pub use canary_types::*;

#[macro_export]
macro_rules! export_abi {
    ($panel_impl: ident) => {
        #[no_mangle]
        pub extern "C" fn bind_panel(panel: u32) -> u32 {
            ::canary_script::abi::bind_panel::<$panel_impl>(panel)
        }

        #[no_mangle]
        pub extern "C" fn update(dt: f32) {
            ::canary_script::abi::update(dt)
        }

        #[no_mangle]
        pub extern "C" fn draw() {
            ::canary_script::abi::draw()
        }

        #[no_mangle]
        pub extern "C" fn on_cursor_event(kind: u32, x: f32, y: f32) {
            ::canary_script::abi::on_cursor_event(kind, x, y)
        }
    };
}

pub mod abi {
    use super::*;
    use num_traits::FromPrimitive;

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

    pub fn bind_panel<T: BindPanel>(panel: u32) -> u32 {
        unsafe {
            let panel = Panel(panel);
            let panel_impl = T::bind(panel);
            let id = PANEL_IMPLS.len() as u32;
            PANEL_IMPLS.push(panel_impl);
            id
        }
    }

    pub fn update(dt: f32) {
        unsafe {
            for panel in PANEL_IMPLS.iter_mut() {
                panel.update(dt);
            }
        }
    }

    pub fn draw() {
        unsafe {
            for panel in PANEL_IMPLS.iter_mut() {
                panel.draw();
            }
        }
    }

    pub fn on_cursor_event(kind: u32, x: f32, y: f32) {
        let panel = unsafe { &mut PANEL_IMPLS[0] };
        let at = canary_types::Vec2 { x, y };
        let kind = CursorEventKind::from_u32(kind).unwrap();
        panel.on_cursor_event(kind, at);
    }
}

pub trait BindPanel {
    fn bind(panel: Panel) -> Box<dyn PanelImpl>;
}

pub trait PanelImpl {
    fn update(&mut self, dt: f32);
    fn draw(&mut self);
    fn on_cursor_event(&mut self, kind: CursorEventKind, at: Vec2);
}

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

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

    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,
            )
        }
    }
}

extern "C" {
    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,
    );
}