use kahlo::{math::PixelSideOffsets, prelude::*};

use crate::{
    component::Component,
    layout::{LayoutNode, LayoutNodeAccess, LayoutNodeContainer, SizePolicy},
    theme::Theme,
    ui::UIHandle,
    window::RenderFormat,
};

use super::Widget;

pub struct Frame<C: Component> {
    layout: LayoutNode,
    child: Option<Box<dyn Widget<C>>>,
    _ghost: std::marker::PhantomData<C>,
}

impl<C: Component> Frame<C> {
    pub fn new(uih: &UIHandle) -> Self {
        let mut nnode = uih.new_layout_node();
        nnode
            .set_height_policy(SizePolicy::expanding(1))
            .set_width_policy(SizePolicy::expanding(1));
        Self {
            layout: nnode,
            child: None,
            _ghost: Default::default(),
        }
    }

    pub fn set_child(&mut self, child: Box<dyn Widget<C>>) {
        self.child = Some(child);
        self.layout.relayout();
    }
}

impl<C: Component> LayoutNodeContainer for Frame<C> {
    fn layout_node(&self) -> &LayoutNode {
        &self.layout
    }
    fn layout_child(&self, ndx: usize) -> Option<LayoutNodeAccess> {
        if ndx == 0 {
            Some(self.child.as_ref()?.layout_node())
        } else {
            None
        }
    }
    fn layout_child_count(&self) -> usize {
        if self.child.is_some() {
            1
        } else {
            0
        }
    }
}

impl<C: Component> Widget<C> for Frame<C> {
    fn poll(
        &mut self,
        _uih: &mut UIHandle,
        _input_state: Option<&crate::input::InputState>,
    ) -> Vec<C::Msg> {
        vec![]
    }
    fn layout_node(&self) -> LayoutNodeAccess {
        LayoutNodeAccess::new(self)
    }
    fn layout_node_mut(&mut self) -> &mut LayoutNode {
        &mut self.layout
    }
    fn render(&self, theme: &Theme, target: &mut kahlo::BitmapMut<RenderFormat>) {
        let area = self.layout.render_area().unwrap();

        target.fill_region(area, theme.border);
        target.fill_region(
            area.inner_box(PixelSideOffsets::new_all_same(theme.border_width as i32)),
            theme.panel,
        );
    }
}