// Domain permission checking against the portal OpenFGA verify endpoint.
// Mirrors fingerprint-agent internal/permit: `domain:<code>` first, then a
// `domain:idid` fallback — either allow passes, and every failure closes.
// Results are cached per operator phone for DOMAIN_TTL_MS.
export const DOMAIN_TTL_MS = 5 * 60 * 1000;
export const CACHE_FRESH = 'CACHE_FRESH';
/** Outbound OpenFGA verify timeout — a hung portal must not pin a request. */
export const VERIFY_TIMEOUT_MS = 5000;

export function stripPhonePrefix(phone) {
  return (phone || '').replace(/^\+/, '');
}

async function verifyOnce(fetchImpl, portalUrl, phone, object, relation = 'capture_biometric') {
  const r = await fetchImpl(`${portalUrl.replace(/\/+$/, '')}/api/openfga/verify`, {
    method: 'POST',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({
      subsystem: 'idid',
      user: `user:${phone}`,
      relation,
      object,
    }),
    signal: AbortSignal.timeout(VERIFY_TIMEOUT_MS),
  });
  if (r.status !== 200) throw new Error(`verify status ${r.status}`);
  const out = await r.json();
  if (!out?.ok) throw new Error('verify returned ok=false');
  return !!out.allowed;
}

// true = allowed, false = denied; throws when neither object could answer.
export async function checkDomain(fetchImpl, portalUrl, phone, code) {
  let answered = false;
  for (const object of [`domain:${code}`, 'domain:idid']) {
    try {
      const allowed = await verifyOnce(fetchImpl, portalUrl, phone, object, 'capture_biometric');
      answered = true;
      if (allowed) return true;
    } catch {
      // try the fallback object; if neither answers we fail closed below
    }
  }
  if (!answered) throw new Error(`verify failed for domain:${code} and domain:idid`);
  return false;
}

/**
 * Single-object permission check for an arbitrary relation — fail closed:
 * returns true only for an explicit ok+allowed, false on denial, and throws
 * when the check itself fails.
 */
export async function checkPermission(fetchImpl, portalUrl, phone, { relation, object }) {
  return verifyOnce(fetchImpl, portalUrl, phone, object, relation);
}

/**
 * Cached `crop_image` permission on domain:idid for the cropper. Same shape as
 * permittedDomains: 5-minute per-phone cache, `force` bypasses the cache for
 * live checks and refuses while fresh, failures fail closed (denied).
 * Returns { allowed, checkedAt }.
 */
export async function cropPermission({
  phone,
  portalUrl,
  fetchImpl = fetch,
  cache,
  ttlMs = DOMAIN_TTL_MS,
  now = Date.now,
  force = false,
}) {
  const hit = cache.get(phone);
  const fresh = !!(hit && now() - hit.checkedAt < ttlMs);
  if (fresh && !force) {
    return { allowed: hit.allowed, checkedAt: hit.checkedAt };
  }
  const checkedAt = now();
  let allowed = false;
  try {
    allowed = await checkPermission(fetchImpl, portalUrl, phone, {
      relation: 'crop_image',
      object: 'domain:idid',
    });
  } catch {
    allowed = false; // fail closed
  }
  cache.set(phone, { allowed, checkedAt });
  return { allowed, checkedAt };
}

/**
 * Permitted domain codes for phone, cached per phone for ttlMs.
 * force=true re-checks everything; while the cache is still fresh it refuses
 * with an error whose .code is CACHE_FRESH. Unanswered checks exclude the
 * domain (fail closed). Returns { codes, checkedAt }.
 */
export async function permittedDomains({
  domains,
  phone,
  portalUrl,
  fetchImpl = fetch,
  cache,
  ttlMs = DOMAIN_TTL_MS,
  now = Date.now,
  force = false,
}) {
  const hit = cache.get(phone);
  const fresh = !!(hit && now() - hit.checkedAt < ttlMs);
  if (fresh && !force) return { codes: hit.codes, checkedAt: hit.checkedAt };
  if (fresh && force) {
    const e = new Error('permission cache is still fresh');
    e.code = CACHE_FRESH;
    throw e;
  }
  const settled = await Promise.all(
    domains.map((d) =>
      checkDomain(fetchImpl, portalUrl, phone, d.code)
        .then((ok) => (ok ? d.code : null))
        .catch(() => null)
    )
  );
  const codes = settled.filter(Boolean);
  const checkedAt = now();
  cache.set(phone, { codes, checkedAt });
  return { codes, checkedAt };
}