import React, { createContext, useContext, useEffect, useState } from 'react';
import { UserProfile } from './types';
import { AuthService } from './services/AuthService';

interface AuthContextType {
  user: any | null; // backward compatibility
  profile: UserProfile | null;
  loading: boolean;
  login: (id: string, pin: string) => Promise<void>;
  logout: () => Promise<void>;
  registerStudent: (data: any) => Promise<UserProfile>;
  registerTeacher: (data: any) => Promise<UserProfile>;
}

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

export function AuthProvider({ children }: { children: React.ReactNode }) {
  const [profile, setProfile] = useState<UserProfile | null>(() => {
    const saved = localStorage.getItem('local_user_profile');
    try {
      return saved ? JSON.parse(saved) : null;
    } catch {
      return null;
    }
  });
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    async function checkSession() {
      try {
        const token = localStorage.getItem('local_user_token');
        const headers: Record<string, string> = {};
        if (token) {
          headers['Authorization'] = `Bearer ${token}`;
        }
        const response = await fetch('/api/auth/me', { headers });
        if (response.ok) {
          const profileData = await response.json();
          setProfile(profileData);
          localStorage.setItem('local_user_profile', JSON.stringify(profileData));
        } else {
          setProfile(null);
          localStorage.removeItem('local_user_profile');
          localStorage.removeItem('local_user_token');
        }
      } catch (err) {
        console.warn("Failed to retrieve user session during refresh:", err);
      } finally {
        setLoading(false);
      }
    }
    checkSession();
  }, []);

  const login = async (idOrEmail: string, pinOrPassword: string) => {
    const isEmail = idOrEmail.includes('@');
    const { user: profileData, customToken } = isEmail
      ? await AuthService.loginWithEmail(idOrEmail, pinOrPassword)
      : await AuthService.login(idOrEmail, pinOrPassword);
    setProfile(profileData);
    localStorage.setItem('local_user_profile', JSON.stringify(profileData));
    if (customToken) {
      localStorage.setItem('local_user_token', customToken);
    }
  };

  const logout = async () => {
    const token = localStorage.getItem('local_user_token');
    const headers: Record<string, string> = {};
    if (token) {
      headers['Authorization'] = `Bearer ${token}`;
    }
    await fetch('/api/auth/logout', { method: 'POST', headers }).catch(() => {});
    setProfile(null);
    localStorage.removeItem('local_user_profile');
    localStorage.removeItem('local_user_token');
  };

  const registerStudent = async (data: any) => {
    const { user: profileData, customToken } = data.email && data.password
      ? await AuthService.registerStudentWithEmail(data)
      : await AuthService.registerStudent(data);
    setProfile(profileData);
    localStorage.setItem('local_user_profile', JSON.stringify(profileData));
    if (customToken) {
      localStorage.setItem('local_user_token', customToken);
    }
    return profileData;
  };

  const registerTeacher = async (data: any) => {
    const { user: profileData, customToken } = data.email && data.password
      ? await AuthService.registerTeacherWithEmail(data)
      : await AuthService.registerTeacher(data);
    setProfile(profileData);
    localStorage.setItem('local_user_profile', JSON.stringify(profileData));
    if (customToken) {
      localStorage.setItem('local_user_token', customToken);
    }
    return profileData;
  };

  return (
    <AuthContext.Provider value={{ user: profile, profile, loading, login, logout, registerStudent, registerTeacher }}>
      {children}
    </AuthContext.Provider>
  );
}

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