use crate::{Color, Vec2, CursorEventKind};

static mut PANEL_IMPLS: Vec<Box<dyn PanelImpl>> = Vec::new();

#[no_mangle]
pub extern "C" fn bind_panel(panel: u32) -> u32 {
    unsafe {
        let panel = UiPanel::bind(panel);
        let panel_impl = Box::new(crate::DummyPanel::bind(panel));
        let id = PANEL_IMPLS.len() as u32;
        PANEL_IMPLS.push(panel_impl);
        id
    }
}

#[no_mangle]
pub extern "C" fn update(dt: f32) {
    unsafe {
        for panel in PANEL_IMPLS.iter_mut() {
            panel.update(dt);
        }
    }
}

#[macro_export]
macro_rules! handle_cursor_event {
    ($event: ident, $kind: expr) => {
        #[no_mangle]
        pub extern "C" fn $event(id: u32, x: f32, y: f32) {
            unsafe {
                let panel = &mut PANEL_IMPLS[id as usize];
                let at = Vec2::new(x, y);
                (&mut *panel).on_cursor_event($kind, at);
            }
        }
    };
}

handle_cursor_event!(on_hover, CursorEventKind::Hover);
handle_cursor_event!(on_select, CursorEventKind::Select);
handle_cursor_event!(on_drag, CursorEventKind::Drag);
handle_cursor_event!(on_deselect, CursorEventKind::Deselect);

#[allow(unused)]
pub trait PanelImpl {
    fn update(&mut self, dt: f32) {}
    fn on_cursor_event(&mut self, kind: CursorEventKind, at: Vec2) {}
}

extern "C" {
    fn UiPanel_getWidth(panel: u32) -> f32;
    fn UiPanel_getHeight(panel: u32) -> f32;
    fn UiPanel_setSize(panel: u32, width: f32, height: f32);
    fn UiPanel_setColor(panel: u32, r: f32, g: f32, b: f32, a: f32);

    #[link_name = "UiPanel_drawTriangle"]
    fn UiPanel_drawTriangle(
        panel: u32,
        x1: f32,
        y1: f32,
        x2: f32,
        y2: f32,
        x3: f32,
        y3: f32,
        r: f32,
        g: f32,
        b: f32,
        a: f32,
    );
}

#[repr(transparent)]
#[derive(Copy, Clone)]
pub struct UiPanel(u32);

impl UiPanel {
    pub unsafe fn bind(id: u32) -> Self {
        Self(id)
    }

    pub fn get_width(&self) -> f32 {
        unsafe { UiPanel_getWidth(self.0) }
    }

    pub fn get_height(&self) -> f32 {
        unsafe { UiPanel_getHeight(self.0) }
    }

    pub fn set_size(&mut self, width: f32, height: f32) {
        unsafe { UiPanel_setSize(self.0, width, height) }
    }

    pub fn set_color(&mut self, color: &Color) {
        unsafe { UiPanel_setColor(self.0, color.r, color.g, color.b, color.a) }
    }

    pub fn draw_triangle(&self, v1: Vec2, v2: Vec2, v3: Vec2, color: Color) {
        unsafe {
            UiPanel_drawTriangle(
                self.0, v1.x, v1.y, v2.x, v2.y, v3.x, v3.y, color.r, color.g, color.b, color.a,
            )
        }
    }
}