added functional export student group result to html

CharlieBackend.Business/Services/FileServices/ExportFileServices/ExportServiceHtml.cs

@@ -55,11 +55,18 @@ public async Task<Result<FileDto>> GetStudentClassbook(StudentsClassbookResultDt
                     "student classbook can't be returned in html format");
         }
 
-        public Task<Result<FileDto>> GetStudentGroupResults(StudentGroupsResultsDto data)
+        public async Task<Result<FileDto>> GetStudentGroupResults(StudentGroupsResultsDto data)
         {
-            return Task.FromResult(Result<FileDto>.GetError(
-                    ErrorCode.ValidationError,
-                    "student classbook can't be returned in html format"));
+            using var studentGroupResults = new StudentGroupResultsExportHTML("Student Group Results");
+
+            studentGroupResults.FillFileAsync(data);
+
+            return Result<FileDto>.GetSuccess(new FileDto()
+            {
+                ByteArray = await studentGroupResults.GetByteArrayAsync(),
+                ContentType = studentGroupResults.GetContentType(),
+                Filename = studentGroupResults.GetFileName()
+            });
         }
 
         public Task<Result<FileDto>> GetStudentResults(StudentsResultsDto data)

CharlieBackend.Business/Services/FileServices/ExportFileServices/Html/StudentGroupResultsExportHTML.cs

@@ -0,0 +1,98 @@
+using CharlieBackend.Core.DTO.Dashboard;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CharlieBackend.Business.Services.FileServices.ExportFileServices.Html
+{
+	public class StudentGroupResultsExportHTML : BaseFileExportHTML
+	{
+		private string _fileName;
+		private const int _CourseColumnNumber = 0;
+		private const int _StudentGroupColumnNumber = 1;
+		private const int _AverageMarkColumnNumber = 2;
+
+		public StudentGroupResultsExportHTML(string fileName)
+		{
+			_fileName = fileName;
+		}
+		public void FillFileAsync(StudentGroupsResultsDto data)
+		{
+			if (data == null)
+			{
+				return;
+			}
+			FillAverageMarks(data.AverageStudentGroupsMarks);
+
+			FillAverageVisits(data.AverageStudentGroupsVisits);
+		}
+
+		public void FillAverageMarks(IEnumerable<AverageStudentGroupMarkDto> AverageStudentGroupsMarks)
+		{
+			if (AverageStudentGroupsMarks.Any())
+			{
+				var orderedList = AverageStudentGroupsMarks.OrderBy(x => x.StudentGroup);
+				string[] headers = new string[] { "Course", "Student Group", "Average mark" };
+				string[][] rows = new string[orderedList.Count()][];
+
+				for (int i = 0; i < rows.Length; i++)
+				{
+					var group = orderedList.ElementAt(i);
+					rows[i] = new string[headers.Length];
+					rows[i][_CourseColumnNumber] = AverageStudentGroupsMarks.First().Course;
+					rows[i][_StudentGroupColumnNumber] = group.StudentGroup;
+					rows[i][_AverageMarkColumnNumber] = Math.Round((decimal)group.AverageMark, 2).ToString();
+				}
+
+				StringBuilder table = HtmlGenerator.GenerateTable(headers, rows);
+				StringBuilder html = HtmlGenerator.GenerateHtml(_fileName, table);
+				byte[] byteLine = ConvertLineToArray(html.ToString());
+				_memoryStream.Write(byteLine);
+			}
+		}
+
+		public void FillAverageVisits(IEnumerable<AverageStudentGroupVisitDto> AverageStudentGroupsVisits)
+		{
+			if (AverageStudentGroupsVisits.Any())
+			{
+				var orderedList = AverageStudentGroupsVisits.OrderBy(x => x.StudentGroup);
+				string[] headers = new string[] { "Course", "Student Group", "Average visits" };
+				string[][] rows = new string[orderedList.Count()][];
+
+				for (int i = 0; i < rows.Length; i++)
+				{
+					var group = orderedList.ElementAt(i);
+					rows[i] = new string[headers.Length];
+					rows[i][_CourseColumnNumber] = AverageStudentGroupsVisits.First().Course;
+					rows[i][_StudentGroupColumnNumber] = group.StudentGroup;
+					rows[i][_AverageMarkColumnNumber] = ((double)group.AverageVisitPercentage / 100).ToString();
+				}
+
+				StringBuilder table = HtmlGenerator.GenerateTable(headers, rows);
+				StringBuilder html = HtmlGenerator.GenerateHtml(_fileName, table);
+				byte[] byteLine = ConvertLineToArray(html.ToString());
+				_memoryStream.Write(byteLine);
+
+			}
+		}
+
+		private byte[] ConvertLineToArray(string line)
+		{
+			byte[] array = new byte[line.Length];
+
+			for (int i = 0; i < line.Length; i++)
+			{
+				array[i] = (byte)line[i];
+			}
+
+			return array;
+		}
+
+		public override string GetFileName()
+		{
+			return "StudentGroupResult_" + DateTime.Now.ToString("yyyy-MM-dd") + ".html";
+		}
+	}
+}

CharlieBackend.Core/DTO/Dashboard/StudentGroupResults/StudentsGroupsResultsDto.cs

@@ -7,5 +7,12 @@ public class StudentGroupsResultsDto
         public IEnumerable<AverageStudentGroupVisitDto> AverageStudentGroupsVisits { get; set; }
 
         public IEnumerable<AverageStudentGroupMarkDto> AverageStudentGroupsMarks { get; set; }
+
+        public StudentGroupsResultsDto()
+		{
+            AverageStudentGroupsVisits = new List<AverageStudentGroupVisitDto>();
+            AverageStudentGroupsMarks = new List<AverageStudentGroupMarkDto>();
+        }
+
     }
 }