// jQuery.event.swipe
// 0.5
// Stephen Band

// Dependencies
// jQuery.event.move 1.2

// One of swipeleft, swiperight, swipeup or swipedown is triggered on
// moveend, when the move has covered a threshold ratio of the dimension
// of the target node, or has gone really fast. Threshold and velocity
// sensitivity changed with:
//
// jQuery.event.special.swipe.settings.threshold
// jQuery.event.special.swipe.settings.sensitivity

( function ( thisModule ) {
	if ( typeof define === 'function' && define.amd ) {
		// AMD. Register as an anonymous module.
		define( [ 'jquery', undefined, 'jquery.event.move' ], thisModule );
	} else if (
		typeof module !== 'undefined' &&
		module !== null &&
		module.exports
	) {
		module.exports = thisModule;
	} else {
		// Browser globals
		thisModule( jQuery );
	}
} )( function ( jQuery, undefined ) {
	var add = jQuery.event.add,
		remove = jQuery.event.remove,
		// Just sugar, so we can have arguments in the same order as
		// add and remove.
		trigger = function ( node, type, data ) {
			jQuery.event.trigger( type, data, node );
		},
		settings = {
			// Ratio of distance over target finger must travel to be
			// considered a swipe.
			threshold: 0.4,
			// Faster fingers can travel shorter distances to be considered
			// swipes. 'sensitivity' controls how much. Bigger is shorter.
			sensitivity: 6,
		};

	function moveend( e ) {
		var w, h, event;

		w = e.currentTarget.offsetWidth;
		h = e.currentTarget.offsetHeight;

		// Copy over some useful properties from the move event
		event = {
			distX: e.distX,
			distY: e.distY,
			velocityX: e.velocityX,
			velocityY: e.velocityY,
			finger: e.finger,
		};

		// Find out which of the four directions was swiped
		if ( e.distX > e.distY ) {
			if ( e.distX > -e.distY ) {
				if (
					e.distX / w > settings.threshold ||
					( ( e.velocityX * e.distX ) / w ) * settings.sensitivity > 1
				) {
					event.type = 'swiperight';
					trigger( e.currentTarget, event );
				}
			} else {
				if (
					-e.distY / h > settings.threshold ||
					( ( e.velocityY * e.distY ) / w ) * settings.sensitivity > 1
				) {
					event.type = 'swipeup';
					trigger( e.currentTarget, event );
				}
			}
		} else {
			if ( e.distX > -e.distY ) {
				if (
					e.distY / h > settings.threshold ||
					( ( e.velocityY * e.distY ) / w ) * settings.sensitivity > 1
				) {
					event.type = 'swipedown';
					trigger( e.currentTarget, event );
				}
			} else {
				if (
					-e.distX / w > settings.threshold ||
					( ( e.velocityX * e.distX ) / w ) * settings.sensitivity > 1
				) {
					event.type = 'swipeleft';
					trigger( e.currentTarget, event );
				}
			}
		}
	}

	function getData( node ) {
		var data = jQuery.data( node, 'event_swipe' );

		if ( ! data ) {
			data = { count: 0 };
			jQuery.data( node, 'event_swipe', data );
		}

		return data;
	}

	jQuery.event.special.swipe =
		jQuery.event.special.swipeleft =
		jQuery.event.special.swiperight =
		jQuery.event.special.swipeup =
		jQuery.event.special.swipedown =
			{
				setup: function ( data, namespaces, eventHandle ) {
					var data = getData( this );

					// If another swipe event is already setup, don't setup again.
					if ( data.count++ > 0 ) {
						return;
					}

					add( this, 'moveend', moveend );

					return true;
				},

				teardown: function () {
					var data = getData( this );

					// If another swipe event is still setup, don't teardown.
					if ( --data.count > 0 ) {
						return;
					}

					remove( this, 'moveend', moveend );

					return true;
				},

				settings: settings,
			};
} );