use crate::{
    event_loop::state::FrameStatus,
    platform_specific::wayland::{
        event_loop::state::SctkState, sctk_event::SctkEvent,
    },
};
use sctk::{
    delegate_pointer,
    reexports::client::Proxy,
    seat::pointer::{
        CursorIcon, PointerEvent, PointerEventKind, PointerHandler,
    },
};
use winit::{
    dpi::PhysicalPosition,
    event::{
        ButtonSource, MouseButton, MouseScrollDelta, PointerKind,
        PointerSource, TouchPhase, WindowEvent,
    },
};

impl PointerHandler for SctkState {
    fn pointer_frame(
        &mut self,
        conn: &sctk::reexports::client::Connection,
        _qh: &sctk::reexports::client::QueueHandle<Self>,
        pointer: &sctk::reexports::client::protocol::wl_pointer::WlPointer,
        events: &[sctk::seat::pointer::PointerEvent],
    ) {
        let (is_active, my_seat) =
            match self.seats.iter_mut().enumerate().find_map(|(i, s)| {
                if s.ptr.as_ref().map(|p| p.pointer()) == Some(pointer) {
                    Some((i, s))
                } else {
                    None
                }
            }) {
                Some((i, s)) => (i == 0, s),
                None => return,
            };

        // track events, but only forward for the active seat
        for e in events {
            if my_seat.active_icon != my_seat.icon {
                // Restore cursor that was set by appliction, or default
                my_seat.set_cursor(
                    conn,
                    my_seat.icon.unwrap_or(CursorIcon::Default),
                );
            }

            if is_active {
                let id = winit::window::WindowId::from_raw(
                    e.surface.id().as_ptr() as usize,
                );
                if self.windows.iter().any(|w| w.window.id() == id) {
                    continue;
                }
                let entry = self
                    .frame_status
                    .entry(e.surface.id())
                    .or_insert(FrameStatus::RequestedRedraw);
                if matches!(entry, FrameStatus::Received) {
                    *entry = FrameStatus::Ready;
                }
                if let PointerEventKind::Motion { time } = &e.kind {
                    self.sctk_events.push(SctkEvent::PointerEvent {
                        variant: PointerEvent {
                            surface: e.surface.clone(),
                            position: e.position,
                            kind: PointerEventKind::Motion { time: *time },
                        },
                        ptr_id: pointer.clone(),
                        seat_id: my_seat.seat.clone(),
                    });
                } else {
                    self.sctk_events.push(SctkEvent::Winit(
                        id,
                        match e.kind {
                            PointerEventKind::Enter { serial } => {
                                WindowEvent::PointerEntered {
                                    device_id: Default::default(),
                                    position: e.position.into(),
                                    primary: is_active,
                                    kind: PointerKind::Mouse,
                                }
                            }
                            PointerEventKind::Leave { serial } => {
                                WindowEvent::PointerLeft {
                                    device_id: Default::default(),
                                    position: Some(e.position.into()),
                                    primary: is_active,
                                    kind: PointerKind::Mouse,
                                }
                            }
                            PointerEventKind::Motion { time } => {
                                WindowEvent::PointerMoved {
                                    device_id: Default::default(),
                                    position: e.position.into(),
                                    primary: is_active,
                                    source: PointerSource::Mouse,
                                }
                            }
                            PointerEventKind::Press {
                                time,
                                button,
                                serial,
                            } => WindowEvent::PointerButton {
                                device_id: Default::default(),
                                state: winit::event::ElementState::Pressed,
                                button: ButtonSource::Mouse(
                                    wayland_button_to_winit(button),
                                ),
                                position: e.position.into(),
                                primary: is_active,
                            },
                            PointerEventKind::Release {
                                time,
                                button,
                                serial,
                            } => WindowEvent::PointerButton {
                                device_id: Default::default(),
                                state: winit::event::ElementState::Released,
                                button: ButtonSource::Mouse(
                                    wayland_button_to_winit(button),
                                ),
                                position: e.position.into(),
                                primary: is_active,
                            },
                            PointerEventKind::Axis {
                                time,
                                horizontal,
                                vertical,
                                source,
                            } => WindowEvent::MouseWheel {
                                device_id: Default::default(),
                                delta: if horizontal.discrete > 0 {
                                    MouseScrollDelta::LineDelta(
                                        horizontal.discrete as f32,
                                        vertical.discrete as f32,
                                    )
                                } else {
                                    MouseScrollDelta::PixelDelta(
                                        PhysicalPosition::new(
                                            horizontal.absolute,
                                            vertical.absolute,
                                        ),
                                    )
                                },
                                phase: if horizontal.stop {
                                    TouchPhase::Ended
                                } else {
                                    TouchPhase::Moved
                                },
                            },
                        },
                    ));
                }
            }
            match e.kind {
                PointerEventKind::Enter { .. } => {
                    _ = my_seat.ptr_focus.replace(e.surface.clone());
                }
                PointerEventKind::Leave { .. } => {
                    _ = my_seat.ptr_focus.take();
                    _ = my_seat.active_icon = None;
                }
                PointerEventKind::Press {
                    time,
                    button,
                    serial,
                } => {
                    _ = my_seat.last_ptr_press.replace((time, button, serial));
                }
                // TODO revisit events that ought to be handled and change internal state
                _ => {}
            }
        }
    }
}

/// Convert the Wayland button into winit.
fn wayland_button_to_winit(button: u32) -> MouseButton {
    // These values are coming from <linux/input-event-codes.h>.
    const BTN_LEFT: u32 = 0x110;
    const BTN_RIGHT: u32 = 0x111;
    const BTN_MIDDLE: u32 = 0x112;
    const BTN_SIDE: u32 = 0x113;
    const BTN_EXTRA: u32 = 0x114;
    const BTN_FORWARD: u32 = 0x115;
    const BTN_BACK: u32 = 0x116;

    match button {
        BTN_LEFT => MouseButton::Left,
        BTN_RIGHT => MouseButton::Right,
        BTN_MIDDLE => MouseButton::Middle,
        BTN_BACK | BTN_SIDE => MouseButton::Back,
        BTN_FORWARD | BTN_EXTRA => MouseButton::Forward,
        button => MouseButton::try_from_u8(button as u8)
            .unwrap_or(MouseButton::Button32), // TODO why was Other variant removed?
    }
}

delegate_pointer!(SctkState);