import 'dart:convert';

import 'supplement.dart';
import 'supplement_intake.dart';
import 'sync_enums.dart';

/// Model representing the complete sync data structure
/// This is what gets serialized to JSON and synced via WebDAV
class SyncData {
  final int version;
  final String deviceId;
  final String deviceName;
  final DateTime syncTimestamp;
  final List<Supplement> supplements;
  final List<SupplementIntake> intakes;
  final Map<String, dynamic> metadata;

  const SyncData({
    required this.version,
    required this.deviceId,
    required this.deviceName,
    required this.syncTimestamp,
    required this.supplements,
    required this.intakes,
    this.metadata = const {},
  });

  /// Convert sync data to JSON map
  Map<String, dynamic> toJson() {
    return {
      'version': version,
      'deviceId': deviceId,
      'deviceName': deviceName,
      'syncTimestamp': syncTimestamp.toIso8601String(),
      'supplements': supplements.map((s) => s.toMap()).toList(),
      'intakes': intakes.map((i) => i.toMap()).toList(),
      'metadata': metadata,
    };
  }

  /// Create sync data from JSON map
  factory SyncData.fromJson(Map<String, dynamic> json) {
    return SyncData(
      version: json['version'] ?? 1,
      deviceId: json['deviceId'] ?? '',
      deviceName: json['deviceName'] ?? 'Unknown Device',
      syncTimestamp: json['syncTimestamp'] != null
          ? DateTime.parse(json['syncTimestamp'])
          : DateTime.now(),
      supplements: (json['supplements'] as List<dynamic>? ?? [])
          .map((s) => Supplement.fromMap(s as Map<String, dynamic>))
          .toList(),
      intakes: (json['intakes'] as List<dynamic>? ?? [])
          .map((i) => SupplementIntake.fromMap(i as Map<String, dynamic>))
          .toList(),
      metadata: json['metadata'] as Map<String, dynamic>? ?? {},
    );
  }

  /// Convert sync data to JSON string
  String toJsonString() {
    return jsonEncode(toJson());
  }

  /// Create sync data from JSON string
  factory SyncData.fromJsonString(String jsonString) {
    final json = jsonDecode(jsonString) as Map<String, dynamic>;
    return SyncData.fromJson(json);
  }

  /// Create a copy with updated values
  SyncData copyWith({
    int? version,
    String? deviceId,
    String? deviceName,
    DateTime? syncTimestamp,
    List<Supplement>? supplements,
    List<SupplementIntake>? intakes,
    Map<String, dynamic>? metadata,
  }) {
    return SyncData(
      version: version ?? this.version,
      deviceId: deviceId ?? this.deviceId,
      deviceName: deviceName ?? this.deviceName,
      syncTimestamp: syncTimestamp ?? this.syncTimestamp,
      supplements: supplements ?? this.supplements,
      intakes: intakes ?? this.intakes,
      metadata: metadata ?? this.metadata,
    );
  }

  @override
  String toString() {
    return 'SyncData(version: $version, deviceId: $deviceId, '
        'deviceName: $deviceName, syncTimestamp: $syncTimestamp, '
        'supplements: ${supplements.length}, intakes: ${intakes.length})';
  }
}

/// Model representing a sync conflict
class SyncConflict {
  final String syncId;
  final ConflictType type;
  final DateTime localTimestamp;
  final DateTime remoteTimestamp;
  final Map<String, dynamic> localData;
  final Map<String, dynamic> remoteData;
  final ConflictResolutionStrategy? suggestedResolution;

  const SyncConflict({
    required this.syncId,
    required this.type,
    required this.localTimestamp,
    required this.remoteTimestamp,
    required this.localData,
    required this.remoteData,
    this.suggestedResolution,
  });

  Map<String, dynamic> toJson() {
    return {
      'syncId': syncId,
      'type': type.name,
      'localTimestamp': localTimestamp.toIso8601String(),
      'remoteTimestamp': remoteTimestamp.toIso8601String(),
      'localData': localData,
      'remoteData': remoteData,
      'suggestedResolution': suggestedResolution?.name,
    };
  }

  factory SyncConflict.fromJson(Map<String, dynamic> json) {
    return SyncConflict(
      syncId: json['syncId'],
      type: ConflictType.values.firstWhere(
        (e) => e.name == json['type'],
        orElse: () => ConflictType.modification,
      ),
      localTimestamp: DateTime.parse(json['localTimestamp']),
      remoteTimestamp: DateTime.parse(json['remoteTimestamp']),
      localData: json['localData'] as Map<String, dynamic>,
      remoteData: json['remoteData'] as Map<String, dynamic>,
      suggestedResolution: json['suggestedResolution'] != null
          ? ConflictResolutionStrategy.values.firstWhere(
              (e) => e.name == json['suggestedResolution'],
              orElse: () => ConflictResolutionStrategy.manual,
            )
          : null,
    );
  }

