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authornsfisis <nsfisis@gmail.com>2026-02-04 22:51:01 +0900
committernsfisis <nsfisis@gmail.com>2026-02-04 22:51:01 +0900
commit2d617f236fa3fbd39a0a7def23199a36cfa0b4c2 (patch)
treef6c4afb9d1690e4ee821cb2795ec04e2de1879b8 /src/shared/date.ts
parent62beeeab74b844b7a7819345c844114428450d96 (diff)
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fix(study): use 3 AM boundary for counting today's new card reviews
countTodayNewCardReviews was using midnight (0:00) as the start of day, inconsistent with the 3 AM study day boundary used elsewhere. Reviews between 0:00-3:00 AM were incorrectly counted as the next day's budget. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Diffstat (limited to 'src/shared/date.ts')
-rw-r--r--src/shared/date.ts21
1 files changed, 21 insertions, 0 deletions
diff --git a/src/shared/date.ts b/src/shared/date.ts
index 583d2a6..3b34f14 100644
--- a/src/shared/date.ts
+++ b/src/shared/date.ts
@@ -1,4 +1,25 @@
/**
+ * Returns the start-of-day boundary for the current study day.
+ *
+ * The "study day" is defined as 3:00 AM to the next day's 3:00 AM.
+ *
+ * - If current time >= 3:00 AM, start = today 3:00 AM local time
+ * - If current time < 3:00 AM, start = yesterday 3:00 AM local time
+ */
+export function getStartOfStudyDayBoundary(now: Date = new Date()): Date {
+ const boundary = new Date(now);
+ boundary.setMinutes(0, 0, 0);
+
+ if (boundary.getHours() < 3) {
+ // Move to previous day
+ boundary.setDate(boundary.getDate() - 1);
+ }
+
+ boundary.setHours(3);
+ return boundary;
+}
+
+/**
* Returns the end-of-day boundary for due card comparison.
*
* The "study day" is defined as 3:00 AM to the next day's 3:00 AM.