class CommodityRateHistory {
  final int? id;
  final String commodityCode;
  final String? commodityName;
  final String? purity;
  final double rate;
  final DateTime effectiveAt;
  final String? source;
  final int? createdBy;
  final DateTime? createdAt;

  CommodityRateHistory({
    this.id,
    required this.commodityCode,
    this.commodityName,
    this.purity,
    required this.rate,
    required this.effectiveAt,
    this.source,
    this.createdBy,
    this.createdAt,
  });

  factory CommodityRateHistory.fromJson(Map<String, dynamic> json) {
    return CommodityRateHistory(
      id: json['id'] is int ? json['id'] : int.tryParse(json['id']?.toString() ?? ''),
      commodityCode: (json['commodityCode'] ?? json['commodity_code'] ?? json['commodityName'] ?? json['commodity_name'] ?? '').toString(),
      commodityName: json['commodityName'] ?? json['commodity_name'],
      purity: json['purity'],
      rate: (json['rate'] as num?)?.toDouble() ?? 0.0,
      effectiveAt: json['effectiveAt'] != null 
          ? DateTime.parse(json['effectiveAt'].toString()) 
          : (json['effective_at'] != null ? DateTime.parse(json['effective_at'].toString()) : DateTime.now()),
      source: json['source'],
      createdBy: json['createdBy'] ?? json['created_by'],
      createdAt: json['createdAt'] != null 
          ? DateTime.parse(json['createdAt'].toString()) 
          : (json['created_at'] != null ? DateTime.parse(json['created_at'].toString()) : null),
    );
  }

  Map<String, dynamic> toJson() {
    return {
      if (id != null) 'id': id,
      'commodityCode': commodityCode,
      'commodityName': commodityName ?? commodityCode,
      if (purity != null) 'purity': purity,
      'rate': rate,
      'effectiveAt': effectiveAt.toIso8601String(),
      if (source != null) 'source': source,
      if (createdBy != null) 'createdBy': createdBy,
    };
  }
}