<template>
	<view>
		<movable-area :style="'height:' + scrollHeight + 'px;width:100%'">
			<movable-view :style="'height:' + (topHeight + scrollHeight) + 'px;width:100%;z-index:3'" direction="vertical"
			 :out-of-bounds="true" :disabled="!scrollmark || status == 3" :y="y" :damping="50" @touchstart="touchstart"
			 @touchend="touchend" @change="change">
				<view :style="'height:' + topHeight + 'px;position:relative'">
					<slot name="top"></slot>
				</view>
				<scroll-view :style="'height:' + scrollHeight + 'px;'" :scroll-y="status !== 3" :scroll-with-animation="scrollAnimation"
				 :scroll-top="top" @scroll="scroll" @scrolltolower="scrolltolower">
					<view>
						<slot name="content"></slot>
						<template v-if="downLoading">
							<slot name="bottom"></slot>
						</template>
					</view>
				</scroll-view>
			</movable-view>
		</movable-area>
	</view>
</template>

<script>
	export default {
		props: {
			downLoading: {
				//控制下面下拉加载区的显示 , 默认关闭
				type: Boolean,
				default: false
			},
			scrollHeight: {
				//scroll显示区的高度(px)
				type: Number,
				default: 550
			},
			topHeight: {
				//下拉区的高度(px)
				type: Number,
				default: 60
			},
			interruptPosition: {
				//暂停区的高度(px)
				type: Number,
				default: 40
			},
			damping: {
				//回弹动画的速度 , 值越大越快
				type: Number,
				default: 50
			},
			scrollTop: {
				//即scroll-top属性 设置竖向滚动条位置
				type: Number,
				default: 0
			},
			scrollAnimation: {
				type: Boolean,
				default: false
			}
		},
		data() {
			return {
				isTouch: false, //触摸的标识
				y: 0, //控制y
				diff: 0, //定值topHeight-interruptPotion
				scrollmark: true,
				timeId: null,
				top: 0,
				status: 0,
				count: 0.01,
				scrollCount: 0.01,
				fingers: 0, //记录手指数
				clearFingers: null, //清除手指定时器
			};
		},
		changePositon() {

		},
		created() {
			this.y = -this.topHeight;
			this.diff = this.interruptPosition - this.topHeight;
		},
		methods: {
			change(e) {
				//为3即是正在回弹状态
				if (this.status == 3 || !this.isTouch) return;

				if (e.detail.y >= this.diff || this.fingers > 1) {
					this.status = 2;
				} else if (e.detail.y < this.diff) {
					this.status = 1;
				}
			},
			touchstart(e) {
				this.fingers++;
				this.isTouch = true;
			},
			touchend(e) {
				clearTimeout(this.clearFingers);
				this.clearFingers = setTimeout(() => {
					this.fingers = 0;
					//重置手指数防止bug;
				}, 200);
				this.fingers--;
				if (this.status == 3 || this.fingers != 0) return; //防止多指下滑问题 , 匹配手指 只用到最后一次touchend;栈的思想
				this.isTouch = false;
				if (this.scrollmark) {
					if (this.status == 2) {
						this.status = 3;
						this.y = this.diff;
						this.$emit('interrupt', () => {
							this.y = -this.topHeight - 0.02;
							setTimeout(() => {
								this.$emit('finished');
								this.status = 0; //回弹过程中
								this.y = -this.topHeight; //结束之后，再次设置y坐标
							}, 200);
						});
					} else if (this.status == 1) {
						this.status = 3;
						this.y = -this.topHeight + this.count;
						//微小改变 否则无响应
						this.count = -this.count;
						setTimeout(() => {
							this.status = 0; //回弹过程中
						}, 200);
					}
				}
			},

			scroll(e) {
				//事件
				this.$emit('scroll', e)
				clearTimeout(this.timeId);
				this.scrollmark = false;
				this.timeId = setTimeout(() => {
					if (e.detail.scrollTop <= 15 || e.detail.scrollTop - e.detail.deltaY <= 0) {
						this.top = 0 + this.count;
						this.$emit('scrolltoupper', e)
						this.scrollCount = -this.scrollCount;
						this.scrollmark = true;
					}
				}, 100);
			},
			scrolltolower(e) {
				this.$emit('scrolltolower', e);
			}
		},
		watch: {
			status(value) {
				if (this.status == 2) this.$emit('pushToInterrupt');
				else if (this.status == 1) this.$emit('backToInterrupt');
			},
			scrollTop() {
				
				setTimeout(() => {
						   this.top =  this.scrollTop
				}, 80);
				
				//this.top = this.scrollTop;
			}
		}
	};
</script>

<style></style>