public async Task <CourseEnrollment> GetCourseEnrollmentAsync(string courseTitle)
{
Guard.NotNullOrEmpty(courseTitle, nameof(courseTitle));
var filter = Builders <BsonDocument> .Filter
.Eq(Fields.CourseTitle, courseTitle);
var document = await _context.Courses
.Find(filter)
.SingleOrDefaultAsync();
if (document == null)
{
return(null);
}
BsonDocument summaryDoc = FromBson.GetSummaryDocument(document);
return(new CourseEnrollment(
courseId: FromBson.GetId(document),
courseVersion: FromBson.GetVersion(document),
courseTitle: FromBson.GetCourseTitle(document),
capacity: FromBson.GetCourseCapacity(document),
students: FromBson.GetCourseStudents(document),
summary: new CourseSummary(
ageMin: FromBson.GetSummaryMin(summaryDoc),
ageMax: FromBson.GetSummaryMax(summaryDoc),
ageSum: FromBson.GetSummarySum(summaryDoc),
ageAvg: FromBson.GetSummaryAvg(summaryDoc),
studentCount: FromBson.GetSummaryStudentCount(summaryDoc)
)
));
}