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use std::{cell::RefCell, collections::BTreeMap};

use dces::prelude::*;

use crate::{
    render::RenderContext2D, theming::*, tree::Tree, utils::prelude::*, widget_base::mark_as_dirty,
};

use super::{component, component_try_mut, Layout};

/// Place widgets absolute on the screen.
#[derive(Default)]
pub struct AbsoluteLayout {
    desired_size: RefCell<DirtySize>,
}

impl AbsoluteLayout {
    pub fn new() -> Self {
        AbsoluteLayout::default()
    }
}

impl Layout for AbsoluteLayout {
    fn measure(
        &self,
        render_context_2_d: &mut RenderContext2D,
        entity: Entity,
        ecm: &mut EntityComponentManager<Tree, StringComponentStore>,
        layouts: &BTreeMap<Entity, Box<dyn Layout>>,
        theme: &Theme,
    ) -> DirtySize {
        let window = ecm.entity_store().root();

        if let Ok(bounds) = ecm.component_store().get::<Rectangle>("bounds", window) {
            self.desired_size
                .borrow_mut()
                .set_size(bounds.width(), bounds.height());
        }

        for index in 0..ecm.entity_store().children[&entity].len() {
            let child = ecm.entity_store().children[&entity][index];
            if let Some(child_layout) = layouts.get(&child) {
                let dirty = child_layout
                    .measure(render_context_2_d, child, ecm, layouts, theme)
                    .dirty()
                    || self.desired_size.borrow().dirty();

                self.desired_size.borrow_mut().set_dirty(dirty);
            }
        }

        *self.desired_size.borrow()
    }

    fn arrange(
        &self,
        render_context_2_d: &mut RenderContext2D,
        _parent_size: (f64, f64),
        entity: Entity,
        ecm: &mut EntityComponentManager<Tree, StringComponentStore>,
        layouts: &BTreeMap<Entity, Box<dyn Layout>>,
        theme: &Theme,
    ) -> (f64, f64) {
        if component::<Visibility>(ecm, entity, "visibility") == Visibility::Collapsed {
            self.desired_size.borrow_mut().set_size(0.0, 0.0);
            return (0.0, 0.0);
        }

        if let Some(bounds) = component_try_mut::<Rectangle>(ecm, entity, "bounds") {
            bounds.set_width(self.desired_size.borrow().width());
            bounds.set_height(self.desired_size.borrow().height());
        }

        mark_as_dirty("bounds", entity, ecm);

        for index in 0..ecm.entity_store().children[&entity].len() {
            let child = ecm.entity_store().children[&entity][index];
            if let Some(child_layout) = layouts.get(&child) {
                child_layout.arrange(
                    render_context_2_d,
                    (
                        self.desired_size.borrow().width(),
                        self.desired_size.borrow().height(),
                    ),
                    child,
                    ecm,
                    layouts,
                    theme,
                );
            }
        }

        self.desired_size.borrow_mut().set_dirty(false);
        self.desired_size.borrow().size()
    }
}

impl Into<Box<dyn Layout>> for AbsoluteLayout {
    fn into(self) -> Box<dyn Layout> {
        Box::new(self)
    }
}