// src/hooks/useAuth.js
import { useState, useContext, createContext, useCallback, useEffect } from 'react';
import { useNavigate } from 'react-router-dom';
import { login as apiLogin, logout as apiLogout, refreshToken as apiRefreshToken } from '../services/auth';
import { useLocalStorage } from './useLocalStorage';

const AuthContext = createContext();

export const AuthProvider = ({ children }) => {
  const [user, setUser] = useState(null);
  const [authTokens, setAuthTokens] = useLocalStorage('authTokens', null);
  const [userType, setUserType] = useLocalStorage('userType', 'Enthusiast');
  const [isRefreshing, setIsRefreshing] = useState(false);
  const navigate = useNavigate();

  const parseJwt = (token) => {
    try {
      return JSON.parse(atob(token.split('.')[1]));
    } catch (e) {
      return null;
    }
  };

  const login = useCallback(async (username, password) => {
    try {
      const { access_token, refresh_token } = await apiLogin(username, password);
      setAuthTokens({
        access: access_token,
        refresh: refresh_token
      });
      setUser(username);
      return { success: true };
    } catch (error) {
      return { success: false, error: error.message };
    }
  }, [setAuthTokens]);

  const logout = useCallback(async () => {
    try {
      if (authTokens?.access) {
        await apiLogout(authTokens.access);
      }
      setAuthTokens(null);
      setUser(null);
      navigate('/login');
    } catch (error) {
      console.error('Logout error:', error);
      // Even if logout API fails, clear local tokens
      setAuthTokens(null);
      setUser(null);
    }
  }, [authTokens, setAuthTokens, navigate]);

  const refreshToken = useCallback(async () => {
    if (!authTokens?.refresh || isRefreshing) return;
    
    setIsRefreshing(true);
    try {
      const { access_token, refresh_token } = await apiRefreshToken({
        refresh_token: authTokens.refresh
      });
      setAuthTokens({
        access: access_token,
        refresh: refresh_token
      });
      return access_token;
    } catch (error) {
      console.error('Token refresh failed:', error);
      logout(); // Full logout if refresh fails
      throw error;
    } finally {
      setIsRefreshing(false);
    }
  }, [authTokens, isRefreshing, setAuthTokens, logout]);

  // Auto-refresh token when it's about to expire
  useEffect(() => {
    const refreshInterval = setInterval(() => {
      if (authTokens?.access) {
        const { exp } = parseJwt(authTokens.access);
        // Refresh token if it expires in less than 5 minutes
        if (exp * 1000 - Date.now() < 300000) {
          refreshToken();
        }
      }
    }, 60000); // Check every minute

    return () => clearInterval(refreshInterval);
  }, [authTokens, refreshToken]);

  const getAccessToken = useCallback(async () => {
    if (!authTokens?.access) return null;
    
    const { exp } = parseJwt(authTokens.access);
    if (exp * 1000 - Date.now() < 30000) { // If expires in <30 seconds
      return await refreshToken();
    }
    return authTokens.access;
  }, [authTokens, refreshToken]);

  const value = {
    user,
    authTokens,
    userType,
    setUserType,
    isAuthenticated: !!authTokens?.access,
    isRefreshing,
    login,
    logout,
    refreshToken,
    getAccessToken
  };

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

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