import 'package:flutter/foundation.dart';

enum SyncStatus {
  localOnly,
  queued,
  waitingForNetwork,
  uploading,
  synced,
  failed,
  retryWait,
  authRequired,
  cancelled;

  bool get isTerminal => this == synced || this == failed || this == cancelled;
  bool get isPending => this == queued || this == waitingForNetwork || this == retryWait || this == authRequired;
  bool get isInProgress => this == uploading;
}

@immutable
class SyncItem {
  static const int schemaVersion = 2;
  final int localRideId;
  final String providerId;
  final SyncStatus status;
  final DateTime createdAt;
  final int attemptCount;
  final DateTime? lastAttemptAt;
  final DateTime? nextRetryAt;
  final DateTime? uploadedAt;
  final String? remoteId;
  final String? lastError;
  final String? bundleLocalPath;

  const SyncItem({required this.localRideId, required this.providerId, this.status = SyncStatus.queued, required this.createdAt, this.attemptCount = 0, this.lastAttemptAt, this.nextRetryAt, this.uploadedAt, this.remoteId, this.lastError, this.bundleLocalPath});

  String get key => '$providerId:$localRideId';
  String get idempotencyKey => key;

  bool isEligibleForAttempt(DateTime now) {
    if (status.isTerminal || status == SyncStatus.uploading) return false;
    if (status == SyncStatus.retryWait && nextRetryAt != null) return !now.isBefore(nextRetryAt!);
    return true;
  }

  SyncItem copyWith({int? localRideId, String? providerId, SyncStatus? status, DateTime? createdAt, int? attemptCount, DateTime? lastAttemptAt, DateTime? nextRetryAt, DateTime? uploadedAt, String? remoteId, String? lastError, String? bundleLocalPath, bool clearLastError = false, bool clearNextRetry = false, bool clearRemoteId = false, bool clearUploadedAt = false}) => SyncItem(
        localRideId: localRideId ?? this.localRideId,
        providerId: providerId ?? this.providerId,
        status: status ?? this.status,
        createdAt: createdAt ?? this.createdAt,
        attemptCount: attemptCount ?? this.attemptCount,
        lastAttemptAt: lastAttemptAt ?? this.lastAttemptAt,
        nextRetryAt: clearNextRetry ? null : (nextRetryAt ?? this.nextRetryAt),
        uploadedAt: clearUploadedAt ? null : (uploadedAt ?? this.uploadedAt),
        remoteId: clearRemoteId ? null : (remoteId ?? this.remoteId),
        lastError: clearLastError ? null : (lastError ?? this.lastError),
        bundleLocalPath: bundleLocalPath ?? this.bundleLocalPath,
      );

  Map<String, dynamic> toJson() => {
        'schemaVersion': schemaVersion,
        'localRideId': localRideId,
        'providerId': providerId,
        'status': status.name,
        'createdAt': createdAt.toIso8601String(),
        'attemptCount': attemptCount,
        'lastAttemptAt': lastAttemptAt?.toIso8601String(),
        'nextRetryAt': nextRetryAt?.toIso8601String(),
        'uploadedAt': uploadedAt?.toIso8601String(),
        'remoteId': remoteId,
        'lastError': lastError,
        'bundleLocalPath': bundleLocalPath,
      };

  factory SyncItem.fromJson(Map<String, dynamic> json) {
    final id = (json['localRideId'] as num?)?.toInt();
    final provider = json['providerId'];
    final createdRaw = json['createdAt'];
    if (id == null || id <= 0 || provider is! String || provider.trim().isEmpty || createdRaw is! String) throw const FormatException('Invalid sync item identity');
    final created = DateTime.tryParse(createdRaw);
    if (created == null) throw const FormatException('Invalid createdAt');
    DateTime? date(String key) {
      final v = json[key];
      if (v == null) return null;
      if (v is! String) throw FormatException('Invalid $key');
      return DateTime.tryParse(v);
    }
    final attempts = (json['attemptCount'] as num?)?.toInt() ?? 0;
    if (attempts < 0) throw const FormatException('Negative attemptCount');
    return SyncItem(localRideId: id, providerId: provider.trim(), status: SyncStatus.values.firstWhere((e) => e.name == json['status'], orElse: () => SyncStatus.queued), createdAt: created, attemptCount: attempts, lastAttemptAt: date('lastAttemptAt'), nextRetryAt: date('nextRetryAt'), uploadedAt: date('uploadedAt'), remoteId: json['remoteId'] as String?, lastError: json['lastError'] as String?, bundleLocalPath: json['bundleLocalPath'] as String?);
  }

  @override
  bool operator ==(Object other) => identical(this, other) || other is SyncItem && localRideId == other.localRideId && providerId == other.providerId && status == other.status && attemptCount == other.attemptCount && nextRetryAt == other.nextRetryAt && remoteId == other.remoteId && lastError == other.lastError;
  @override
  int get hashCode => Object.hash(localRideId, providerId, status, attemptCount, nextRetryAt, remoteId, lastError);
}

@immutable
class SyncResult {
  final bool success;
  final String? remoteId;
  final String? errorMessage;
  final bool isRetryable;
  final bool requiresAuth;
  final DateTime timestamp;
  SyncResult({required this.success, this.remoteId, this.errorMessage, this.isRetryable = true, this.requiresAuth = false, DateTime? timestamp}) : timestamp = timestamp ?? DateTime.now();
  SyncResult.success({required String remoteId, DateTime? timestamp}) : this(success: true, remoteId: remoteId, isRetryable: false, requiresAuth: false, timestamp: timestamp);
  SyncResult.temporaryFailure(String message, {DateTime? timestamp}) : this(success: false, errorMessage: message, isRetryable: true, timestamp: timestamp);
  SyncResult.permanentFailure(String message, {DateTime? timestamp}) : this(success: false, errorMessage: message, isRetryable: false, timestamp: timestamp);
  SyncResult.authRequired({String message = 'Authentication credentials required for sync', DateTime? timestamp}) : this(success: false, errorMessage: message, isRetryable: true, requiresAuth: true, timestamp: timestamp);
}

@immutable
class SyncManagerState {
  final bool isProcessing;
  final int pendingCount;
  final int syncedCount;
  final int failedCount;
  final DateTime? lastSuccessfulSync;
  final String? lastError;
  final String activeProviderId;

  const SyncManagerState({this.isProcessing = false, this.pendingCount = 0, this.syncedCount = 0, this.failedCount = 0, this.lastSuccessfulSync, this.lastError, this.activeProviderId = 'none'});

  SyncManagerState copyWith({bool? isProcessing, int? pendingCount, int? syncedCount, int? failedCount, DateTime? lastSuccessfulSync, String? lastError, String? activeProviderId, bool clearLastError = false}) => SyncManagerState(
        isProcessing: isProcessing ?? this.isProcessing,
        pendingCount: pendingCount ?? this.pendingCount,
        syncedCount: syncedCount ?? this.syncedCount,
        failedCount: failedCount ?? this.failedCount,
        lastSuccessfulSync: lastSuccessfulSync ?? this.lastSuccessfulSync,
        lastError: clearLastError ? null : (lastError ?? this.lastError),
        activeProviderId: activeProviderId ?? this.activeProviderId,
      );
}