/*!
 * jQuery UI Touch Punch 0.2.2
 *
 * Copyright 2011, Dave Furfero
 * Dual licensed under the MIT or GPL Version 2 licenses.
 *
 * Depends:
 *  jquery.ui.widget.js
 *  jquery.ui.mouse.js
 */
( function( $ ) {
	// Detect touch support
	$.support.touch = 'ontouchend' in document;

	// Ignore browsers without touch support
	if ( ! $.support.touch ) {
		return;
	}

	var mouseProto = $.ui.mouse.prototype,
		_mouseInit = mouseProto._mouseInit,
		touchHandled;

	/**
	 * Simulate a mouse event based on a corresponding touch event
	 *
	 * @param {Object} event A touch event
	 * @param {string} simulatedType The corresponding mouse event
	 */
	function simulateMouseEvent( event, simulatedType ) {
		// Ignore multi-touch events
		if ( event.originalEvent.touches.length > 1 ) {
			return;
		}

		event.preventDefault();

		var touch = event.originalEvent.changedTouches[0],
			simulatedEvent = document.createEvent( 'MouseEvents' );

		// Initialize the simulated mouse event using the touch event's coordinates
		simulatedEvent.initMouseEvent(
			simulatedType, // type
			true, // bubbles
			true, // cancelable
			window, // view
			1, // detail
			touch.screenX, // screenX
			touch.screenY, // screenY
			touch.clientX, // clientX
			touch.clientY, // clientY
			false, // ctrlKey
			false, // altKey
			false, // shiftKey
			false, // metaKey
			0, // button
			null // relatedTarget
		);

		// Dispatch the simulated event to the target element
		event.target.dispatchEvent( simulatedEvent );
	}

	/**
	 * Handle the jQuery UI widget's touchstart events
	 *
	 * @param {Object} event The widget element's touchstart event
	 */
	mouseProto._touchStart = function( event ) {
		var self = this;

		// Ignore the event if another widget is already being handled
		if ( touchHandled || ! self._mouseCapture( event.originalEvent.changedTouches[0] ) ) {
			return;
		}

		// Set the flag to prevent other widgets from inheriting the touch event
		touchHandled = true;

		// Track movement to determine if interaction was a click
		self._touchMoved = false;

		// Simulate the mouseover event
		simulateMouseEvent( event, 'mouseover' );

		// Simulate the mousemove event
		simulateMouseEvent( event, 'mousemove' );

		// Simulate the mousedown event
		simulateMouseEvent( event, 'mousedown' );
	};

	/**
	 * Handle the jQuery UI widget's touchmove events
	 *
	 * @param {Object} event The document's touchmove event
	 */
	mouseProto._touchMove = function( event ) {
		// Ignore event if not handled
		if ( ! touchHandled ) {
			return;
		}

		// Interaction was not a click
		this._touchMoved = true;

		// Simulate the mousemove event
		simulateMouseEvent( event, 'mousemove' );
	};

	/**
	 * Handle the jQuery UI widget's touchend events
	 *
	 * @param {Object} event The document's touchend event
	 */
	mouseProto._touchEnd = function( event ) {
		// Ignore event if not handled
		if ( ! touchHandled ) {
			return;
		}

		// Simulate the mouseup event
		simulateMouseEvent( event, 'mouseup' );

		// Simulate the mouseout event
		simulateMouseEvent( event, 'mouseout' );

		// If the touch interaction did not move, it should trigger a click
		if ( ! this._touchMoved ) {
			// Simulate the click event
			simulateMouseEvent( event, 'click' );
		}

		// Unset the flag to allow other widgets to inherit the touch event
		touchHandled = false;
	};

	/**
	 * A duck punch of the $.ui.mouse _mouseInit method to support touch events.
	 * This method extends the widget with bound touch event handlers that
	 * translate touch events to mouse events and pass them to the widget's
	 * original mouse event handling methods.
	 */
	mouseProto._mouseInit = function() {
		var self = this;

		// Delegate the touch handlers to the widget's element
		self.element
			.bind( 'touchstart', $.proxy( self, '_touchStart' ) )
			.bind( 'touchmove', $.proxy( self, '_touchMove' ) )
			.bind( 'touchend', $.proxy( self, '_touchEnd' ) );

		// Call the original $.ui.mouse init method
		_mouseInit.call( self );
	};
}( jQuery ) );
