///
/// CCC provider specification models.
///

import 'package:letusmsg/ccc/cipher_constants.dart';

/// Execution strategy for provider routing inside CCC.
enum CccExecutionMode {
  strict,
  efficient,
  auto,
}

CccExecutionMode cccExecutionModeFromString(String raw) {
  switch (raw.trim().toLowerCase()) {
    case 'strict':
      return CccExecutionMode.strict;
    case 'efficient':
      return CccExecutionMode.efficient;
    case 'auto':
      return CccExecutionMode.auto;
    default:
      throw ArgumentError('Unsupported CCC execution mode: $raw');
  }
}

/// Logical provider identities used by CCC channel profiles.
enum CccCryptoProvider {
  cryptography,
  wolfssl,
  openssl,
  boringssl,
}

/// Provider entry in a CCC provider chain.
///
/// Each provider advertises the ciphers it contributes to the channel plan.
class CccProviderSpec {
  final CccCryptoProvider provider;
  final List<int> ciphers;

  const CccProviderSpec({
    required this.provider,
    required this.ciphers,
  });

  Map<String, dynamic> toMap() {
    return {
      'provider': provider.name,
      'ciphers': ciphers,
    };
  }
}

/// Per-provider, per-cipher capability metadata.
class CccCipherCapability {
  /// Whether the provider is currently available in this codebase/runtime.
  ///
  /// `true` means the provider can be selected as primary in `auto` mode.
  /// `false` means it can still appear in route planning metadata but should
  /// not be chosen as active primary until availability changes.
  final bool available;

  /// Whether input/output format is identical across providers for this cipher.
  ///
  /// This guards fallback safety. If this is `false`, fallback should be
  /// treated as incompatible for that cipher unless a migration adapter exists.
  final bool deterministicIo;

  /// Relative efficiency score from 0..100 (higher = faster/cheaper).
  ///
  /// Used by `efficient` mode to rank candidate providers for a cipher.
  final int efficiencyScore;

  /// Relative reliability score from 0..100 (higher = more trusted/stable).
  ///
  /// Used as tie-breaker when efficiency scores are equal.
  final int reliabilityScore;

  /// Creates immutable provider capability metadata used by CCC route planning.
  ///
  /// Parameter meanings:
  /// - [available]: runtime/provider readiness flag.
  /// - [deterministicIo]: indicates safe cross-provider fallback compatibility.
  /// - [efficiencyScore]: performance rank (0..100), higher is better.
  /// - [reliabilityScore]: confidence rank (0..100), higher is better.
  const CccCipherCapability({
    required this.available,
    required this.deterministicIo,
    required this.efficiencyScore,
    required this.reliabilityScore,
  });
}

/// Runtime/provider capability registry used by CCC route planning.
class CccProviderCatalog {
  /// Placeholder score used until benchmark pipeline is implemented.
  ///
  /// TODO(j3g): Replace with measured values from automated perf/reliability
  /// benchmark suite per provider/cipher.
  ///
  /// Example efficiency calculation (normalized 0..100):
  ///   efficiency = normalize(throughputMBps / latencyMs)
  ///
  /// Example reliability calculation (normalized 0..100):
  ///   reliability = normalize((1 - errorRate) * 100 - crashPenalty - cvePenalty)
  static const int pendingEfficiencyScore = 50;
  static const int pendingReliabilityScore = 50;

  static const CccCipherCapability _availableDeterministicPending = CccCipherCapability(
    available: true,
    deterministicIo: true,
    efficiencyScore: pendingEfficiencyScore,
    reliabilityScore: pendingReliabilityScore,
  );

  static const CccCipherCapability _unavailableDeterministicPending = CccCipherCapability(
    available: false,
    deterministicIo: true,
    efficiencyScore: pendingEfficiencyScore,
    reliabilityScore: pendingReliabilityScore,
  );

  static const Map<CccCryptoProvider, Map<int, CccCipherCapability>> capabilities = {
    CccCryptoProvider.cryptography: {
      CipherConstants.AES_GCM_256: _availableDeterministicPending,
      CipherConstants.CHACHA20_POLY1305: _availableDeterministicPending,
      CipherConstants.XCHACHA20_POLY1305: _availableDeterministicPending,
      CipherConstants.HMAC_SHA512: _availableDeterministicPending,
      CipherConstants.BLAKE2B: _availableDeterministicPending,
    },
    CccCryptoProvider.wolfssl: {
      CipherConstants.AES_GCM_256: _unavailableDeterministicPending,
      CipherConstants.CHACHA20_POLY1305: _unavailableDeterministicPending,
      CipherConstants.XCHACHA20_POLY1305: _unavailableDeterministicPending,
      CipherConstants.HMAC_SHA512: _unavailableDeterministicPending,
      CipherConstants.BLAKE2B: _unavailableDeterministicPending,
    },
    CccCryptoProvider.openssl: {
      CipherConstants.AES_GCM_256: _unavailableDeterministicPending,
      CipherConstants.CHACHA20_POLY1305: _unavailableDeterministicPending,
      CipherConstants.HMAC_SHA512: _unavailableDeterministicPending,
      CipherConstants.BLAKE2B: _unavailableDeterministicPending,
    },
    CccCryptoProvider.boringssl: {
      CipherConstants.AES_GCM_256: _unavailableDeterministicPending,
      CipherConstants.CHACHA20_POLY1305: _unavailableDeterministicPending,
      CipherConstants.XCHACHA20_POLY1305: _unavailableDeterministicPending,
      CipherConstants.HMAC_SHA512: _unavailableDeterministicPending,
      CipherConstants.BLAKE2B: _unavailableDeterministicPending,
    },
  };

  static CccCipherCapability? capability(CccCryptoProvider provider, int cipher) {
    return capabilities[provider]?[cipher];
  }

  static bool supports(CccCryptoProvider provider, int cipher) {
    return capability(provider, cipher) != null;
  }

  static List<CccCryptoProvider> providersSupporting(
    int cipher, {
    bool availableOnly = true,
  }) {
    final ranked = <({CccCryptoProvider provider, CccCipherCapability capability})>[];
    for (final entry in capabilities.entries) {
      final cap = entry.value[cipher];
      if (cap == null) continue;
      if (availableOnly && !cap.available) continue;
      ranked.add((provider: entry.key, capability: cap));
    }

    ranked.sort((a, b) {
      final perf = b.capability.efficiencyScore.compareTo(a.capability.efficiencyScore);
      if (perf != 0) return perf;
      return b.capability.reliabilityScore.compareTo(a.capability.reliabilityScore);
    });

    return ranked.map((item) => item.provider).toList(growable: false);
  }
}