private Slide GetInitialSlideForStartup(string courseId, List <Unit> orderedVisibleUnits, bool isInstructor)
{
var userId = User.Identity.GetUserId();
var lastVisit = visitsRepo.FindLastVisit(courseId, userId);
var orderedVisibleSlides = orderedVisibleUnits.SelectMany(u => u.GetSlides(isInstructor)).ToList();
if (lastVisit != null)
{
var lastVisitedSlide = orderedVisibleSlides.FirstOrDefault(s => s.Id == lastVisit.SlideId);
if (lastVisitedSlide != null)
{
return(lastVisitedSlide);
}
if (isInstructor)
{
var instructorNoteSlide = orderedVisibleUnits.FirstOrDefault(u => u.Id == lastVisit.SlideId)?.InstructorNote?.Slide;
if (instructorNoteSlide != null)
{
return(instructorNoteSlide);
}
}
}
var unorderedVisitedIds = visitsRepo.GetIdOfVisitedSlides(courseId, userId);
var lastVisitedVisibleSlide = orderedVisibleSlides.LastOrDefault(slide => unorderedVisitedIds.Contains(slide.Id));
if (lastVisitedVisibleSlide != null)
{
return(lastVisitedVisibleSlide);
}
return(orderedVisibleSlides.Any() ? orderedVisibleSlides.First() : null);
}