kramer/src/tui.rs

use std::io;
use std::sync::mpsc;

use ratatui::crossterm;
use ratatui::layout::{Constraint, Layout};
use ratatui::symbols::border;
use ratatui::widgets::{Block, Widget};
use ratatui::{DefaultTerminal, Frame};

#[derive(Debug, Default)]
pub struct Tui {
    // bool::default() -> false
    exit: bool,
}

impl Tui {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn run(
        &mut self,
        terminal: &mut DefaultTerminal,
        rx: mpsc::Receiver<Event>,
    ) -> io::Result<()> {
        while !self.exit {
            // Render frame.
            terminal.draw(|frame| self.draw(frame))?;

            // Event handler
            // unwraps, bc what could go wrong?
            match rx.recv().unwrap() {
                Event::Input(key_event) => self.handle_key_event(key_event)?,
            }
        }

        Ok(())
    }

    pub fn draw(&self, frame: &mut Frame) {
        frame.render_widget(self, frame.area());
    }

    pub fn handle_key_event(&mut self, key_event: crossterm::event::KeyEvent) -> io::Result<()> {
        if key_event.kind == crossterm::event::KeyEventKind::Press
            && key_event.code == crossterm::event::KeyCode::Char('q')
        {
            self.exit = true;
        }

        Ok(())
    }
}

// impl on reference to avoid accidentally mutating.
impl Widget for &Tui {
    fn render(self, area: ratatui::prelude::Rect, buf: &mut ratatui::prelude::Buffer)
    where
        Self: Sized,
    {
        let [main_area, _info_area] =
            Layout::vertical([Constraint::Percentage(75), Constraint::Fill(1)]).areas(area);

        let main_block = Block::bordered()
            .title(" Viewer ")
            .border_set(border::THICK);
        main_block.render(main_area, buf);
    }
}

pub enum Event {
    Input(crossterm::event::KeyEvent),
}

pub fn input_fetcher(tx: mpsc::Sender<Event>) {
    loop {
        // unwraps, bc what could go wrong?
        match crossterm::event::read().unwrap() {
            crossterm::event::Event::Key(key_event) => tx.send(Event::Input(key_event)).unwrap(),
            _ => (),
        }
    }
}