use std::io;

use crossterm::event::{self, Event, KeyCode, KeyEvent, KeyEventKind};

use ratatui::{
    buffer::Buffer,
    layout::{Rect, Constraint, Layout, Spacing},
    style::Stylize,
    symbols::{border, merge::MergeStrategy},
    text::{Line, Text},
    widgets::{Block, Paragraph, Widget},
    DefaultTerminal, Frame,
};

fn main() -> io::Result<()> {
    ratatui::run(|terminal| {
        loop {
            terminal.draw(render)?;

            let should_exit: bool = exit_app()?;
            if should_exit { break; }
        }
        
        Ok(())
    })
}

fn render(frame: &mut Frame) {
    use Constraint::{Fill, Length, Min};

    let [top_area, rest_area] =
        Layout::vertical([Fill(1), Fill(12)]).areas(frame.area());

    let [main_area, output_area] =
        Layout::vertical([Fill(9), Fill(3)])
            .spacing(Spacing::Overlap(1))
            .areas(rest_area);   
            
    let [left_main_area, right_main_area] =
        Layout::horizontal([Fill(2), Fill(5)])
            .spacing(Spacing::Overlap(1))
            .areas(main_area);

    let [left_output_area, right_output_area] =
        Layout::horizontal([Fill(5), Fill(1)])
            .spacing(Spacing::Overlap(1))
            .areas(output_area);

    frame.render_widget(Block::bordered(), top_area);

    frame.render_widget(Block::bordered().merge_borders(MergeStrategy::Exact), left_output_area);
    frame.render_widget(Block::bordered().merge_borders(MergeStrategy::Exact), right_output_area);
    frame.render_widget(Block::bordered().merge_borders(MergeStrategy::Exact), left_main_area);
    frame.render_widget(Block::bordered().merge_borders(MergeStrategy::Exact), right_main_area);   
}

fn exit_app() -> io::Result<bool> {
    match event::read()? {
        Event::Key(key) if key.kind == KeyEventKind::Press => match key.code {
            KeyCode::Char('q') => return Ok(true),
            _ => {}
        },
        _ => {}
    }
    Ok(false)
}