// backend/utils/smsService.js
// Centralised Twilio helper + DB helpers for the Reminders feature.
// Now *also* writes back status → reminders.status and sent_at so the
// cron‑job doesn’t need its own UPDATE logic.

import twilio from 'twilio';
import { v4 as uuid } from 'uuid';
import db from '../config/mysqlPool.js';

const {
  TWILIO_ACCOUNT_SID,
  TWILIO_AUTH_TOKEN,
  TWILIO_MESSAGING_SERVICE_SID
} = process.env;

if (!TWILIO_ACCOUNT_SID || !TWILIO_AUTH_TOKEN || !TWILIO_MESSAGING_SERVICE_SID) {
  throw new Error('Twilio env vars missing; check env or PM2 config');
}

const client = twilio(TWILIO_ACCOUNT_SID, TWILIO_AUTH_TOKEN);

/* ────────────────────────────────────────────────────────────── *
   Immediate send + status update
   ------------------------------------------------------------------ */
export async function sendSMS ({ reminderId = null, to, body }) {
  try {
    const msg = await client.messages.create({
      to,
      body,
      messagingServiceSid: TWILIO_MESSAGING_SERVICE_SID
    });

    // Mark success if we were called from reminderCron
    if (reminderId) {
      await db.execute(
        `UPDATE reminders
           SET status   = 'sent',
               sent_at  = UTC_TIMESTAMP(),
               twilio_sid = ?
         WHERE id = ?`,
        [msg.sid, reminderId]
      );
    }

    return msg;
  } catch (err) {
    // Persist failure so we don’t keep retrying blindly
    if (reminderId) {
      await db.execute(
        `UPDATE reminders
           SET status   = 'failed',
               sent_at  = UTC_TIMESTAMP(),
               error_code = ?
         WHERE id = ?`,
        [err.code || null, reminderId]
      );
    }
    throw err;   // propagate so cron can log
  }
}

/* ────────────────────────────────────────────────────────────── *
   Persist a *future* reminder row
   ------------------------------------------------------------------ */
export async function createReminder ({ userId, phone, body, sendAtUtc }) {
  const id = uuid();
  const mysqlDateTime = new Date(sendAtUtc)
    .toISOString()
    .slice(0, 19)         // 2025-06-17T22:00:00
    .replace('T', ' ');   // 2025-06-17 22:00:00

  await db.execute(
    `INSERT INTO reminders (id, user_id, phone_e164, message_body, send_at_utc)
         VALUES (?,?,?,?,?)`,
    [id, userId, phone, body.slice(0, 320), mysqlDateTime]
  );

  return id;
}