"use client";

// ============================================================================
// Auth Provider
// ============================================================================

import React, {
  createContext,
  useContext,
  useState,
  useEffect,
  useCallback,
} from "react";
import { useRouter } from "next/navigation";
import { authApi } from "@/lib/api";
import { USE_MOCKS, STORAGE_KEYS } from "@/lib/utils/constants";
import type { User } from "@/lib/types/api";

interface AuthContextType {
  user: User | null;
  loading: boolean;
  error: string | null;
  login: (token: string) => Promise<void>;
  loginMock: () => Promise<void>;
  logout: () => void;
  refreshUser: () => Promise<void>;
}

const AuthContext = createContext<AuthContextType | undefined>(undefined);

export const useAuth = () => {
  const context = useContext(AuthContext);
  if (!context) {
    throw new Error("useAuth must be used within AuthProvider");
  }
  return context;
};

interface AuthProviderProps {
  children: React.ReactNode;
}

export const AuthProvider: React.FC<AuthProviderProps> = ({ children }) => {
  const [user, setUser] = useState<User | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const router = useRouter();

  // Initialize auth state on mount
  useEffect(() => {
    const initAuth = async () => {
      try {
        if (!authApi.isAuthenticated()) {
          setLoading(false);
          return;
        }

        // Try to get user from storage first
        const storedUser = authApi.getUserFromStorage();
        if (storedUser) {
          setUser(storedUser);
          setLoading(false);
          return;
        }

        // If no stored user, fetch from API
        const userData = await authApi.me();
        setUser(userData);
      } catch (err: any) {
        console.error("Auth initialization error:", err);
        // Clear invalid tokens
        authApi.logout();
      } finally {
        setLoading(false);
      }
    };

    initAuth();
  }, []);

  // Login with token from Telegram bot
  const login = useCallback(
    async (token: string) => {
      try {
        setLoading(true);
        setError(null);

        // Exchange token for JWT
        await authApi.complete(token);

        // Fetch user data with the JWT token
        if (!USE_MOCKS) {
          const userData = await authApi.me();
          setUser(userData);
          
          // Save user to storage
          if (typeof window !== "undefined") {
            localStorage.setItem(STORAGE_KEYS.USER, JSON.stringify(userData));
          }
        } else {
          // For mocks, get user from mock data
          const userData = authApi.getUserFromStorage();
          setUser(userData);
        }

        // Redirect to home
        router.push("/");
      } catch (err: any) {
        const errorMessage = err?.detail || err?.error?.message || "Ошибка авторизации";
        setError(errorMessage);
        throw err;
      } finally {
        setLoading(false);
      }
    },
    [router]
  );

  // Mock login (for development without backend)
  const loginMock = useCallback(async () => {
    if (!USE_MOCKS) {
      throw new Error("Mock login is only available in mock mode");
    }

    try {
      setLoading(true);
      setError(null);

      // Use mock token
      await login("mock_token_123");
    } catch (err: any) {
      const errorMessage = err?.error?.message || "Ошибка мок-авторизации";
      setError(errorMessage);
      throw err;
    } finally {
      setLoading(false);
    }
  }, [login]);

  // Logout
  const logout = useCallback(() => {
    authApi.logout();
    setUser(null);
    router.push("/login");
  }, [router]);

  // Refresh user data
  const refreshUser = useCallback(async () => {
    try {
      const userData = await authApi.me();
      setUser(userData);
    } catch (err) {
      console.error("Error refreshing user:", err);
      throw err;
    }
  }, []);

  const value: AuthContextType = {
    user,
    loading,
    error,
    login,
    loginMock,
    logout,
    refreshUser,
  };

  return <AuthContext.Provider value={value}>{children}</AuthContext.Provider>;
};