#[macro_use]
extern crate serde;
#[macro_use]
extern crate log;
#[macro_use]
extern crate futures;

mod config;
mod mail;

use anyhow::Result;
use clap::Clap;
use futures::future::{
    select,
    Either::{Left, Right},
    FutureExt,
};
use tokio::sync::oneshot;

use crate::config::{Config, MailAccountConfig, TlsMethod};

type ExitListener = oneshot::Receiver<()>;

/// The panorama daemon runs in the background and communicates with other panorama components over Unix sockets.
#[derive(Debug, Clap)]
struct Options {
    // /// Config file path (defaults to XDG)
    // #[clap(long = "config", short = 'c')]
    // config_file: Option<PathBuf>,
    /// Verbose mode (-v, -vv, -vvv, etc)
    #[clap(short = 'v', long = "verbose", parse(from_occurrences))]
    verbose: usize,
}

#[tokio::main]
async fn main() -> Result<()> {
    let opt = Options::parse();

    stderrlog::new()
        .module(module_path!())
        .verbosity(opt.verbose)
        .init()
        .unwrap();

    let (_, mut config_watcher) = config::spawn_config_watcher_system()?;

    loop {
        let (exit_tx, exit_rx) = oneshot::channel();
        let new_config = config_watcher.borrow().clone();
        tokio::spawn(run_with_config(new_config, exit_rx));

        // wait till the config has changed, then tell the current thread to stop
        config_watcher.changed().await?;
        let _ = exit_tx.send(());
    }
}

async fn run_with_config(config: Config, exit: ExitListener) -> Result<()> {
    debug!("new config");

    let mut notify_mail_threads = Vec::new();
    for (account_name, account) in config.mail_accounts {
        let (exit_tx, exit_rx) = oneshot::channel();
        tokio::spawn(run_single_mail_account(account_name, account, exit_rx));
        notify_mail_threads.push(exit_tx);
    }

    exit.await?;
    for exit_tx in notify_mail_threads {
        let _ = exit_tx.send(());
    }

    Ok(())
}

async fn run_single_mail_account(
    account_name: String,
    account: MailAccountConfig,
    exit: ExitListener,
) -> Result<()> {
    debug!("connecting to account {}", account_name);

    let imap_cookie = ImapClient::open(
        &account.imap.server,
        account.imap.port,
        matches!(account.imap.tls, TlsMethod::On),
    );

    pin_mut!(imap_cookie);
    pin_mut!(exit);

    let (imap, exit) = match select(imap_cookie, exit).await {
        Left(res) => res,
        Right(_) => return Ok(()),
    };

    debug!("connected to {}", account.imap.server);
    let imap = imap?;
    let mut exit = exit.fuse();

    loop {
        select! {
            _ = exit => break,
        }
    }

    debug!("disconnecting from account {}", account_name);
    Ok(())
}