/**
 * 用户相关 React Hooks
 */

import { useCallback, useEffect, useState } from 'react';
import { useUserManagerStore } from './userStore';
import { userManager } from './UserManager';
import type { UserDTO } from '../../types/dto';

// ==================== useCurrentUser ====================

export interface UseCurrentUserResult {
  user: UserDTO | null;
  isLoading: boolean;
  refresh: () => Promise<UserDTO | null>;
}

/**
 * 获取当前用户 hook
 * 自动加载，支持缓存和后台刷新
 */
export function useCurrentUser(): UseCurrentUserResult {
  const user = useUserManagerStore(state => state.currentUser);
  const isLoading = useUserManagerStore(state => state.isLoadingCurrentUser);
  const [hasFetched, setHasFetched] = useState(false);

  useEffect(() => {
    if (!hasFetched) {
      setHasFetched(true);
      useUserManagerStore.getState().setLoadingCurrentUser(true);
      userManager.getCurrentUser().finally(() => {
        useUserManagerStore.getState().setLoadingCurrentUser(false);
      });
    }
  }, [hasFetched]);

  const refresh = useCallback(async () => {
    useUserManagerStore.getState().setLoadingCurrentUser(true);
    try {
      return await userManager.getCurrentUser(true);
    } finally {
      useUserManagerStore.getState().setLoadingCurrentUser(false);
    }
  }, []);

  return { user, isLoading, refresh };
}

// ==================== useUser ====================

export interface UseUserResult {
  user: UserDTO | null;
  isLoading: boolean;
  refresh: () => Promise<UserDTO | null>;
}

/**
 * 根据 ID 获取用户 hook
 * 自动加载，支持缓存和后台刷新
 */
export function useUser(userId: string | undefined | null): UseUserResult {
  const user = useUserManagerStore(state =>
    userId ? (state.usersMap.get(userId)?.data ?? null) : null
  );
  const isLoading = useUserManagerStore(state =>
    userId ? state.loadingUserIds.has(userId) : false
  );
  const [hasFetched, setHasFetched] = useState(false);

  useEffect(() => {
    if (!userId) return;
    if (!hasFetched) {
      setHasFetched(true);
      useUserManagerStore.getState().setLoadingUser(userId, true);
      userManager.getUserById(userId).finally(() => {
        useUserManagerStore.getState().setLoadingUser(userId, false);
      });
    }
  }, [userId, hasFetched]);

  const refresh = useCallback(async () => {
    if (!userId) return null;
    useUserManagerStore.getState().setLoadingUser(userId, true);
    try {
      return await userManager.getUserById(userId, true);
    } finally {
      useUserManagerStore.getState().setLoadingUser(userId, false);
    }
  }, [userId]);

  return { user, isLoading, refresh };
}

// ==================== useUsers ====================

export interface UseUsersResult {
  getUser: (id: string) => UserDTO | null;
  refreshUser: (id: string) => Promise<UserDTO | null>;
}

/**
 * 多用户获�?hook
 * 用于批量获取多个用户信息
 */
export function useUsers(userIds: string[]): UseUsersResult {
  const usersMap = useUserManagerStore(state => state.usersMap);
  const loadingUserIds = useUserManagerStore(state => state.loadingUserIds);
  const [fetchedIds, setFetchedIds] = useState<Set<string>>(new Set());

  useEffect(() => {
    userIds.forEach(id => {
      if (!fetchedIds.has(id) && !loadingUserIds.has(id)) {
        setFetchedIds(prev => new Set(prev).add(id));
        useUserManagerStore.getState().setLoadingUser(id, true);
        userManager.getUserById(id).finally(() => {
          useUserManagerStore.getState().setLoadingUser(id, false);
        });
      }
    });
  }, [userIds, fetchedIds, loadingUserIds]);

  const getUser = useCallback((id: string) => {
    return usersMap.get(id)?.data ?? null;
  }, [usersMap]);

  const refreshUser = useCallback(async (id: string) => {
    useUserManagerStore.getState().setLoadingUser(id, true);
    try {
      return await userManager.getUserById(id, true);
    } finally {
      useUserManagerStore.getState().setLoadingUser(id, false);
    }
  }, []);

  return { getUser, refreshUser };
}