From 8babacbeeef0648eded65bbfcc02cbc0d3d17d59 Mon Sep 17 00:00:00 2001
From: Jarrett Ye <jarrett.ye@outlook.com>
Date: Thu, 12 Sep 2024 14:08:31 +0800
Subject: [PATCH] Feat/get retrievability

---
 fsrs.go | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fsrs.go b/fsrs.go
index 8ae0e37..bad4760 100644
--- a/fsrs.go
+++ b/fsrs.go
@@ -19,3 +19,13 @@ func (f *FSRS) Repeat(card Card, now time.Time) RecordLog {
 func (f *FSRS) Next(card Card, now time.Time, grade Rating) SchedulingInfo {
 	return f.scheduler(card, now).Review(grade)
 }
+
+func (f *FSRS) GetRetrievability(card Card, now time.Time) float64 {
+	if card.State == New {
+		return 0
+	} else {
+		elapsedDays := now.Sub(card.LastReview).Hours() / 24
+		retrievability := f.Parameters.forgettingCurve(elapsedDays, card.Stability)
+		return retrievability
+	}
+}