/// <summary>
/// Gets the level that will be associated to the SRS entry matching the
/// given group in the current state.
/// </summary>
/// <returns>New level for the entity.</returns>
private SrsLevel GetUpdatedLevel(SrsQuestionGroup group)
{
// Take the upper/lower level depending on the success state.
int modifier = group.IsWrong ? -1 : 1;
SrsLevel newLevel = newLevel = SrsLevelStore.Instance.GetLevelByValue(
group.Reference.CurrentGrade + modifier);
// If the upper/lower level could not be obtained, (as this may
// be the case when at max/min level), use the current one.
// Note that this still may return a null value if the levels
// were not loaded correctly or if the configuration has changed.
return newLevel ?? SrsLevelStore.Instance.GetLevelByValue(
group.Reference.CurrentGrade);
}
/// <summary>
/// Called to update the SRS entry referred by a question group that was
/// answered.
/// </summary>
/// <param name="group">Question group answered.</param>
private void UpdateAnsweredGroup(SrsQuestionGroup group)
{
// Get the new level of the item.
SrsLevel newLevel = GetUpdatedLevel(group);
// Update its grade and next answer date.
if (newLevel != null)
{
// Set the next answer date according to the delay of the new level.
if (newLevel.Delay.HasValue)
{
group.Reference.NextAnswerDate =
DateTime.UtcNow
+ newLevel.Delay.Value;
}
else
{
group.Reference.NextAnswerDate = null;
}
group.Reference.CurrentGrade = newLevel.Value;
}
else
{
// If there is no new level and no current level, the delay is null.
group.Reference.NextAnswerDate = null;
}
// Update the success/failure count.
if (group.IsWrong)
{
group.Reference.FailureCount++;
}
else
{
group.Reference.SuccessCount++;
}
// Update the entry in the DB.
UpdateEntry(group.Reference);
}