class ReminderPayload {
  final String eventId;
  final String title;
  final DateTime startAt;
  final DateTime? endAt;
  final String timezone;
  final String? location;
  final String? notes;
  final String? color;
  final ReminderPayloadMode mode;
  final List<String> aggregateIds;
  final int? fireTimeBucket;
  final int version;

  const ReminderPayload({
    required this.eventId,
    required this.title,
    required this.startAt,
    required this.timezone,
    this.endAt,
    this.location,
    this.notes,
    this.color,
    this.mode = ReminderPayloadMode.single,
    this.aggregateIds = const [],
    this.fireTimeBucket,
    this.version = 1,
  });

  ReminderPayload copyWith({
    String? eventId,
    String? title,
    DateTime? startAt,
    DateTime? endAt,
    String? timezone,
    String? location,
    String? notes,
    String? color,
    ReminderPayloadMode? mode,
    List<String>? aggregateIds,
    int? fireTimeBucket,
    int? version,
  }) {
    return ReminderPayload(
      eventId: eventId ?? this.eventId,
      title: title ?? this.title,
      startAt: startAt ?? this.startAt,
      endAt: endAt ?? this.endAt,
      timezone: timezone ?? this.timezone,
      location: location ?? this.location,
      notes: notes ?? this.notes,
      color: color ?? this.color,
      mode: mode ?? this.mode,
      aggregateIds: aggregateIds ?? this.aggregateIds,
      fireTimeBucket: fireTimeBucket ?? this.fireTimeBucket,
      version: version ?? this.version,
    );
  }

  Map<String, dynamic> toJson() {
    return {
      'eventId': eventId,
      'title': title,
      'startAt': startAt.toIso8601String(),
      'endAt': endAt?.toIso8601String(),
      'timezone': timezone,
      'location': location,
      'notes': notes,
      'color': color,
      'mode': mode.value,
      'aggregateIds': aggregateIds,
      'fireTimeBucket': fireTimeBucket,
      'version': version,
    };
  }

  factory ReminderPayload.fromJson(Map<String, dynamic> json) {
    final eventId = (json['eventId'] as String?) ?? '';
    if (eventId.isEmpty) {
      throw const FormatException('eventId is required');
    }

    final startAtRaw = json['startAt'] as String?;
    if (startAtRaw == null || startAtRaw.isEmpty) {
      throw const FormatException('startAt is required');
    }
    final parsedStartAt = DateTime.parse(startAtRaw);

    final mode = ReminderPayloadMode.fromValue(
      (json['mode'] as String?) ?? 'single',
    );
    final aggregateIds = (json['aggregateIds'] as List<dynamic>? ?? const [])
        .map((item) => item.toString())
        .toList();
    if (mode == ReminderPayloadMode.aggregate && aggregateIds.length < 2) {
      throw const FormatException('aggregateIds must contain at least 2 items');
    }

    return ReminderPayload(
      eventId: eventId,
      title: (json['title'] as String?) ?? '',
      startAt: parsedStartAt,
      endAt: json['endAt'] != null
          ? DateTime.parse(json['endAt'] as String)
          : null,
      timezone: (json['timezone'] as String?) ?? 'UTC',
      location: json['location'] as String?,
      notes: json['notes'] as String?,
      color: json['color'] as String?,
      mode: mode,
      aggregateIds: aggregateIds,
      fireTimeBucket: json['fireTimeBucket'] as int?,
      version: (json['version'] as int?) ?? 1,
    );
  }

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) {
      return true;
    }
    return other is ReminderPayload &&
        other.eventId == eventId &&
        other.title == title &&
        other.startAt == startAt &&
        other.endAt == endAt &&
        other.timezone == timezone &&
        other.location == location &&
        other.notes == notes &&
        other.color == color &&
        other.mode == mode &&
        _listEquals(other.aggregateIds, aggregateIds) &&
        other.fireTimeBucket == fireTimeBucket &&
        other.version == version;
  }

  @override
  int get hashCode {
    return Object.hash(
      eventId,
      title,
      startAt,
      endAt,
      timezone,
      location,
      notes,
      color,
      mode,
      Object.hashAll(aggregateIds),
      fireTimeBucket,
      version,
    );
  }
}

enum ReminderPayloadMode {
  single('single'),
  aggregate('aggregate');

  const ReminderPayloadMode(this.value);

  final String value;

  static ReminderPayloadMode fromValue(String raw) {
    return ReminderPayloadMode.values.firstWhere(
      (item) => item.value == raw,
      orElse: () => ReminderPayloadMode.single,
    );
  }
}

bool _listEquals(List<String> left, List<String> right) {
  if (left.length != right.length) {
    return false;
  }
  for (var i = 0; i < left.length; i++) {
    if (left[i] != right[i]) {
      return false;
    }
  }
  return true;
}