use std::{
    error::Error,
    io,
    time::{Duration, Instant},
};

use crossterm::{
    event::{self, DisableMouseCapture, EnableMouseCapture, Event, KeyCode},
    execute,
    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
};
use ratatui::{
    prelude::*,
    widgets::{block::Title, *},
};

#[derive(Clone)]
pub struct SinSignal {
    x: f64,
    interval: f64,
    period: f64,
    scale: f64,
}

impl SinSignal {
    pub fn new(interval: f64, period: f64, scale: f64) -> SinSignal {
        SinSignal {
            x: 0.0,
            interval,
            period,
            scale,
        }
    }
}

impl Iterator for SinSignal {
    type Item = (f64, f64);
    fn next(&mut self) -> Option<Self::Item> {
        let point = (self.x, (self.x * 1.0 / self.period).sin() * self.scale);
        self.x += self.interval;
        Some(point)
    }
}

struct App {
    signal1: SinSignal,
    data1: Vec<(f64, f64)>,
    signal2: SinSignal,
    data2: Vec<(f64, f64)>,
    window: [f64; 2],
}

impl App {
    fn new() -> App {
        let mut signal1 = SinSignal::new(0.2, 3.0, 18.0);
        let mut signal2 = SinSignal::new(0.1, 2.0, 10.0);
        let data1 = signal1.by_ref().take(200).collect::<Vec<(f64, f64)>>();
        let data2 = signal2.by_ref().take(200).collect::<Vec<(f64, f64)>>();
        App {
            signal1,
            data1,
            signal2,
            data2,
            window: [0.0, 20.0],
        }
    }

    fn on_tick(&mut self) {
        for _ in 0..5 {
            self.data1.remove(0);
        }
        self.data1.extend(self.signal1.by_ref().take(5));
        for _ in 0..10 {
            self.data2.remove(0);
        }
        self.data2.extend(self.signal2.by_ref().take(10));
        self.window[0] += 1.0;
        self.window[1] += 1.0;
    }
}

fn main() -> Result<(), Box<dyn Error>> {
    // setup terminal
    enable_raw_mode()?;
    let mut stdout = io::stdout();
    execute!(stdout, EnterAlternateScreen, EnableMouseCapture)?;
    let backend = CrosstermBackend::new(stdout);
    let mut terminal = Terminal::new(backend)?;

    // create app and run it
    let tick_rate = Duration::from_millis(250);
    let app = App::new();
    let res = run_app(&mut terminal, app, tick_rate);

    // restore terminal
    disable_raw_mode()?;
    execute!(
        terminal.backend_mut(),
        LeaveAlternateScreen,
        DisableMouseCapture
    )?;
    terminal.show_cursor()?;

    if let Err(err) = res {
        println!("{err:?}");
    }

    Ok(())
}

fn run_app<B: Backend>(
    terminal: &mut Terminal<B>,
    mut app: App,
    tick_rate: Duration,
) -> io::Result<()> {
    let mut last_tick = Instant::now();
    loop {
        terminal.draw(|f| ui(f, &app))?;

        let timeout = tick_rate.saturating_sub(last_tick.elapsed());
        if crossterm::event::poll(timeout)? {
            if let Event::Key(key) = event::read()? {
                if let KeyCode::Char('q') = key.code {
                    return Ok(());
                }
            }
        }
        if last_tick.elapsed() >= tick_rate {
            app.on_tick();
            last_tick = Instant::now();
        }
    }
}

fn ui(f: &mut Frame, app: &App) {
    let size = f.size();
    let vertical_chunks = Layout::new(
        Direction::Vertical,
        [Constraint::Percentage(40), Constraint::Percentage(60)],
    )
    .split(size);

    // top chart
    render_chart1(f, vertical_chunks[0], app);

    let horizontal_chunks = Layout::new(
        Direction::Horizontal,
        [Constraint::Ratio(1, 2), Constraint::Ratio(1, 2)],
    )
    .split(vertical_chunks[1]);

    // bottom left
    render_line_chart(f, horizontal_chunks[0]);
    // bottom right
    render_scatter(f, horizontal_chunks[1]);
}

fn render_chart1(f: &mut Frame, area: Rect, app: &App) {
    let x_labels = vec![
        Span::styled(
            format!("{}", app.window[0]),
            Style::default().add_modifier(Modifier::BOLD),
        ),
        Span::raw(format!("{}", (app.window[0] + app.window[1]) / 2.0)),
        Span::styled(
            format!("{}", app.window[1]),
            Style::default().add_modifier(Modifier::BOLD),
        ),
    ];
    let datasets = vec![
        Dataset::default()
            .name("data2")
            .marker(symbols::Marker::Dot)
            .style(Style::default().fg(Color::Cyan))
            .data(&app.data1),
        Dataset::default()
            .name("data3")
            .marker(symbols::Marker::Braille)
            .style(Style::default().fg(Color::Yellow))
            .data(&app.data2),
    ];

