/**
 * mui gestures
 * @param {type} $
 * @param {type} window
 * @returns {undefined}
 */
(function($, window) {
	$.EVENT_START = 'touchstart';
	$.EVENT_MOVE = 'touchmove';
	$.EVENT_END = 'touchend';
	$.EVENT_CANCEL = 'touchcancel';
	$.EVENT_CLICK = 'click';
	$.gestures = {
		session: {}
	};
	/**
	 * Gesture preventDefault
	 * @param {type} e
	 * @returns {undefined}
	 */
	$.preventDefault = function(e) {
		e.preventDefault();
	};
	/**
	 * Gesture stopPropagation
	 * @param {type} e
	 * @returns {undefined}
	 */
	$.stopPropagation = function(e) {
		e.stopPropagation();
	};

	/**
	 * register gesture
	 * @param {type} gesture
	 * @returns {$.gestures}
	 */
	$.addGesture = function(gesture) {
		return $.addAction('gestures', gesture);

	};

	var round = Math.round;
	var abs = Math.abs;
	var sqrt = Math.sqrt;
	var atan = Math.atan;
	var atan2 = Math.atan2;
	/**
	 * distance
	 * @param {type} p1
	 * @param {type} p2
	 * @returns {Number}
	 */
	var getDistance = function(p1, p2, props) {
		if (!props) {
			props = ['x', 'y'];
		}
		var x = p2[props[0]] - p1[props[0]];
		var y = p2[props[1]] - p1[props[1]];
		return sqrt((x * x) + (y * y));
	};
	/**
	 * scale
	 * @param {Object} starts
	 * @param {Object} moves
	 */
	var getScale = function(starts, moves) {
		if (starts.length >= 2 && moves.length >= 2) {
			var props = ['pageX', 'pageY'];
			return getDistance(moves[1], moves[0], props) / getDistance(starts[1], starts[0], props);
		}
		return 1;
	};
	/**
	 * angle
	 * @param {type} p1
	 * @param {type} p2
	 * @returns {Number}
	 */
	var getAngle = function(p1, p2, props) {
		if (!props) {
			props = ['x', 'y'];
		}
		var x = p2[props[0]] - p1[props[0]];
		var y = p2[props[1]] - p1[props[1]];
		return atan2(y, x) * 180 / Math.PI;
	};
	/**
	 * direction
	 * @param {Object} x
	 * @param {Object} y
	 */
	var getDirection = function(x, y) {
		if (x === y) {
			return '';
		}
		if (abs(x) >= abs(y)) {
			return x > 0 ? 'left' : 'right';
		}
		return y > 0 ? 'up' : 'down';
	};
	/**
	 * rotation
	 * @param {Object} start
	 * @param {Object} end
	 */
	var getRotation = function(start, end) {
		var props = ['pageX', 'pageY'];
		return getAngle(end[1], end[0], props) - getAngle(start[1], start[0], props);
	};
	/**
	 * px per ms
	 * @param {Object} deltaTime
	 * @param {Object} x
	 * @param {Object} y
	 */
	var getVelocity = function(deltaTime, x, y) {
		return {
			x: x / deltaTime || 0,
			y: y / deltaTime || 0
		};
	};
	/**
	 * detect gestures
	 * @param {type} event
	 * @param {type} touch
	 * @returns {undefined}
	 */
	var detect = function(event, touch) {
		if ($.gestures.stoped) {
			return;
		}
		$.doAction('gestures', function(index, gesture) {
			if (!$.gestures.stoped) {
				if ($.options.gestureConfig[gesture.name] !== false) {
					gesture.handle(event, touch);
				}
			}
		});
	};
	/**
	 * 暂时无用
	 * @param {Object} node
	 * @param {Object} parent
	 */
	var hasParent = function(node, parent) {
		while (node) {
			if (node == parent) {
				return true;
			}
			node = node.parentNode;
		}
		return false;
	};

	var uniqueArray = function(src, key, sort) {
		var results = [];
		var values = [];
		var i = 0;

