import React, { createContext, useContext, useState, useEffect, ReactNode } from 'react';
import { User, UserRole } from '../types';

interface AuthContextType {
  user: User | null;
  login: (email: string, password: string) => Promise<boolean>;
  logout: () => void;
  isAuthenticated: boolean;
}

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;
};

// Mock users database - in production, this would be in a real database
const MOCK_USERS = [
  {
    id: '1',
    email: 'admin@company.com',
    password: 'admin123',
    name: 'Admin User',
    role: 'admin' as UserRole,
  },
  {
    id: '2',
    email: 'hr@company.com',
    password: 'hr123',
    name: 'HR Manager',
    role: 'hr' as UserRole,
  },
  {
    id: '3',
    email: 'payroll@company.com',
    password: 'payroll123',
    name: 'Payroll Admin',
    role: 'payroll' as UserRole,
  },
  {
    id: '4',
    email: 'manager@company.com',
    password: 'manager123',
    name: 'Team Manager',
    role: 'manager' as UserRole,
  },
  {
    id: '5',
    email: 'employee@company.com',
    password: 'employee123',
    name: 'John Doe',
    role: 'employee' as UserRole,
  },
];

export const AuthProvider: React.FC<{ children: ReactNode }> = ({ children }) => {
  const [user, setUser] = useState<User | null>(null);

  useEffect(() => {
    // Check for stored session
    const storedUser = localStorage.getItem('user');
    if (storedUser) {
      try {
        setUser(JSON.parse(storedUser));
      } catch (e) {
        localStorage.removeItem('user');
      }
    }
  }, []);

  const login = async (email: string, password: string): Promise<boolean> => {
    // Simulate API call delay
    await new Promise(resolve => setTimeout(resolve, 500));
    
    const foundUser = MOCK_USERS.find(
      u => u.email === email && u.password === password
    );

    if (foundUser) {
      const userData: User = {
        id: foundUser.id,
        name: foundUser.name,
        email: foundUser.email,
        role: foundUser.role,
      };
      setUser(userData);
      localStorage.setItem('user', JSON.stringify(userData));
      return true;
    }
    return false;
  };

  const logout = () => {
    setUser(null);
    localStorage.removeItem('user');
  };

  return (
    <AuthContext.Provider value={{ user, login, logout, isAuthenticated: !!user }}>
      {children}
    </AuthContext.Provider>
  );
};