/// <summary>
/// 学生开始课后任务，生成题目
/// </summary>
public void GenerateTaskSubjectsAutoAfterStudy(int studyTaskId, int studentId)
{
StudentStudyBll studyBll = new StudentStudyBll();
SubjectBll subjectBll = new SubjectBll();
Yw_StudyTask task = StudyTaskRepository.Get(studyTaskId);
Yw_StudentTask stuTask = StudentTaskRepository.GetByStudentTask(studentId, studyTaskId);
if (task == null || stuTask == null)
{
return;
}
Yw_StudentLessonAnswerExt answer = studyBll.GetLessonAnswer(task.Ysk_LessonProgressId) as Yw_StudentLessonAnswerExt;
if (answer == null)
{
return;
}
List <StudentAnswerBase> problemAnswers = answer.Yla_Answer_Obj.SelectMany(x => x.AnswerCollection).Where(x => x.ResultStars < 5).ToList();
List <Tuple <int, int> > errorSubjects = problemAnswers.GroupBy(x => x.SubjectId).
Select(x => new Tuple <int, int>(x.Key, x.Min(y => y.ResultStars))).ToList();
List <DtoLesTaskSubject> subjects = subjectBll.GetLessonTaskSubject(task.Ysk_LessonId, errorSubjects);
var groups = subjects.OrderBy(x => x.Number)
.GroupBy(x => new { ErrorSubjectId = x.ErrorSubjectId, Score = x.Score })
.OrderBy(x => x.Key.Score);
Dictionary <int, DtoLesTaskSubject> subjectSelected = new Dictionary <int, DtoLesTaskSubject>();
List <WrapSubjectGroup> wrapGroups = new List <WrapSubjectGroup>();
foreach (IGrouping <dynamic, DtoLesTaskSubject> group in groups)
{
wrapGroups.Add(new WrapSubjectGroup(group.Key.Score, group.ToList()));
}
bool hasSubject = false;
bool reachMax = false;
int maxSubjectCount = groups.Count() > 50 ? groups.Count() : 50;//每个错题至少推一个关联题目
int loopTime = 0;
while (loopTime < maxSubjectCount)
{
hasSubject = false;
foreach (WrapSubjectGroup group in wrapGroups)
{
bool result = group.TakeSubject(subjectSelected);
if (result)
{
if (subjectSelected.Count >= maxSubjectCount)
{
reachMax = true;
break;
}
hasSubject = true;
}
}
if (!hasSubject || reachMax)
{
break;
}
loopTime++;
}
if (subjectSelected.Count > 0)
{
task.Ysk_SubjectIds = string.Join(",", subjectSelected.OrderBy(x => x.Value.SubjectType).Select(x => x.Value.SubjectId));
task.Ysk_SubjectCount = subjectSelected.Count;
task.Ysk_Score = 5 * subjectSelected.Count;
StudyTaskRepository.Update(task);
stuTask.Yuk_SubjectCount = subjectSelected.Count;
StudentTaskRepository.Update(stuTask);
}
}
