"use strict";

// Main application menu bar
Toolkit.MenuBar = class MenuBar extends Toolkit.Component {

    // Object constructor
    constructor(application, options) {
        super(application, "div");

        // Configure instance fields
        this.expanded  = null;
        this.lastFocus = null;
        this.menuBar   = this;
        this.menus     = [];
        this.name      = options.name || "";

        // Configure element
        this.element.style.display  = "flex";
        this.element.style.position = "relative";
        this.element.style.zIndex   = "1";
        this.element.setAttribute("role", "menubar");

        // Configure properties
        this.setName(this.name);
        application.addComponent(this);
    }



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

    // Create a Menu and associate it with the application and component
    newMenu(options, index) {
        let menu = new Toolkit.Menu(this, options);

        // Determine the ordinal position of the element within the container
        index = !(typeof index == "number") ? this.menus.length :
            Math.floor(Math.min(Math.max(0, index), this.menus.length));

        // Add the menu to the menu bar
        let ref = this.menus[index];
        this.element.insertBefore(menu.element, ref ? ref.element : null);
        this.menus.splice(index, 0, menu);
        menu.element.insertAdjacentElement("afterend", menu.menu);

        // Ensure only the first menu is focusable
        for (let x = 0; x < this.menus.length; x++)
            this.menus[x].element.setAttribute("tabindex", x==0 ? "0" : "-1");

        return menu;
    }

    // Specify the menu's accessible name
    setName(name) {
        this.name = name || "";
        this.localize();
    }



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

    // Notify of a change to component focus
    focusChanged(from, to) {

        // Configure tabstop on the first menu
        if (this.menus.length > 0)
            this.menus[0].element.setAttribute("tabindex",
                this.contains(to) ? "-1" : "0");

        // Retain a reference to the previously focused element
        if (!this.contains(from)) {
            if (from == null)
                from = document.body;
            if ("component" in from)
                from = from.component;
            this.lastFocus = from;
        }

        super.focusChanged(from, to);
    }

    // Update display text with localized strings
    localize() {
        let text = this.name;
        if (this.application)
            text = this.application.translate(text, this);
        this.element.setAttribute("aria-label", text);
    }

    // Return focus to where it was before the menu was activated
    restoreFocus() {
        let elm = this.lastFocus;
        if (elm == null)
            elm = document.body;
        elm.focus();
    }

};