import { watchAdStart, watchAdReward } from "@/api/system.js";
import { useUserStore } from "@/stores/user";

class AdManager {
  constructor() {
    this.videoAd = null;
    this.rewardToken = "";
    this.isLoaded = false;
    this.isAdShowing = false; // 新增：标记广告是否正在展示
    this.adUnitId = "adunit-d7a28e0357d98947"; // Default ID from RewardAd.vue
    
    // 彻底废除预初始化。
    // 在微信小程序中，如果在页面未完全就绪时调用 createRewardedVideoAd，
    // 会导致底层寻找挂载点失败，抛出 `insertTextView:fail` 等严重渲染错误。
    // 因此改为：只在用户真正点击“看广告”时才进行初始化。
  }

  /**
   * Initializes the ad instance synchronously when needed.
   * @param {string} adUnitId 
   */
  _initSync(adUnitId) {
    if (this.videoAd && this.adUnitId === adUnitId) {
      return true; // Already initialized for this ID
    }

    this.adUnitId = adUnitId || this.adUnitId;

    // #ifdef MP-WEIXIN || MP-ALIPAY || MP-TOUTIAO || MP-QQ
    if (uni.createRewardedVideoAd) {
      try {
        // Destroy old instance if ID changed
        if (this.videoAd) {
          if (this.videoAd.destroy) {
            try {
              this.videoAd.destroy();
            } catch (destroyErr) {
              console.error("Ad Manager: destroy old ad failed", destroyErr);
            }
          }
          this.videoAd = null;
        }

        // 核心修复：微信小程序官方建议使用单例，且多次调用 createRewardedVideoAd 传入相同的 adUnitId 会返回同一个实例。
        // 但如果在短时间内销毁又立即创建，底层可能会发生不可预知的渲染报错（如找不到 parent 节点）。
        // 因此，我们只需安全地获取实例，并重新绑定事件。
        this.videoAd = uni.createRewardedVideoAd({
          adUnitId: this.adUnitId
        });

        if (this.videoAd) {
          // 清理之前可能存在的残留事件，防止重复触发和内存泄漏导致底层崩溃
          if (this.videoAd.offLoad) this.videoAd.offLoad();
          if (this.videoAd.offError) this.videoAd.offError();
          if (this.videoAd.offClose) this.videoAd.offClose();

          this.videoAd.onLoad(() => {
            console.log("Ad Manager: Ad Loaded");
            this.isLoaded = true;
          });

          this.videoAd.onError((err) => {
            console.error("Ad Manager: Ad Load Error", err);
            this.isLoaded = false;
          });
          return true;
        }
      } catch (e) {
        console.error("Ad Manager Init Error", e);
        return false;
      }
    }
    // #endif
    return false;
  }

  /**
   * Show the rewarded video ad.
   * Handles the full flow: start session -> show ad -> verify completion -> claim reward -> refresh assets.
   * @param {string} [adUnitId] - Optional adUnitId to override the default.
   * @param {string} [providedToken] - Optional token if watchAdStart was already called externally.
   * @returns {Promise<boolean>} Resolves with true if reward was claimed, false otherwise.
   */
  async showVideoAd(adUnitId, providedToken) {
    if (this.isAdShowing || this.isStarting) {
      console.log("Ad Manager: Ad is already starting or showing");
      return false;
    }
    
    this.isStarting = true;

    // 延迟到这一步才初始化，避开页面渲染期
    const canInit = this._initSync(adUnitId);
    
    if (!canInit || !this.videoAd) {
      uni.showToast({ title: "当前环境不支持广告", icon: "none" });
      this.isStarting = false;
      return false;
    }

    try {
      // Step 1: Start Ad Session (if not provided)
      if (providedToken) {
        this.rewardToken = providedToken;
      } else {
        const startRes = await watchAdStart();
        if (!startRes || !startRes.rewardToken) {
          uni.showToast({ title: "广告启动失败，请稍后再试", icon: "none" });
          this.isStarting = false;
          return false;
        }
        this.rewardToken = startRes.rewardToken;
      }

      // Step 2: Show Ad
      try {
        this.isAdShowing = true;
        this.isStarting = false;
        await this.videoAd.show();
      } catch (e) {
        // Retry load and show
        try {
          await this.videoAd.load();
          await this.videoAd.show();
        } catch (loadErr) {
          this.isAdShowing = false;
          console.error("Ad Manager: Retry load failed", loadErr);
          throw loadErr;
        }
      }

      // Step 3: Wait for Close
      return new Promise((resolve) => {
        const onCloseHandler = async (res) => {
          // 延迟 500ms 释放状态，防止从广告返回页面时（onShow）立即触发 DOM 大量更新，导致底层 insertTextView:fail 崩溃
          setTimeout(() => {
            this.isAdShowing = false;
          }, 500);

          // 安全地解绑事件
          try {
            if (this.videoAd && this.videoAd.offClose) {
              this.videoAd.offClose(onCloseHandler); // Clean up listener
            }
          } catch (offErr) {
             console.error("Ad Manager: offClose error", offErr);
          }

          if (res && res.isEnded) {
            // Step 4: Claim Reward
            // Only claim if token wasn't provided externally (if provided, external component claims it)
            if (!providedToken) {
              await this._claimReward(this.rewardToken);
            }
            resolve(true);
          } else {
            uni.showToast({ title: "观看完整广告才能获取奖励哦", icon: "none" });
            resolve(false);
          }
        };

        try {
          this.videoAd.onClose(onCloseHandler);
        } catch (onErr) {
           console.error("Ad Manager: onClose error", onErr);
           resolve(false);
        }
      });

    } catch (e) {
      console.error("Ad Manager: Show failed", e);
      uni.showToast({ title: "广告加载失败，请稍后再试", icon: "none" });
      return false;
    }
  }

  async _claimReward(token) {
    try {
      uni.showLoading({ title: "发放奖励中..." });
      const res = await watchAdReward(token);
      if (res) {
        uni.showToast({
          title: "获得50积分",
          icon: "success",
        });
        // Refresh user assets
        const userStore = useUserStore();
        await userStore.fetchUserAssets();
      }
    } catch (e) {
      console.error("Ad Manager: Reward claim failed", e);
      uni.showToast({ title: "奖励发放失败", icon: "none" });
    } finally {
      uni.hideLoading();
    }
  }
}

export default new AdManager();