var MIN_DISTANCE = 10;

function changeData(newValue, oldValue, ownerInstance, instance) {
	var state = instance.getState();
	if (newValue.left != undefined) {
		state.left = newValue.left
	}
	if (newValue.bounce != undefined) {
		state.bounce = newValue.bounce
	}
	// console.log('changeData', JSON.stringify(newValue))
}

/**
 * 开始触摸操作
 * @param {Object} e
 * @param {Object} ins
 */
function touchstart(e, ins) {
	var instance = e.instance;
	// 计算滑动开始位置
	stopTouchStart(e, ins)
}

/**
 * 开始滑动操作
 * @param {Object} e
 * @param {Object} ownerInstance
 */
function touchmove(e, ownerInstance) {
	var instance = e.instance;
	// 是否可以滑动页面
	stopTouchMove(e);
	if (e.preventDefault) {
		// 阻止页面滚动
		e.preventDefault()
	}
	// var state = instance.getState();
	 // && state.bounce
	move(instance, ownerInstance)
	return false
}

/**
 * 结束触摸操作
 * @param {Object} e
 * @param {Object} ownerInstance
 */
function touchend(e, ownerInstance) {
	var instance = e.instance;
	var state = instance.getState()
	ownerInstance.callMethod('moveEnd', {
		velocity: Math.abs(state.deltaX / state.timing),
		direction: state.direction,
		deltaX: state.deltaX,
		deltaY: state.deltaY
	})
}

/**
 * 设置移动距离
 * @param {Object} instance
 * @param {Object} ownerInstance
 */
function move(instance, ownerInstance) {
	var state = instance.getState()
	var value = state.deltaX || 0
	var state = instance.getState()
	if (state.direction == 'horizontal') {
		// instance.requestAnimationFrame(function() {
		// 	instance.setStyle({
		// 		transform: 'translateX(' + value + 'px)',
		// 		'-webkit-transform': 'translateX(' + value + 'px)'
		// 	})
		// })
		ownerInstance.callMethod('moveTo', {
			deltaX: value,
			deltaY: state.deltaY || 0,
			left: state.left + value
		})
	}

}

/**
 * 滑动中，是否禁止打开
 * @param {Object} event
 */
function stopTouchMove(event) {
	var instance = event.instance;
	var state = instance.getState();
	var touch = event.touches[0];
	state.timing = getDate().getTime() - state.startTime;
	state.deltaX = touch.clientX - state.startX;
	state.deltaY = touch.clientY - state.startY;
	state.offsetX = Math.abs(state.deltaX);
	state.offsetY = Math.abs(state.deltaY);
	state.direction = state.direction || getDirection(state.offsetX, state.offsetY);
}

/**
 * 设置滑动开始位置
 * @param {Object} event
 */
function stopTouchStart(event) {
	var instance = event.instance;
	var state = instance.getState();
	resetTouchStatus(instance);
	var touch = event.touches[0];
	state.startTime = getDate().getTime();
	state.startX = touch.clientX;
	state.startY = touch.clientY;
}

function getDirection(x, y) {
	if (x > y && x > MIN_DISTANCE) {
		return 'horizontal';
	}
	if (y > x && y > MIN_DISTANCE) {
		return 'vertical';
	}
	return '';
}

/**
 * 重置滑动状态
 * @param {Object} event
 */
function resetTouchStatus(instance) {
	var state = instance.getState();
	state.direction = '';
	state.deltaX = 0;
	state.deltaY = 0;
	state.offsetX = 0;
	state.offsetY = 0;
}

module.exports = {
	changeData: changeData,
	touchstart: touchstart,
	touchmove: touchmove,
	touchend: touchend
}