<template>
	<div>
		<div class="mask" v-show="isShowSelect" @click="isShowSelect = !isShowSelect"></div>
		<el-popover placement="bottom-start" :width="width" trigger="manual" v-model="isShowSelect" @hide="popoverHide">
			<el-tree class="common-tree" :style="style" ref="tree" :data="data" :props="defaultProps"
				:show-checkbox="multiple" :node-key="nodeKey" :check-strictly="checkStrictly" default-expand-all
				:expand-on-click-node="false" :check-on-click-node="multiple" :highlight-current="true"
				@node-click="handleNodeClick" @check-change="handleCheckChange"></el-tree>
			<el-select :style="selectStyle" slot="reference" ref="select" :size="size" v-model="selectedData"
				:multiple="multiple" :clearable="clearable" :collapse-tags="collapseTags"
				@click.native="isShowSelect = !isShowSelect" @remove-tag="removeSelectedNodes"
				@clear="removeSelectedNode" @change="changeSelectedNodes" class="tree-select">
				<el-option v-for="(item, idx) in options" :key="idx" :label="item.label" :value="item.value">
				</el-option>
			</el-select>
		</el-popover>
	</div>
</template>

<script>
	export default {
		name: "tree-select",
		props: {
			// 树结构数据
			data: {
				type: Array,
				default () {
					return [];
				}
			},
			defaultProps: {
				type: Object,
				default () {
					return {};
				}
			},
			// 配置是否可多选
			multiple: {
				type: Boolean,
				default () {
					return false;
				}
			},
			// 配置是否可清空选择
			clearable: {
				type: Boolean,
				default () {
					return false;
				}
			},
			// 配置多选时是否将选中值按文字的形式展示
			collapseTags: {
				type: Boolean,
				default () {
					return false;
				}
			},
			nodeKey: {
				type: String,
				default () {
					return "id";
				}
			},
			// 显示复选框情况下，是否严格遵循父子不互相关联
			checkStrictly: {
				type: Boolean,
				default () {
					return false;
				}
			},
			// 默认选中的节点key数组
			checkedKeys: {
				type: Array,
				default () {
					return [];
				}
			},
			size: {
				type: String,
				default () {
					return "";
				}
			},
			width: {
				type: Number,
				default () {
					return 250;
				}
			},
			height: {
				type: Number,
				default () {
					return 300;
				}
			}
		},
		data() {
			return {
				isShowSelect: false, // 是否显示树状选择器
				options: [],
				selectedData: [], // 选中的节点
				style: "width:" + this.width + "px;" + "height:" + this.height + "px;",
				selectStyle: "width:" + (this.width + 24) + "px;",
				checkedIds: [],
				checkedData: []
			};
		},
		mounted() {
			this.initCheckedData();
		},
		methods: {
			// 单选时点击tree节点，设置select选项
			setSelectOption(node) {
				let tmpMap = {};
				tmpMap.value = node.key;
				tmpMap.label = node.label;
				this.options = [];
				this.options.push(tmpMap);
				this.selectedData = node.key;
			},
			// 单选，选中传进来的节点
			checkSelectedNode(checkedKeys) {
				var item = checkedKeys[0];
				this.$refs.tree.setCurrentKey(item);
				var node = this.$refs.tree.getNode(item);
				this.setSelectOption(node);
			},
			// 多选，勾选上传进来的节点
			checkSelectedNodes(checkedKeys) {
				this.$refs.tree.setCheckedKeys(checkedKeys);
			},
			// 单选，清空选中
			clearSelectedNode() {
				this.selectedData = "";
				this.$refs.tree.setCurrentKey(null);
			},
			// 多选，清空所有勾选
			clearSelectedNodes() {
				var checkedKeys = this.$refs.tree.getCheckedKeys(); // 所有被选中的节点的 key 所组成的数组数据
				for (let i = 0; i < checkedKeys.length; i++) {
					this.$refs.tree.setChecked(checkedKeys[i], false);
				}
			},
			initCheckedData() {
				if (this.multiple) {
					// 多选
					if (this.checkedKeys.length > 0) {
						this.checkSelectedNodes(this.checkedKeys);
					} else {
						this.clearSelectedNodes();
					}
				} else {
					// 单选
					if (this.checkedKeys.length > 0) {
						this.checkSelectedNode(this.checkedKeys);
					} else {
						this.clearSelectedNode();
					}
				}
			},
			popoverHide() {
				if (this.multiple) {
					this.checkedIds = this.$refs.tree.getCheckedKeys(); // 所有被选中的节点的 key 所组成的数组数据
					this.checkedData = this.$refs.tree.getCheckedNodes(); // 所有被选中的节点所组成的数组数据
				} else {
					this.checkedIds = this.$refs.tree.getCurrentKey();
					this.checkedData = this.$refs.tree.getCurrentNode();
				}
				this.$emit("popoverHide", this.checkedIds, this.checkedData);
			},
			// 单选，节点被点击时的回调,返回被点击的节点数据
			handleNodeClick(data, node) {
				if (!this.multiple) {
					this.setSelectOption(node);
					this.isShowSelect = !this.isShowSelect;
					this.$emit("change", this.selectedData);
				}
			},
			// 多选，节点勾选状态发生变化时的回调
			handleCheckChange() {
				var checkedKeys = this.$refs.tree.getCheckedKeys(); // 所有被选中的节点的 key 所组成的数组数据
				this.options = checkedKeys.map(item => {
					var node = this.$refs.tree.getNode(item); // 所有被选中的节点对应的node
					let tmpMap = {};
					tmpMap.value = node.key;
					tmpMap.label = node.label;
					return tmpMap;
				});
				this.selectedData = this.options.map(item => {
					return item.value;
				});
				this.$emit("change", this.selectedData);
			},
			// 多选,删除任一select选项的回调
			removeSelectedNodes(val) {
				this.$refs.tree.setChecked(val, false);
				var node = this.$refs.tree.getNode(val);
				if (!this.checkStrictly && node.childNodes.length > 0) {
					this.treeToList(node).map(item => {
						if (item.childNodes.length <= 0) {
							this.$refs.tree.setChecked(item, false);
						}
					});
					this.handleCheckChange();
				}
				this.$emit("change", this.selectedData);
			},
			treeToList(tree) {
				var queen = [];
				var out = [];
				queen = queen.concat(tree);
				while (queen.length) {
					var first = queen.shift();
					if (first.childNodes) {
						queen = queen.concat(first.childNodes);
					}
					out.push(first);
				}
				return out;
			},
			// 单选,清空select输入框的回调
			removeSelectedNode() {
				this.clearSelectedNode();
				this.$emit("change", this.selectedData);
			},
			// 选中的select选项改变的回调
			changeSelectedNodes(selectedData) {
				// 多选,清空select输入框时，清除树勾选
				if (this.multiple && selectedData.length <= 0) {
					this.clearSelectedNodes();
				}
				this.$emit("change", this.selectedData);
			}
		},
		watch: {
			isShowSelect() {
				// 隐藏select自带的下拉框
				this.$refs.select.blur();
			}
		}
	};
</script>

<style>
	.mask {
		width: 100%;
		height: 100%;
		position: fixed;
		top: 0;
		left: 0;
		opacity: 0;
		z-index: 11;
	}

	.common-tree {
		overflow: auto;
	}

	.tree-select {
		z-index: 111;
	}
</style>
