use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};

use super::{app::App, event::{Event, EventReceiver}};

pub struct EventHandler {
    events: EventReceiver,
}

impl EventHandler {
    pub fn new(events: EventReceiver) -> Self {
        EventHandler { events }
    }

    pub fn handle_next_event(&mut self, app: &mut App) {
        match self.events.recv() {
            Event::Key(key_event) => Self::handle_key_event(app, key_event),
            Event::Mouse(_) => {}
            Event::Resize(_, _) => {}
        }
    }

    fn handle_key_event(app: &mut App, key_event: KeyEvent) {
        match key_event.code {
            // Exit application on `ESC` or `q`.
            KeyCode::Esc | KeyCode::Char('q') => {
                app.quit();
            }
            // Exit application on `Ctrl-C`.
            KeyCode::Char('c') | KeyCode::Char('C') => {
                if key_event.modifiers == KeyModifiers::CONTROL {
                    app.quit();
                }
            }
            // Category change.
            KeyCode::Left => {
                app.decrement_category();
            }
            KeyCode::Right => {
                app.increment_category();
            }
            // Selection change.
            KeyCode::Up => {
                app.decrement_selection();
            }
            KeyCode::Down => {
                app.increment_selection();
            }
            // Other keys.
            _ => {}
        }
    }
}