/*!
 * matrix-lolopener v0.1.0
 *
 * Copyright (C) 2026 The 1312 Media Collective
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#![recursion_limit = "256"]

mod config;
mod matrix;
mod mqtt;

use tokio::{
    sync::{Notify, broadcast, mpsc},
    time::{sleep, Duration},
    task::JoinHandle,
};

use crate::{
    config::Config,
    matrix::login_and_sync,
    mqtt::{MQTT, StatusMessage},
};

use std::sync::{ Arc, Mutex };
use tracing::{ info, debug };

use clap::Parser;

/// Matrix bot posting when the front door is opened or closed
#[derive(Parser, Debug)]
#[command(version, about, long_about = None)]
struct Args {
    /// Configuration file path
    #[arg(short, long, default_value_t = "config.yml".into())]
    config: String,
}

#[derive(PartialEq, Clone, Copy, Debug)]
enum DoorSensorStatus {
    Open,
    Closed,
}
#[derive(Debug)]
struct LolOpenerState {
    sensor_status: Option<DoorSensorStatus>,
    pending: Option<(DoorSensorStatus, String)>,
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    tracing_subscriber::fmt::init();

    let args = Args::parse();

    let config = Config::load(&args.config).unwrap_or_else(|e| {
        panic!("Failed to load config: {e:?}")
    });
    let config = Arc::new(config);

    let matrix_ready = Arc::new(Notify::new());

    // This channel is used for sending messages to the matrix module,
    // it holds a tuple with an HTML message and a list of rooms to post to
    let (bcast_tx, bcast_rx) = broadcast::channel::<(String, Vec<String>)>(1024);

    let handle: JoinHandle<_> = {
        let matrix_ready = Arc::clone(&matrix_ready);
        let config = Arc::clone(&config);

        tokio::spawn(async move {
            debug!("Waiting until matrix is ready");
            matrix_ready.notified().await;
            info!("Matrix is ready");

            let current_state = Arc::new(Mutex::new(LolOpenerState {
                sensor_status: None,
                pending: None
            }));
            let current_state = Arc::clone(&current_state);

            let (debounce_tx, mut debounce_rx) = mpsc::unbounded_channel::<(DoorSensorStatus, String)>();
            let debounce_delay = config.debounce_delay;
            let rooms = config.rooms.clone();
            let handle = tokio::spawn(async move {

                while let Some((new_status, msg)) = debounce_rx.recv().await {
                    let should_wait = {
                        //XXX: Panic if the lock is poisoned
                        let mut state = current_state.lock().unwrap();
                        let should_wait = state.pending.is_none();

                        state.pending = Some((new_status, msg));
                        should_wait
                    };

                    if should_wait {
                        let tx = bcast_tx.clone();
                        let rooms = rooms.clone();
                        let state = current_state.clone();

                        tokio::spawn(async move {
                            sleep(Duration::from_secs(debounce_delay)).await;

                            let msg = {
                                //XXX: Panic if the lock is poisoned
                                let mut state = state.lock().unwrap();
                                let pending = state.pending.take();

                                match pending {
                                    Some((status, msg))
                                        if state.sensor_status.as_ref() != Some(&status) => {
                                            state.sensor_status = Some(status);
                                            Some(msg)
                                        }

                                    _ => None,
                                }
                            };

                            if let Some(msg) = msg {
                                debug!("Sending msg {}", msg);
                                //XXX: Panic if the matrix module can't get the message
                                tx.send((msg, rooms)).unwrap();
                            }
                        });
                    }
                }
            });

            let mut mqtt = MQTT::new(config.mqtt.clone()).await;
            mqtt.subscribe(move |status: StatusMessage| {
                let (new_status, msg) = match status {
                    StatusMessage { contact: true, .. } => (DoorSensorStatus::Closed, "🔴 Le LOL est fermé :("),
                    StatusMessage { contact: false, .. } => (DoorSensorStatus::Open, "🟢 Le LOL est ouvert :)"),
                };

                //XXX: Panic if the channel is closed
                debounce_tx.send((new_status, String::from(msg))).unwrap();

            }).await.unwrap(); //XXX: Panic if the mqtt broker fails

            handle.abort();
            handle.await.unwrap();
        })
    };

    login_and_sync(
        config.homeserver_uri.clone(),
        &config.auth,
        matrix_ready,
        bcast_rx
    ).await?;

    handle.abort();
    handle.await?;

    Ok(())
}