use cairo::{
    Context, FontSlant, FontWeight, Format, ImageSurface, LineCap, LinearGradient, Pattern,
    TextExtents,
};
use glib::Object;
use gtk::{prelude::*, subclass::prelude::*};
use std::{
    cell::RefCell,
    rc::Rc,
    time::{Duration, Instant},
};

const WIDTH: i32 = 1600;
const HEIGHT: i32 = 600;

#[derive(Clone, Copy, Debug)]
enum Event {
    Frames(u8),
    Time(Duration),
}

struct TimeoutAnimation {
    intensity: f64,
    duration: f64,
    ascending: bool,
}

impl TimeoutAnimation {
    fn tick(&mut self, frames_elapsed: u8) {
        let step_size = 1. / (self.duration * 60.);
        if self.ascending {
            self.intensity = self.intensity + step_size * frames_elapsed as f64;
            if self.intensity > 1. {
                self.intensity = 1.0;
                self.ascending = false;
            }
        } else {
            self.intensity = self.intensity - step_size * frames_elapsed as f64;
            if self.intensity < 0. {
                self.intensity = 0.0;
                self.ascending = true;
            }
        }
    }
}

pub struct SplashPrivate {
    text: Rc<RefCell<String>>,
    time: Rc<RefCell<Duration>>,
    background: Rc<RefCell<Pattern>>,
    time_extents: Rc<RefCell<Option<TextExtents>>>,
    width: Rc<RefCell<i32>>,
    height: Rc<RefCell<i32>>,

    timeout_animation: Rc<RefCell<Option<TimeoutAnimation>>>,
}

impl SplashPrivate {
    fn set_text(&self, text: String) {
        *self.text.borrow_mut() = text;
    }

    fn set_time(&self, time: Duration) {
        *self.time.borrow_mut() = time;
    }

    fn redraw_background(&self) {
        let background =
            ImageSurface::create(Format::Rgb24, *self.width.borrow(), *self.height.borrow())
                .unwrap();
        let context = Context::new(background).unwrap();
        context.push_group();
        context.set_source_rgb(0., 0., 0.);
        let _ = context.paint();

        context.select_font_face("Alegreya Sans SC", FontSlant::Normal, FontWeight::Bold);
        context.set_font_size(128.);

        let center_x = *self.width.borrow() as f64 / 2.;
        let center_y = *self.height.borrow() as f64 / 2.;

        let title_extents = context.text_extents(&self.text.borrow()).unwrap();
        let title_width = title_extents.width();
        let title_height = title_extents.height();

        {
            let start_length = center_x - title_width / 2. - title_height - 20.;

            let title_cutout = AsymLineCutout {
                orientation: gtk::Orientation::Horizontal,
                start_x: 20.,
                start_y: center_y - 20. - title_height / 2.,
                start_length,
                total_length: *self.width.borrow() as f64 - 120.,
                cutout_length: title_width,
                height: title_height,
                invert: false,
            };

            context.set_line_cap(LineCap::Round);
            context.set_source_rgb(0.7, 0., 1.);
            context.set_line_width(2.);
            title_cutout.draw(&context);
            let _ = context.stroke();
        }

        {
            let title_baseline_x = center_x - title_width / 2.;
            let title_baseline_y = center_y - 20.;

            let gradient = LinearGradient::new(
                title_baseline_x,
                title_baseline_y - title_height,
                title_baseline_x,
                title_baseline_y,
            );
            gradient.add_color_stop_rgb(0.2, 0.7, 0.0, 1.0);
            gradient.add_color_stop_rgb(0.8, 0.2, 0.0, 1.0);
            context.move_to(title_baseline_x, title_baseline_y);
            let _ = context.set_source(gradient);
            let _ = context.show_text(&self.text.borrow());
        }

        {
            context.set_source_rgb(0.7, 0., 1.);
            AsymLine {
                orientation: gtk::Orientation::Horizontal,
                start_x: 100.,
                start_y: *self.height.borrow() as f64 / 2. + 100.,
                start_length: 400.,
                height: 50.,
                total_length: 650.,
                invert: true,
            }
            .draw(&context);
            let _ = context.stroke();
        }

