import cron from 'node-cron';
import pool from '../config/database.js';
import {
  sendDemoExpiryReminderMail,
  sendDemoLastDayMail,
  sendDemoExpiredMail,
} from './mail.js';

// Findet Demo-Tenants, deren Ablauf in [from, to] liegt UND fuer die noch
// keine entsprechende Benachrichtigung versandt wurde, schickt die Mail
// und markiert die Spalte mit NOW().
async function processWindow({ flagColumn, daysFrom, daysTo, sender }) {
  const [rows] = await pool.query(
    `SELECT id, name, kontakt_email, slug, demo_expires_at
       FROM tenants
      WHERE typ = 'demo'
        AND kontakt_email IS NOT NULL
        AND ${flagColumn} IS NULL
        AND demo_expires_at IS NOT NULL
        AND demo_expires_at BETWEEN DATE_ADD(NOW(), INTERVAL ? DAY)
                                AND DATE_ADD(NOW(), INTERVAL ? DAY)`,
    [daysFrom, daysTo]
  );
  for (const t of rows) {
    try {
      await sender(t);
      await pool.query(`UPDATE tenants SET ${flagColumn} = NOW() WHERE id = ?`, [t.id]);
      console.log(`[expiry] ${flagColumn} -> ${t.kontakt_email} (slug=${t.slug})`);
    } catch (e) {
      console.error(`[expiry] Mail-Fehler ${flagColumn} fuer ${t.kontakt_email}:`, e.message);
    }
  }
}

async function processExpiredToday() {
  const [rows] = await pool.query(
    `SELECT id, name, kontakt_email, slug, demo_expires_at
       FROM tenants
      WHERE typ = 'demo'
        AND kontakt_email IS NOT NULL
        AND notified_expired_at IS NULL
        AND demo_expires_at IS NOT NULL
        AND demo_expires_at <= NOW()`
  );
  for (const t of rows) {
    try {
      await sendDemoExpiredMail({ to: t.kontakt_email, name: t.name });
      await pool.query(
        `UPDATE tenants SET notified_expired_at = NOW(),
                            status = 'abgelaufen'
         WHERE id = ?`,
        [t.id]
      );
      console.log(`[expiry] expired-mail -> ${t.kontakt_email} (slug=${t.slug})`);
    } catch (e) {
      console.error(`[expiry] expired-Mail-Fehler ${t.kontakt_email}:`, e.message);
    }
  }
}

export async function runExpiryCheck() {
  console.log('[expiry] check start', new Date().toISOString());
  // 7-Tage-Erinnerung: Ablauf in [6, 7] Tagen
  await processWindow({
    flagColumn: 'notified_7d_at',
    daysFrom: 6, daysTo: 7,
    sender: (t) => sendDemoExpiryReminderMail({
      to: t.kontakt_email, name: t.name, slug: t.slug,
      daysLeft: 7, expiresAt: t.demo_expires_at,
    }),
  });
  // 1-Tag-Erinnerung: Ablauf in [0, 1] Tagen (aber noch nicht abgelaufen)
  await processWindow({
    flagColumn: 'notified_1d_at',
    daysFrom: 0, daysTo: 1,
    sender: (t) => sendDemoLastDayMail({
      to: t.kontakt_email, name: t.name, slug: t.slug,
      expiresAt: t.demo_expires_at,
    }),
  });
  // Heute (oder bereits) abgelaufen
  await processExpiredToday();
  console.log('[expiry] check done');
}

export function startExpiryCron() {
  // Taeglich um 08:00 Uhr (Server-Zeit = UTC). Anpassbar via env CRON_EXPIRY_AT
  const expr = process.env.CRON_EXPIRY_AT || '0 8 * * *';
  cron.schedule(expr, () => {
    runExpiryCheck().catch(e => console.error('[expiry] cron error:', e));
  });
  console.log('[expiry] cron registriert:', expr);
}