public async Task <RatingByLessonDto> GetWorstLessonByMarkByStudentId(int studentId, DateTime startDate, DateTime endDate)
{
var today = DateTime.Today;
var marksStream = _repository.GetMarksForTimeByStudentId(studentId, startDate, endDate);
var marks = new List <Mark>();
await foreach (var mark in marksStream)
{
marks.Add(mark);
}
var worstLesson = new RatingByLessonDto();
foreach (var group in marks.GroupBy(x => x.SubjectId))
{
var count = 0;
var sum = 0.0;
foreach (var item in group)
{
count++;
sum += item.Grade ?? 0;
}
if (count != 0 && (sum / count < worstLesson.Rating || worstLesson.Rating == 0))
{
worstLesson.Rating = Math.Round((sum / count), 2);
worstLesson.LessonId = group.Key;
//worstLesson.LessonId = group.FirstOrDefault()?.Subject?.Id;
}
}
return(worstLesson);
}
public static RatingByLessonViewModel ToViewModel(this RatingByLessonDto dto)
{
if (dto == null)
{
throw new ArgumentNullException(nameof(RatingByLessonDto));
}
return(new RatingByLessonViewModel
{
Rating = dto.Rating,
LessonId = dto.LessonId
});
}