mod app;
mod config;
mod rpc;

use std::{
    error::Error,
    io,
    sync::OnceLock,
    time::{Duration, Instant},
};

use crabidy_core::proto::crabidy::{get_update_stream_response::Update as StreamUpdate, PlayState};

use crossterm::{
    event::{self, DisableMouseCapture, EnableMouseCapture, Event, KeyEventKind},
    execute,
    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
};
use flume::{Receiver, Sender};

use ratatui::{backend::CrosstermBackend, Terminal};
use tokio::select;
use tokio_stream::StreamExt;

use app::{bindings, App, DispatchResult, MessageFromUi, MessageToUi};
use config::Config;
use rpc::RpcClient;
use tracing::{error, info, warn};

static CONFIG: OnceLock<Config> = OnceLock::new();

/// Logs to a file: the terminal is owned by the TUI, so writing log lines to
/// stdout/stderr would corrupt the interface.
fn init_tracing() -> Option<tracing_appender::non_blocking::WorkerGuard> {
    use tracing_subscriber::{prelude::*, EnvFilter};

    let log_dir = dirs::state_dir()
        .or_else(dirs::cache_dir)
        .unwrap_or_else(std::env::temp_dir)
        .join("crabidy");
    if let Err(err) = std::fs::create_dir_all(&log_dir) {
        eprintln!(
            "could not create log directory {}: {err}",
            log_dir.display()
        );
        return None;
    }
    let file_appender = tracing_appender::rolling::daily(&log_dir, "cbd-tui.log");
    let (non_blocking, guard) = tracing_appender::non_blocking(file_appender);
    let env_filter = EnvFilter::try_from_default_env()
        .unwrap_or_else(|_| EnvFilter::new("info,cbd_tui=debug,crabidy_core=debug"));
    tracing_subscriber::registry()
        .with(env_filter)
        .with(
            tracing_subscriber::fmt::layer()
                .with_writer(non_blocking)
                .with_ansi(false)
                .with_target(true),
        )
        .init();
    Some(guard)
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let _log_guard = init_tracing();
    let config = CONFIG.get_or_init(|| crabidy_core::init_config("cbd-tui.toml"));

    let (ui_tx, rx): (Sender<MessageFromUi>, Receiver<MessageFromUi>) = flume::unbounded();
    let (tx, ui_rx): (Sender<MessageToUi>, Receiver<MessageToUi>) = flume::unbounded();

    // FIXME: unwrap
    tokio::spawn(async move { orchestrate(config, (tx, rx)).await.unwrap() });

    tokio::task::spawn_blocking(|| {
        run_ui(ui_tx, ui_rx);
    })
    .await?;

    Ok(())
}

async fn orchestrate(
    config: &'static Config,
    (tx, rx): (Sender<MessageToUi>, Receiver<MessageFromUi>),
) -> Result<(), Box<dyn Error>> {
    info!(address = config.server.address, "connecting to server");
    let mut rpc_client = rpc::RpcClient::connect(&config.server.address).await?;

    if let Some(root_node) = rpc_client.get_library_node(crabidy_core::ROOT_PATH).await? {
        tx.send(MessageToUi::ReplaceLibraryNode(root_node.clone()))?;
    }

    let init_data = rpc_client.init().await?;
    info!("received initial state from server");
    tx.send_async(MessageToUi::Init(init_data)).await?;

    loop {
        if let Err(err) = poll(&mut rpc_client, &rx, &tx).await {
            error!("request to server failed: {err}");
        }
    }
}

