import { Injectable, Logger } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';

import {
  getVerificationEmailTemplate,
  getPasswordResetTemplate,
  getWelcomeEmailTemplate,
} from './templates';

export interface EmailOptions {
  to: string;
  subject: string;
  html: string;
  text?: string;
  cc?: string[];
  bcc?: string[];
  replyTo?: string;
}

@Injectable()
export class EmailService {
  private readonly logger = new Logger(EmailService.name);
  private readonly endpoint: string;

  constructor(private readonly configService: ConfigService) {
    this.endpoint =
      this.configService.get<string>('EMAIL_API_URL') ||
      'https://email.routes.hiffi.com/superlabs/v1/send';
    this.logger.log(`Email service initialized → ${this.endpoint}`);
  }

  async sendEmail(options: EmailOptions): Promise<boolean> {
    const payload: Record<string, any> = {
      to: [options.to],
      subject: options.subject,
      html: options.html,
    };

    if (options.text) payload.text = options.text;
    if (options.cc && options.cc.length > 0) payload.cc = options.cc;
    if (options.bcc && options.bcc.length > 0) payload.bcc = options.bcc;
    if (options.replyTo) payload.reply_to = options.replyTo;

    try {
      const res = await fetch(this.endpoint, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(payload),
      });

      const data = await res.json().catch(() => null);

      if (!res.ok || !data?.ok) {
        const errMsg = data?.error || `HTTP ${res.status}`;
        this.logger.error(`Failed to send email to ${options.to}: ${errMsg}`);
        return false;
      }

      this.logger.log(`Email sent successfully to ${options.to}`);
      return true;
    } catch (error: any) {
      this.logger.error(`Email API request failed for ${options.to}: ${error.message}`);
      return false;
    }
  }

  // ==========================================
  // EMAIL VERIFICATION
  // ==========================================
  async sendVerificationEmail(email: string, token: string, name?: string): Promise<boolean> {
    const frontendUrl = this.configService.get<string>('FRONTEND_URL') || 'http://localhost:3000';
    const verificationUrl = `${frontendUrl}/verify-email?token=${token}`;

    const html = getVerificationEmailTemplate({ verificationUrl, name });
    const text = `Welcome to RE-QuestN! Please verify your email by clicking this link: ${verificationUrl}`;

    return this.sendEmail({
      to: email,
      subject: 'Verify Your Email - RE-QuestN',
      html,
      text,
    });
  }

  // ==========================================
  // PASSWORD RESET
  // ==========================================
  async sendPasswordResetEmail(email: string, resetUrl: string): Promise<boolean> {
    const html = getPasswordResetTemplate({ resetUrl });
    const text = `Reset your password by clicking this link: ${resetUrl}. This link will expire in 1 hour.`;

    return this.sendEmail({
      to: email,
      subject: 'Reset Your Password - RE-QuestN',
      html,
      text,
    });
  }

  // ==========================================
  // WELCOME EMAIL
  // ==========================================
  async sendWelcomeEmail(email: string, name?: string): Promise<boolean> {
    const frontendUrl = this.configService.get<string>('FRONTEND_URL') || 'http://localhost:3000';
    const html = getWelcomeEmailTemplate({ name, frontendUrl });
    const text = `Welcome to RE-QuestN, ${name || 'User'}! Your real estate journey starts now.`;

    return this.sendEmail({
      to: email,
      subject: 'Welcome to RE-QuestN!',
      html,
      text,
    });
  }
}