import * as React from "react";
import {
  DataNode,
  FlattenNode,
  NodeElement,
  DataEntity,
  Key,
  EventDataNode
} from "../interface";
import { toArray, getPosition, isTreeNode } from "../utils/common-util";
import { TreeNodeProps } from "../tree-node";

const getKey = (key: Key, pos: string) => {
  if (key !== null && key !== undefined) {
    return key;
  }
  return pos;
};

/**
 * Convert `children` of Tree into `treeData` structure.
 */

const convertTreeToData = (rootNodes: React.ReactNode): DataNode[] => {
  const dig = (node: React.ReactNode): DataNode[] => {
    const treeNodes = toArray(node) as NodeElement[];
    return treeNodes
      .map(treeNode => {
        //Filter invalid node
        if (!isTreeNode(treeNode)) {
          return null;
        }
        const { key } = treeNode;
        const { children, ...rest } = treeNode.props;

        const dataNode: DataNode = {
          key,
          ...rest
        };

        const parsedChildren = dig(children);
        if (parsedChildren.length) {
          dataNode.children = parsedChildren;
        }
        return dataNode;
      })
      .filter((dataNode: DataNode) => dataNode);
  };
  return dig(rootNodes);
};

/**
 * Flat nest tree data into flatten list,
 * this is used for virtual list render.
 * @param treeNodeList Origin data node list
 * @param expandedKeys
 * need expanded keys, provide `true` means all expanded
 */

const flattenTreeData = (
  treeNodeList: DataNode[] = [],
  expandedKeys: Key[] | true = []
): FlattenNode[] => {
  const expandedKeySet = new Set(expandedKeys === true ? [] : expandedKeys);
  const flattenList: FlattenNode[] = [];

  const dig = (list: DataNode[], parent: FlattenNode = null): FlattenNode[] => {
    return list.map((treeNode, index) => {
      const pos: string = getPosition(parent ? parent.pos : "0", index);
      const mergedKey = getKey(treeNode.key, pos);

      //Add FlattenDataNode into list
      const flattenNode: FlattenNode = {
        ...treeNode,
        parent,
        pos,
        children: null,
        data: treeNode,
        isStart: [...(parent ? parent.isStart : []), index === 0],
        isEnd: [...(parent ? parent.isEnd : []), index === list.length - 1]
      };
      flattenList.push(flattenNode);

      //Loop treeNode children
      if (expandedKeys === true || expandedKeySet.has(mergedKey)) {
        flattenNode.children = dig(treeNode.children || [], flattenNode);
      } else {
        flattenNode.children = [];
      }
      return flattenNode;
    });
  };
  dig(treeNodeList);
  return flattenList;
};

// Traverse all the data by `treeData`

const traverseDataNodes = (
  dataNodes: DataNode[],
  callback: (data: {
    node: DataNode;
    index: number;
    pos: string;
    key: Key;
    parentPos: string | number;
    level: number;
  }) => void
) => {
  const processNode = (
    node: DataNode,
    index?: number,
    parent?: { node: DataNode; pos: string; level: number }
  ) => {
    const children = node ? node.children : dataNodes;
    const pos = node ? getPosition(parent.pos, index) : "0";

    //Process node if is not root
    if (node) {
      const data = {
        node,
        index,
        pos,
        key: node.key !== null ? node.key : pos,
        parentPos: parent.node ? parent.pos : null,
        level: parent.level + 1
      };

      callback(data);
    }
    //Process children node
    if (children) {
      children.forEach((subNode, subIndex) => {
        processNode(subNode, subIndex, {
          node,
          pos,
          level: parent ? parent.level + 1 : -1
        });
      });
    }
  };
  processNode(null);
};

interface Wrapper {
  posEntities: Record<string, DataEntity>;
  keyEntities: Record<Key, DataEntity>;
}

//Convert `treeData` into entity records
const convertDataToEntities = (
  dataNodes: DataNode[],
  {
    initWrapper,
    processEntity,
    onProcessFinished
  }: {
    initWrapper?: (wrapper: Wrapper) => Wrapper;
    processEntity?: (entity: DataEntity, wrapper: Wrapper) => void;
    onProcessFinished?: (wrapper: Wrapper) => void;
  } = {}
) => {
  const posEntities = {};
  const keyEntities = {};
  let wrapper = {
    posEntities,
    keyEntities
  };
  if (initWrapper) {
    wrapper = initWrapper(wrapper) || wrapper;
  }
  traverseDataNodes(dataNodes, item => {
    const { node, index, pos, key, parentPos, level } = item;
    const entity: DataEntity = { node, index, key, pos, level };

    const mergedKey = getKey(key, pos);

    posEntities[pos] = entity;
    keyEntities[mergedKey] = entity;

    // Fill children
    entity.parent = posEntities[parentPos];
    if (entity.parent) {
      entity.parent.children = entity.parent.children || [];
      entity.parent.children.push(entity);
    }

    if (processEntity) {
      processEntity(entity, wrapper);
    }
  });
  if (onProcessFinished) {
    onProcessFinished(wrapper);
  }
  return wrapper;
};

interface TreeNodeRequiredProps {
  expandedKeys: Key[];
  selectedKeys: Key[];
  loadedKeys: Key[];
  loadingKeys: Key[];
  dragOverNodeKey: Key;
  dropPosition: number;
  keyEntities: Record<Key, DataEntity>;
}

//Get TreeNode props with Tree props
const getTreeNodeProps = (
  key: Key,
  {
    expandedKeys,
    selectedKeys,
    loadedKeys,
    loadingKeys,
    dragOverNodeKey,
    dropPosition,
    keyEntities
  }: TreeNodeRequiredProps
) => {
  const entity = keyEntities[key];

  const treeNodeProps = {
    eventKey: key,
    expanded: expandedKeys.indexOf(key) !== -1,
    selected: selectedKeys.indexOf(key) !== -1,
    loaded: loadedKeys.indexOf(key) !== -1,
    loading: loadingKeys.indexOf(key) !== -1,
    pos: String(entity ? entity.pos : ""),

    //Drag props
    dragOver: dragOverNodeKey === key && dropPosition === 0,
    dragOverGapTop: dragOverNodeKey === key && dropPosition === -1,
    dragOverGapBottom: dragOverNodeKey === key && dropPosition === 1
  };
  return treeNodeProps;
};

//Convert Node Props to Event Data
const convertNodePropsToEventData = (props: TreeNodeProps): EventDataNode => {
  const {
    data,
    expanded,
    selected,
    loaded,
    loading,
    dragOver,
    dragOverGapTop,
    dragOverGapBottom,
    pos,
    active
  } = props;

  const eventData = {
    ...data,
    expanded,
    selected,
    loaded,
    loading,
    dragOver,
    dragOverGapTop,
    dragOverGapBottom,
    pos,
    active
  };

  if (!("props" in eventData)) {
    Object.defineProperty(eventData, "props", {
      get() {
        return props;
      }
    });
  }
  return eventData;
};

export {
  getKey,
  convertTreeToData,
  flattenTreeData,
  traverseDataNodes,
  convertDataToEntities,
  TreeNodeRequiredProps,
  getTreeNodeProps,
  convertNodePropsToEventData
};