use crate::app::App;
use ratatui::{
    Frame,
    buffer::Buffer,
    layout::Rect,
    style::Stylize,
    symbols::border,
    text::{Line, Text},
    widgets::{Block, Paragraph, Widget},
};

/// Explicitly declare lifetime as App is a reference;
/// Runtime is only instantiated for render
struct Runtime<'a> {
    app: &'a App,
}

pub fn draw(frame: &mut Frame, app: &App) {
    let run = Runtime { app };
    frame.render_widget(&run, frame.area());
}

impl<'a> Widget for &Runtime<'a> {
    fn render(self, area: Rect, buf: &mut Buffer) {
        let title = Line::from(" Counter App Tutorial ".bold());
        let instructions = Line::from(vec![
            " Decrement ".into(),
            "<Left>".blue().bold(),
            " Increment ".into(),
            "<Right>".blue().bold(),
            " Quit ".into(),
            "<Q> ".blue().bold(),
        ]);
        let block = Block::bordered()
            .title(title.centered())
            .title_bottom(instructions.centered())
            .border_set(border::THICK);

        let counter_text = Text::from(vec![Line::from(vec![
            "Value: ".into(),
            self.app.display_counter().yellow(),
        ])]);

        Paragraph::new(counter_text)
            .centered()
            .block(block)
            .render(area, buf);
    }
}

#[cfg(test)]
mod tests {

    use super::*;
    use ratatui::style::Style;

    #[test]
    fn render() {
        let mut app = App::default();
        assert!(app.init_context().is_ok());
        let runtime = Runtime { app: &app };

        let mut buf = Buffer::empty(Rect::new(0, 0, 50, 4));

        runtime.render(buf.area, &mut buf);

        let mut expected = Buffer::with_lines(vec![
            "┏━━━━━━━━━━━━━ Counter App Tutorial ━━━━━━━━━━━━━┓",
            "┃                    Value: 0                    ┃",
            "┃                                                ┃",
            "┗━ Decrement <Left> Increment <Right> Quit <Q> ━━┛",
        ]);
        let title_style = Style::new().bold();
        let counter_style = Style::new().yellow();
        let key_style = Style::new().blue().bold();

        expected.set_style(Rect::new(14, 0, 22, 1), title_style);
        expected.set_style(Rect::new(28, 1, 1, 1), counter_style);
        expected.set_style(Rect::new(13, 3, 6, 1), key_style);
        expected.set_style(Rect::new(30, 3, 7, 1), key_style);
        expected.set_style(Rect::new(43, 3, 4, 1), key_style);

        assert_eq!(buf, expected);
    }
}