async fn poll(
    rpc_client: &mut RpcClient,
    rx: &Receiver<MessageFromUi>,
    tx: &Sender<MessageToUi>,
) -> Result<(), Box<dyn Error>> {
    select! {
        Ok(msg) = &mut rx.recv_async() => {
            match msg {
                MessageFromUi::GetLibraryNode(path) => {
                    if let Some(node) = rpc_client.get_library_node(&path).await? {
                        let _ = tx.send(MessageToUi::ReplaceLibraryNode(node.clone()));
                    }
                },
                MessageFromUi::CreateNode { parent_path, title } => {
                    // Navigates the library into the created node on
                    // success; on failure the library stays where it is.
                    match rpc_client.create_library_node(&parent_path, &title).await {
                        Ok(node) => {
                            let _ = tx.send(MessageToUi::ReplaceLibraryNode(node.clone()));
                        }
                        Err(err) => {
                            error!(parent_path, title, "failed to create node: {err}");
                        }
                    }
                },
                MessageFromUi::RenameNode { path, new_title } => {
                    // Navigates the library into the renamed node on success;
                    // on failure the library stays where it is.
                    match rpc_client.rename_library_node(&path, &new_title).await {
                        Ok(node) => {
                            let _ = tx.send(MessageToUi::ReplaceLibraryNode(node.clone()));
                        }
                        Err(err) => {
                            error!(path, new_title, "failed to rename node: {err}");
                        }
                    }
                },
                MessageFromUi::DeleteNode { path } => {
                    // Shows the refreshed parent listing on success; on
                    // failure the library stays where it is.
                    match rpc_client.delete_library_node(&path).await {
                        Ok(parent) => {
                            let _ = tx.send(MessageToUi::ReplaceLibraryNode(parent.clone()));
                        }
                        Err(err) => {
                            error!(path, "failed to delete node: {err}");
                        }
                    }
                },
                MessageFromUi::AppendTracks(uuids) => {
                    rpc_client.append_tracks(uuids).await?
                }
                MessageFromUi::QueueTracks(uuids) => {
                    rpc_client.queue_tracks(uuids).await?
                }
                MessageFromUi::InsertTracks(uuids, pos) => {
                    rpc_client.insert_tracks(uuids, pos).await?
                }
                MessageFromUi::RemoveTracks(positions) => {
                    rpc_client.remove_tracks(positions).await?
                }
                MessageFromUi::ReplaceQueue(uuids) => {
                    rpc_client.replace_queue(uuids).await?
                }
                MessageFromUi::NextTrack => {
                    rpc_client.next_track().await?
                }
                MessageFromUi::PrevTrack => {
                    rpc_client.prev_track().await?
                }
                MessageFromUi::RestartTrack => {
                    rpc_client.restart_track().await?
                }
                MessageFromUi::SetCurrentTrack(pos) => {
                    rpc_client.set_current_track(pos).await?
                }
                MessageFromUi::TogglePlay => {
                    rpc_client.toggle_play().await?
                }
                MessageFromUi::ChangeVolume(delta) => {
                    rpc_client.change_volume(delta).await?
                }
                MessageFromUi::ToggleMute => {
                    rpc_client.toggle_mute().await?
                }
                MessageFromUi::ToggleShuffle => {
                    rpc_client.toggle_shuffle().await?
                }
                MessageFromUi::ToggleRepeat => {
                    rpc_client.toggle_repeat().await?
                }
                MessageFromUi::ClearQueue(exclude_current) => {
                    rpc_client.clear_queue(exclude_current).await?
                }
            }
        }
        Some(resp) = rpc_client.update_stream.next() => {
            match resp {
                Ok(resp) => {
                    if let Some(update) = resp.update {
                        tx.send_async(MessageToUi::Update(update)).await?;
                    }
                }
                Err(err) => {
                    warn!("update stream broke, reconnecting: {err}");
                    rpc_client.reconnect_update_stream().await;
                    info!("update stream reconnected");
                }

            }
        }
    }

    Ok(())
}

fn run_ui(tx: Sender<MessageFromUi>, rx: Receiver<MessageToUi>) {
    // setup terminal
    enable_raw_mode().unwrap();
    let mut stdout = io::stdout();
    execute!(stdout, EnterAlternateScreen, EnableMouseCapture).unwrap();
    let backend = CrosstermBackend::new(stdout);
    let mut terminal = Terminal::new(backend).unwrap();

    // create app and run it
    let mut app = App::new(tx);
    let tick_rate = Duration::from_millis(100);
    let mut last_tick = Instant::now();

    loop {
        for message in rx.try_iter() {
            match message {
                MessageToUi::ReplaceLibraryNode(node) => {
                    app.library.update(node);
                }
                MessageToUi::Init(init_data) => {
                    if let Some(queue) = init_data.queue {
                        app.queue.update_queue(queue);
                    }
                    if let Some(track) = init_data.queue_track {
                        app.now_playing.update_track(track.track);
                        app.queue.update_position(track.queue_position as usize);
                    }
                    if let Ok(ps) = PlayState::try_from(init_data.play_state) {
                        app.now_playing.update_play_state(ps);
                    }
                    if let Some(mods) = init_data.mods {
                        app.now_playing.update_modifiers(&mods);
                    }
                }
                MessageToUi::Update(update) => match update {
                    StreamUpdate::Queue(queue) => {
                        app.queue.update_queue(queue);
                    }
                    StreamUpdate::QueueTrack(track) => {
                        app.now_playing.update_track(track.track);
                        app.queue.update_position(track.queue_position as usize);
                    }
                    StreamUpdate::Position(pos) => app.now_playing.update_position(pos),
                    StreamUpdate::PlayState(play_state) => {
                        if let Ok(ps) = PlayState::try_from(play_state) {
                            app.now_playing.update_play_state(ps);
                        }
                    }
                    StreamUpdate::Mods(mods) => {
                        app.now_playing.update_modifiers(&mods);
                    }
                    StreamUpdate::Mute(_) => { /* FIXME: implement */ }
                    StreamUpdate::Volume(_) => { /* FIXME: implement */ }
                },
            }
        }

        if let Err(err) = terminal.draw(|f| app.render(f)) {
            error!("failed to draw frame: {err}");
            break;
        }

        let timeout = tick_rate
            .checked_sub(last_tick.elapsed())
            .unwrap_or_else(|| Duration::from_secs(0));

        if event::poll(timeout).unwrap() {
            if let Event::Key(key) = event::read().unwrap() {
                if key.kind == KeyEventKind::Press {
                    // The input overlay is strictly modal: while it is open,
                    // keys edit the buffer and the bindings table (including
                    // quit) is unreachable.
                    if app.input.is_some() {
                        app.handle_input_key(key);
                    } else if let Some(action) = bindings::lookup(app.focus, app.show_help, key) {
                        if app.dispatch(action) == DispatchResult::Quit {
                            break;
                        }
                    }
                }
            }
        }

        if last_tick.elapsed() >= tick_rate {
            last_tick = Instant::now();
        }
    }

    // restore terminal
    disable_raw_mode().unwrap();
    execute!(
        terminal.backend_mut(),
        LeaveAlternateScreen,
        DisableMouseCapture
    )
    .unwrap();
    terminal.show_cursor().unwrap();
}