private double CalculateHardInterval(CardHistoryEntry lastHistoryEntry, CardHistoryEntry currentHistoryEntry, double lastInterval)
{
double reviewDelay = CalculateReviewDelay(lastHistoryEntry.EntryTime.TimeOfDay, currentHistoryEntry.EntryTime.TimeOfDay, lastInterval);
return(Math.Max(lastInterval + 1,
((lastInterval + (reviewDelay / 4.0)) * 1.2 * intervalModifier)));
}
private double CalculateEasyInterval(CardHistoryEntry lastHistoryEntry, CardHistoryEntry currentHistoryEntry, double lastInterval, double understandingFactor)
{
double reviewDelay = CalculateReviewDelay(lastHistoryEntry.EntryTime.TimeOfDay, currentHistoryEntry.EntryTime.TimeOfDay, lastInterval);
return(Math.Max(CalculateNormalInterval(lastHistoryEntry, currentHistoryEntry, lastInterval, understandingFactor) + 1,
((lastInterval + reviewDelay) * (understandingFactor / 1000.0) * intervalModifier * easyIntervalModifier)));
}
private AnkiCardIntervalData CalculateCardIntervalData(Card c)
{
IEnumerable <CardHistoryEntry> history = c.HistoryEntries;
history = history.OrderBy(x => x.EntryTime);
double uf = 0;
double interval = 0;
CardHistoryEntry lastHistoryEntry = null;
foreach (CardHistoryEntry historyEntry in history)
{
if (lastHistoryEntry == null)
{
interval = newInterval;
lastHistoryEntry = historyEntry;
}
switch (historyEntry.TrialPerformance)
{
case TrialPerformance.Fail:
uf = CalculateFailFactor(uf);
interval = interval * newInterval;
break;
case TrialPerformance.Easy:
uf = CalculateEasyFactor(uf);
interval = CalculateEasyInterval(lastHistoryEntry, historyEntry, interval, uf);
break;
case TrialPerformance.Normal:
uf = CalculateNormalFactor(uf);
interval = CalculateNormalInterval(lastHistoryEntry, historyEntry, interval, uf);
break;
case TrialPerformance.Hard:
uf = CalculateHardFactor(uf);
interval = CalculateHardInterval(lastHistoryEntry, historyEntry, interval);
break;
default:
throw new InvalidDataBaseOperationException(String.Format("Unsupported TrialPerformance value in card history: {0}", historyEntry.TrialPerformance));
}
lastHistoryEntry = historyEntry;
}
var cardIntervalData = new AnkiCardIntervalData()
{
lastReview = lastHistoryEntry?.EntryTime,
card = c,
interval = interval,
understandingFactor = uf
};
return(cardIntervalData);
}
