use kahlo::{colour::Colour, math::PixelBox, prelude::*};

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

use super::Widget;

pub struct Label<C: Component> {
    lnode: LeafLayoutNode,
    text: Option<String>,
    _ghost: std::marker::PhantomData<C>,
}

impl<C: Component> Label<C> {
    pub fn new(uih: &UIHandle) -> Self {
        let mut node = uih.new_layout_node();
        node.set_width_policy(SizePolicy::expands(1))
            .set_height_policy(SizePolicy {
                minimum: 20,
                desired: 20,
                slack_weight: 0,
            });
        Self {
            lnode: LeafLayoutNode::new(node),
            text: None,
            _ghost: Default::default(),
        }
    }

    pub fn set_text(&mut self, text: String) {
        self.text = Some(text);
    }
}

impl<C: Component> Widget<C> for Label<C> {
    fn poll(
        &mut self,
        _uih: &mut UIHandle,
        _input_state: Option<&crate::input::InputState>,
    ) -> Vec<<C as Component>::Msg> {
        vec![]
    }

    fn layout_node(&self) -> LayoutNodeAccess {
        LayoutNodeAccess::new(&self.lnode)
    }
    fn layout_node_mut(&mut self) -> &mut LayoutNode {
        &mut self.lnode
    }

    fn render(&self, theme: &Theme, surface: &mut kahlo::RgbaBitmap) {
        let Some(text) = self.text.as_ref() else { return };
        let line = theme.make_line(text.as_str());
        let rendered = line.render_line();

        let render_location = self.layout_node().cached_rect().unwrap();

        surface.fill_masked(
            &rendered,
            &PixelBox::from_size(rendered.size()),
            &render_location.origin,
            theme.foreground,
            kahlo::colour::BlendMode::SourceAlpha,
        );
    }
}