/**
 * IconElement is often mixed into other classes to generate an icon.
 * Icons are graphics, about the size of normal text. They are used to aid the user
 * in locating a control or to convey information in a space-efficient way. See the
 * [OOjs UI documentation on MediaWiki] [1] for a list of icons
 * included in the library.
 *
 * [1]: https://www.mediawiki.org/wiki/OOjs_UI/Widgets/Icons,_Indicators,_and_Labels#Icons
 *
 * @abstract
 * @class
 *
 * @constructor
 * @param {Object} [config] Configuration options
 * @cfg {jQuery} [$icon] The icon element created by the class. If this configuration is omitted,
 *  the icon element will use a generated `<span>`. To use a different HTML tag, or to specify that
 *  the icon element be set to an existing icon instead of the one generated by this class, set a
 *  value using a jQuery selection. For example:
 *
 *      // Use a <div> tag instead of a <span>
 *     $icon: $("<div>")
 *     // Use an existing icon element instead of the one generated by the class
 *     $icon: this.$element
 *     // Use an icon element from a child widget
 *     $icon: this.childwidget.$element
 * @cfg {Object|string} [icon=''] The symbolic name of the icon (e.g., ‘remove’ or ‘menu’), or a map of
 *  symbolic names.  A map is used for i18n purposes and contains a `default` icon
 *  name and additional names keyed by language code. The `default` name is used when no icon is keyed
 *  by the user's language.
 *
 *  Example of an i18n map:
 *
 *     { default: 'bold-a', en: 'bold-b', de: 'bold-f' }
 *  See the [OOjs UI documentation on MediaWiki] [2] for a list of icons included in the library.
 * [2]: https://www.mediawiki.org/wiki/OOjs_UI/Widgets/Icons,_Indicators,_and_Labels#Icons
 * @cfg {string|Function} [iconTitle] A text string used as the icon title, or a function that returns title
 *  text. The icon title is displayed when users move the mouse over the icon.
 */
OO.ui.IconElement = function OoUiIconElement( config ) {
	// Configuration initialization
	config = config || {};

	// Properties
	this.$icon = null;
	this.icon = null;
	this.iconTitle = null;

	// Initialization
	this.setIcon( config.icon || this.constructor.static.icon );
	this.setIconTitle( config.iconTitle || this.constructor.static.iconTitle );
	this.setIconElement( config.$icon || $( '<span>' ) );
};

/* Setup */

OO.initClass( OO.ui.IconElement );

/* Static Properties */

/**
 * The symbolic name of the icon (e.g., ‘remove’ or ‘menu’), or a map of symbolic names. A map is used
 * for i18n purposes and contains a `default` icon name and additional names keyed by
 * language code. The `default` name is used when no icon is keyed by the user's language.
 *
 * Example of an i18n map:
 *
 *     { default: 'bold-a', en: 'bold-b', de: 'bold-f' }
 *
 * Note: the static property will be overridden if the #icon configuration is used.
 *
 * @static
 * @inheritable
 * @property {Object|string}
 */
OO.ui.IconElement.static.icon = null;

/**
 * The icon title, displayed when users move the mouse over the icon. The value can be text, a
 * function that returns title text, or `null` for no title.
 *
 * The static property will be overridden if the #iconTitle configuration is used.
 *
 * @static
 * @inheritable
 * @property {string|Function|null}
 */
OO.ui.IconElement.static.iconTitle = null;

/* Methods */

/**
 * Set the icon element. This method is used to retarget an icon mixin so that its functionality
 * applies to the specified icon element instead of the one created by the class. If an icon
 * element is already set, the mixin’s effect on that element is removed. Generated CSS classes
 * and mixin methods will no longer affect the element.
 *
 * @param {jQuery} $icon Element to use as icon
 */
OO.ui.IconElement.prototype.setIconElement = function ( $icon ) {
	if ( this.$icon ) {
		this.$icon
			.removeClass( 'oo-ui-iconElement-icon oo-ui-icon-' + this.icon )
			.removeAttr( 'title' );
	}

	this.$icon = $icon
		.addClass( 'oo-ui-iconElement-icon' )
		.toggleClass( 'oo-ui-icon-' + this.icon, !!this.icon );
	if ( this.iconTitle !== null ) {
		this.$icon.attr( 'title', this.iconTitle );
	}
};

/**
 * Set icon by symbolic name (e.g., ‘remove’ or ‘menu’). Use `null` to remove an icon.
 * The icon parameter can also be set to a map of icon names. See the #icon config setting
 * for an example.
 *
 * @param {Object|string|null} icon A symbolic icon name, a {@link #icon map of icon names} keyed
 *  by language code, or `null` to remove the icon.
 * @chainable
 */
OO.ui.IconElement.prototype.setIcon = function ( icon ) {
	icon = OO.isPlainObject( icon ) ? OO.ui.getLocalValue( icon, null, 'default' ) : icon;
	icon = typeof icon === 'string' && icon.trim().length ? icon.trim() : null;

	if ( this.icon !== icon ) {
		if ( this.$icon ) {
			if ( this.icon !== null ) {
				this.$icon.removeClass( 'oo-ui-icon-' + this.icon );
			}
			if ( icon !== null ) {
				this.$icon.addClass( 'oo-ui-icon-' + icon );
			}
		}
		this.icon = icon;
	}

	this.$element.toggleClass( 'oo-ui-iconElement', !!this.icon );
	this.updateThemeClasses();

	return this;
};

/**
 * Set the icon title. Use `null` to remove the title.
 *
 * @param {string|Function|null} iconTitle A text string used as the icon title,
 *  a function that returns title text, or `null` for no title.
 * @chainable
 */
OO.ui.IconElement.prototype.setIconTitle = function ( iconTitle ) {
	iconTitle = typeof iconTitle === 'function' ||
		( typeof iconTitle === 'string' && iconTitle.length ) ?
			OO.ui.resolveMsg( iconTitle ) : null;

	if ( this.iconTitle !== iconTitle ) {
		this.iconTitle = iconTitle;
		if ( this.$icon ) {
			if ( this.iconTitle !== null ) {
				this.$icon.attr( 'title', iconTitle );
			} else {
				this.$icon.removeAttr( 'title' );
			}
		}
	}

	return this;
};

/**
 * Get the symbolic name of the icon.
 *
 * @return {string} Icon name
 */
OO.ui.IconElement.prototype.getIcon = function () {
	return this.icon;
};

/**
 * Get the icon title. The title text is displayed when a user moves the mouse over the icon.
 *
 * @return {string} Icon title text
 */
OO.ui.IconElement.prototype.getIconTitle = function () {
	return this.iconTitle;
};