<template>
	<view :class="'wf-page wf-page'+type">
		<!--    left    -->
		<view>
			<view id="left" v-if="leftList.length">
				<view v-for="(item,index) in leftList" :key="index" class="wf-item" @tap="itemTap(item)">
					<WaterfallsFlowItem :item="item" :isStore="isStore" :type="type" @goShop="goShop" :sale_type="sale_type" />
				</view>
			</view>
		</view>
		<!--    right    -->
		<view>
			<view id="right" v-if="rightList.length">
				<view v-for="(item,index) in rightList" :key="index" class="wf-item" @tap="itemTap(item)">
					<WaterfallsFlowItem :item="item" :isStore="isStore" :type="type" @goShop="goShop" :sale_type="sale_type" />
				</view>
			</view>
		</view>
	</view>
</template>

<script>
	// +----------------------------------------------------------------------
	// | CRMEB [ CRMEB赋能开发者，助力企业发展 ]
	// +----------------------------------------------------------------------
	// | Copyright (c) 2016~2023 https://www.crmeb.com All rights reserved.
	// +----------------------------------------------------------------------
	// | Licensed CRMEB并不是自由软件，未经许可不能去掉CRMEB相关版权
	// +----------------------------------------------------------------------
	// | Author: CRMEB Team <admin@crmeb.com>
	// +----------------------------------------------------------------------
	import WaterfallsFlowItem from '../WaterfallsFlowItem/WaterfallsFlowItem.vue'

	export default {
		components: {
			WaterfallsFlowItem
		},
		props: {
			// 瀑布流列表
			wfList: {
				type: Array,
				require: true
			},
			updateNum: {
				type: Number,
				default: 10
			},
			type: {
				type: Number,
				default: 0
			},
			isStore: {
				type: [String, Number],
				default: '1'
			},
      sale_type: {
        type: [String, Number],
        default: '1'
      }
		},
		data() {
			return {
				allList: [], // 全部列表
				leftList: [], // 左边列表
				rightList: [], // 右边列表
				mark: 0, // 列表标记
				boxHeight: [], // 下标0和1分别为左列和右列高度
			};
		},
		watch: {
			// 监听列表数据变化
			wfList: {
				handler(nVal, oVal) {
					// 如果数据为空或新的列表数据少于旧的列表数据（通常为下拉刷新或切换排序或使用筛选器），初始化变量
					if (!this.wfList.length ||
						(this.wfList.length === this.updateNum && this.wfList.length <= this.allList.length)) {
						this.allList = [];
						this.leftList = [];
						this.rightList = [];
						this.boxHeight = [];
						this.mark = 0;
					}

					// 如果列表有值，调用waterfall方法
					if (this.wfList.length) {
						this.allList = this.wfList;
						this.leftList = [];
						this.rightList = [];
						this.boxHeight = [];
						this.allList.forEach((v, i) => {
							if (this.allList.length < 3 || (this.allList.length <= 7 && this.allList.length - i >
									1) || (this.allList.length > 7 && this.allList.length - i > 2)) {
								if (i % 2) {
									this.rightList.push(v);
								} else {
									this.leftList.push(v);
								}
							}
						});
						if (this.allList.length < 3) {
							this.mark = this.allList.length + 1;
						} else if (this.allList.length <= 7) {
							this.mark = this.allList.length - 1;
						} else {
							this.mark = this.allList.length - 2;
						}
						if (this.mark < this.allList.length) {
							this.waterFall()
						}
					}
				},
				immediate: true,
				deep: true
			},
			mounted() {},

			// 监听标记，当标记发生变化，则执行下一个item排序
			mark() {
				const len = this.allList.length;
				if (this.mark < len && this.mark !== 0 && this.boxHeight.length) {
					this.waterFall();
				}
			}
		},
		methods: {
			// 瀑布流排序
			waterFall() {
				const i = this.mark;
				if (i == 0) {
					// 初始化，从左边开始插入
					this.leftList.push(this.allList[i]);
					// 更新左边列表高度
					this.getViewHeight(0);
				} else if (i == 1) {
					// 第二个item插入，默认为右边插入
					this.rightList.push(this.allList[i]);
					// 更新右边列表高度
					this.getViewHeight(1);
				} else {
					// 根据左右列表高度判断下一个item应该插入哪边
					if (!this.boxHeight.length) {
						this.rightList.length < this.leftList.length ?
							this.rightList.push(this.allList[i]) :
							this.leftList.push(this.allList[i]);
					} else {
						const leftOrRight = this.boxHeight[0] > this.boxHeight[1] ? 1 : 0;
						if (leftOrRight) {
							this.rightList.push(this.allList[i])
						} else {
							this.leftList.push(this.allList[i])
						}
					}
					// 更新插入列表高度
					this.getViewHeight();
				}
			},
			// 获取列表高度
			getViewHeight() {
				// 使用nextTick，确保页面更新结束后，再请求高度
				this.$nextTick(() => {
					setTimeout(() => {
						uni.createSelectorQuery().in(this).select('#right').boundingClientRect(res => {
							res ? this.boxHeight[1] = res.height : '';
							uni.createSelectorQuery().in(this).select('#left').boundingClientRect(
								res => {
									res ? this.boxHeight[0] = res.height : '';
									this.mark = this.mark + 1;
								}).exec();
						}).exec();
					}, 100)
				})
			},
			// item点击
			itemTap(item) {
				this.$emit('itemTap', item)
			},
			// item点击
			goShop(item) {
				this.$emit('goShop', item)
			}
		}
	}
</script>

<style lang="scss" scoped>
	$page-padding: 10px;
	$grid-gap: 10px;

	.wf-page {
		display: grid;
		grid-template-columns: 1fr 1fr;
		grid-gap: $grid-gap;
	}

	.wf-item {
		width: calc((100vw - 2 * #{$page-padding} - #{$grid-gap}) / 2);
		padding-bottom: $grid-gap;
	}

	.wf-page1 .wf-item {
		margin-top: 20rpx;
		background-color: #fff;
		border-radius: 20rpx;
		padding-bottom: 0;
	}

	.wf-item-page {
		padding-bottom: 20rpx;
	}
</style>