import { v4 as uuidv4 } from 'uuid';
import { EmailVerificationToken, AuthenticatedUser } from './auth.types';
import { mailgunService } from '../mailgun.service';
import { AccountStatus } from './auth.constants';
import { databaseService } from '../database';

const TOKEN_EXPIRY_HOURS = 24;

export class EmailVerificationService {
  async generateVerificationToken(
    user: AuthenticatedUser
  ): Promise<EmailVerificationToken> {
    const token = uuidv4().replace(/-/g, ''); // Generate a random token using UUID
    const expiresAt = new Date();
    expiresAt.setHours(expiresAt.getHours() + TOKEN_EXPIRY_HOURS);

    const verificationToken: EmailVerificationToken = {
      userId: user._id,
      email: user.email || '',
      token,
      expiresAt,
    };

    // Store token in localStorage for demo (in production, save to database)
    const tokens = JSON.parse(
      localStorage.getItem('verification_tokens') || '[]'
    );
    tokens.push(verificationToken);
    localStorage.setItem('verification_tokens', JSON.stringify(tokens));

    // Send verification email via Mailgun
    if (user.email) {
      const emailSent = await mailgunService.sendVerificationEmail(
        user.email,
        token
      );
      if (!emailSent) {
        console.warn('Failed to send verification email');
      }
    }

    return verificationToken;
  }

  async validateVerificationToken(
    token: string
  ): Promise<AuthenticatedUser | null> {
    // Get tokens from localStorage
    const tokens = JSON.parse(
      localStorage.getItem('verification_tokens') || '[]'
    );
    const verificationToken = tokens.find(
      (t: EmailVerificationToken) => t.token === token
    );

    if (!verificationToken) {
      return null;
    }

    // Check if token is expired
    if (new Date() > new Date(verificationToken.expiresAt)) {
      return null;
    }

    // Find the user (in production, this would be a proper database lookup)
    const user = await databaseService.findUserByEmail(verificationToken.email);

    return user as AuthenticatedUser;
  }

  async markEmailVerified(user: AuthenticatedUser): Promise<void> {
    // Update user in database
    const updatedUser = {
      ...user,
      emailVerified: true,
      status: AccountStatus.ACTIVE,
    };

    await databaseService.updateUser(updatedUser);

    // Remove used token
    const tokens = JSON.parse(
      localStorage.getItem('verification_tokens') || '[]'
    );
    const filteredTokens = tokens.filter(
      (t: EmailVerificationToken) => t.userId !== user._id
    );
    localStorage.setItem('verification_tokens', JSON.stringify(filteredTokens));
  }

  async sendPasswordResetEmail(email: string, token: string): Promise<boolean> {
    return mailgunService.sendPasswordResetEmail(email, token);
  }
}