import { getNodeChildren, convertTreeToEntities } from '../vc-tree/src/util'
import { getSlots } from '../_util/props-util'

const Record = {
  None: 'node',
  Start: 'start',
  End: 'end',
}

// TODO: Move this logic into `rc-tree`
function traverseNodesKey (rootChildren, callback) {
  const nodeList = getNodeChildren(rootChildren) || []

  function processNode (node) {
    const { key } = node
    const children = getSlots(node).default
    if (callback(key) !== false) {
      traverseNodesKey(children, callback)
    }
  }

  nodeList.forEach(processNode)
}

export function getFullKeyList (children) {
  const { keyEntities } = convertTreeToEntities(children)
  return [...keyEntities.keys()]
}

/** 计算选中范围，只考虑expanded情况以优化性能 */
export function calcRangeKeys (rootChildren, expandedKeys, startKey, endKey) {
  const keys = []
  let record = Record.None

  if (startKey && startKey === endKey) {
    return [startKey]
  }
  if (!startKey || !endKey) {
    return []
  }

  function matchKey (key) {
    return key === startKey || key === endKey
  }

  traverseNodesKey(rootChildren, (key) => {
    if (record === Record.End) {
      return false
    }

    if (matchKey(key)) {
      // Match test
      keys.push(key)

      if (record === Record.None) {
        record = Record.Start
      } else if (record === Record.Start) {
        record = Record.End
        return false
      }
    } else if (record === Record.Start) {
      // Append selection
      keys.push(key)
    }

    if (expandedKeys.indexOf(key) === -1) {
      return false
    }

    return true
  })

  return keys
}