use std::sync::{Arc, Mutex};

use crate::event::{ElementState, MouseButton, MouseScrollDelta, TouchPhase, WindowEvent, ModifiersState};

use super::DeviceId;
use super::event_loop::WindowEventsSink;
use super::window::WindowStore;

use smithay_client_toolkit::reexports::client::protocol::wl_pointer::{self, Event as PtrEvent, WlPointer};
use smithay_client_toolkit::reexports::client::protocol::wl_seat;

pub fn implement_pointer(
    seat: &wl_seat::WlSeat,
    sink: Arc<Mutex<WindowEventsSink>>,
    store: Arc<Mutex<WindowStore>>,
    modifiers_tracker: Arc<Mutex<ModifiersState>>,
) -> WlPointer {
    let mut mouse_focus = None;
    let mut axis_buffer = None;
    let mut axis_discrete_buffer = None;
    let mut axis_state = TouchPhase::Ended;

    seat.get_pointer(|pointer| {
        pointer.implement_closure(move |evt, pointer| {
            let mut sink = sink.lock().unwrap();
            let store = store.lock().unwrap();
            match evt {
                PtrEvent::Enter {
                    surface,
                    surface_x,
                    surface_y,
                    ..
                } => {
                    let wid = store.find_wid(&surface);
                    if let Some(wid) = wid {
                        mouse_focus = Some(wid);
                        sink.send_event(
                            WindowEvent::CursorEntered {
                                device_id: crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId)),
                            },
                            wid,
                        );
                        sink.send_event(
                            WindowEvent::CursorMoved {
                                device_id: crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId)),
                                position: (surface_x, surface_y).into(),
                                modifiers: modifiers_tracker.lock().unwrap().clone(),
                            },
                            wid,
                        );
                    }
                }
                PtrEvent::Leave { surface, .. } => {
                    mouse_focus = None;
                    let wid = store.find_wid(&surface);
                    if let Some(wid) = wid {
                        sink.send_event(
                            WindowEvent::CursorLeft {
                                device_id: crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId)),
                            },
                            wid,
                        );
                    }
                }
                PtrEvent::Motion {
                    surface_x,
                    surface_y,
                    ..
                } => {
                    if let Some(wid) = mouse_focus {
                        sink.send_event(
                            WindowEvent::CursorMoved {
                                device_id: crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId)),
                                position: (surface_x, surface_y).into(),
                                modifiers: modifiers_tracker.lock().unwrap().clone(),
                            },
                            wid,
                        );
                    }
                }
                PtrEvent::Button { button, state, .. } => {
                    if let Some(wid) = mouse_focus {
                        let state = match state {
                            wl_pointer::ButtonState::Pressed => ElementState::Pressed,
                            wl_pointer::ButtonState::Released => ElementState::Released,
                            _ => unreachable!()
                        };
                        let button = match button {
                            0x110 => MouseButton::Left,
                            0x111 => MouseButton::Right,
                            0x112 => MouseButton::Middle,
                            // TODO figure out the translation ?
                            _ => return,
                        };
                        sink.send_event(
                            WindowEvent::MouseInput {
                                device_id: crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId)),
                                state: state,
                                button: button,
                                modifiers: modifiers_tracker.lock().unwrap().clone(),
                            },
                            wid,
                        );
                    }
                }
                PtrEvent::Axis { axis, value, .. } => {
                    if let Some(wid) = mouse_focus {
                        if pointer.as_ref().version() < 5 {
                            let (mut x, mut y) = (0.0, 0.0);
                            // old seat compatibility
                            match axis {
                                // wayland vertical sign convention is the inverse of winit
                                wl_pointer::Axis::VerticalScroll => y -= value as f32,
                                wl_pointer::Axis::HorizontalScroll => x += value as f32,
                                _ => unreachable!()
                            }
                            sink.send_event(
                                WindowEvent::MouseWheel {
                                    device_id: crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId)),
                                    delta: MouseScrollDelta::PixelDelta((x as f64, y as f64).into()),
                                    phase: TouchPhase::Moved,
                                    modifiers: modifiers_tracker.lock().unwrap().clone(),
                                },
                                wid,
                            );
                        } else {
                            let (mut x, mut y) = axis_buffer.unwrap_or((0.0, 0.0));
                            match axis {
                                // wayland vertical sign convention is the inverse of winit
                                wl_pointer::Axis::VerticalScroll => y -= value as f32,
                                wl_pointer::Axis::HorizontalScroll => x += value as f32,
                                _ => unreachable!()
                            }
                            axis_buffer = Some((x, y));
                            axis_state = match axis_state {
                                TouchPhase::Started | TouchPhase::Moved => TouchPhase::Moved,
                                _ => TouchPhase::Started,
                            }
                        }
                    }
                }
                PtrEvent::Frame => {
                    let axis_buffer = axis_buffer.take();
                    let axis_discrete_buffer = axis_discrete_buffer.take();
                    if let Some(wid) = mouse_focus {
                        if let Some((x, y)) = axis_discrete_buffer {
                            sink.send_event(
                                WindowEvent::MouseWheel {
                                    device_id: crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId)),
                                    delta: MouseScrollDelta::LineDelta(x as f32, y as f32),
                                    phase: axis_state,
                                    modifiers: modifiers_tracker.lock().unwrap().clone(),
                                },
                                wid,
                            );
                        } else if let Some((x, y)) = axis_buffer {
                            sink.send_event(
                                WindowEvent::MouseWheel {
                                    device_id: crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId)),
                                    delta: MouseScrollDelta::PixelDelta((x as f64, y as f64).into()),
                                    phase: axis_state,
                                    modifiers: modifiers_tracker.lock().unwrap().clone(),
                                },
                                wid,
                            );
                        }
                    }
                }
                PtrEvent::AxisSource { .. } => (),
                PtrEvent::AxisStop { .. } => {
                    axis_state = TouchPhase::Ended;
                }
                PtrEvent::AxisDiscrete { axis, discrete } => {
                    let (mut x, mut y) = axis_discrete_buffer.unwrap_or((0, 0));
                    match axis {
                        // wayland vertical sign convention is the inverse of winit
                        wl_pointer::Axis::VerticalScroll => y -= discrete,
                        wl_pointer::Axis::HorizontalScroll => x += discrete,
                        _ => unreachable!()
                    }
                    axis_discrete_buffer = Some((x, y));
                    axis_state = match axis_state {
                        TouchPhase::Started | TouchPhase::Moved => TouchPhase::Moved,
                        _ => TouchPhase::Started,
                    }
                },
                _ => unreachable!()
            }
        }, ())
    }).unwrap()
}