"use strict";

// Base features for all components
Toolkit.Component = class Component {

    // Object constructor
    constructor(application, tagname) {

        // Configure instance fields
        this.application     = application;
        this.containers      = [ this ];
        this.element         = document.createElement(tagname);
        this.id              = this.element.id = Toolkit.id();
        this.parent          = null;
        this.properties      = {};
        this.resizeListeners = [];

        // Configure component
        this.element.component = this;
    }



    ///////////////////////////// Public Methods //////////////////////////////

    // Add a callback for resize events
    addResizeListener(listener) {
        if (this.resizeListeners.indexOf(listener) != -1)
            return;
        if (this.resizeListeners.length == 0)
            new ResizeObserver(()=>this.onresize()).observe(this.element);
        this.resizeListeners.push(listener);
    }

    // Remove the component from its parent
    remove() {
        this.parent && this.parent.remove(this);
    }

    // Retrieve the bounding box of the element
    getBounds() {
        return this.element.getBoundingClientRect();
    }

    // Specify the height of the element
    setHeight(height) {
        if (height === null)
            this.element.style.removeProperty("height");
        else this.element.style.height = height;
    }

    // Specify the width of the element
    setWidth(width) {
        if (width === null)
            this.element.style.removeProperty("width");
        else this.element.style.width = width;
    }



    ///////////////////////////// Package Methods /////////////////////////////

    // Determine whether this component contains another
    contains(comp) {
        if (comp == null)
            return false;
        if (comp instanceof Toolkit.Component)
            comp = comp.element;
        for (let cont of this.containers)
            if ((cont instanceof Toolkit.Component ? cont.element : cont)
                .contains(comp)) return true;
        return false;
    }

    // Notify of a change to component focus
    focusChanged(from, to) {
        if (this.parent != null)
            this.parent.focusChanged(from, to);
    }



    ///////////////////////////// Private Methods /////////////////////////////

    // Resize event handler
    onresize() {
        let bounds = this.getBounds();
        for (let listener of this.resizeListeners)
            listener(bounds, this);
    }

};