import { find, Node } from 'cc';
import { GuideStep } from '../../NewbieGuidePlugin-v1.0.0/NewbieGuidePlugin-v1.0.0/scripts/GuideStep';
import { BlockManager } from '../CombatSystem/BlockManager';
import EventBus, { GameEvents } from '../Core/EventBus';

/**
 * 新手引导步骤：提示并等待玩家将任意方块拖到网格
 * 触发条件：场景中存在方块选择区域，且尚未放置任何方块
 * 完成条件：BlockManager 检测到至少一个方块已移动到 PlacedBlocks
 */
export class DragBlockToGridStep extends GuideStep {
  private _blockManager: BlockManager | null = null;
  private _pollTimer: any = null;
  private _dragEventsReady = false;
  private _unsubscribers: Array<() => void> = [];

  constructor() {
    super('drag_block_to_grid');
  }

  public canTrigger(): boolean {
    // 查找 BlockManager（位于方块选择系统下）
    const root = find('Canvas');
    if (!root) return false;

    // 在整棵树中查找 BlockManager 组件
    const nodes: Node[] = [];
    const stack: Node[] = [root];
    while (stack.length) {
      const n = stack.pop()!;
      nodes.push(n);
      for (const child of n.children) stack.push(child);
    }

    for (const n of nodes) {
      const bm = n.getComponent(BlockManager as any) as BlockManager | null;
      if (bm) {
        this._blockManager = bm;
        break;
      }
    }

    if (!this._blockManager) return false;

    // 如果已经有方块被放置则不触发
    const hasPlaced = typeof (this._blockManager as any).hasPlacedBlocks === 'function'
      ? (this._blockManager as any).hasPlacedBlocks()
      : false;
    if (hasPlaced) return false;

    // 确认方块选择 UI 存在（避免在战斗中或加载前触发）
    const selectionUI = find('Canvas/GameLevelUI/BlockSelectionUI');
    return !!selectionUI;
  }

  public doExecute(): void {
    // 监听拖拽相关事件，便于在拖拽区域就绪时给出提示或开始轮询
    const bus = EventBus.getInstance();

    const onSetup = () => {
      this._dragEventsReady = true;
    };
    bus.on(GameEvents.SETUP_BLOCK_DRAG_EVENTS, onSetup, this);
    this._unsubscribers.push(() => bus.off(GameEvents.SETUP_BLOCK_DRAG_EVENTS, onSetup, this));

    const onDragEnd = () => {
      // 尝试立即检测一次是否已经放置成功
      this.checkPlacedAndComplete();
    };
    bus.on(GameEvents.BLOCK_DRAG_END, onDragEnd, this);
    this._unsubscribers.push(() => bus.off(GameEvents.BLOCK_DRAG_END, onDragEnd, this));

    // 启动轮询，容错检测放置完成（避免事件遗漏）
    this._pollTimer = setInterval(() => this.checkPlacedAndComplete(), 500);
  }

  private checkPlacedAndComplete() {
    if (!this._blockManager) return;
    try {
      const hasPlaced = typeof (this._blockManager as any).hasPlacedBlocks === 'function'
        ? (this._blockManager as any).hasPlacedBlocks()
        : false;
      if (hasPlaced) {
        this.complete();
      }
    } catch (e) {
      console.error('[DragBlockToGridStep] 检测放置状态失败:', e);
    }
  }

  protected onComplete(): void {
    // 清理事件与轮询
    for (const unsub of this._unsubscribers) {
      try { unsub(); } catch {}
    }
    this._unsubscribers = [];
    if (this._pollTimer) {
      clearInterval(this._pollTimer);
      this._pollTimer = null;
    }
    // 记录由基类完成 complete() 统一处理
  }
}

export default DragBlockToGridStep;