/**
 * matrix-feedbot v0.1.0
 *
 * Copyright (C) 2024 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/>.
 */

mod config;
mod matrix;
mod feedreader;
mod state;

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

use crate::{
    config::Config,
    matrix::login_and_sync,
    feedreader::{
        fetch_and_parse_feed,
        format_entry
    },
    state::FeedReaderStateDb
};

use std::{ sync::Arc, cmp::max };
use tracing::{ info, debug, error };
use chrono::DateTime;

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

    let config = Config::load("bots.yaml").expect("Failed to load config");
    let config = Arc::new(config);

    // This message passing 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(1024);

    let state_db = FeedReaderStateDb::new("state.yaml").await
        .expect("Failed to initialize feed reader state db");

    let handles: Vec<JoinHandle<_>> = config.feeds.clone().into_iter().map(|feed_config| {
        let state_db = Arc::clone(&state_db);
        let bcast_tx = bcast_tx.clone();

        tokio::spawn(async move {

            loop {
                let feed: Option<_> = match fetch_and_parse_feed(&feed_config.url).await {
                    Ok(f) => Some(f),
                    Err(e) => {
                        error!("Failed to parse feed {}: {:?}",
                            feed_config.url,
                            e
                        );
                        None
                    }
                };

                let feed = if feed.is_none() {
                    debug!("Sleeping for {} seconds before refreshing this feed", feed_config.delay);
                    sleep(Duration::from_secs(feed_config.delay)).await;
                    continue;
                } else {
                    feed.unwrap()
                };

                let rooms = feed_config.rooms.clone();

                debug!("Retrieving state ts for feed with uri {}", feed.uri);
                let state_ts = state_db.get(feed.uri.as_str())
                    .unwrap_or(DateTime::from_timestamp(1, 0).unwrap());
                debug!("db has state ts {} for this feed", state_ts);

                let mut max_ts = state_ts.clone();

                for entry in feed.model.entries.iter().rev() {
                    // FIXME: nasty clone business going on here... use Arc instead?
                    let parsed = format_entry(feed.clone(), (*entry).clone()).unwrap();
                    debug!("parsed entry with title: {}, updated on {}", parsed.title, parsed.ts);

                    if parsed.ts > state_ts {
                        info!("Entry {} has not been posted yet, sending to matrix", entry.id);
                        let msg = parsed.formatted.unwrap();
                        bcast_tx.send((msg, rooms.clone())).unwrap();

                        max_ts = max(max_ts, parsed.ts);
                    }
                }

                if state_ts != max_ts {
                    info!("updating state from {} to {}", state_ts, max_ts);
                    state_db.set(feed.uri.as_str(), max_ts).await;
                    debug!("State update complete");
                }

                debug!("Sleeping for {} seconds before refreshing this feed", feed_config.delay);
                sleep(Duration::from_secs(feed_config.delay)).await;
            }
        })
    }).collect();

    login_and_sync::<(String, Vec<String>)>(
        config.homeserver_uri.clone().into(),
        &config.username,
        &config.password,
        &config.default_room,
        bcast_rx
    ).await?;

    for h in handles {
        h.abort();
        h.await?;
    }

    Ok(())
}