"use strict";

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

    // Object constructor
    constructor(application, tagname, options) {
        options = options || {};

        // Configure instance fields
        this.application     = application;
        this.containers      = [ this ];
        this.display         = null;
        this.element         = document.createElement(tagname);
        this.id              = this.element.id = Toolkit.id();
        this.parent          = null;
        this.properties      = {};
        this.resizeListeners = [];
        this.resizeObserver  = null;
        this.visible         = "visible" in options ? !!options.visible : true;

        // Configure component
        this.element.component = this;
        this.setVisible(this.visible);
    }



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

    // Add a callback for resize events
    addResizeListener(listener) {
        if (this.resizeListeners.indexOf(listener) != -1)
            return;
        if (this.resizeObserver == null) {
            this.resizeObserver = new ResizeObserver(()=>this.onresized());
            this.resizeObserver.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();
    }

    // Retrieve the display CSS property of the visible element
    getDisplay() {
        return this.display;
    }

    // Determine whether the component is visible
    isVisible() {
        for (let comp = this; comp != null; comp = comp.parent)
            if (!comp.visible)
                return false;
        return true;
    }

    // Specify the display CSS property of the visible element
    setDisplay(display) {
        this.display = display || null;
        this.setVisible(this.visible);
    }

    // Specify the height of the element
    setHeight(height) {
        if (height === null)
            this.element.style.removeProperty("height");
        else this.element.style.height =
            typeof height == "number" ? height + "px" : height
    }

    // Specify the horizontal position of the component
    setLeft(left) {
        if (left === null)
            this.element.style.removeProperty("left");
        else this.element.style.left =
            typeof left == "number" ? left + "px" : left ;
    }

    // Specify the absolute position of the component
    setLocation(left, top) {
        this.setLeft(left);
        this.setTop (top );
    }

    // Specify both the width and the height of the component
    setSize(width, height) {
        this.setHeight(height);
        this.setWidth (width );
    }

    // Specify the vertical position of the component
    setTop(top) {
        if (top === null)
            this.element.style.removeProperty("top");
        else this.element.style.top =
            typeof top == "number" ? top + "px" : top ;
    }

    // Specify whether the component is visible
    setVisible(visible) {
        this.visible = visible = !!visible;
        if (visible) {
            if (this.display == null)
                this.element.style.removeProperty("display");
            else this.element.style.display = this.display;
        } else this.element.style.display = "none";
    }

    // Specify the width of the element
    setWidth(width) {
        if (width === null)
            this.element.style.removeProperty("width");
        else this.element.style.width =
            typeof width == "number" ? width + "px" : 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;
    }



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

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

};