export default {
  props: {
    localdata: {
      type: [Array, Object],
      default () {
        return []
      }
    },
    collection: {
      type: String,
      default: ''
    },
    action: {
      type: String,
      default: ''
    },
    field: {
      type: String,
      default: ''
    },
    orderby: {
      type: String,
      default: ''
    },
    where: {
      type: [String, Object],
      default: ''
    },
    pageData: {
      type: String,
      default: 'add'
    },
    pageCurrent: {
      type: Number,
      default: 1
    },
    pageSize: {
      type: Number,
      default: 20
    },
    getcount: {
      type: [Boolean, String],
      default: false
    },
    getone: {
      type: [Boolean, String],
      default: false
    },
    gettree: {
      type: [Boolean, String],
      default: false
    },
    manual: {
      type: Boolean,
      default: false
    },
    value: {
      type: [Array, String, Number],
      default () {
        return []
      }
    },
    preload: {
      type: Boolean,
      default: false
    },
    stepSearh: {
      type: Boolean,
      default: true
    },
    selfField: {
      type: String,
      default: ''
    },
    parentField: {
      type: String,
      default: ''
    },
    multiple: {
      type: Boolean,
      default: false
    }
  },
  data() {
    return {
      loading: false,
      errorMessage: '',
      loadMore: {
        contentdown: '',
        contentrefresh: '',
        contentnomore: ''
      },
      dataList: [],
      selected: [],
      selectedIndex: 0,
      page: {
        current: this.pageCurrent,
        size: this.pageSize,
        count: 0
      }
    }
  },
  computed: {
    isLocaldata() {
      return this.localdata.length > 0
    },
    postField() {
      return `${this.field}, ${this.parentField} as parent_value`
    }
  },
  created() {
    this.$watch(() => {
      var al = [];
      ['pageCurrent',
        'pageSize',
        'value',
        'localdata',
        'collection',
        'action',
        'field',
        'orderby',
        'where',
        'getont',
        'getcount',
        'gettree'
      ].forEach(key => {
        al.push(this[key])
      });
      return al
    }, (newValue, oldValue) => {
      let needReset = false
      for (let i = 2; i < newValue.length; i++) {
        if (newValue[i] != oldValue[i]) {
          needReset = true
          break
        }
      }
      if (newValue[0] != oldValue[0]) {
        this.page.current = this.pageCurrent
      }
      this.page.size = this.pageSize

      this.onPropsChange()
    })
    this._treeData = []
  },
  methods: {
    onPropsChange() {
      this._treeData = []
    },
    getCommand(options = {}) {
      /* eslint-disable no-undef */
      let db = uniCloud.database()

      const action = options.action || this.action
      if (action) {
        db = db.action(action)
      }

      const collection = options.collection || this.collection
      db = db.collection(collection)

      const where = options.where || this.where
      if (!(!where || !Object.keys(where).length)) {
        db = db.where(where)
      }

      const field = options.field || this.field
      if (field) {
        db = db.field(field)
      }

      const orderby = options.orderby || this.orderby
      if (orderby) {
        db = db.orderBy(orderby)
      }

      const current = options.pageCurrent !== undefined ? options.pageCurrent : this.page.current
      const size = options.pageSize !== undefined ? options.pageSize : this.page.size
      const getCount = options.getcount !== undefined ? options.getcount : this.getcount
      const getTree = options.gettree !== undefined ? options.gettree : this.gettree

      const getOptions = {
        getCount,
        getTree
      }
      if (options.getTreePath) {
        getOptions.getTreePath = options.getTreePath
      }

      db = db.skip(size * (current - 1)).limit(size).get(getOptions)

      return db
    },
    getTreePath(callback) {
      if (this.loading) {
        return
      }
      this.loading = true

      this.getCommand({
        field: this.postField,
        getTreePath: {
          startWith: `${this.selfField}=='${this.value}'`
        }
      }).then((res) => {
        this.loading = false
        let treePath = []
        this._extractTreePath(res.result.data, treePath)
        this.selected = treePath
        callback && callback()
      }).catch((err) => {
        this.loading = false
        this.errorMessage = err
      })
    },
    loadData() {
      if (this.isLocaldata) {
        this._processLocalData()
        return
      }

      if (this.value.length) {
        this._loadNodeData((data) => {
          this._treeData = data
          this._updateBindData()
          this._updateSelected()
        })
        return
      }

      if (this.stepSearh) {
        this._loadNodeData((data) => {
          this._treeData = data
          this._updateBindData()
        })
      } else {
        this._loadAllData((data) => {
          this._treeData = []
          this._extractTree(data, this._treeData, null)
          this._updateBindData()
        })
      }
    },
    _loadAllData(callback) {
      if (this.loading) {
        return
      }
      this.loading = true

