use crate::image::Image;
use crate::vec2::Vec2;
use rand::Rng;
use std::num::NonZeroU32;
use winit::dpi::LogicalSize;
use winit::event::VirtualKeyCode::Escape;
use winit::event::{
    ElementState, Event as WinitEvent, MouseButton as WinitMouseButton, WindowEvent,
};
use winit::event_loop::{ControlFlow, EventLoop};
use winit::window::WindowBuilder;

pub enum MouseButton {
    Left,
    Right,
    Middle,
    WheelUp,
    WheelDown,
    Forward,
    Back,
}

pub enum Event {
    MouseClick(MouseButton, Vec2<i32>),
}

pub trait Game {
    fn new(window_state: &mut WindowState) -> Self;
    fn update(&mut self, window_state: &mut WindowState);
    fn on_event(&mut self, window_state: &mut WindowState, event: Event);
    fn draw(&self, target: &mut Image);
}

pub struct WindowState {
    palette: [u32; 256],
    mouse_pos: Vec2<i32>,
}

impl WindowState {
    fn new() -> Self {
        WindowState {
            palette: [0u32; 256],
            mouse_pos: Vec2::zero(),
        }
    }
    pub fn set_palette(&mut self, index: u8, r: u8, g: u8, b: u8) {
        self.palette[index as usize] =
            (r as u32) | ((g as u32) << 8) | ((b as u32) << 16) | 0xff000000;
    }

    pub fn scramble_palette(&mut self) {
        let mut rng = rand::thread_rng();
        for i in 0..=255 {
            self.set_palette(i, rng.gen(), rng.gen(), rng.gen());
        }
    }

    pub fn mouse_pos(&self) -> Vec2<i32> {
        self.mouse_pos
    }
}

pub fn run<T: Game + 'static>(width: i32, height: i32) {
    let event_loop = EventLoop::new();
    let window = {
        let size = LogicalSize::new(width as f64, height as f64);
        WindowBuilder::new()
            .with_title("Skunk 2D")
            .with_inner_size(size)
            .with_min_inner_size(size)
            //.with_decorations(false)
            //.with_maximized(true)
            .build(&event_loop)
            .unwrap()
    };

    //todo: replace Pixels with custom thingie (startup time slow because wgpu?)
    let context = unsafe { softbuffer::Context::new(&window) }.unwrap();
    let mut surface = unsafe { softbuffer::Surface::new(&context, &window) }.unwrap();
    let mut screen = Image::new(Vec2 {
        x: width,
        y: height,
    });
    let mut window_state = WindowState::new();
    let mut game = T::new(&mut window_state);

    event_loop.run(move |event, _, control_flow| {
        match event {
            WinitEvent::NewEvents(_) => {}
            WinitEvent::WindowEvent {
                event: window_event,
                ..
            } => {
                match window_event {
                    WindowEvent::Resized(_) => {}
                    WindowEvent::Moved(_) => {}
                    WindowEvent::CloseRequested => {}
                    WindowEvent::Destroyed => {}
                    WindowEvent::DroppedFile(_) => {}
                    WindowEvent::HoveredFile(_) => {}
                    WindowEvent::HoveredFileCancelled => {}
                    WindowEvent::ReceivedCharacter(_) => {}
                    WindowEvent::Focused(_) => {}
                    WindowEvent::KeyboardInput { input, .. } => {
                        //todo: actually do input handling
                        if let Some(k) = input.virtual_keycode {
                            if k == Escape {
                                *control_flow = ControlFlow::Exit;
                            }
                        };
                        if *control_flow == ControlFlow::Exit {
                            return;
                        }
                    }
                    WindowEvent::ModifiersChanged(_) => {}
                    WindowEvent::Ime(_) => {}
                    WindowEvent::CursorMoved { position, .. } => {
                        window_state.mouse_pos = Vec2 {
                            x: position.x as i32,
                            y: position.y as i32,
                        }
                    }
                    WindowEvent::CursorEntered { .. } => {}
                    WindowEvent::CursorLeft { .. } => {}
                    WindowEvent::MouseWheel { .. } => {}
                    WindowEvent::MouseInput { button, state, .. } => {
                        let b = match button {
                            WinitMouseButton::Left => MouseButton::Left,
                            WinitMouseButton::Right => MouseButton::Right,
                            WinitMouseButton::Middle => MouseButton::Middle,
                            //todo: handle other mousebuttons
                            WinitMouseButton::Other(b) => match b {
                                _ => MouseButton::Back,
                            },
                        };
                        match state {
                            ElementState::Pressed => {
                                let e = Event::MouseClick(b, window_state.mouse_pos);
                                game.on_event(&mut window_state, e);
                            }
                            ElementState::Released => {}
                        }
                    }
                    WindowEvent::TouchpadMagnify { .. } => {}
                    WindowEvent::SmartMagnify { .. } => {}
                    WindowEvent::TouchpadRotate { .. } => {}
                    WindowEvent::TouchpadPressure { .. } => {}
                    WindowEvent::AxisMotion { .. } => {}
                    WindowEvent::Touch(_) => {}
                    WindowEvent::ScaleFactorChanged { .. } => {}
                    WindowEvent::ThemeChanged(_) => {}
                    WindowEvent::Occluded(_) => {}
                }
            }
            WinitEvent::DeviceEvent { .. } => {}
            WinitEvent::UserEvent(_) => {}
            WinitEvent::Suspended => {}
            WinitEvent::Resumed => {}
            WinitEvent::MainEventsCleared => {}
            WinitEvent::RedrawRequested(_) => {
                game.draw(&mut screen);

                let (width, height) = {
                    let size = window.inner_size();
                    (size.width, size.height)
                };
                surface
                    .resize(
                        NonZeroU32::new(width).unwrap(),
                        NonZeroU32::new(height).unwrap(),
                    )
                    .unwrap();

                let mut buf = surface.buffer_mut().unwrap();
                for i in 0..(width * height) as usize {
                    buf[i] = window_state.palette[screen.data()[i] as usize];
                }
                buf.present().unwrap();
            }
            WinitEvent::RedrawEventsCleared => {}
            WinitEvent::LoopDestroyed => {}
        }

        game.update(&mut window_state);
        window.request_redraw();
    });
}