// Maps event names, keeps consented customers and hashes PII for Meta CAPI
const EVENT_MAP = {
  'page_view':   'PageView',
  'add_to_cart': 'AddToCart',
  'purchase':    'Purchase',
};

async function sha256(str) {
  const buf = new TextEncoder().encode(str.trim().toLowerCase());
  const digest = await crypto.subtle.digest('SHA-256', buf);
  return Array.from(new Uint8Array(digest)).map(b => b.toString(16).padStart(2, '0')).join('');
}

async function transform({ events, profiles }) {
  const out = [];
  for (const ev of events) {
    const profile = profiles.find(p => p.id === ev.user_id) ?? {};
    if (!profile.ads_consent) continue;  // no consent, nothing is sent
    const user_data = {};
    if (profile.email) user_data.em = await sha256(profile.email);
    if (profile.phone) user_data.ph = await sha256(profile.phone);
    if (profile.fbclid) user_data.fbc = `fb.1.${ev.ts}.${profile.fbclid}`;
    out.push({ ...ev, event_type: EVENT_MAP[ev.event_type] ?? ev.event_type, user_data });
  }
  return out;
}