        {
            context.set_source_rgb(0.7, 0., 1.);
            AsymLine {
                orientation: gtk::Orientation::Horizontal,
                start_x: *self.width.borrow() as f64 / 2. + 100.,
                start_y: *self.height.borrow() as f64 / 2. + 200.,
                start_length: 600.,
                height: 50.,
                total_length: 650.,
                invert: false,
            }
            .draw(&context);
            let _ = context.stroke();
        }

        let background = context.pop_group().unwrap();

        *self.background.borrow_mut() = background;
    }
}

#[glib::object_subclass]
impl ObjectSubclass for SplashPrivate {
    const NAME: &'static str = "Splash";
    type Type = Splash;
    type ParentType = gtk::DrawingArea;

    fn new() -> SplashPrivate {
        // Set up a default plain black background
        let background = ImageSurface::create(Format::Rgb24, WIDTH, HEIGHT).unwrap();
        let context = Context::new(background).unwrap();
        context.push_group();
        context.set_source_rgb(0., 0., 0.);
        let _ = context.paint();
        let background = context.pop_group().unwrap();

        SplashPrivate {
            text: Rc::new(RefCell::new(String::from(""))),
            time: Rc::new(RefCell::new(Duration::ZERO)),
            background: Rc::new(RefCell::new(background)),
            time_extents: Rc::new(RefCell::new(None)),
            width: Rc::new(RefCell::new(WIDTH)),
            height: Rc::new(RefCell::new(HEIGHT)),
            timeout_animation: Rc::new(RefCell::new(None)),
        }
    }
}
impl ObjectImpl for SplashPrivate {}
impl WidgetImpl for SplashPrivate {}
impl DrawingAreaImpl for SplashPrivate {}

glib::wrapper! {
    pub struct Splash(ObjectSubclass<SplashPrivate>) @extends gtk::DrawingArea, gtk::Widget;
}

impl Splash {
    pub fn new(text: String, time: Duration) -> Self {
        let s: Self = Object::builder().build();
        s.set_width_request(WIDTH);
        s.set_height_request(HEIGHT);

        s.imp().set_text(text);
        s.imp().set_time(time);
        s.imp().redraw_background();

        s.set_draw_func({
            let s = s.clone();
            move |_, context, width, height| {
                let background = s.imp().background.borrow();
                let _ = context.set_source(&*background);
                let _ = context.paint();

                let time = s.imp().time.borrow().clone();
                let minutes = time.as_secs() / 60;
                let seconds = time.as_secs() % 60;

                let center_x = width as f64 / 2.;
                let center_y = height as f64 / 2.;

                {}

                {
                    context.select_font_face(
                        "Alegreya Sans SC",
                        FontSlant::Normal,
                        FontWeight::Bold,
                    );
                    context.set_font_size(128.);

                    let time = format!("{:02}' {:02}\"", minutes, seconds);

                    let time_extents = context.text_extents(&time).unwrap();

                    let mut saved_extents = s.imp().time_extents.borrow_mut();
                    if saved_extents.is_none() {
                        *saved_extents = Some(time_extents.clone());
                    }

                    let time_baseline_x = center_x - time_extents.width() / 2.;
                    let time_baseline_y = center_y + 100.;

                    /*
                    match *s.imp().timeout_animation.borrow() {
                        Some(ref animation) => {
                            context.set_source_rgb(animation.intensity / 2., 0., 0.);
                            RoundedRectangle {
                                x: time_baseline_x - 5.,
                                y: time_baseline_y + 10.,
                                width: time_extents.width() + 15.,
                                height: time_extents.height() + 15.,
                            }
                            .draw(&context);
                            // let _ = context.fill();
                        }
                        None => {}
                    }
                    */