    let chart = Chart::new(datasets)
        .block(
            Block::default()
                .title("Chart 1".cyan().bold())
                .borders(Borders::ALL),
        )
        .x_axis(
            Axis::default()
                .title("X Axis")
                .style(Style::default().fg(Color::Gray))
                .labels(x_labels)
                .bounds(app.window),
        )
        .y_axis(
            Axis::default()
                .title("Y Axis")
                .style(Style::default().fg(Color::Gray))
                .labels(vec!["-20".bold(), "0".into(), "20".bold()])
                .bounds([-20.0, 20.0]),
        );

    f.render_widget(chart, area);
}

fn render_line_chart(f: &mut Frame, area: Rect) {
    let datasets = vec![Dataset::default()
        .name("Line from only 2 points")
        .marker(symbols::Marker::Braille)
        .style(Style::default().fg(Color::Yellow))
        .graph_type(GraphType::Line)
        .data(&[(1., 1.), (4., 4.)])];

    let chart = Chart::new(datasets)
        .block(
            Block::default()
                .title(
                    Title::default()
                        .content("Line chart".cyan().bold())
                        .alignment(Alignment::Center),
                )
                .borders(Borders::ALL),
        )
        .x_axis(
            Axis::default()
                .title("X Axis")
                .style(Style::default().gray())
                .bounds([0.0, 5.0])
                .labels(vec!["0".bold(), "2.5".into(), "5.0".bold()]),
        )
        .y_axis(
            Axis::default()
                .title("Y Axis")
                .style(Style::default().gray())
                .bounds([0.0, 5.0])
                .labels(vec!["0".bold(), "2.5".into(), "5.0".bold()]),
        )
        .legend_position(Some(LegendPosition::TopLeft))
        .hidden_legend_constraints((Constraint::Ratio(1, 2), Constraint::Ratio(1, 2)));

    f.render_widget(chart, area)
}

fn render_scatter(f: &mut Frame, area: Rect) {
    let datasets = vec![
        Dataset::default()
            .name("Heavy")
            .marker(Marker::Dot)
            .graph_type(GraphType::Scatter)
            .style(Style::new().yellow())
            .data(&HEAVY_PAYLOAD_DATA),
        Dataset::default()
            .name("Medium")
            .marker(Marker::Braille)
            .graph_type(GraphType::Scatter)
            .style(Style::new().magenta())
            .data(&MEDIUM_PAYLOAD_DATA),
        Dataset::default()
            .name("Small")
            .marker(Marker::Dot)
            .graph_type(GraphType::Scatter)
            .style(Style::new().cyan())
            .data(&SMALL_PAYLOAD_DATA),
    ];

    let chart = Chart::new(datasets)
        .block(
            Block::new().borders(Borders::all()).title(
                Title::default()
                    .content("Scatter chart".cyan().bold())
                    .alignment(Alignment::Center),
            ),
        )
        .x_axis(
            Axis::default()
                .title("Year")
                .bounds([1960., 2020.])
                .style(Style::default().fg(Color::Gray))
                .labels(vec!["1960".into(), "1990".into(), "2020".into()]),
        )
        .y_axis(
            Axis::default()
                .title("Cost")
                .bounds([0., 75000.])
                .style(Style::default().fg(Color::Gray))
                .labels(vec!["0".into(), "37 500".into(), "75 000".into()]),
        )
        .hidden_legend_constraints((Constraint::Ratio(1, 2), Constraint::Ratio(1, 2)));

    f.render_widget(chart, area);
}

// Data from https://ourworldindata.org/space-exploration-satellites
const HEAVY_PAYLOAD_DATA: [(f64, f64); 9] = [
    (1965., 8200.),
    (1967., 5400.),
    (1981., 65400.),
    (1989., 30800.),
    (1997., 10200.),
    (2004., 11600.),
    (2014., 4500.),
    (2016., 7900.),
    (2018., 1500.),
];

const MEDIUM_PAYLOAD_DATA: [(f64, f64); 29] = [
    (1963., 29500.),
    (1964., 30600.),
    (1965., 177900.),
    (1965., 21000.),
    (1966., 17900.),
    (1966., 8400.),
    (1975., 17500.),
    (1982., 8300.),
    (1985., 5100.),
    (1988., 18300.),
    (1990., 38800.),
    (1990., 9900.),
    (1991., 18700.),
    (1992., 9100.),
    (1994., 10500.),
    (1994., 8500.),
    (1994., 8700.),
    (1997., 6200.),
    (1999., 18000.),
    (1999., 7600.),
    (1999., 8900.),
    (1999., 9600.),
    (2000., 16000.),
    (2001., 10000.),
    (2002., 10400.),
    (2002., 8100.),
    (2010., 2600.),
    (2013., 13600.),
    (2017., 8000.),
];

const SMALL_PAYLOAD_DATA: [(f64, f64); 23] = [
    (1961., 118500.),
    (1962., 14900.),
    (1975., 21400.),
    (1980., 32800.),
    (1988., 31100.),
    (1990., 41100.),
    (1993., 23600.),
    (1994., 20600.),
    (1994., 34600.),
    (1996., 50600.),
    (1997., 19200.),
    (1997., 45800.),
    (1998., 19100.),
    (2000., 73100.),
    (2003., 11200.),
    (2008., 12600.),
    (2010., 30500.),
    (2012., 20000.),
    (2013., 10600.),
    (2013., 34500.),
    (2015., 10600.),
    (2018., 23100.),
    (2019., 17300.),
];