/**
 * Mailgun Email Service
 * This service handles email sending via Mailgun API
 */

import { getMailgunConfig, type MailgunConfig } from './mailgun.config';
import { getAppConfig } from '../config/unified.config';

interface EmailTemplate {
  subject: string;
  html: string;
  text?: string;
}

export class MailgunService {
  private config: MailgunConfig;

  constructor() {
    this.config = getMailgunConfig();

    // Log configuration status on startup
    const status = this.getConfigurationStatus();
    if (status.mode === 'development') {
      console.warn(
        '📧 Mailgun Service: Running in development mode (emails will be logged only)'
      );
      console.warn(
        '💡 To enable real emails, configure Mailgun credentials in .env.local'
      );
    } else {
      console.warn(
        '📧 Mailgun Service: Configured for production with domain:',
        status.domain
      );
    }
  }

  private getVerificationEmailTemplate(verificationUrl: string): EmailTemplate {
    return {
      subject: 'Verify Your Email - Medication Reminder',
      html: `
        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
          <h2 style="color: #4f46e5;">Verify Your Email Address</h2>
          <p>Thank you for signing up for Medication Reminder! Please click the button below to verify your email address:</p>
          <div style="text-align: center; margin: 30px 0;">
            <a href="${verificationUrl}"
              style="background-color: #4f46e5; color: white; padding: 12px 24px; text-decoration: none; border-radius: 6px; display: inline-block;">
              Verify Email Address
            </a>
          </div>
          <p>Or copy and paste this link into your browser:</p>
          <p style="word-break: break-all; color: #6b7280;">${verificationUrl}</p>
          <p style="color: #6b7280; font-size: 14px;">This link will expire in 24 hours.</p>
        </div>
      `,
      text: `
        Verify Your Email - Medication Reminder

        Thank you for signing up! Please verify your email by visiting:
        ${verificationUrl}

        This link will expire in 24 hours.
      `,
    };
  }

  private getPasswordResetEmailTemplate(resetUrl: string): EmailTemplate {
    return {
      subject: 'Reset Your Password - Medication Reminder',
      html: `
        <div style="font-family: Arial, sans-serif; max-width: 600px; margin: 0 auto;">
          <h2 style="color: #4f46e5;">Reset Your Password</h2>
          <p>You requested to reset your password. Click the button below to set a new password:</p>
          <div style="text-align: center; margin: 30px 0;">
            <a href="${resetUrl}"
              style="background-color: #4f46e5; color: white; padding: 12px 24px; text-decoration: none; border-radius: 6px; display: inline-block;">
              Reset Password
            </a>
          </div>
          <p>Or copy and paste this link into your browser:</p>
          <p style="word-break: break-all; color: #6b7280;">${resetUrl}</p>
          <p style="color: #6b7280; font-size: 14px;">This link will expire in 1 hour. If you didn't request this, please ignore this email.</p>
        </div>
      `,
      text: `
        Reset Your Password - Medication Reminder

        You requested to reset your password. Visit this link to set a new password:
        ${resetUrl}

        This link will expire in 1 hour. If you didn't request this, please ignore this email.
      `,
    };
  }

  async sendEmail(to: string, template: EmailTemplate): Promise<boolean> {
    try {
      // Production Mailgun API call
      const formData = new FormData();
      formData.append(
        'from',
        `${this.config.fromName} <${this.config.fromEmail}>`
      );
      formData.append('to', to);
      formData.append('subject', template.subject);
      formData.append('html', template.html);
      if (template.text) {
        formData.append('text', template.text);
      }

      const response = await fetch(
        `${this.config.baseUrl}/${this.config.domain}/messages`,
        {
          method: 'POST',
          headers: {
            Authorization: `Basic ${btoa(`api:${this.config.apiKey}`)}`,
          },
          body: formData,
        }
      );

      if (!response.ok) {
        const errorText = await response.text();
        throw new Error(`Mailgun API error: ${response.status} - ${errorText}`);
      }

      const result = await response.json();
      console.warn('📧 Email sent successfully via Mailgun:', {
        to,
        subject: template.subject,
        messageId: result.id,
      });

      return true;
    } catch (error: unknown) {
      console.error('Email sending failed:', error);
      return false;
    }
  }

  async sendVerificationEmail(email: string, token: string): Promise<boolean> {
    const verificationUrl = `${getAppConfig().baseUrl}/verify-email?token=${token}`;
    const template = this.getVerificationEmailTemplate(verificationUrl);
    return this.sendEmail(email, template);
  }

  async sendPasswordResetEmail(email: string, token: string): Promise<boolean> {
    const resetUrl = `${getAppConfig().baseUrl}/reset-password?token=${token}`;
    const template = this.getPasswordResetEmailTemplate(resetUrl);
    return this.sendEmail(email, template);
  }

  // Get configuration status for debugging
  getConfigurationStatus(): {
    configured: boolean;
    mode: 'development' | 'production';
    domain: string;
    fromEmail: string;
  } {
    const configured =
      !!this.config.apiKey &&
      !!this.config.domain &&
      !!this.config.baseUrl &&
      !!this.config.fromEmail &&
      !!this.config.fromName;
    const mode: 'development' | 'production' = configured
      ? 'production'
      : 'development';
    return {
      configured,
      mode,
      domain: this.config.domain,
      fromEmail: this.config.fromEmail,
    };
  }
}

export const mailgunService = new MailgunService();