import { computed, obx, uniqueId } from '@ali/lowcode-globals';
import {
  Designer,
  ISensor,
  LocateEvent,
  isDragNodeObject,
  isDragAnyObject,
  DragObject,
  Scroller,
  ScrollTarget,
  IScrollable,
  DropLocation,
  isLocationChildrenDetail,
  LocationChildrenDetail,
  LocationDetailType,
  NodeParent,
  contains,
  Node,
} from '@ali/lowcode-designer';
import { Tree } from './tree';
import TreeNode from './tree-node';
import { IndentTrack } from './helper/indent-track';
import DwellTimer from './helper/dwell-timer';
import { EventEmitter } from 'events';

export interface IScrollBoard {
  scrollToNode(treeNode: TreeNode, detail?: any): void;
}

class TreeMaster {
  private emitter = new EventEmitter();
  private currentFixed?: OutlineMain;
  constructor(readonly designer: Designer) {
    designer.dragon.onDragstart((e) => {
      const tree = this.currentTree;
      if (tree) {
        tree.document.selection.getTopNodes().forEach((node) => {
          tree.getTreeNode(node).setExpanded(false);
        });
      }
      if (!this.currentFixed) {
        this.emitter.emit('enable-builtin');
      }
    });
    designer.activeTracker.onChange(({ node, detail }) => {
      const tree = this.currentTree;
      if (!tree || node.document !== tree.document) {
        return;
      }

      const treeNode = tree.getTreeNode(node);
      if (detail && isLocationChildrenDetail(detail)) {
        treeNode.expand(true);
      } else {
        treeNode.expandParents();
      }

      this.boards.forEach((board) => {
        board.scrollToNode(treeNode, detail);
      });
    });
  }

  setFixed(entry: OutlineMain) {
    this.currentFixed = entry;
  }

  unFixed(entry: OutlineMain) {
    if (entry === this.currentFixed) {
      this.currentFixed = undefined;
    }
  }

  onceEnableBuiltin(fn: () => void): () => void {
    this.emitter.once('enable-builtin', fn);
    return () => {
      this.emitter.removeListener('enable-builtin', fn);
    }
  }

  private boards = new Set<IScrollBoard>();
  addBoard(board: IScrollBoard) {
    this.boards.add(board);
  }
  removeBoard(board: IScrollBoard) {
    this.boards.delete(board);
  }

  purge() {
    this.emitter.removeAllListeners();
    // todo others purge
  }

  private treeMap = new Map<string, Tree>();
  @computed get currentTree(): Tree | null {
    const doc = this.designer?.currentDocument;
    if (doc) {
      const id = doc.id;
      if (this.treeMap.has(id)) {
        return this.treeMap.get(id)!;
      }
      const tree = new Tree(doc);
      // TODO: listen purge event to remove
      this.treeMap.set(id, tree);
      return tree;
    }
    return null;
  }
}

const mastersMap = new Map<Designer, TreeMaster>();
export function getTreeMaster(designer: Designer): TreeMaster {
  let master = mastersMap.get(designer);
  if (!master) {
    master = new TreeMaster(designer);
    mastersMap.set(designer, master);
  }
  return master;
}

export class OutlineMain implements ISensor, IScrollBoard, IScrollable {
  private _designer?: Designer;
  @obx.ref private _master?: TreeMaster;
  get master() {
    return this._master;
  }
  @computed get currentTree() {
    return this._master?.currentTree;
  }
  readonly id = uniqueId('outline');

  private fixed = false;
  constructor(readonly editor: any, at?: string) {
    let inited = false;
    const setup = () => {
      if (inited) {
        return false;
      }
      inited = true;
      if (editor.designer) {
        this.setupDesigner(editor.designer);
      } else {
        editor.once('designer.mount', (designer: Designer) => {
          this.setupDesigner(designer);
        });
      }
    };

    if (at === '__IN_SETTINGS__') {
      setup();
    } else {
      editor.on('leftPanel.show', (key: string) => {
        if (key === at) {
          setup();
          if (this.master) {
            this.master.setFixed(this);
          } else {
            this.fixed = true;
          }
          document.documentElement.classList.add('lowcode-has-fixed-tree');
        } else {
          document.documentElement.classList.remove('lowcode-has-fixed-tree');
          if (this.master) {
            this.master.unFixed(this);
          } else {
            this.fixed = false;
          }
        }
      });
      // editor.once('outlinePane.visible', setup);
    }
  }

  /**
   * @see ISensor
   */
  fixEvent(e: LocateEvent): LocateEvent {
    if (e.fixed) {
      return e;
    }

    const notMyEvent = e.originalEvent.view?.document !== document;

    if (!e.target || notMyEvent) {
      e.target = document.elementFromPoint(e.canvasX!, e.canvasY!);
    }