  /// Get human-readable description of the conflict
  String get description {
    switch (type) {
      case ConflictType.modification:
        return 'Item modified on both devices';
      case ConflictType.deletion:
        return 'Item deleted on one device, modified on another';
      case ConflictType.creation:
        return 'Item created with same ID on both devices';
    }
  }

  /// Determine if local version is newer
  bool get isLocalNewer => localTimestamp.isAfter(remoteTimestamp);

  /// Determine if remote version is newer
  bool get isRemoteNewer => remoteTimestamp.isAfter(localTimestamp);

  /// Check if timestamps are identical
  bool get haveSameTimestamp => localTimestamp.isAtSameMomentAs(remoteTimestamp);
}

/// Types of sync conflicts
enum ConflictType {
  /// Both local and remote versions were modified
  modification,

  /// One version was deleted while the other was modified
  deletion,

  /// Same item was created on both devices
  creation,
}

/// Model for sync operation results
class SyncResult {
  final bool success;
  final DateTime timestamp;
  final SyncOperationStatus status;
  final String? error;
  final List<SyncConflict> conflicts;
  final SyncStatistics statistics;

  const SyncResult({
    required this.success,
    required this.timestamp,
    required this.status,
    this.error,
    this.conflicts = const [],
    this.statistics = const SyncStatistics(),
  });

  Map<String, dynamic> toJson() {
    return {
      'success': success,
      'timestamp': timestamp.toIso8601String(),
      'status': status.name,
      'error': error,
      'conflicts': conflicts.map((c) => c.toJson()).toList(),
      'statistics': statistics.toJson(),
    };
  }

  factory SyncResult.fromJson(Map<String, dynamic> json) {
    return SyncResult(
      success: json['success'] ?? false,
      timestamp: DateTime.parse(json['timestamp']),
      status: SyncOperationStatus.values.firstWhere(
        (e) => e.name == json['status'],
        orElse: () => SyncOperationStatus.idle,
      ),
      error: json['error'],
      conflicts: (json['conflicts'] as List<dynamic>? ?? [])
          .map((c) => SyncConflict.fromJson(c as Map<String, dynamic>))
          .toList(),
      statistics: json['statistics'] != null
          ? SyncStatistics.fromJson(json['statistics'] as Map<String, dynamic>)
          : const SyncStatistics(),
    );
  }

  /// Create a failed sync result
  factory SyncResult.failure({
    required String error,
    required SyncOperationStatus status,
    List<SyncConflict> conflicts = const [],
  }) {
    return SyncResult(
      success: false,
      timestamp: DateTime.now(),
      status: status,
      error: error,
      conflicts: conflicts,
    );
  }

  /// Create a successful sync result
  factory SyncResult.success({
    List<SyncConflict> conflicts = const [],
    SyncStatistics statistics = const SyncStatistics(),
  }) {
    return SyncResult(
      success: true,
      timestamp: DateTime.now(),
      status: conflicts.isEmpty
          ? SyncOperationStatus.success
          : SyncOperationStatus.conflictsDetected,
      conflicts: conflicts,
      statistics: statistics,
    );
  }
}

/// Statistics about sync operations
class SyncStatistics {
  final int supplementsUploaded;
  final int supplementsDownloaded;
  final int intakesUploaded;
  final int intakesDownloaded;
  final int conflictsResolved;
  final Duration syncDuration;

  const SyncStatistics({
    this.supplementsUploaded = 0,
    this.supplementsDownloaded = 0,
    this.intakesUploaded = 0,
    this.intakesDownloaded = 0,
    this.conflictsResolved = 0,
    this.syncDuration = Duration.zero,
  });

  Map<String, dynamic> toJson() {
    return {
      'supplementsUploaded': supplementsUploaded,
      'supplementsDownloaded': supplementsDownloaded,
      'intakesUploaded': intakesUploaded,
      'intakesDownloaded': intakesDownloaded,
      'conflictsResolved': conflictsResolved,
      'syncDurationMs': syncDuration.inMilliseconds,
    };
  }

  factory SyncStatistics.fromJson(Map<String, dynamic> json) {
    return SyncStatistics(
      supplementsUploaded: json['supplementsUploaded'] ?? 0,
      supplementsDownloaded: json['supplementsDownloaded'] ?? 0,
      intakesUploaded: json['intakesUploaded'] ?? 0,
      intakesDownloaded: json['intakesDownloaded'] ?? 0,
      conflictsResolved: json['conflictsResolved'] ?? 0,
      syncDuration: Duration(milliseconds: json['syncDurationMs'] ?? 0),
    );
  }

  int get totalUploaded => supplementsUploaded + intakesUploaded;
  int get totalDownloaded => supplementsDownloaded + intakesDownloaded;
  int get totalSynced => totalUploaded + totalDownloaded;

  @override
  String toString() {
    return 'SyncStatistics(uploaded: $totalUploaded, downloaded: $totalDownloaded, '
        'conflicts: $conflictsResolved, duration: ${syncDuration.inSeconds}s)';
  }
}