class CacheDecision {
  final bool canUseCached;
  final bool shouldRefreshInBackground;
  final bool mustBlockForNetwork;

  const CacheDecision({
    required this.canUseCached,
    required this.shouldRefreshInBackground,
    required this.mustBlockForNetwork,
  });
}

class CachePolicy {
  final Duration softTtl;
  final Duration hardTtl;
  final Duration minRefreshInterval;

  const CachePolicy({
    required this.softTtl,
    required this.hardTtl,
    this.minRefreshInterval = Duration.zero,
  });

  CacheDecision evaluate({required DateTime now, required DateTime fetchedAt}) {
    final age = now.difference(fetchedAt);
    if (age >= hardTtl) {
      return const CacheDecision(
        canUseCached: false,
        shouldRefreshInBackground: false,
        mustBlockForNetwork: true,
      );
    }

    if (age >= softTtl) {
      final shouldRefresh = age >= minRefreshInterval;
      return CacheDecision(
        canUseCached: true,
        shouldRefreshInBackground: shouldRefresh,
        mustBlockForNetwork: false,
      );
    }

    return const CacheDecision(
      canUseCached: true,
      shouldRefreshInBackground: false,
      mustBlockForNetwork: false,
    );
  }
}