public DateTime NextReview(IReviewItem item)
{
var now = _clock.Now();
if(item.CorrectReviewStreak == 0)
return now;
if(item.CorrectReviewStreak == 1)
return item.ReviewDate.AddDays(6);
var easinessFactor = DifficultyRatingToEasinessFactor(item.DifficultyRating.Percentage);
var daysSincePreviousReview = (item.ReviewDate - item.PreviousCorrectReview).Days;
var daysUntilNextReview = (daysSincePreviousReview - 1) * easinessFactor;
return item.ReviewDate.AddDays(daysUntilNextReview);
}
public DateTime NextReview(IReviewItem item)
{
var now = _clock.Now();
if (item.CorrectReviewStreak == 0)
{
return(now);
}
if (item.CorrectReviewStreak == 1)
{
return(item.ReviewDate.AddDays(6));
}
var easinessFactor = DifficultyRatingToEasinessFactor(item.DifficultyRating.Percentage);
var daysSincePreviousReview = (item.ReviewDate - item.PreviousCorrectReview).Days;
var daysUntilNextReview = (daysSincePreviousReview - 1) * easinessFactor;
return(item.ReviewDate.AddDays(daysUntilNextReview));
}
public DifficultyRating AdjustDifficulty(IReviewItem item, ReviewOutcome outcome)
{
//EF':=EF+(0.1-(5-q)*(0.08+(5-q)*0.02))
//where:
//EF' - new value of the E-Factor,
//EF - old value of the E-Factor,
//q - quality of the response in the 0-3 grade scale.
//If EF is less than 1.3 then let EF be 1.3.
var currentEasinessFactor = DifficultyRatingToEasinessFactor(item.DifficultyRating.Percentage);
var newEasinessFactor = currentEasinessFactor + (0.1 - (3 - (int)outcome)*(0.08 + (3 - (int)outcome)*0.02));
var newDifficultyRating = EasinessFactorToDifficultyRating(newEasinessFactor);
if (newDifficultyRating > 100)
newDifficultyRating = 100;
if (newDifficultyRating < 0)
newDifficultyRating = 0;
return new DifficultyRating(newDifficultyRating);
}
public DifficultyRating AdjustDifficulty(IReviewItem item, ReviewOutcome outcome)
{
//EF':=EF+(0.1-(5-q)*(0.08+(5-q)*0.02))
//where:
//EF' - new value of the E-Factor,
//EF - old value of the E-Factor,
//q - quality of the response in the 0-3 grade scale.
//If EF is less than 1.3 then let EF be 1.3.
var currentEasinessFactor = DifficultyRatingToEasinessFactor(item.DifficultyRating.Percentage);
var newEasinessFactor = currentEasinessFactor + (0.1 - (3 - (int)outcome) * (0.08 + (3 - (int)outcome) * 0.02));
var newDifficultyRating = EasinessFactorToDifficultyRating(newEasinessFactor);
if (newDifficultyRating > 100)
{
newDifficultyRating = 100;
}
if (newDifficultyRating < 0)
{
newDifficultyRating = 0;
}
return(new DifficultyRating(newDifficultyRating));
}
private static bool IsNewItem(IReviewItem item)
{
return(item.ReviewDate == DateTime.MinValue);
}
public bool IsDue(IReviewItem item)
{
var nextReview = ReviewStrategy.NextReview(item);
return(nextReview <= Clock.Now());
}
public DateTime NextReview(IReviewItem item)
{
return DateTime.Now;
}
public DifficultyRating AdjustDifficulty(IReviewItem item, ReviewOutcome outcome)
{
return DifficultyRating.Easiest;
}
public DateTime NextReview(IReviewItem item)
{
return(DateTime.Now);
}
public DifficultyRating AdjustDifficulty(IReviewItem item, ReviewOutcome outcome)
{
return(DifficultyRating.Easiest);
}