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

@Injectable()
export class MailService {
  private readonly logger = new Logger(MailService.name);
  private transporter: nodemailer.Transporter;

  constructor(private readonly configService: ConfigService) {
    this.transporter = nodemailer.createTransport({
      host: this.configService.get<string>('SMTP_HOST', ''),
      port: this.configService.get<number>('SMTP_PORT', 587),
      secure: this.configService.get<string>('SMTP_SECURE', 'false') === 'true',
      auth: {
        user: this.configService.get<string>('SMTP_USER', ''),
        pass: this.configService.get<string>('SMTP_PASS', ''),
      },
    });
  }

  async sendMail(options: {
    to: string;
    subject: string;
    body: string;
    html?: string;
    attachments?: { filename: string; content: Buffer }[];
    smtpOverride?: {
      host: string;
      port: number;
      secure: boolean;
      user: string;
      pass: string;
      from: string;
    };
  }): Promise<void> {
    let transporter = this.transporter;
    const globalFromEmail = this.configService.get<string>(
      'SMTP_FROM',
      'paperless@localhost',
    );
    const globalFromName = this.configService.get<string>('SMTP_FROM_NAME', '');
    let from = globalFromName
      ? `"${globalFromName}" <${globalFromEmail}>`
      : globalFromEmail;

    if (options.smtpOverride) {
      const o = options.smtpOverride;
      transporter = nodemailer.createTransport({
        host: o.host,
        port: o.port,
        secure: o.secure,
        auth: { user: o.user, pass: o.pass },
      });
      from = o.from || from;
    } else {
      this.logger.debug(
        `SMTP config — host: ${this.configService.get('SMTP_HOST')} port: ${this.configService.get('SMTP_PORT')} secure: ${this.configService.get('SMTP_SECURE')} user: ${this.configService.get('SMTP_USER')} from: ${from}`,
      );
    }

    const info = await transporter.sendMail({
      from,
      to: options.to,
      subject: options.subject,
      text: options.body,
      html: options.html,
      attachments: options.attachments?.map((a) => ({
        filename: a.filename,
        content: a.content,
      })),
    });

    this.logger.log(
      `Mail gesendet an ${options.to}: "${options.subject}" — messageId: ${info.messageId} accepted: ${JSON.stringify(info.accepted)} rejected: ${JSON.stringify(info.rejected)} response: ${info.response}`,
    );
  }
}