mod proxy;
mod runner;
mod state;
mod window_target;

pub use self::proxy::Proxy;
pub use self::window_target::WindowTarget;

use super::{backend, device, monitor, window};
use crate::event::{DeviceId, ElementState, Event, KeyboardInput, WindowEvent};
use crate::event_loop as root;
use crate::window::WindowId;

use std::collections::{vec_deque::IntoIter as VecDequeIter, VecDeque};
use std::marker::PhantomData;

pub struct EventLoop<T: 'static> {
    elw: root::EventLoopWindowTarget<T>,
}

impl<T> EventLoop<T> {
    pub fn new() -> Self {
        EventLoop {
            elw: root::EventLoopWindowTarget {
                p: WindowTarget::new(),
                _marker: PhantomData,
            },
        }
    }

    pub fn available_monitors(&self) -> VecDequeIter<monitor::Handle> {
        VecDeque::new().into_iter()
    }

    pub fn primary_monitor(&self) -> monitor::Handle {
        monitor::Handle
    }

    pub fn run<F>(self, mut event_handler: F) -> !
    where
        F: 'static + FnMut(Event<T>, &root::EventLoopWindowTarget<T>, &mut root::ControlFlow),
    {
        let target = root::EventLoopWindowTarget {
            p: self.elw.p.clone(),
            _marker: PhantomData,
        };

        let runner = self.elw.p.run(Box::new(move |event, flow| {
            event_handler(event, &target, flow)
        }));

        backend::Document::on_blur(|| {
            runner.send_event(Event::WindowEvent {
                window_id: WindowId(window::Id),
                event: WindowEvent::Focused(false),
            });
        });

        backend::Document::on_focus(|| {
            runner.send_event(Event::WindowEvent {
                window_id: WindowId(window::Id),
                event: WindowEvent::Focused(true),
            });
        });

        backend::Document::on_key_down(|scancode, virtual_keycode, modifiers| {
            runner.send_event(Event::WindowEvent {
                window_id: WindowId(window::Id),
                event: WindowEvent::KeyboardInput {
                    device_id: DeviceId(unsafe { device::Id::dummy() }),
                    input: KeyboardInput {
                        scancode,
                        state: ElementState::Pressed,
                        virtual_keycode,
                        modifiers,
                    },
                },
            });
        });

        backend::Document::on_key_up(|scancode, virtual_keycode, modifiers| {
            runner.send_event(Event::WindowEvent {
                window_id: WindowId(window::Id),
                event: WindowEvent::KeyboardInput {
                    device_id: DeviceId(unsafe { device::Id::dummy() }),
                    input: KeyboardInput {
                        scancode,
                        state: ElementState::Released,
                        virtual_keycode,
                        modifiers,
                    },
                },
            });
        });

        // Throw an exception to break out of Rust exceution and use unreachable to tell the
        // compiler this function won't return, giving it a return type of '!'
        backend::throw(
            "Using exceptions for control flow, don't mind me. This isn't actually an error!",
        );

        unreachable!();
    }

    pub fn create_proxy(&self) -> Proxy<T> {
        self.elw.p.proxy()
    }

    pub fn window_target(&self) -> &root::EventLoopWindowTarget<T> {
        &self.elw
    }
}