                    let gradient = LinearGradient::new(
                        time_baseline_x,
                        time_baseline_y - time_extents.height(),
                        time_baseline_x,
                        time_baseline_y,
                    );
                    match *s.imp().timeout_animation.borrow() {
                        Some(ref animation) => {
                            gradient.add_color_stop_rgba(0.2, 0.2, 0.0, 1.0, animation.intensity);
                            gradient.add_color_stop_rgba(0.8, 0.7, 0.0, 1.0, animation.intensity);
                            let _ = context.set_source(gradient);
                        }
                        None => {
                            gradient.add_color_stop_rgb(0.2, 0.2, 0.0, 1.0);
                            gradient.add_color_stop_rgb(0.8, 0.7, 0.0, 1.0);
                            let _ = context.set_source(gradient);
                        }
                    }
                    context.move_to(time_baseline_x, time_baseline_y);
                    let _ = context.show_text(&time);
                };

                match *s.imp().time_extents.borrow() {
                    Some(extents) => {
                        context.set_source_rgb(0.7, 0.0, 1.0);
                        let time_meter = SlashMeter {
                            orientation: gtk::Orientation::Horizontal,
                            start_x: center_x + extents.width() / 2. + 50.,
                            start_y: center_y + 100.,
                            count: 5,
                            fill_count: minutes as u8,
                            height: 60.,
                            length: 100.,
                        };
                        time_meter.draw(&context);
                    }
                    None => {}
                }
            }
        });

        s.connect_resize(|s, width, height| {
            *s.imp().width.borrow_mut() = width;
            *s.imp().height.borrow_mut() = height;
            s.imp().redraw_background();
        });

        s
    }

    pub fn set_time(&self, time: Duration) {
        self.imp().set_time(time);
        if time == Duration::ZERO {
            *self.imp().timeout_animation.borrow_mut() = Some(TimeoutAnimation {
                intensity: 1.,
                duration: 1.,
                ascending: false,
            });
        }
        self.queue_draw();
    }

    pub fn tick(&self, frames_elapsed: u8) {
        let mut animation = self.imp().timeout_animation.borrow_mut();
        match *animation {
            Some(ref mut animation) => {
                animation.tick(frames_elapsed);
                self.queue_draw();
            }
            None => {}
        }
    }
}

struct AsymLineCutout {
    orientation: gtk::Orientation,
    start_x: f64,
    start_y: f64,
    start_length: f64,
    total_length: f64,
    cutout_length: f64,
    height: f64,
    invert: bool,
}

impl AsymLineCutout {
    fn draw(&self, context: &Context) {
        let dodge = if self.invert {
            self.height
        } else {
            -self.height
        };
        match self.orientation {
            gtk::Orientation::Horizontal => {
                context.move_to(self.start_x, self.start_y);
                context.line_to(self.start_x + self.start_length, self.start_y);
                context.line_to(
                    self.start_x + self.start_length + self.height,
                    self.start_y + dodge,
                );
                context.line_to(
                    self.start_x + self.start_length + self.height + self.cutout_length,
                    self.start_y + dodge,
                );
                context.line_to(
                    self.start_x
                        + self.start_length
                        + self.height
                        + self.cutout_length
                        + (self.height / 2.),
                    self.start_y + dodge / 2.,
                );
                context.line_to(self.total_length, self.start_y + dodge / 2.);
            }
            gtk::Orientation::Vertical => {
                context.move_to(self.start_x, self.start_y);
                context.line_to(self.start_x, self.start_y + self.start_length);
                context.line_to(
                    self.start_x + dodge,
                    self.start_y + self.start_length + self.height,
                );
                context.line_to(
                    self.start_x + dodge,
                    self.start_y + self.start_length + self.height + self.cutout_length,
                );
                context.line_to(
                    self.start_x + dodge / 2.,
                    self.start_y
                        + self.start_length
                        + self.height
                        + self.cutout_length
                        + (self.height / 2.),
                );
                context.line_to(self.start_x + dodge / 2., self.total_length);
            }
            _ => panic!("unknown orientation"),
        }
    }
}

