lum_ccc_rust/flutter_src/ccc/ccc_iso_operation.dart

///
/// Data structure for crypto operations in isolates
/// Handles serialization for isolate communication
///
import 'package:worker_manager/worker_manager.dart';
import 'ccc_iso_operation_id.dart';
import 'cipher_constants.dart';

/// Type of cryptographic operation
enum OperationType { 
  encrypt, 
  decrypt;
  
  @override
  String toString() => name;
  
  static OperationType fromString(String value) {
    return OperationType.values.firstWhere(
      (type) => type.name == value,
      orElse: () => throw ArgumentError('Invalid OperationType: $value'),
    );
  }
}

/// Cryptographic operation data for isolate workers
/// 
/// Key derivation (future ratchet implementation):
/// - channelUuid: Scope for key derivation (each channel has unique root key)
/// - messageSequence: Per-message key derivation index
/// - Final key = ratchet(channelRootKey, messageSequence)
/// 
/// Same derived key encrypts: MsgData + attachment files + thumbnails
class CryptoOperation {
  final String id;
  final List<int> data;
  final List<int> cipherSequence;
  final Map<String, dynamic> params;
  final OperationType type;
  final WorkPriority priority;
  final String channelUuid;       // Channel UUID for key derivation scope
  final int? messageSequence;     // Future: ratchet index for per-message key
  final DateTime timestamp;
  
  /// Create new crypto operation with auto-generated ID
  CryptoOperation({
    required this.data,
    required this.cipherSequence,
    required this.params,
    required this.type,
    required this.channelUuid,
    this.messageSequence,
    this.priority = WorkPriority.high,
  }) : id = CryptoOperationId.generate(),
       timestamp = DateTime.now();
  
  /// Create crypto operation with custom ID (for testing)
  CryptoOperation.withId({
    required this.id,
    required this.data,
    required this.cipherSequence,
    required this.params,
    required this.type,
    required this.channelUuid,
    this.messageSequence,
    this.priority = WorkPriority.high,
  }) : timestamp = DateTime.now();
  
  /// Create operation for encryption
  factory CryptoOperation.encrypt({
    required List<int> plaintext,
    required List<int> cipherSequence,
    required Map<String, dynamic> params,
    required String channelUuid,
    int? messageSequence,
    bool isUserMessage = false,
  }) {
    return CryptoOperation(
      data: plaintext,
      cipherSequence: cipherSequence,
      params: params,
      type: OperationType.encrypt,
      channelUuid: channelUuid,
      messageSequence: messageSequence,
      priority: isUserMessage ? WorkPriority.immediately : WorkPriority.high,
    );
  }
  
  /// Create operation for decryption
  factory CryptoOperation.decrypt({
    required List<int> ciphertext,
    required List<int> cipherSequence,
    required Map<String, dynamic> params,
    required String channelUuid,
    int? messageSequence,
  }) {
    return CryptoOperation(
      data: ciphertext,
      cipherSequence: cipherSequence,
      params: params,
      type: OperationType.decrypt,
      channelUuid: channelUuid,
      messageSequence: messageSequence,
      priority: WorkPriority.high,
    );
  }
  
  /// Serialize for isolate communication
  Map<String, dynamic> toMap() {
    return {
      'id': id,
      'data': data,
      'cipherSequence': cipherSequence,
      'params': params,
      'type': type.name,
      'priority': priority.index,
      'channelUuid': channelUuid,
      'messageSequence': messageSequence,
      'timestamp': timestamp.millisecondsSinceEpoch,
    };
  }
  
  /// Deserialize from isolate communication
  static CryptoOperation fromMap(Map<String, dynamic> map) {
    return CryptoOperation.withId(
      id: map['id'] as String,
      data: List<int>.from(map['data'] as List),
      cipherSequence: List<int>.from(map['cipherSequence'] as List),
      params: Map<String, dynamic>.from(map['params'] as Map),
      type: OperationType.fromString(map['type'] as String),
      channelUuid: map['channelUuid'] as String,
      messageSequence: map['messageSequence'] as int?,
      priority: WorkPriority.values[map['priority'] as int],
    );
  }
  
  /// Get cipher sequence as human-readable string
  String get cipherSequenceDescription {
    return CipherConstants.getSequenceDescription(cipherSequence);
  }
  
  /// Validate cipher sequence
  bool get hasValidCipherSequence {
    return CipherConstants.isValidSequence(cipherSequence);
  }
  
  /// Get data size in bytes
  int get dataSize => data.length;
  
  /// Get operation age
  Duration get age => DateTime.now().difference(timestamp);
  
  /// Check if operation is high priority
  bool get isHighPriority => priority == WorkPriority.immediately;
  
  /// Copy with new priority
  CryptoOperation copyWithPriority(WorkPriority newPriority) {
    return CryptoOperation.withId(
      id: id,
      data: data,
      cipherSequence: cipherSequence,
      params: params,
      type: type,
      channelUuid: channelUuid,
      messageSequence: messageSequence,
      priority: newPriority,
    );
  }
  
  @override
  String toString() {
    return 'CryptoOperation('
        'id: $id, '
        'type: $type, '
        'dataSize: ${dataSize}B, '
        'ciphers: ${cipherSequence.length}, '
        'priority: $priority, '
        'channel: $channelUuid'
        ')';
  }
  
  @override
  bool operator ==(Object other) =>
      identical(this, other) ||
      other is CryptoOperation &&
          runtimeType == other.runtimeType &&
          id == other.id;
  
  @override
  int get hashCode => id.hashCode;
}