import mailchimp = require('@mailchimp/mailchimp_transactional');
import fetch from 'node-fetch';
import { emailConfig } from '../../config/email';
import { PendingEmail } from '../../types';

// Email storage
export const pendingEmails = new Map<string, PendingEmail>();

export class EmailService {
  static async sendTransactionalEmail(to: string, templateName: string, subject: string, templateVariables: Record<string, string>): Promise<{ success: boolean; result?: any; error?: string }> {
    try {
      const mailchimpClient = mailchimp(emailConfig.MAILCHIMP_API_KEY!);

      const message = {
        template_name: templateName,
        template_content: [],
        message: {
          global_merge_vars: this.buildVariables(templateVariables),
          from_email: emailConfig.FROM_EMAIL,
          from_name: emailConfig.FROM_NAME,
          subject: subject,
          to: [
            {
              email: to,
              type: 'to'
            }
          ]
        }
      };

      const result = await mailchimpClient.messages.sendTemplate(message);
      return { success: true, result };
    } catch (error) {
      console.error('Erreur envoi email:', error);
      return { success: false, error: 'Échec de l\'envoi de l\'email' };
    }
  }

  static buildVariables(templateVariables: Record<string, string>): Array<{ name: string; content: string }> {
    return Object.keys(templateVariables).map(key => ({
      name: key,
      content: templateVariables[key]
    }));
  }

  // Add to Mailchimp diffusion list
  static async addToMailchimpList(email: string): Promise<{ success: boolean; data?: any; error?: string }> {
    try {
      const url = `https://us17.api.mailchimp.com/3.0/lists/${emailConfig.MAILCHIMP_LIST_ID}/members`;

      const response = await fetch(url, {
        method: 'POST',
        headers: {
          'Authorization': `apikey ${emailConfig.MAILCHIMP_KEY}`,
          'Content-Type': 'application/json'
        },
        body: JSON.stringify({
          email_address: email,
          status: 'subscribed'
        })
      });

      if (!response.ok) {
        throw new Error(`HTTP error! status: ${response.status}`);
      }

      const data = await response.json();
      return { success: true, data };
    } catch (error) {
      console.error('Erreur ajout à la liste:', error);
      return { success: false, error: 'Échec de l\'ajout à la liste Mailchimp' };
    }
  }

  static async retryFailedEmails(): Promise<void> {
    for (const [emailId, emailData] of pendingEmails) {
      if (emailData.attempts >= 10) {
        pendingEmails.delete(emailId);
        continue;
      }

      const nextRetryDate = new Date(emailData.lastAttempt);
      nextRetryDate.setMinutes(nextRetryDate.getMinutes() + Math.pow(emailData.attempts, 2));

      if (Date.now() >= nextRetryDate.getTime()) {
        try {
          const result = await this.sendTransactionalEmail(
            emailData.to,
            emailData.templateName,
            emailData.subject,
            emailData.templateVariables
          );

          if (result.success) {
            pendingEmails.delete(emailId);
          } else {
            emailData.attempts += 1;
            emailData.lastAttempt = Date.now();
          }
        } catch (error) {
          emailData.attempts += 1;
          emailData.lastAttempt = Date.now();
        }
      }
    }
  }
}