use std::collections::HashMap;
use domain::WidgetId;
use crate::BoundingBox;

pub struct RenderTree {
    pub widget_bounds: HashMap<WidgetId, BoundingBox>,
}

impl RenderTree {
    pub fn get_widget_bounds(&self, id: WidgetId) -> Option<&BoundingBox> {
        self.widget_bounds.get(&id)
    }

    pub fn diff(&self, other: &RenderTree) -> Vec<WidgetId> {
        let mut changed = Vec::new();
        for (id, bounds) in &self.widget_bounds {
            match other.widget_bounds.get(id) {
                Some(prev) if prev == bounds => {}
                _ => changed.push(*id),
            }
        }
        for id in other.widget_bounds.keys() {
            if !self.widget_bounds.contains_key(id) {
                changed.push(*id);
            }
        }
        changed
    }
}