lookupHashForImageName function

Implementation

Future<String?> lookupHashForImageName(
  String storedName, {
  String? scope,
}) async {
  try {
    await _ensureCollectionDirExists(IMAGE_INDEX_COLLECTION);
  } catch (_) {}

  final wanted = _normalizeStoredNameForMatch(storedName);
  if (wanted.isEmpty) return null;
  final wantedBase = _basenameOfStoredName(wanted);
  final wantedScope = _canonicalizeScope((scope ?? '').trim());
  final legacyScope = _legacyScopeForCanonical(wantedScope);

  final docs = await imageIndexCollection.get();
  if (docs == null || docs.isEmpty) return null;

  int scopeRank(String docScopeRaw) {
    final docScope = _canonicalizeScope(docScopeRaw.trim());
    if (wantedScope.isEmpty) {
      return docScope.isEmpty ? 0 : 1;
    }
    if (docScope == wantedScope) return 0;
    if (legacyScope != wantedScope && docScope == legacyScope) return 1;
    if (docScope.isEmpty) return 2;
    return 3;
  }

  String? bestHash;
  int? bestScore;

  for (final entry in docs.entries) {
    final raw = entry.value;
    if (raw is! Map) continue;
    final map = Map<String, dynamic>.from(raw);
    final hash = map['hash']?.toString().trim();
    final indexedName = map['storedName']?.toString().trim();
    if (hash == null ||
        hash.isEmpty ||
        indexedName == null ||
        indexedName.isEmpty) {
      continue;
    }

    final normalizedIndexed = _normalizeStoredNameForMatch(indexedName);
    final exactMatch = normalizedIndexed == wanted;
    final baseMatch = _basenameOfStoredName(normalizedIndexed) == wantedBase;
    if (!exactMatch && !baseMatch) continue;

    final rank = scopeRank(map['scope']?.toString() ?? '');
    if (rank >= 3) continue;

    final matchRank = exactMatch ? 0 : 1;
    final score = rank * 10 + matchRank;
    if (bestScore == null || score < bestScore) {
      bestScore = score;
      bestHash = hash;
    }
  }

  return bestHash;
}