mod ratatui_utils;
mod widget;

use log::{debug, error, info};
use tokio::sync::mpsc;
use tokio_stream::StreamExt;
use tui_logger::{TuiWidgetEvent, TuiWidgetState};
use widget::{help::HelpWidget, score::ScoreListWidget};

use std::{panic, sync::Arc, time::Duration};

use crossterm::event::{Event, EventStream, KeyCode, KeyEventKind};
use harmony::{maestro::Maestro, score::Score};
use ratatui::{
    self, Frame,
    layout::{Constraint, Layout, Position},
    style::{Color, Style},
    widgets::{Block, Borders, ListItem},
};

pub mod tui {
    // Export any necessary modules or types from the internal tui module
}

/// Initializes the terminal UI with the provided Maestro instance.
///
/// # Arguments
///
/// * `maestro` - A reference to the Maestro instance containing registered scores.
///
/// # Example
///
/// ```rust
/// use harmony;
/// use harmony_tui::init;
///
/// #[harmony::main]
/// pub async fn main(maestro: harmony::Maestro) {
///     maestro.register(DeploymentScore::new("nginx-test", "nginx"));
///     maestro.register(OKDLoadBalancerScore::new(&maestro.inventory, &maestro.topology));
///     // Register other scores as needed
///
///     init(maestro).await.unwrap();
/// }
/// ```
pub async fn init(maestro: Maestro) -> Result<(), Box<dyn std::error::Error>> {
    HarmonyTUI::new(maestro).init().await
}

pub struct HarmonyTUI {
    score: ScoreListWidget,
    should_quit: bool,
    tui_state: TuiWidgetState,
}

#[derive(Debug)]
enum HarmonyTuiEvent {
    LaunchScore(ScoreItem),
}

impl HarmonyTUI {
    pub fn new(maestro: Maestro) -> Self {
        let maestro = Arc::new(maestro);
        let (_handle, sender) = Self::start_channel(maestro.clone());
        let score = ScoreListWidget::new(Self::scores_list(&maestro), sender);

        HarmonyTUI {
            should_quit: false,
            score,
            tui_state: TuiWidgetState::new(),
        }
    }

    fn start_channel(
        maestro: Arc<Maestro>,
    ) -> (tokio::task::JoinHandle<()>, mpsc::Sender<HarmonyTuiEvent>) {
        let (sender, mut receiver) = mpsc::channel::<HarmonyTuiEvent>(32);
        let handle = tokio::spawn(async move {
            info!("Starting message channel receiver loop");
            while let Some(event) = receiver.recv().await {
                info!("Received event {event:#?}");
                match event {
                    HarmonyTuiEvent::LaunchScore(score_item) => {
                        let maestro = maestro.clone();

                        let joinhandle_result =
                            tokio::spawn(async move { maestro.interpret(score_item.0).await })
                                .await;

                        match joinhandle_result {
                            Ok(interpretation_result) => match interpretation_result {
                                Ok(success) => info!("Score execution successful {success:?}"),
                                Err(error) => error!("Score failed {error:?}"),
                            },
                            Err(joinhandle_failure) => {
                                error!("Score execution TASK FAILED! {:#?}", joinhandle_failure);
                            }
                        }
                    }
                }
            }
            info!("STOPPING message channel receiver loop");
        });

        (handle, sender)
    }

    pub async fn init(mut self) -> Result<(), Box<dyn std::error::Error>> {
        // Set max_log_level to Trace
        tui_logger::init_logger(log::LevelFilter::Info).unwrap();
        // Set default level for unknown targets to Trace
        tui_logger::set_default_level(log::LevelFilter::Info);
        tui_logger::set_log_file("harmony.log").unwrap();

        color_eyre::install()?;
        let mut terminal = ratatui::init();
        log_panics::init();
        terminal.hide_cursor()?;

        // TODO improve performance here
        // Refreshing the entire terminal 10 times a second does not seem very smart
        let period = Duration::from_secs_f32(1.0 / 10.0);
        let mut interval = tokio::time::interval(period);
        let mut events = EventStream::new();

        while !self.should_quit {
            tokio::select! {
                _ = interval.tick() => { terminal.draw(|frame| self.render(frame))?; },
                Some(Ok(event)) = events.next() => self.handle_event(&event).await,
            }
        }

        ratatui::restore();

        Ok(())
    }

    fn render(&self, frame: &mut Frame) {
        let size = frame.area();
        frame.set_cursor_position(Position::new(size.x / 2, size.y / 2));

        let [app_area, help_area] =
            Layout::vertical([Constraint::Percentage(100), Constraint::Min(4)]).areas(frame.area());

        let help_block = Block::default().borders(Borders::TOP);
        frame.render_widget(&help_block, help_area);
        frame.render_widget(HelpWidget::new(), help_block.inner(help_area));

        let [list_area, output_area] =
            Layout::horizontal([Constraint::Min(30), Constraint::Percentage(100)]).areas(app_area);

        let block = Block::default().borders(Borders::RIGHT);
        frame.render_widget(&block, list_area);
        self.score.render(list_area, frame);
        let tui_logger = tui_logger::TuiLoggerWidget::default()
            .style_error(Style::default().fg(Color::Red))
            .style_warn(Style::default().fg(Color::LightRed))
            .style_info(Style::default().fg(Color::LightGreen))
            .style_debug(Style::default().fg(Color::Gray))
            .style_trace(Style::default().fg(Color::Gray))
            .state(&self.tui_state);
        frame.render_widget(tui_logger, output_area)
    }

    fn scores_list(maestro: &Maestro) -> Vec<ScoreItem> {
        let scores = maestro.scores();
        let scores_read = scores.read().expect("Should be able to read scores");
        scores_read
            .iter()
            .map(|s| ScoreItem(s.clone_box()))
            .collect()
    }

    async fn handle_event(&mut self, event: &Event) {
        debug!("Got event {event:?}");
        if let Event::Key(key) = event {
            if key.kind == KeyEventKind::Press {
                match key.code {
                    KeyCode::Char('q') | KeyCode::Esc => self.should_quit = true,
                    KeyCode::PageUp => self.tui_state.transition(TuiWidgetEvent::PrevPageKey),
                    KeyCode::PageDown => self.tui_state.transition(TuiWidgetEvent::NextPageKey),
                    KeyCode::Char('G') | KeyCode::End => {
                        self.tui_state.transition(TuiWidgetEvent::EscapeKey)
                    }
                    _ => self.score.handle_event(event).await,
                }
            }
        }
    }
}

#[derive(Debug)]
struct ScoreItem(Box<dyn Score>);

impl ScoreItem {
    pub fn clone(&self) -> Self {
        Self(self.0.clone_box())
    }
}

impl Into<ListItem<'_>> for &ScoreItem {
    fn into(self) -> ListItem<'static> {
        ListItem::new(self.0.name())
    }
}