on the loopback interface. Not
    // actually required, but usually a good idea.

    let ear = TcpListener::bind("127.0.0.1:0").expect("bind port");
    let addr = ear.local_addr().expect("retrieve port");

    // Here we start up the webview and actually run the server. The
    // async block is the asynchronous entry point for the program
    // (like tokio::main or async_std::main), so any server set up
    // code that needs to run in an async context should be there, as
    // well as the code to actually run the server. When the async
    // block finishes executing, the program will close.

    drteeth::launch("Axum Demo", addr, async move {
        Server::from_tcp(ear)
            .unwrap()
            .serve(app.into_make_service())
            .with_graceful_shutdown(async {
                shutdown_rx.await.ok();
            })
            .await
            .unwrap();
    })
    .unwrap();
}