Products - mock service

using System.Text.Json;
using Task05.Models;

namespace Task05.Services
{
    public interface IDataMock
    {
        List<Product> GetProducts();
        List<Receipt> GetReceipts();
    }

    public class DataMock : IDataMock
    {
        private readonly IWebHostEnvironment _env;

        private readonly List<Product> _products = new List<Product>();
        private readonly List<Receipt> _receipts = new List<Receipt>();
        private readonly Random _random = new Random(142911);

        private string GenerateHexString(int length)
            => string.Concat(Enumerable.Range(0, length).Select(_ => _random.Next(16).ToString("X")));

        public DataMock(IWebHostEnvironment env) {
            _env = env;

            var productsJson = File.ReadAllText(Path.Combine(_env.WebRootPath, "products-mock.json"));
            var options = new JsonSerializerOptions { PropertyNameCaseInsensitive = true };
            _products = JsonSerializer.Deserialize<List<Product>>(productsJson, options) ?? new List<Product>();

            for (int i = 0; i < 100; i++)
            {
                var receipt = new Receipt {
                    Id = i + 1,
                    Code = GenerateHexString(20),
                    Items = new List<ReceiptItem>(),
                };

                for (int j = 0; j < 3; j++)
                {
                    var product = _products[_random.Next(_products.Count)];
                    var quantity = _random.Next(10);

                    var receiptItem = new ReceiptItem
                    {
                        ItemNo = j + 1,
                        ProductName = product.Title,
                        Price = product.Price,
                        Quantity = quantity,
                        Value = Math.Round(product.Price * quantity, 2),
                    };

                    receipt.Items.Add(receiptItem);
                }

                receipt.Total = receipt.Items.Sum(x => x.Value);

                _receipts.Add(receipt);
            }
        }

        public List<Product> GetProducts()
        {
            return _products;
        }

        public List<Receipt> GetReceipts()
        {
            return _receipts;
        }
    }
}