    // documentModel : 目标文档
    e.documentModel = this._designer?.currentDocument;

    // 事件已订正
    e.fixed = true;
    return e;
  }

  private indentTrack = new IndentTrack();
  private dwell = new DwellTimer((target, event) => {
    const document = target.document;
    const designer = document.designer;
    let index: any;
    let focus: any;
    let valid = true;
    if (target.isSlotContainer()) {
      index = null;
      focus = { type: 'slots' };
    } else {
      index = 0;
      valid = document.checkNesting(target, event.dragObject as any);
    }
    designer.createLocation({
      target,
      source: this.id,
      event,
      detail: {
        type: LocationDetailType.Children,
        index,
        focus,
        valid,
      },
    });
  });
  /**
   * @see ISensor
   */
  locate(e: LocateEvent): DropLocation | undefined | null {
    this.sensing = true;
    this.scroller?.scrolling(e);

    const tree = this._master?.currentTree;
    if (!tree || !this._shell) {
      return null;
    }

    const document = tree.document;
    const designer = document.designer;
    const { globalY, dragObject } = e;
    const pos = getPosFromEvent(e, this._shell);
    const irect = this.getInsertionRect();
    const originLoc = document.dropLocation;
    if (originLoc && ((pos && pos === 'unchanged') || (irect && globalY >= irect.top && globalY <= irect.bottom))) {
      const loc = originLoc.clone(e);
      const indented = this.indentTrack.getIndentParent(originLoc, loc);
      if (indented) {
        const [parent, index] = indented;
        if (checkRecursion(parent, dragObject)) {
          if (tree.getTreeNode(parent).expanded) {
            this.dwell.reset();
            return designer.createLocation({
              target: parent,
              source: this.id,
              event: e,
              detail: {
                type: LocationDetailType.Children,
                index,
                valid: document.checkNesting(parent, e.dragObject as any),
              },
            });
          }

          (originLoc.detail as LocationChildrenDetail).focus = {
            type: 'node',
            node: parent,
          };
          // focus try expand go on
          this.dwell.focus(parent, e);
        } else {
          this.dwell.reset();
        }
      } else {
        // FIXME: recreate new location
        if ((originLoc.detail as LocationChildrenDetail).near) {
          (originLoc.detail as LocationChildrenDetail).near = undefined;
          this.dwell.reset();
        }
      }
      return;
    }

    this.indentTrack.reset();

    if (pos && pos !== 'unchanged') {
      let treeNode = tree.getTreeNodeById(pos.nodeId);
      if (treeNode) {
        let focusSlots = pos.focusSlots;
        let { node } = treeNode;
        if (isDragNodeObject(dragObject)) {
          const nodes = dragObject.nodes;
          let i = nodes.length;
          let p: any = node;
          while (i-- > 0) {
            if (contains(nodes[i], p)) {
              p = nodes[i].parent;
            }
          }
          if (p !== node) {
            node = p || document.rootNode;
            treeNode = tree.getTreeNode(node);
            focusSlots = false;
          }
        }

        if (focusSlots) {
          this.dwell.reset();
          return designer.createLocation({
            target: node as NodeParent,
            source: this.id,
            event: e,
            detail: {
              type: LocationDetailType.Children,
              index: null,
              valid: false,
              focus: { type: 'slots' },
            },
          });
        }

        if (!treeNode.isRoot()) {
          const loc = this.getNear(treeNode, e);
          this.dwell.tryFocus(loc);
          return loc;
        }
      }
    }

    const loc = this.drillLocate(tree.root, e);
    this.dwell.tryFocus(loc);
    return loc;
  }

  private getNear(treeNode: TreeNode, e: LocateEvent, index?: number, rect?: DOMRect) {
    const document = treeNode.tree.document;
    const designer = document.designer;
    const { globalY, dragObject } = e;
    // TODO: check dragObject is anyData
    const { node, expanded } = treeNode;
    if (!rect) {
      rect = this.getTreeNodeRect(treeNode);
      if (!rect) {
        return null;
      }
    }
    if (index == null) {
      index = node.index;
    }

    if (node.isSlotRoot) {
      // 是个插槽根节点
      if (!treeNode.isContainer() && !treeNode.isSlotContainer()) {
        return designer.createLocation({
          target: node.parent!,
          source: this.id,
          event: e,
          detail: {
            type: LocationDetailType.Children,
            index: null,
            near: { node, pos: 'replace' },
            valid: true, // TODO: future validation the slot limit
          },
        });
      }
      const loc1 = this.drillLocate(treeNode, e);
      if (loc1) {
        return loc1;
      }

      return designer.createLocation({
        target: node.parent!,
        source: this.id,
        event: e,
        detail: {
          type: LocationDetailType.Children,
          index: null,
          valid: false,
          focus: { type: 'slots' },
        },
      });
    }

    let focusNode: Node | undefined;
    // focus
    if (!expanded && (treeNode.isContainer() || treeNode.isSlotContainer())) {
      focusNode = node;
    }

