import { User, UserRole, UserProfile } from '../types';
import { deleteAllUserData } from './storage';

const USERS_KEY = 'gymflow_users';

interface StoredUser extends User {
  password: string; // In a real app, this would be a hash
}

const ADMIN_EMAIL = process.env.ADMIN_EMAIL || 'admin@gymflow.ai';
const ADMIN_PASSWORD = process.env.ADMIN_PASSWORD || 'admin123';

export const getUsers = (): StoredUser[] => {
  try {
    const data = localStorage.getItem(USERS_KEY);
    return data ? JSON.parse(data) : [];
  } catch {
    return [];
  }
};

const saveUsers = (users: StoredUser[]) => {
  localStorage.setItem(USERS_KEY, JSON.stringify(users));
};

export const login = (email: string, password: string): { success: boolean; user?: User; error?: string } => {
  // 1. Check Admin
  if (email === ADMIN_EMAIL && password === ADMIN_PASSWORD) {
    return {
      success: true,
      user: {
        id: 'admin_001',
        email: ADMIN_EMAIL,
        role: 'ADMIN',
        isFirstLogin: false,
        profile: { weight: 80 }
      }
    };
  }

  // 2. Check Users
  const users = getUsers();
  const found = users.find(u => u.email.toLowerCase() === email.toLowerCase());

  if (found && found.password === password) {
    if (found.isBlocked) {
        return { success: false, error: 'Account is blocked' };
    }
    // Return user without password field
    const { password, ...userSafe } = found;
    return { success: true, user: userSafe };
  }

  return { success: false, error: 'Invalid credentials' };
};

export const createUser = (email: string, password: string): { success: boolean; error?: string } => {
  const users = getUsers();
  if (users.find(u => u.email.toLowerCase() === email.toLowerCase())) {
    return { success: false, error: 'User already exists' };
  }

  const newUser: StoredUser = {
    id: crypto.randomUUID(),
    email,
    password,
    role: 'USER',
    isFirstLogin: true,
    profile: { weight: 70 }
  };

  users.push(newUser);
  saveUsers(users);
  return { success: true };
};

export const deleteUser = (userId: string) => {
    let users = getUsers();
    users = users.filter(u => u.id !== userId);
    saveUsers(users);
    deleteAllUserData(userId);
};

export const toggleBlockUser = (userId: string, block: boolean) => {
    const users = getUsers();
    const u = users.find(u => u.id === userId);
    if (u) {
        u.isBlocked = block;
        saveUsers(users);
    }
};

export const adminResetPassword = (userId: string, newPass: string) => {
    const users = getUsers();
    const u = users.find(u => u.id === userId);
    if (u) {
        u.password = newPass;
        u.isFirstLogin = true; // Force them to change it
        saveUsers(users);
    }
};

export const updateUserProfile = (userId: string, profile: Partial<UserProfile>) => {
  const users = getUsers();
  const idx = users.findIndex(u => u.id === userId);
  if (idx >= 0) {
    users[idx].profile = { ...users[idx].profile, ...profile };
    saveUsers(users);
  }
};

export const changePassword = (userId: string, newPassword: string) => {
  const users = getUsers();
  const idx = users.findIndex(u => u.id === userId);
  if (idx >= 0) {
    users[idx].password = newPassword;
    users[idx].isFirstLogin = false;
    saveUsers(users);
  }
};

export const getCurrentUserProfile = (userId: string): UserProfile | undefined => {
    if (userId === 'admin_001') return { weight: 80 }; // Mock admin profile
    const users = getUsers();
    return users.find(u => u.id === userId)?.profile;
}