import nodemailer from 'nodemailer';
import { Resend } from 'resend';

const FROM = process.env.MAIL_FROM || 'Dockly-Pfandsystem Demo <demo@dockly.de>';

let transporter = null;
if (process.env.SMTP_HOST && process.env.SMTP_USER && process.env.SMTP_PASS) {
  transporter = nodemailer.createTransport({
    host: process.env.SMTP_HOST,
    port: parseInt(process.env.SMTP_PORT || '587'),
    secure: (process.env.SMTP_SECURE || 'false') === 'true', // 587 = STARTTLS (secure=false)
    auth: {
      user: process.env.SMTP_USER,
      pass: process.env.SMTP_PASS,
    },
  });
  console.log('[mail] SMTP transport aktiv:', process.env.SMTP_HOST);
}

const resend = process.env.RESEND_API_KEY ? new Resend(process.env.RESEND_API_KEY) : null;

async function sendMail({ to, subject, html }) {
  if (transporter) {
    const info = await transporter.sendMail({ from: FROM, to, subject, html });
    console.log('[mail] SMTP sent:', to, 'msgId:', info.messageId);
    return { provider: 'smtp', messageId: info.messageId, accepted: info.accepted, rejected: info.rejected };
  }
  if (resend) {
    const r = await resend.emails.send({ from: FROM, to, subject, html });
    console.log('[mail] Resend sent:', to, 'id:', r.data?.id);
    return { provider: 'resend', id: r.data?.id, error: r.error };
  }
  console.log('[mail-dev] (kein Provider konfiguriert) ->', to, subject);
  return { dev: true };
}

export async function sendDemoInviteMail({ to, name, slug, password, loginUrl, days }) {
  const html = `
    <div style="font-family:system-ui,Segoe UI,Helvetica,Arial,sans-serif;max-width:560px;margin:auto">
      <h2 style="color:#051e23">Willkommen im Dockly-Pfandsystem-Demo</h2>
      <p>Hallo ${name},</p>
      <p>dein <strong>${days}-Tage Demo-Zugang</strong> ist bereit. Du kannst alle Funktionen
         in Ruhe testen und eigene Beispieldaten anlegen.</p>
      <div style="background:#f1f7f8;border:1px solid #b9d2d7;border-radius:8px;padding:16px;margin:16px 0">
        <p style="margin:4px 0"><strong>Login-URL:</strong> <a href="${loginUrl}">${loginUrl}</a></p>
        <p style="margin:4px 0"><strong>E-Mail:</strong> ${to}</p>
        <p style="margin:4px 0"><strong>Passwort:</strong> <code>${password}</code></p>
        <p style="margin:4px 0"><strong>Tenant-Kennung:</strong> ${slug}</p>
      </div>
      <p>Bitte ändere dein Passwort nach dem ersten Login.</p>
      <p style="color:#64748b;font-size:12px">Diese Mail wurde automatisch versandt vom Dockly-Pfandsystem-Demo-Portal.</p>
    </div>`;
  return sendMail({ to, subject: `Dein Dockly-Pfandsystem-Demo-Zugang (${days} Tage)`, html });
}

// Test-Endpoint Helper
export async function sendTestMail(to) {
  const html = `
    <div style="font-family:system-ui,Segoe UI,Helvetica,Arial,sans-serif;max-width:560px;margin:auto">
      <h2 style="color:#051e23">Dockly-Pfandsystem Demo - SMTP-Test</h2>
      <p>Diese Test-Mail bestätigt, dass der Mail-Versand über
         <code>${process.env.SMTP_HOST || 'kein SMTP'}</code> funktioniert.</p>
      <p>Absender: <code>${FROM}</code></p>
      <p>Zeitstempel: ${new Date().toISOString()}</p>
    </div>`;
  return sendMail({ to, subject: 'Dockly-Pfandsystem Demo - SMTP-Test', html });
}