    // before
    const titleRect = this.getTreeTitleRect(treeNode) || rect;
    if (globalY < titleRect.top + titleRect.height / 2) {
      return designer.createLocation({
        target: node.parent!,
        source: this.id,
        event: e,
        detail: {
          type: LocationDetailType.Children,
          index,
          valid: document.checkNesting(node.parent!, dragObject as any),
          near: { node, pos: 'before' },
          focus: checkRecursion(focusNode, dragObject) ? { type: 'node', node: focusNode } : undefined,
        },
      });
    }

    if (globalY > titleRect.bottom) {
      focusNode = undefined;
    }

    if (expanded) {
      // drill
      const loc = this.drillLocate(treeNode, e);
      if (loc) {
        return loc;
      }
    }

    // after
    return designer.createLocation({
      target: node.parent!,
      source: this.id,
      event: e,
      detail: {
        type: LocationDetailType.Children,
        index: index + 1,
        valid: document.checkNesting(node.parent!, dragObject as any),
        near: { node, pos: 'after' },
        focus: checkRecursion(focusNode, dragObject) ? { type: 'node', node: focusNode } : undefined,
      },
    });
  }

  private drillLocate(treeNode: TreeNode, e: LocateEvent): DropLocation | null {
    const document = treeNode.tree.document;
    const designer = document.designer;
    const { dragObject, globalY } = e;

    if (!checkRecursion(treeNode.node, dragObject)) {
      return null;
    }

    if (isDragAnyObject(dragObject)) {
      // TODO: future
      return null;
    }

    const container = treeNode.node as NodeParent;
    const detail: LocationChildrenDetail = {
      type: LocationDetailType.Children,
    };
    const locationData: any = {
      target: container,
      detail,
      source: this.id,
      event: e,
    };
    const isSlotContainer = treeNode.isSlotContainer();
    const isContainer = treeNode.isContainer();

    if (container.isSlotRoot && !treeNode.expanded) {
      // 未展开，直接定位到内部第一个节点
      if (isSlotContainer) {
        detail.index = null;
        detail.focus = { type: 'slots' };
        detail.valid = false;
      } else {
        detail.index = 0;
        detail.valid = document.checkNesting(container, dragObject);
      }
    }

    let items: TreeNode[] | null = null;
    let slotsRect: DOMRect | undefined;
    let focusSlots = false;
    // isSlotContainer
    if (isSlotContainer) {
      slotsRect = this.getTreeSlotsRect(treeNode);
      if (slotsRect) {
        if (globalY <= slotsRect.bottom) {
          focusSlots = true;
          items = treeNode.slots;
        } else if (!isContainer) {
          // 不在 slots 范围，又不是 container 的情况，高亮 slots 区
          detail.index = null;
          detail.focus = { type: 'slots' };
          detail.valid = false;
          return designer.createLocation(locationData);
        }
      }
    }

    if (!items && isContainer) {
      items = treeNode.children;
    }

    if (!items) {
      return null;
    }

    const l = items.length;
    let index = 0;
    let before = l < 1;
    let current: TreeNode | undefined;
    let currentIndex = index;
    for (; index < l; index++) {
      current = items[index];
      currentIndex = index;
      const rect = this.getTreeNodeRect(current);
      if (!rect) {
        continue;
      }

      // rect
      if (globalY < rect.top) {
        before = true;
        break;
      }

      if (globalY > rect.bottom) {
        continue;
      }

      const loc = this.getNear(current, e, index, rect);
      if (loc) {
        return loc;
      }
    }

    if (focusSlots) {
      detail.focus = { type: 'slots' };
      detail.valid = false;
      detail.index = null;
    } else {
      if (current) {
        detail.index = before ? currentIndex : currentIndex + 1;
        detail.near = { node: current.node, pos: before ? 'before' : 'after' };
      } else {
        detail.index = l;
      }
      detail.valid = document.checkNesting(container, dragObject);
    }

    return designer.createLocation(locationData);
  }

  /**
   * @see ISensor
   */
  isEnter(e: LocateEvent): boolean {
    if (!this._shell) {
      return false;
    }
    const rect = this._shell.getBoundingClientRect();
    return e.globalY >= rect.top && e.globalY <= rect.bottom && e.globalX >= rect.left && e.globalX <= rect.right;
  }

  private tryScrollAgain: number | null = null;
  /**
   * @see IScrollBoard
   */
  scrollToNode(treeNode: TreeNode, detail?: any, tryTimes = 0) {
    if (tryTimes < 1 && this.tryScrollAgain) {
      (window as any).cancelIdleCallback(this.tryScrollAgain);
      this.tryScrollAgain = null;
    }
    if (this.sensing || !this.bounds || !this.scroller || !this.scrollTarget) {
      // is a active sensor
      return;
    }

