// src/hooks/usePostHogRedux.js
import { useCallback } from 'react';
import { useDispatch, useSelector } from 'react-redux';
import {
  trackEvent,
  identifyUser,
  resetUser,
  optIn,
  optOut,
  selectPostHog,
  selectIsInitialized,
  selectUser,
  selectFeatureFlags,
  selectFeatureFlag,
  selectIsOptedOut,
  selectStats,
  flushCachedEvents,
} from '../store/slices/posthogSlice';
import { trackPageView } from '../lib/posthog';

/**
 * PostHog Redux Hook
 * 提供便捷的 PostHog 功能访问接口
 *
 * 用法示例:
 *
 * ```jsx
 * import { usePostHogRedux } from 'hooks/usePostHogRedux';
 * import { RETENTION_EVENTS } from 'lib/constants';
 *
 * function MyComponent() {
 *   const { track, identify, user, isInitialized } = usePostHogRedux();
 *
 *   const handleClick = () => {
 *     track(RETENTION_EVENTS.NEWS_ARTICLE_CLICKED, {
 *       article_id: '123',
 *       article_title: '标题',
 *     });
 *   };
 *
 *   if (!isInitialized) {
 *     return <div>正在加载...</div>;
 *   }
 *
 *   return (
 *     <div>
 *       <button onClick={handleClick}>点击追踪</button>
 *       {user && <p>当前用户: {user.userId}</p>}
 *     </div>
 *   );
 * }
 * ```
 */
export const usePostHogRedux = () => {
  const dispatch = useDispatch();

  // Selectors
  const posthog = useSelector(selectPostHog);
  const isInitialized = useSelector(selectIsInitialized);
  const user = useSelector(selectUser);
  const featureFlags = useSelector(selectFeatureFlags);
  const stats = useSelector(selectStats);

  // ==================== 追踪事件 ====================

  /**
   * 追踪自定义事件
   * @param {string} eventName - 事件名称（建议使用 constants.js 中的常量）
   * @param {object} properties - 事件属性
   */
  const track = useCallback(
    (eventName, properties = {}) => {
      dispatch(trackEvent({ eventName, properties }));
    },
    [dispatch]
  );

  /**
   * 追踪页面浏览
   * @param {string} pagePath - 页面路径
   * @param {object} properties - 页面属性
   */
  const trackPage = useCallback(
    (pagePath, properties = {}) => {
      trackPageView(pagePath, properties);
    },
    []
  );

  // ==================== 用户管理 ====================

  /**
   * 识别用户（登录后调用）
   * @param {string} userId - 用户 ID
   * @param {object} userProperties - 用户属性
   */
  const identify = useCallback(
    (userId, userProperties = {}) => {
      dispatch(identifyUser({ userId, userProperties }));
    },
    [dispatch]
  );

  /**
   * 重置用户会话（登出时调用）
   */
  const reset = useCallback(() => {
    dispatch(resetUser());
  }, [dispatch]);

  // ==================== 隐私控制 ====================

  /**
   * 用户选择退出追踪
   */
  const optOutTracking = useCallback(() => {
    dispatch(optOut());
  }, [dispatch]);

  /**
   * 用户选择加入追踪
   */
  const optInTracking = useCallback(() => {
    dispatch(optIn());
  }, [dispatch]);

  /**
   * 检查用户是否已退出追踪
   */
  const isOptedOut = selectIsOptedOut();

  // ==================== Feature Flags ====================

  /**
   * 获取特定 Feature Flag 的值
   * @param {string} flagKey - Flag 键名
   * @returns {any} Flag 值
   */
  const getFlag = useCallback(
    (flagKey) => {
      return selectFeatureFlag(flagKey)({ posthog });
    },
    [posthog]
  );

  /**
   * 检查 Feature Flag 是否启用
   * @param {string} flagKey - Flag 键名
   * @returns {boolean}
   */
  const isEnabled = useCallback(
    (flagKey) => {
      const value = getFlag(flagKey);
      return Boolean(value);
    },
    [getFlag]
  );

  // ==================== 离线事件管理 ====================

  /**
   * 刷新缓存的离线事件
   */
  const flushEvents = useCallback(() => {
    dispatch(flushCachedEvents());
  }, [dispatch]);

  // ==================== 返回接口 ====================

  return {
    // 状态
    isInitialized,
    user,
    featureFlags,
    stats,
    posthog, // 完整的 PostHog 状态

    // 追踪方法
    track,
    trackPage,

    // 用户管理
    identify,
    reset,

    // 隐私控制
    optOut: optOutTracking,
    optIn: optInTracking,
    isOptedOut,

    // Feature Flags
    getFlag,
    isEnabled,

    // 离线事件
    flushEvents,
  };
};

// ==================== 便捷 Hooks ====================

/**
 * 仅获取追踪功能的 Hook（性能优化）
 */
export const usePostHogTrack = () => {
  const dispatch = useDispatch();

  const track = useCallback(
    (eventName, properties = {}) => {
      dispatch(trackEvent({ eventName, properties }));
    },
    [dispatch]
  );

  return { track };
};

/**
 * 仅获取 Feature Flags 的 Hook（性能优化）
 */
export const usePostHogFlags = () => {
  const featureFlags = useSelector(selectFeatureFlags);
  const posthog = useSelector(selectPostHog);

  const getFlag = useCallback(
    (flagKey) => {
      return selectFeatureFlag(flagKey)({ posthog });
    },
    [posthog]
  );

  const isEnabled = useCallback(
    (flagKey) => {
      const value = getFlag(flagKey);
      return Boolean(value);
    },
    [getFlag]
  );

  return {
    featureFlags,
    getFlag,
    isEnabled,
  };
};

/**
 * 获取用户信息的 Hook（性能优化）
 */
export const usePostHogUser = () => {
  const user = useSelector(selectUser);
  const dispatch = useDispatch();

  const identify = useCallback(
    (userId, userProperties = {}) => {
      dispatch(identifyUser({ userId, userProperties }));
    },
    [dispatch]
  );

  const reset = useCallback(() => {
    dispatch(resetUser());
  }, [dispatch]);

  return {
    user,
    identify,
    reset,
  };
};

export default usePostHogRedux;