struct AsymLine {
    orientation: gtk::Orientation,
    start_x: f64,
    start_y: f64,
    start_length: f64,
    height: f64,
    total_length: f64,
    invert: bool,
}

impl AsymLine {
    fn draw(&self, context: &Context) {
        let dodge = if self.invert {
            self.height
        } else {
            -self.height
        };
        match self.orientation {
            gtk::Orientation::Horizontal => {
                context.move_to(self.start_x, self.start_y);
                context.line_to(self.start_x + self.start_length, self.start_y);
                context.line_to(
                    self.start_x + self.start_length + self.height,
                    self.start_y + dodge,
                );
                context.line_to(self.start_x + self.total_length, self.start_y + dodge);
            }
            gtk::Orientation::Vertical => {}
            _ => panic!("unknown orientation"),
        }
    }
}

struct RoundedRectangle {
    x: f64,
    y: f64,
    width: f64,
    height: f64,
}

impl RoundedRectangle {
    fn draw(&self, context: &Context) {
        context.arc(
            self.x,
            self.y - self.height / 2.,
            self.height / 2.,
            0.5 * std::f64::consts::PI,
            1.5 * std::f64::consts::PI,
        );
        let _ = context.fill();
        context.arc(
            self.x + self.width,
            self.y - self.height / 2.,
            self.height / 2.,
            1.5 * std::f64::consts::PI,
            0.5 * std::f64::consts::PI,
        );
        let _ = context.fill();
        context.rectangle(self.x, self.y, self.width, -self.height);
        let _ = context.fill();
    }
}

struct SlashMeter {
    orientation: gtk::Orientation,
    start_x: f64,
    start_y: f64,
    count: u8,
    fill_count: u8,
    height: f64,
    length: f64,
}

impl SlashMeter {
    fn draw(&self, context: &Context) {
        match self.orientation {
            gtk::Orientation::Horizontal => {
                let angle: f64 = 0.8;
                let run = self.height / angle.tan();
                let width = self.length as f64 / (self.count as f64 * 2.);

                for c in 0..self.count {
                    context.set_line_width(1.);

                    let start_x = self.start_x + c as f64 * width * 2.;
                    context.move_to(start_x, self.start_y);
                    context.line_to(start_x + run, self.start_y - self.height);
                    context.line_to(start_x + run + width, self.start_y - self.height);
                    context.line_to(start_x + width, self.start_y);
                    context.line_to(start_x, self.start_y);
                    if c < self.fill_count {
                        let _ = context.fill();
                    } else {
                        let _ = context.stroke();
                    }
                }
            }
            gtk::Orientation::Vertical => {}
            _ => panic!("unknown orientation"),
        }
    }
}

fn main() {
    let app = gtk::Application::builder()
        .application_id("com.luminescent-dreams.cyberpunk-splash")
        .build();

    app.connect_activate(move |app| {
        let (gtk_tx, gtk_rx) =
            gtk::glib::MainContext::channel::<Event>(gtk::glib::PRIORITY_DEFAULT);
        let window = gtk::ApplicationWindow::new(app);
        window.present();

        let mut countdown = Duration::from_secs(5);
        let mut next_tick = Instant::now() + Duration::from_secs(1);

        let splash = Splash::new("GTK Kifu".to_owned(), countdown.clone());

        window.set_child(Some(&splash));
        // window.fullscreen();

        window.connect_maximized_notify(|window| {
            window.fullscreen();
        });

        gtk_rx.attach(None, move |event| {
            match event {
                Event::Frames(frames) => splash.tick(frames),
                Event::Time(time) => splash.set_time(time),
            };
            Continue(true)
        });

        std::thread::spawn(move || loop {
            std::thread::sleep(Duration::from_millis(1000 / 60));
            let _ = gtk_tx.send(Event::Frames(1));
            if Instant::now() >= next_tick && countdown > Duration::from_secs(0) {
                countdown = countdown - Duration::from_secs(1);
                let _ = gtk_tx.send(Event::Time(countdown));
                next_tick = next_tick + Duration::from_secs(1);
            }
        });
    });

    app.run();
}