		while (i < src.length) {
			var val = key ? src[i][key] : src[i];
			if (values.indexOf(val) < 0) {
				results.push(src[i]);
			}
			values[i] = val;
			i++;
		}

		if (sort) {
			if (!key) {
				results = results.sort();
			} else {
				results = results.sort(function sortUniqueArray(a, b) {
					return a[key] > b[key];
				});
			}
		}

		return results;
	};
	var getMultiCenter = function(touches) {
		var touchesLength = touches.length;
		if (touchesLength === 1) {
			return {
				x: round(touches[0].pageX),
				y: round(touches[0].pageY)
			};
		}

		var x = 0;
		var y = 0;
		var i = 0;
		while (i < touchesLength) {
			x += touches[i].pageX;
			y += touches[i].pageY;
			i++;
		}

		return {
			x: round(x / touchesLength),
			y: round(y / touchesLength)
		};
	};
	var multiTouch = function() {
		return $.options.gestureConfig.pinch;
	};
	var copySimpleTouchData = function(touch) {
		var touches = [];
		var i = 0;
		while (i < touch.touches.length) {
			touches[i] = {
				pageX: round(touch.touches[i].pageX),
				pageY: round(touch.touches[i].pageY)
			};
			i++;
		}
		return {
			timestamp: $.now(),
			gesture: touch.gesture,
			touches: touches,
			center: getMultiCenter(touch.touches),
			deltaX: touch.deltaX,
			deltaY: touch.deltaY
		};
	};

	var calDelta = function(touch) {
		var session = $.gestures.session;
		var center = touch.center;
		var offset = session.offsetDelta || {};
		var prevDelta = session.prevDelta || {};
		var prevTouch = session.prevTouch || {};

		if (touch.gesture.type === $.EVENT_START || touch.gesture.type === $.EVENT_END) {
			prevDelta = session.prevDelta = {
				x: prevTouch.deltaX || 0,
				y: prevTouch.deltaY || 0
			};

			offset = session.offsetDelta = {
				x: center.x,
				y: center.y
			};
		}
		touch.deltaX = prevDelta.x + (center.x - offset.x);
		touch.deltaY = prevDelta.y + (center.y - offset.y);
	};
	var calTouchData = function(touch) {
		var session = $.gestures.session;
		var touches = touch.touches;
		var touchesLength = touches.length;

		if (!session.firstTouch) {
			session.firstTouch = copySimpleTouchData(touch);
		}

		if (multiTouch() && touchesLength > 1 && !session.firstMultiTouch) {
			session.firstMultiTouch = copySimpleTouchData(touch);
		} else if (touchesLength === 1) {
			session.firstMultiTouch = false;
		}

		var firstTouch = session.firstTouch;
		var firstMultiTouch = session.firstMultiTouch;
		var offsetCenter = firstMultiTouch ? firstMultiTouch.center : firstTouch.center;

		var center = touch.center = getMultiCenter(touches);
		touch.timestamp = $.now();
		touch.deltaTime = touch.timestamp - firstTouch.timestamp;

		touch.angle = getAngle(offsetCenter, center);
		touch.distance = getDistance(offsetCenter, center);

		calDelta(touch);

		touch.offsetDirection = getDirection(touch.deltaX, touch.deltaY);

		touch.scale = firstMultiTouch ? getScale(firstMultiTouch.touches, touches) : 1;
		touch.rotation = firstMultiTouch ? getRotation(firstMultiTouch.touches, touches) : 0;

		calIntervalTouchData(touch);

