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();

    }

}