using ClosedXML.Excel;
using RhSolutions.Api.Models;

namespace RhSolutions.Api.Services
{
	public class ClosedXMLParser : IPricelistParser
	{
		public async IAsyncEnumerable<Product> GetProducts(HttpContext context)
		{
			using (var memoryStream = new MemoryStream())
			{
				if (context == null)
				{
					yield break;
				}
				
				await context.Request.Body.CopyToAsync(memoryStream);
				using (var wb = new XLWorkbook(memoryStream))
				{
					var table = GetTable(wb);
					var rows = table.DataRange.Rows();
					var enumerator = rows.GetEnumerator();
					while (enumerator.MoveNext())
					{
						if (Sku.TryParse(enumerator.Current.Field("Актуальный материал")
							.GetString(), out IEnumerable<Sku> skus))
						{
							yield return ParseRow(enumerator.Current);
						}
					}
					yield break;
				}
			}
		}
		private IXLTable GetTable(XLWorkbook wb)
		{
			var ws = wb.Worksheets.First();
			ws.AutoFilter.IsEnabled = false;
			try
			{
				var firstCellAddress = ws.Search("Программа", System.Globalization.CompareOptions.IgnoreCase)
					.First()
					.Address;

				var lastCellAddress = ws.LastCellUsed().Address;

				return ws.Range(firstCellAddress, lastCellAddress).AsTable();
			}
			catch (Exception ex)
			{
				throw new Exception($"Exception on parsing {ws.Name}:\n{ex.Message}");
			}
		}

		private Product ParseRow(IXLTableRow row)
		{
			string productLine = row.Field("Программа")
				.GetString();
			string productName = row.Field("Наименование")
				.GetString()
				.Split('\n')
				.First();
			Sku.TryParse(row.Field("Актуальный материал")
				.GetString(), out IEnumerable<Sku> productSkus);
			Sku.TryParse(row.Field("Прежний материал")
				.GetString(), out IEnumerable<Sku> deprecatedSkus);

			string measureField = new string(row.Field("Ед. изм.")
				.GetString()
				.ToLower()
				.Where(c => char.IsLetterOrDigit(c))
				.ToArray());
			Measure productMeasure;

			switch (measureField)
			{
				case "кг":
					productMeasure = Measure.Kg;
					break;
				case "м":
					productMeasure = Measure.M;
					break;
				case "м2":
					productMeasure = Measure.M2;
					break;
				case "шт":
					productMeasure = Measure.P;
					break;
				default:
					throw new ArgumentException();
			}

			string shippingSizeField = row.Field("Единица поставки")
				.GetString();

			if (!double.TryParse(shippingSizeField, out double productWarehouseCount))
			{
				productWarehouseCount = 0.0;
			}

			string onWarehouseField = row.Field("Складская программа")
				.GetString();
			bool? IsOnWarehouse;

			switch (onWarehouseField)
			{
				case "x":
					IsOnWarehouse = true;
					break;
				case "под заказ":
					IsOnWarehouse = false;
					break;
				default:
					IsOnWarehouse = null;
					break;
			}

			string priceField = row.Field("Цена брутто \nЕВРО\nбез НДС")
				.GetString();

			if (!decimal.TryParse(priceField, out decimal price))
			{
				price = 0.0M;
			}

			return new Product
			{
				ProductLine = productLine,
				Name = productName,
				ProductSku = productSkus.First().Id,
				DeprecatedSkus = deprecatedSkus.Select(s => s.Id).ToList(),
				ProductMeasure = productMeasure,
				DeliveryMakeUp = productWarehouseCount,
				IsOnWarehouse = IsOnWarehouse,
				Price = price
			};
		}
	}
}