/**
 * Drop legacy Participant indexes from the pre–multi-event schema.
 * The old unique index on { event, email } blocks guest sign-in (no email) because
 * MongoDB treats missing fields as null and only allows one { event: null, email: null } row.
 *
 * Usage (from backend/): node scripts/drop-legacy-participant-indexes.js
 */
require('dotenv').config();
const mongoose = require('mongoose');
const Participant = require('../src/models/Participant');

const LEGACY_INDEX_NAMES = [
  'event_1_email_1',
  'event_1',
  'email_1',
];

async function main() {
  const uri = process.env.MONGODB_URI || process.env.MONGO_URI;
  if (!uri) {
    console.error('Set MONGODB_URI or MONGO_URI');
    process.exit(1);
  }

  await mongoose.connect(uri);
  const coll = mongoose.connection.db.collection('participants');
  const existing = await coll.indexes();
  const names = new Set(existing.map((i) => i.name));

  for (const name of LEGACY_INDEX_NAMES) {
    if (!names.has(name)) {
      console.log(`Skip (not present): ${name}`);
      continue;
    }
    await coll.dropIndex(name);
    console.log(`Dropped legacy index: ${name}`);
  }

  const synced = await Participant.syncIndexes();
  console.log('syncIndexes result:', synced);

  const after = await coll.indexes();
  console.log(
    'Current indexes:',
    after.map((i) => i.name).join(', ')
  );

  await mongoose.disconnect();
}

main().catch((e) => {
  console.error(e);
  process.exit(1);
});