      this.getCommand({
        field: this.postField,
        gettree: true,
        startwith: `${this.selfField}=='${this.value}'`
      }).then((res) => {
        this.loading = false
        callback(res.result.data)
        this.onDataChange()
      }).catch((err) => {
        this.loading = false
        this.errorMessage = err
      })
    },
    _loadNodeData(callback, pw) {
      if (this.loading) {
        return
      }
      this.loading = true

      this.getCommand({
        field: this.postField,
        where: pw || this._postWhere(),
        pageSize: 500
      }).then((res) => {
        this.loading = false
        callback(res.result.data)
        this.onDataChange()
      }).catch((err) => {
        this.loading = false
        this.errorMessage = err
      })
    },
    _postWhere() {
      let result = []
      let selected = this.selected
      result.push(`${this.parentField} == null`)
      if (selected.length) {
        for (var i = 0; i < selected.length - 1; i++) {
          result.push(`${this.parentField} == '${selected[i].value}'`)
        }
      }

      if (this.where) {
        return `(${this.where}) && (${result.join(' || ')})`
      }

      return result.join(' || ')
    },
    _nodeWhere() {
      let result = []
      let selected = this.selected
      if (selected.length) {
        result.push(`${this.parentField} == '${selected[selected.length - 1].value}'`)
      }

      if (this.where) {
        return `(${this.where}) && (${result.join(' || ')})`
      }

      return result.join(' || ')
    },
    _updateSelected() {
      var dl = this.dataList
      var sl = this.selected
      for (var i = 0; i < sl.length; i++) {
        var value = sl[i].value
        var dl2 = dl[i]
        for (var j = 0; j < dl2.length; j++) {
          var item2 = dl2[j]
          if (item2.value === value) {
            sl[i].text = item2.text
            break
          }
        }
      }
    },
    _updateBindData(node) {
      const {
        dataList,
        hasNodes
      } = this._filterData(this._treeData, this.selected)

      let isleaf = this._stepSearh === false && !hasNodes

      if (node) {
        node.isleaf = isleaf
      }

      this.dataList = dataList
      this.selectedIndex = dataList.length - 1

      if (!isleaf && this.selected.length < dataList.length) {
        this.selected.push({
          value: null,
          text: "请选择"
        })
      }

      return {
        isleaf,
        hasNodes
      }
    },
    _filterData(data, paths) {
      let dataList = []

      let hasNodes = true

      dataList.push(data.filter((item) => {
        return item.parent_value === undefined
      }))
      for (let i = 0; i < paths.length; i++) {
        var value = paths[i].value
        var nodes = data.filter((item) => {
          return item.parent_value === value
        })

        if (nodes.length) {
          dataList.push(nodes)
        } else {
          hasNodes = false
        }
      }

      return {
        dataList,
        hasNodes
      }
    },
    _extractTree(nodes, result, parent_value) {
      let list = result || []
      for (let i = 0; i < nodes.length; i++) {
        let node = nodes[i]

        let child = {}
        for (let key in node) {
          if (key !== 'children') {
            child[key] = node[key]
          }
        }
        if (parent_value !== null) {
          child.parent_value = parent_value
        }
        result.push(child)

        let children = node.children
        if (children) {
          this._extractTree(children, result, node.value)
        }
      }
    },
    _extractTreePath(nodes, result) {
      let list = result || []
      for (let i = 0; i < nodes.length; i++) {
        let node = nodes[i]

        let child = {}
        for (let key in node) {
          if (key !== 'children') {
            child[key] = node[key]
          }
        }
        result.push(child)

        let children = node.children
        if (children) {
          this._extractTreePath(children, result)
        }
      }
    },
    _findNodePath(key, nodes, path = []) {
      for (let i = 0; i < nodes.length; i++) {
        let {
          value,
          text,
          children
        } = nodes[i]

        path.push({
          value,
          text
        })

        if (value === key) {
          return path
        }

        if (children) {
          const p = this._findNodePath(key, children, path)
          if (p.length) {
            return p
          }
        }

        path.pop()
      }
      return []
    },
    _processLocalData() {
      this._treeData = []
      this._extractTree(this.localdata, this._treeData)

      var inputValue = this.value
      if (inputValue === undefined) {
        return
      }

      if (Array.isArray(inputValue)) {
        inputValue = inputValue[inputValue.length - 1]
        if (typeof inputValue === 'object' && inputValue.value) {
          inputValue = inputValue.value
        }
      }

      this.selected = this._findNodePath(inputValue, this.localdata)
    }
  }
}