import { Injectable, Logger } from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import {
  MailRecipient,
  NotificationMailer,
} from '@task-stream/api/tracker/application';
import { NotificationReadModel } from '@task-stream/api/tracker/domain';
import { createTransport, Transporter } from 'nodemailer';

/**
 * E-mail copies through SMTP_URL (`smtps://user:pass@smtp.example.org`).
 * Without it nothing is sent and nobody is offered e-mail.
 */
@Injectable()
export class SmtpNotificationMailer extends NotificationMailer {
  private readonly logger = new Logger(SmtpNotificationMailer.name);
  private readonly transport: Transporter | null;
  private readonly from: string;
  private readonly webUrl: string;

  constructor(config: ConfigService) {
    super();
    const url = config.get<string>('SMTP_URL');
    this.transport = url ? createTransport(url) : null;
    this.from =
      config.get<string>('MAIL_FROM') || 'TaskStream <no-reply@pireon.dev>';
    this.webUrl = (config.get<string>('WEB_URL') || '').replace(/\/+$/, '');
    if (this.transport) this.logger.log('E-mail notifications enabled');
  }

  get enabled(): boolean {
    return this.transport !== null;
  }

  async send(
    to: MailRecipient,
    notification: NotificationReadModel,
  ): Promise<void> {
    if (!this.transport) return;
    const link = this.linkTo(notification);
    const subject = notification.issueKey
      ? `[${notification.issueKey}] ${notification.summary}`
      : `[${notification.projectKey}] ${notification.summary}`;
    await this.transport.sendMail({
      from: this.from,
      to: { name: to.name, address: to.email },
      subject: subject.length > 160 ? `${subject.slice(0, 159)}…` : subject,
      text: [
        `Hola ${to.name}:`,
        '',
        notification.summary,
        ...(link ? ['', link] : []),
        '',
        '— TaskStream. Puedes dejar de recibir estos correos desde las notificaciones de la app.',
      ].join('\n'),
    });
  }

  private linkTo(notification: NotificationReadModel): string | null {
    if (!this.webUrl) return null;
    const project = encodeURIComponent(notification.projectKey);
    return notification.issueKey
      ? `${this.webUrl}/p/${project}/issues/${encodeURIComponent(notification.issueKey)}`
      : `${this.webUrl}/p/${project}`;
  }
}