class MatManager {
  List<Map<String, dynamic>> items = [];

  MatManager(this.items);

  void matManager({int? index, Map<String, dynamic>? newItem}) {
    if (index != null && newItem != null) {
      // 更新指定索引的对象
      items[index] = newItem;
    } else if (newItem != null) {

      // 添加新项目
      items.add(newItem);
    } else {
      print('请提供有效的索引或项目');
    }
  }

  void addOrUpdateItem({required var newItem, required var fieldsToMatch}) {
    for (var item in items) {
      bool isMatch = fieldsToMatch.every((field) => item[field] == newItem[field]);
      if (isMatch) {
        item['quantity'] = (item['quantity'] ?? 0) + (newItem['quantity'] ?? 0);
        return;
      }
    }
    items.add(newItem);
  }
}