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

const WIDTH: i32 = 1920;
const HEIGHT: i32 = 1280;

pub struct SplashPrivate {
    text: Rc<RefCell<String>>,
    time: Rc<RefCell<String>>,
    background: Rc<RefCell<Pattern>>,
}

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

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

    fn redraw_background(&self) {
        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();

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

        let center_x = WIDTH as f64 / 2.;
        let center_y = HEIGHT 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: WIDTH 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: HEIGHT 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: WIDTH as f64 / 2. + 100.,
                start_y: HEIGHT as f64 / 2. + 200.,
                start_length: 600.,
                height: 50.,
                total_length: 650.,
                invert: false,
            }
            .draw(&context);
            let _ = context.stroke();
        }

        {
            context.set_font_size(128.);
            let time_extents = context.text_extents(&self.time.borrow()).unwrap();
            let time_baseline_x = center_x - time_extents.width() / 2.;
            let time_baseline_y = center_y + 100.;

            let gradient = LinearGradient::new(
                time_baseline_x,
                time_baseline_y - time_extents.height(),
                time_baseline_x,
                time_baseline_y,
            );
            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);
            context.move_to(time_baseline_x, time_baseline_y);
            let _ = context.set_source(gradient);
            let _ = context.show_text(&self.time.borrow());
        }

        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(String::from(""))),
            background: Rc::new(RefCell::new(background)),
        }
    }
}
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: String) -> 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();
            }
        });

        s
    }
}

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"),
        }
    }
}

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

    app.connect_activate(move |app| {
        let window = gtk::ApplicationWindow::new(app);
        window.present();

        window.set_child(Some(&Splash::new("GTK Kifu".to_owned(), "4:23".to_owned())));
    });

    app.run();
}