/// 文档模型
class Document {
  final String id;
  final String name;
  final String? description;
  final DocumentType type;
  final DocumentStatus status;
  final DateTime createdAt;
  final DateTime? updatedAt;
  final int? fileSize; // bytes
  final String? fileUrl;
  final String? parsedText;
  final Map<String, dynamic>? metadata;

  Document({
    required this.id,
    required this.name,
    this.description,
    required this.type,
    required this.status,
    required this.createdAt,
    this.updatedAt,
    this.fileSize,
    this.fileUrl,
    this.parsedText,
    this.metadata,
  });

  /// 从JSON创建
  factory Document.fromJson(Map<String, dynamic> json) {
    return Document(
      id: json['id'] as String,
      name: json['name'] as String,
      description: json['description'] as String?,
      type: DocumentType.values.firstWhere(
        (e) => e.toString().split('.').last == json['type'],
        orElse: () => DocumentType.other,
      ),
      status: DocumentStatus.values.firstWhere(
        (e) => e.toString().split('.').last == json['status'],
        orElse: () => DocumentStatus.pending,
      ),
      createdAt: DateTime.parse(json['createdAt'] as String),
      updatedAt: json['updatedAt'] != null
          ? DateTime.parse(json['updatedAt'] as String)
          : null,
      fileSize: json['fileSize'] as int?,
      fileUrl: json['fileUrl'] as String?,
      parsedText: json['parsedText'] as String?,
      metadata: json['metadata'] as Map<String, dynamic>?,
    );
  }

  /// 转换为JSON
  Map<String, dynamic> toJson() {
    return {
      'id': id,
      'name': name,
      'description': description,
      'type': type.toString().split('.').last,
      'status': status.toString().split('.').last,
      'createdAt': createdAt.toIso8601String(),
      'updatedAt': updatedAt?.toIso8601String(),
      'fileSize': fileSize,
      'fileUrl': fileUrl,
      'parsedText': parsedText,
      'metadata': metadata,
    };
  }

  /// 复制并更新
  Document copyWith({
    String? id,
    String? name,
    String? description,
    DocumentType? type,
    DocumentStatus? status,
    DateTime? createdAt,
    DateTime? updatedAt,
    int? fileSize,
    String? fileUrl,
    String? parsedText,
    Map<String, dynamic>? metadata,
  }) {
    return Document(
      id: id ?? this.id,
      name: name ?? this.name,
      description: description ?? this.description,
      type: type ?? this.type,
      status: status ?? this.status,
      createdAt: createdAt ?? this.createdAt,
      updatedAt: updatedAt ?? this.updatedAt,
      fileSize: fileSize ?? this.fileSize,
      fileUrl: fileUrl ?? this.fileUrl,
      parsedText: parsedText ?? this.parsedText,
      metadata: metadata ?? this.metadata,
    );
  }

  /// 格式化文件大小
  String get formattedFileSize {
    if (fileSize == null) return '未知';
    if (fileSize! < 1024) return '${fileSize}B';
    if (fileSize! < 1024 * 1024)
      return '${(fileSize! / 1024).toStringAsFixed(2)}KB';
    return '${(fileSize! / (1024 * 1024)).toStringAsFixed(2)}MB';
  }
}

/// 文档类型
enum DocumentType { pdf, word, image, markdown, other }

/// 文档状态
enum DocumentStatus {
  pending, // 待处理
  uploading, // 上传中
  parsing, // 解析中
  processing, // 处理中
  completed, // 已完成
  failed, // 失败
}

extension DocumentStatusExtension on DocumentStatus {
  String get label {
    switch (this) {
      case DocumentStatus.pending:
        return '待处理';
      case DocumentStatus.uploading:
        return '上传中';
      case DocumentStatus.parsing:
        return '解析中';
      case DocumentStatus.processing:
        return '处理中';
      case DocumentStatus.completed:
        return '已完成';
      case DocumentStatus.failed:
        return '失败';
    }
  }
}