	};
	var CAL_INTERVAL = 25;
	var calIntervalTouchData = function(touch) {
		var session = $.gestures.session;
		var last = session.lastInterval || touch;
		var deltaTime = touch.timestamp - last.timestamp;
		var velocity;
		var velocityX;
		var velocityY;
		var direction;

		if (touch.gesture.type != $.EVENT_CANCEL && (deltaTime > CAL_INTERVAL || last.velocity === undefined)) {
			var deltaX = last.deltaX - touch.deltaX;
			var deltaY = last.deltaY - touch.deltaY;

			var v = getVelocity(deltaTime, deltaX, deltaY);
			velocityX = v.x;
			velocityY = v.y;
			velocity = (abs(v.x) > abs(v.y)) ? v.x : v.y;
			direction = getDirection(deltaX, deltaY) || last.direction;

			session.lastInterval = touch;
		} else {
			velocity = last.velocity;
			velocityX = last.velocityX;
			velocityY = last.velocityY;
			direction = last.direction;
		}

		touch.velocity = velocity;
		touch.velocityX = velocityX;
		touch.velocityY = velocityY;
		touch.direction = direction;
	};
	var targetIds = {};
	var getTouches = function(event, touch) {
		var allTouches = $.slice.call(event.touches || event);

		var type = event.type;

		var targetTouches = [];
		var changedTargetTouches = [];

		//当touchstart或touchmove且touches长度为1，直接获得all和changed
		if ((type === $.EVENT_START || type === $.EVENT_MOVE) && allTouches.length === 1) {
			targetIds[allTouches[0].identifier] = true;
			targetTouches = allTouches;
			changedTargetTouches = allTouches;
			touch.target = event.target;
		} else {
			var i = 0;
			var targetTouches = [];
			var changedTargetTouches = [];
			var changedTouches = $.slice.call(event.changedTouches || event);

			touch.target = event.target;
			var sessionTarget = $.gestures.session.target || event.target;
			targetTouches = allTouches.filter(function(touch) {
				return hasParent(touch.target, sessionTarget);
			});

			if (type === $.EVENT_START) {
				i = 0;
				while (i < targetTouches.length) {
					targetIds[targetTouches[i].identifier] = true;
					i++;
				}
			}

			i = 0;
			while (i < changedTouches.length) {
				if (targetIds[changedTouches[i].identifier]) {
					changedTargetTouches.push(changedTouches[i]);
				}
				if (type === $.EVENT_END || type === $.EVENT_CANCEL) {
					delete targetIds[changedTouches[i].identifier];
				}
				i++;
			}

			if (!changedTargetTouches.length) {
				return false;
			}
		}
		targetTouches = uniqueArray(targetTouches.concat(changedTargetTouches), 'identifier', true);
		var touchesLength = targetTouches.length;
		var changedTouchesLength = changedTargetTouches.length;

		if (type === $.EVENT_START && touchesLength - changedTouchesLength === 0) { //first
			touch.isFirst = true;
			$.gestures.touch = $.gestures.session = {
				target: event.target
			};
		}
		touch.isFinal = ((type === $.EVENT_END || type === $.EVENT_CANCEL) && (touchesLength - changedTouchesLength === 0));

		touch.touches = targetTouches;
		touch.changedTouches = changedTargetTouches;
		return true;

	};
	var handleTouchEvent = function(event) {
		var touch = {
			gesture: event
		};
		var touches = getTouches(event, touch);
		if (!touches) {
			return;
		}
		calTouchData(touch);
		detect(event, touch);
		$.gestures.session.prevTouch = touch;
	};
	window.addEventListener($.EVENT_START, handleTouchEvent);
	window.addEventListener($.EVENT_MOVE, handleTouchEvent);
	window.addEventListener($.EVENT_END, handleTouchEvent);
	window.addEventListener($.EVENT_CANCEL, handleTouchEvent);
	//fixed hashchange(android)
	window.addEventListener($.EVENT_CLICK, function(e) {
		//TODO 应该判断当前target是不是在targets.popover内部，而不是非要相等
		if (($.targets.popover && e.target === $.targets.popover) || ($.targets.tab) || $.targets.offcanvas || $.targets.modal) {
			e.preventDefault();
		}
	}, true);


	//增加原生滚动识别
	$.isScrolling = false;
	var scrollingTimeout = null;
	window.addEventListener('scroll', function() {
		$.isScrolling = true;
		scrollingTimeout && clearTimeout(scrollingTimeout);
		scrollingTimeout = setTimeout(function() {
			$.isScrolling = false;
		}, 250);
	});
})(mui, window);