    let rect: ClientRect | undefined;
    if (detail && isLocationChildrenDetail(detail)) {
      rect = this.getInsertionRect();
    } else {
      rect = this.getTreeNodeRect(treeNode);
    }

    if (!rect) {
      if (tryTimes < 3) {
        this.tryScrollAgain = (window as any).requestIdleCallback(() =>
          this.scrollToNode(treeNode, detail, tryTimes + 1),
        );
      }
      return;
    }
    const { scrollHeight, top: scrollTop } = this.scrollTarget;
    const { height, top, bottom } = this.bounds;
    if (rect.top < top || rect.bottom > bottom) {
      const opt: any = {};
      opt.top = Math.min(rect.top + rect.height / 2 + scrollTop - top - height / 2, scrollHeight - height);
      if (rect.height >= height) {
        opt.top = Math.min(scrollTop + rect.top - top, opt.top);
      }
      this.scroller.scrollTo(opt);
    }
    // make tail scroll be sure
    if (tryTimes < 4) {
      this.tryScrollAgain = (window as any).requestIdleCallback(() => this.scrollToNode(treeNode, detail, 4));
    }
  }

  private sensing = false;
  /**
   * @see ISensor
   */
  deactiveSensor() {
    this.sensing = false;
    this.scroller?.cancel();
    this.dwell.reset();
    this.indentTrack.reset();
  }

  /**
   * @see IScrollable
   */
  get bounds(): DOMRect | null {
    if (!this._shell) {
      return null;
    }
    return this._shell.getBoundingClientRect();
  }

  private _scrollTarget?: ScrollTarget;
  /**
   * @see IScrollable
   */
  get scrollTarget() {
    return this._scrollTarget;
  }
  private scroller?: Scroller;

  private setupDesigner(designer: Designer) {
    this._designer = designer;
    this._master = getTreeMaster(designer);
    this._master.addBoard(this);
    if (this.fixed) {
      this._master.setFixed(this);
    }
    designer.dragon.addSensor(this);
    this.scroller = designer.createScroller(this);
  }

  purge() {
    this._designer?.dragon.removeSensor(this);
    this._master?.removeBoard(this);
    // todo purge treeMaster if needed
  }

  private _sensorAvailable = false;
  /**
   * @see ISensor
   */
  get sensorAvailable() {
    return this._sensorAvailable;
  }

  private _shell: HTMLDivElement | null = null;
  mount(shell: HTMLDivElement | null) {
    if (this._shell === shell) {
      return;
    }
    this._shell = shell;
    if (shell) {
      this._scrollTarget = new ScrollTarget(shell);
      this._sensorAvailable = true;
    } else {
      this._scrollTarget = undefined;
      this._sensorAvailable = false;
    }
  }

  private getInsertionRect(): DOMRect | undefined {
    if (!this._shell) {
      return undefined;
    }
    return this._shell.querySelector('.insertion')?.getBoundingClientRect();
  }

  private getTreeNodeRect(treeNode: TreeNode): DOMRect | undefined {
    if (!this._shell) {
      return undefined;
    }
    return this._shell.querySelector(`.tree-node[data-id="${treeNode.id}"]`)?.getBoundingClientRect();
  }

  private getTreeTitleRect(treeNode: TreeNode): DOMRect | undefined {
    if (!this._shell) {
      return undefined;
    }
    return this._shell.querySelector(`.tree-node-title[data-id="${treeNode.id}"]`)?.getBoundingClientRect();
  }

  private getTreeSlotsRect(treeNode: TreeNode): DOMRect | undefined {
    if (!this._shell) {
      return undefined;
    }
    return this._shell.querySelector(`.tree-node-slots[data-id="${treeNode.id}"]`)?.getBoundingClientRect();
  }
}

function checkRecursion(parent: Node | undefined | null, dragObject: DragObject): parent is NodeParent {
  if (!parent) {
    return false;
  }
  if (isDragNodeObject(dragObject)) {
    const nodes = dragObject.nodes;
    if (nodes.some((node) => node.contains(parent))) {
      return false;
    }
  }
  return true;
}

function getPosFromEvent(
  { target }: LocateEvent,
  stop: Element,
): null | 'unchanged' | { nodeId: string; focusSlots: boolean } {
  if (!target || !stop.contains(target)) {
    return null;
  }
  if (target.matches('.insertion')) {
    return 'unchanged';
  }
  target = target.closest('[data-id]');
  if (!target || !stop.contains(target)) {
    return null;
  }

  const nodeId = (target as HTMLDivElement).dataset.id!;
  return {
    focusSlots: target.matches('.tree-node-slots'),
    nodeId,
  };
}