const nodemailer = require('nodemailer');
const handlebars = require('handlebars');
const logger = require('../config/logger');
const { Settings } = require('../models');

class MailService {
  constructor() {
    this.transporter = null;
  }

  async initializeTransporter() {
    try {
      // Get Gmail settings from database
      const gmailUser = await Settings.findOne({ where: { key: 'gmail_user' } });
      const gmailPassword = await Settings.findOne({ where: { key: 'gmail_password' } });
      const gmailFromName = await Settings.findOne({ where: { key: 'gmail_from_name' } });

      // Fallback to env variables
      const user = gmailUser?.value || process.env.GMAIL_USER;
      const pass = gmailPassword?.value || process.env.GMAIL_APP_PASSWORD;
      const fromName = gmailFromName?.value || process.env.GMAIL_FROM_NAME || 'Güvenlik Ekibi';

      if (!user || !pass) {
        throw new Error('Gmail credentials not configured');
      }

      this.transporter = nodemailer.createTransport({
        service: 'gmail',
        auth: {
          user,
          pass,
        },
      });

      this.fromAddress = `"${fromName}" <${user}>`;

      // Verify transporter
      await this.transporter.verify();
      logger.info('Mail service initialized successfully');

      return true;
    } catch (error) {
      logger.error('Failed to initialize mail service:', error);
      throw error;
    }
  }

  async sendMail(to, subject, htmlBody) {
    try {
      if (!this.transporter) {
        await this.initializeTransporter();
      }

      const mailOptions = {
        from: this.fromAddress,
        to,
        subject,
        html: htmlBody,
      };

      const info = await this.transporter.sendMail(mailOptions);

      logger.info(`Mail sent to ${to}: ${info.messageId}`);

      return {
        success: true,
        messageId: info.messageId,
      };
    } catch (error) {
      logger.error(`Failed to send mail to ${to}:`, error);
      throw error;
    }
  }

  renderTemplate(templateHtml, data) {
    try {
      const template = handlebars.compile(templateHtml);
      return template(data);
    } catch (error) {
      logger.error('Failed to render template:', error);
      throw error;
    }
  }

  async testConnection() {
    try {
      await this.initializeTransporter();
      
      // Send actual test email
      const testEmail = await this.sendMail(
        this.transporter.options.auth.user, // Send to self
        'Test Mail - Oltalama Paneli',
        '<h2>✅ Test Başarılı!</h2><p>Gmail ayarlarınız doğru yapılandırılmış ve mail gönderimi çalışıyor.</p><p><strong>Sistem:</strong> Oltalama Test Yönetim Paneli</p>'
      );
      
      return { 
        success: true, 
        message: `Test maili başarıyla gönderildi! (${testEmail.messageId})` 
      };
    } catch (error) {
      return { success: false, error: error.message };
    }
  }
}

module.exports = new MailService();