define([
        '../../Core/defineProperties',
        '../../ThirdParty/knockout',
        '../createCommand'
    ], function(
        defineProperties,
        knockout,
        createCommand) {
    'use strict';

    /**
     * The view model for {@link NavigationHelpButton}.
     * @alias NavigationHelpButtonViewModel
     * @constructor
     */
    function NavigationHelpButtonViewModel() {
        /**
         * Gets or sets whether the instructions are currently shown.  This property is observable.
         * @type {Boolean}
         * @default false
        */
        this.showInstructions = false;

        var that = this;
        this._command = createCommand(function() {
            that.showInstructions = !that.showInstructions;
        });
        this._showClick = createCommand(function() {
            that._touch = false;
        });
        this._showTouch = createCommand(function() {
            that._touch = true;
        });

        this._touch = false;

        /**
         * Gets or sets the tooltip.  This property is observable.
         *
         * @type {String}
         */
        this.tooltip = 'Navigation Instructions';

        knockout.track(this, ['tooltip', 'showInstructions', '_touch']);
    }

    defineProperties(NavigationHelpButtonViewModel.prototype, {
        /**
         * Gets the Command that is executed when the button is clicked.
         * @memberof NavigationHelpButtonViewModel.prototype
         *
         * @type {Command}
         */
        command : {
            get : function() {
                return this._command;
            }
        },

        /**
         * Gets the Command that is executed when the mouse instructions should be shown.
         * @memberof NavigationHelpButtonViewModel.prototype
         *
         * @type {Command}
         */
        showClick : {
            get : function() {
                return this._showClick;
            }
        },

        /**
         * Gets the Command that is executed when the touch instructions should be shown.
         * @memberof NavigationHelpButtonViewModel.prototype
         *
         * @type {Command}
         */
        showTouch : {
            get: function() {
                return this._showTouch;
            }
        }
    });

    return NavigationHelpButtonViewModel;
});
