/// <summary>
/// Converts DTO object to Entity, and adds it to database, if there is no element that satify condition.
/// </summary>
public async Task <ResultMessage <TDto> > Add(TDto dto, Predicate <TEntity> condition)
{
try
{
TEntity entity = await GetSingleOrDefault(condition);
if (entity != null)
{
return(new ResultMessage <TDto>(OperationStatus.Exists));
}
await _context.Set <TEntity>().AddAsync(Mapping.Mapper.Map <TEntity>(dto));
await _context.SaveChangesAsync();
entity = await GetSingleOrDefault(condition);
return(new ResultMessage <TDto>(Mapping.Mapper.Map <TDto>(entity)));
}
catch (DbUpdateException ex)
{
return(new ResultMessage <TDto>(_errorHandler.Handle(ex)));
}
catch (AutoMapperMappingException ex)
{
return(new ResultMessage <TDto>(_errorHandler.Handle(ex)));
}
catch (Exception ex)
{
return(new ResultMessage <TDto>(_errorHandler.Handle(ex)));
}
}
/// <summary>
/// Related specific course with specific study program, and semester.
/// </summary>
/// <param name="courseId">Unique identifer for the course</param>
/// <param name="studyProgram">Study program that needs to be related with specified course</param>
/// <param name="semester">Semester that needs to be related with specified course</param>
/// <returns>True if added, false if not</returns>
public async Task <ResultMessage <bool> > AddInStudyProgram(int courseId, StudyProgram studyProgram, Semester semester)
{
try
{
CourseStudyProgram courseStudyProgram = new CourseStudyProgram()
{
CourseId = courseId,
Semester = semester,
StudyProgram = studyProgram,
StudyYear = semester.GetStudyYear()
};
await _orhedgeContext.AddAsync(courseStudyProgram);
await _orhedgeContext.SaveChangesAsync();
return(new ResultMessage <bool>(true, OperationStatus.Success));
}
catch (DbUpdateException ex)
{
return(new ResultMessage <bool>(false, _errorHandler.Handle(ex)));
}
catch (Exception ex)
{
return(new ResultMessage <bool>(false, _errorHandler.Handle(ex)));
}
}
/// <summary>
/// With this method, specific student has option to rate specific study material.
/// This method uses transactions.
/// </summary>
/// <param name="studyMaterialId">Unique identifier for the study material</param>
/// <param name="authorId">Unique identifier for the author</param>
/// <param name="studentId">Unique identifier for the student that rates material</param>
/// <param name="rating">Given rating</param>
/// <returns></returns>
public async Task <ResultMessage <bool> > Rate(int studyMaterialId, int studentId, int authorId, int rating)
{
using (IDbContextTransaction transaction = await _context.Database.BeginTransactionAsync())
{
StudyMaterialRating smr = await _context.StudyMaterialRatings.FirstOrDefaultAsync(x => x.StudyMaterialId == studyMaterialId && x.StudentId == studentId);
if (smr == null)
{
await _context.StudyMaterialRatings.AddAsync(smr = new StudyMaterialRating()
{
StudentId = studentId,
StudyMaterialId = studyMaterialId,
Rating = rating
});
}
else
{
smr.Rating = rating;
}
try
{
await _context.SaveChangesAsync();
double totalRatingForMaterial = await _context.StudyMaterialRatings
.Where(x => x.StudyMaterialId == studyMaterialId)
.AverageAsync(x => x.Rating);
ResultMessage <bool> updatedMaterial = await _studyMaterialService.UpdateRating(studyMaterialId, totalRatingForMaterial);
if (!updatedMaterial.IsSuccess)
{
return(new ResultMessage <bool>(updatedMaterial.Status, updatedMaterial.Message));
}
double totalRatingForAuthor = await _context.StudyMaterialRatings
.Where(x => x.StudyMaterial.StudentId == authorId)
.AverageAsync(x => x.Rating);
ResultMessage <bool> updatedStudent = await _studentService.UpdateRating(authorId, totalRatingForAuthor);
if (!updatedStudent.IsSuccess)
{
return(new ResultMessage <bool>(updatedStudent.Status, updatedStudent.Message));
}
transaction.Commit();
return(new ResultMessage <bool>(true, OperationStatus.Success));
}
catch (DbUpdateException ex)
{
transaction.Rollback();
return(new ResultMessage <bool>(false, _errorHandler.Handle(ex)));
}
}
}