use glutin::{
    dpi, ContextTrait, DeviceEvent, ElementState, Event, EventsLoop, GlProfile, GlRequest,
    MouseButton, MouseScrollDelta, WindowEvent, WindowedContext,
};

use hedgewars_engine::instance::EngineInstance;

use integral_geometry::Point;
use std::time::Duration;

fn init(event_loop: &EventsLoop, size: dpi::LogicalSize) -> WindowedContext {
    use glutin::{ContextBuilder, WindowBuilder};

    let window = WindowBuilder::new()
        .with_title("hwengine")
        .with_dimensions(size);

    let cxt = ContextBuilder::new()
        .with_gl(GlRequest::Latest)
        .with_gl_profile(GlProfile::Core)
        .build_windowed(window, &event_loop)
        .ok()
        .unwrap();

    unsafe {
        cxt.make_current().unwrap();
        gl::load_with(|ptr| cxt.get_proc_address(ptr) as *const _);

        if let Some(sz) = cxt.get_inner_size() {
            let phys = sz.to_physical(cxt.get_hidpi_factor());

            gl::Viewport(0, 0, phys.width as i32, phys.height as i32);
        }
    }

    cxt
}

fn main() {
    let mut event_loop = EventsLoop::new();
    let (w, h) = (1024.0, 768.0);
    let window = init(&event_loop, dpi::LogicalSize::new(w, h));

    let mut engine = EngineInstance::new();
    engine.world.create_renderer(w as u16, h as u16);

    let mut dragging = false;

    use std::time::Instant;

    let mut now = Instant::now();
    let mut update = Instant::now();

    let mut is_running = true;
    while is_running {
        let curr = Instant::now();
        let delta = curr - now;
        now = curr;
        let ms = delta.as_secs() as f64 * 1000.0 + delta.subsec_millis() as f64;
        window.set_title(&format!("hwengine {:.3}ms", ms));

        if update.elapsed() > Duration::from_millis(10) {
            update = curr;
            engine.world.step()
        }

        event_loop.poll_events(|event| match event {
            Event::WindowEvent { event, .. } => match event {
                WindowEvent::CloseRequested => {
                    is_running = false;
                }
                WindowEvent::MouseInput { button, state, .. } => {
                    if let MouseButton::Right = button {
                        dragging = state == ElementState::Pressed;
                    }
                }

                WindowEvent::MouseWheel { delta, .. } => {
                    let zoom_change = match delta {
                        MouseScrollDelta::LineDelta(x, y) => y as f32 * 0.1f32,
                        MouseScrollDelta::PixelDelta(delta) => {
                            let physical = delta.to_physical(window.get_hidpi_factor());
                            physical.y as f32 * 0.1f32
                        }
                    };
                    engine.world.move_camera(Point::ZERO, zoom_change);
                }
                _ => (),
            },
            Event::DeviceEvent { event, .. } => match event {
                DeviceEvent::MouseMotion { delta } => {
                    if dragging {
                        engine
                            .world
                            .move_camera(Point::new(delta.0 as i32, delta.1 as i32), 0.0)
                    }
                }
                _ => {}
            },
            _ => (),
        });

        unsafe { window.make_current().unwrap() };

        engine.render();
        window.swap_buffers().unwrap();
    }
}