mod widget;

use tokio_stream::StreamExt;
use widget::score::ScoreListWidget;

use std::time::Duration;

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

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 {
    maestro: Maestro,
    score: ScoreListWidget,
    should_quit: bool,
}

impl HarmonyTUI {
    pub fn new(maestro: Maestro) -> Self {
        let score = ScoreListWidget::new(Self::scores_list(&maestro));

        HarmonyTUI {
            maestro,
            should_quit: false,
            score,
        }
    }

    pub async fn init(mut self) -> Result<(), Box<dyn std::error::Error>> {
        color_eyre::install()?;
        let mut terminal = ratatui::init();

        // 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),
            }
        }

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

        let block = Block::default().borders(Borders::RIGHT);
        frame.render_widget(&block, list_area);
        self.score.render(list_area, frame);
    }

    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()
    }

    fn handle_event(&mut self, 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::Char('j') | KeyCode::Down => self.score.scroll_down(),
                    KeyCode::Char('k') | KeyCode::Up => self.score.scroll_up(),
                    KeyCode::Enter => self.score.launch_execution(),
                    KeyCode::Char('y') => self.score.confirm(true),
                    KeyCode::Char('n') => self.score.confirm(false),
                    _ => {}
                }
            }
        }
    }
}

#[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())
    }
}