import { Logger } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import * as nodemailer from 'nodemailer';
import { MailMessage, MailProvider } from './mail-provider';

/// SMTP transport (MAIL_PROVIDER=smtp). Delivery failures are logged and
/// swallowed — callers treat email as best-effort.
export class SmtpMailProvider implements MailProvider {
  private readonly logger = new Logger('MailProvider');
  private readonly from: string;
  private readonly transport: nodemailer.Transporter;

  constructor(config: ConfigService) {
    this.from = config.getOrThrow<string>('MAIL_FROM');
    this.transport = nodemailer.createTransport({
      host: config.getOrThrow<string>('SMTP_HOST'),
      port: Number(config.get<string>('SMTP_PORT') ?? 587),
      secure: config.get<string>('SMTP_SECURE') === 'true',
      auth: config.get<string>('SMTP_USER')
        ? {
            user: config.getOrThrow<string>('SMTP_USER'),
            pass: config.getOrThrow<string>('SMTP_PASS'),
          }
        : undefined,
    });
  }

  async send(message: MailMessage): Promise<boolean> {
    try {
      await this.transport.sendMail({
        from: this.from,
        to: message.to,
        subject: message.subject,
        text: message.text,
        html: message.html,
      });
      return true;
    } catch (err) {
      this.logger.error(
        `Failed to send "${message.subject}" to ${message.to}: ${(err as Error).message}`,
      );
      return false;
    }
  }
}