import 'package:uuid/uuid.dart';

enum MessageRole { user, assistant, system }

enum MessageType { text, voice, image }

enum MessageStatus { sending, sent, error }

class Message {
  final String id;
  final MessageRole role;
  final MessageType type;
  final String content;
  final String? audioUri;
  final String? imageBase64;
  final String? mimeType;
  final int timestamp;
  final MessageStatus? status;
  final int? duration;

  const Message({
    required this.id,
    required this.role,
    required this.type,
    required this.content,
    required this.timestamp,
    this.audioUri,
    this.imageBase64,
    this.mimeType,
    this.status,
    this.duration,
  });

  factory Message.text({
    required MessageRole role,
    required String content,
    MessageStatus? status,
  }) {
    return Message(
      id: const Uuid().v4(),
      role: role,
      type: MessageType.text,
      content: content,
      timestamp: DateTime.now().millisecondsSinceEpoch,
      status: status,
    );
  }

  factory Message.voice({
    required MessageRole role,
    required String audioUri,
    String content = '',
    int? duration,
    MessageStatus? status,
  }) {
    return Message(
      id: const Uuid().v4(),
      role: role,
      type: MessageType.voice,
      content: content,
      audioUri: audioUri,
      timestamp: DateTime.now().millisecondsSinceEpoch,
      duration: duration,
      status: status,
    );
  }

  factory Message.image({
    required MessageRole role,
    required String imageBase64,
    String content = '',
    String? mimeType,
    MessageStatus? status,
  }) {
    return Message(
      id: const Uuid().v4(),
      role: role,
      type: MessageType.image,
      content: content,
      imageBase64: imageBase64,
      mimeType: mimeType,
      timestamp: DateTime.now().millisecondsSinceEpoch,
      status: status,
    );
  }

  Message copyWith({
    String? content,
    String? audioUri,
    String? imageBase64,
    String? mimeType,
    MessageStatus? status,
    int? duration,
  }) {
    return Message(
      id: id,
      role: role,
      type: type,
      content: content ?? this.content,
      audioUri: audioUri ?? this.audioUri,
      imageBase64: imageBase64 ?? this.imageBase64,
      mimeType: mimeType ?? this.mimeType,
      timestamp: timestamp,
      status: status ?? this.status,
      duration: duration ?? this.duration,
    );
  }

  Map<String, dynamic> toJson() {
    return {
      'id': id,
      'role': role.name,
      'type': type.name,
      'content': content,
      if (audioUri != null) 'audioUri': audioUri,
      if (imageBase64 != null) 'imageBase64': imageBase64,
      if (mimeType != null) 'mimeType': mimeType,
      'timestamp': timestamp,
      if (status != null) 'status': status!.name,
      if (duration != null) 'duration': duration,
    };
  }

  /// Lightweight JSON for persistence (strips base64 audio, keeps file paths and images).
  Map<String, dynamic> toJsonLight() {
    // Keep audioUri if it's a file path (starts with '/') — these are saved audio files.
    // Strip base64 audio data (large, temp) — those won't survive restart.
    final keepAudio = audioUri != null && audioUri!.startsWith('/');
    return {
      'id': id,
      'role': role.name,
      'type': type.name,
      'content': content,
      if (keepAudio) 'audioUri': audioUri,
      'timestamp': timestamp,
      if (status != null) 'status': status!.name,
      if (duration != null) 'duration': duration,
      // Keep imageBase64 — images are typically 50-200 KB and must survive restart.
      if (imageBase64 != null) 'imageBase64': imageBase64,
      if (mimeType != null) 'mimeType': mimeType,
    };
  }

  factory Message.fromJson(Map<String, dynamic> json) {
    return Message(
      id: json['id'] as String,
      role: MessageRole.values.byName(json['role'] as String),
      type: MessageType.values.byName(json['type'] as String),
      content: json['content'] as String? ?? '',
      audioUri: json['audioUri'] as String?,
      imageBase64: json['imageBase64'] as String?,
      mimeType: json['mimeType'] as String?,
      timestamp: json['timestamp'] as int,
      status: json['status'] != null
          ? MessageStatus.values.byName(json['status'] as String)
          : null,
      duration: json['duration'] as int?,
    );
  }

  /// Returns true if this is a voice message that has neither audio nor text.
  bool get isEmptyVoice =>
      type == MessageType.voice &&
      (audioUri == null || audioUri!.isEmpty) &&
      content.isEmpty;

  /// Returns true if this is a text message with no content (empty bubble).
  bool get isEmptyText =>
      type == MessageType.text &&
      content.trim().isEmpty &&
      imageBase64 == null;
}