Fix the simple-SRS ratchet, the graduation counter, and the 8,000-card queue

CLAUDE.md

@@ -31,6 +31,16 @@ designed past.
 - Do not invent a requirement to justify a design. If the task is lookup, a
   page-marking feature nobody asked for is not evidence that an index is needed.
 
+## The SRS schedulers are measured, not argued
+
+`stores/simple-srs.ts` is a Midori clone and every scheduling rule in it has been changed
+on simulated evidence; some tempting changes were measured and rejected. Read
+[docs/simple-srs-decisions.md](docs/simple-srs-decisions.md) before editing it or the
+simple-SRS branches of `app/(tabs)/lists/study.tsx`. Simulate a deck through
+`nextSimpleReview` itself rather than reimplementing the rules — the lapse bug survived
+every test for months because the tests called `simpleGraduate` directly and the defect
+was in the argument the screen passed it.
+
 ## Reader lookup and furigana scoring is settled — measure before you touch it
 
 Tap ranking, furigana resolution, counter readings and the deinflection rule

components/DueCardsSection.tsx

@@ -6,7 +6,12 @@ import { useUserDb } from "@/db/user-provider";
 import { useSync } from "@/db/sync-provider";
 import { useListsStore } from "@/stores/lists";
 import { getCardStateDistribution, type CardDistribution } from "@/lib/practice-stats";
-import { srsEpochDaysToDate, endOfLogicalDayEpochDays } from "@/stores/simple-srs";
+import {
+  srsEpochDaysToDate,
+  endOfLogicalDayEpochDays,
+  resolveNewPerSession,
+  learningCapFor,
+} from "@/stores/simple-srs";
 import { useAtomValue } from "jotai";
 import { dayResetHourAtom } from "@/stores/settings";
 import type { FlashcardMode } from "@/db/types";
@@ -122,14 +127,34 @@ export function DueCardsSection({
     if (flashcardMode === "simple_srs") {
       const rows = await userDb.getAllAsync<{ dueDays: number }>(
         `SELECT simple_n as dueDays
-         FROM srs_cards WHERE list_id = ? AND simple_stage IS NOT NULL AND deleted_at IS NULL`,
+         FROM srs_cards WHERE list_id = ? AND simple_stage = 1 AND deleted_at IS NULL`,
         [listId],
       );
       for (const row of rows) {
         const dueDate = srsEpochDaysToDate(row.dueDays);
         const idx = dateToBucketIndex(dueDate, dayResetHour);
         counts[idx]++;
       }
+      // What the session will actually serve, not what the deck holds: cards in
+      // learning are all due now and the session shows three times the
+      // new-card cap of them, plus up to a cap of unseen cards. Counting the
+      // deck promised 8,000 due where the session showed thirty and then said
+      // it was done; ignoring the new cards under-reported a fresh list as 0.
+      const capRow = await userDb.getFirstAsync<{ new_per_session: number | null }>(
+        "SELECT new_per_session FROM lists WHERE id = ?",
+        [listId],
+      );
+      const newCap = resolveNewPerSession(capRow?.new_per_session);
+      const pending = await userDb.getFirstAsync<{ learning: number; unseen: number }>(
+        // SUM(CASE …) rather than COUNT(*) FILTER, which needs SQLite 3.30+.
+        `SELECT
+           SUM(CASE WHEN simple_stage = 0 AND simple_n <= ? THEN 1 ELSE 0 END) as learning,
+           SUM(CASE WHEN simple_stage IS NULL THEN 1 ELSE 0 END) as unseen
+         FROM srs_cards WHERE list_id = ? AND deleted_at IS NULL`,
+        [endOfLogicalDayEpochDays(dayResetHour), listId],
+      );
+      counts[0] += Math.min(pending?.learning ?? 0, learningCapFor(newCap));
+      counts[0] += Math.min(pending?.unseen ?? 0, newCap);
     } else {
       const newRow = await userDb.getFirstAsync<{ c: number }>(
         "SELECT COUNT(*) as c FROM srs_cards WHERE list_id = ? AND state = 0 AND deleted_at IS NULL",

components/FlashcardSettingsModal.tsx

@@ -14,6 +14,7 @@ import { alert } from "@/lib/confirm";
 import { requestVoicePermissions } from "@/lib/voice-recognition";
 import { useSync } from "@/db/sync-provider";
 import type { CardFace, FlashcardMode } from "@/db/types";
+import { DEFAULT_NEW_PER_SESSION } from "@/stores/simple-srs";
 
 interface FlashcardSettingsModalProps {
   visible: boolean;
@@ -55,6 +56,7 @@ export function FlashcardSettingsModal({
   const [buttonAnimation, setButtonAnimation] = useAtom(flashcardButtonAnimationAtom);
   const [learningStepsText, setLearningStepsText] = useState("");
   const [relearningStepsText, setRelearningStepsText] = useState("");
+  const [newPerSessionText, setNewPerSessionText] = useState("");
   const [hasKanjiEntries, setHasKanjiEntries] = useState(false);
 
   const inputMode = voiceMode
@@ -85,6 +87,7 @@ export function FlashcardSettingsModal({
       setMnemonicCloze(list.mnemonicCloze ?? false);
       setLearningStepsText(list.learningSteps ? list.learningSteps.join(", ") : "");
       setRelearningStepsText(list.relearningSteps ? list.relearningSteps.join(", ") : "");
+      setNewPerSessionText(list.newPerSession != null ? String(list.newPerSession) : "");
     }
   }, [visible, list]);
 
@@ -121,6 +124,23 @@ export function FlashcardSettingsModal({
   async function handleSave() {
     if (!userDb) return;
 
+    // Empty means "use the default", not zero: a cap of 0 would send a list
+    // with nothing due straight to the done screen. The input only shows for
+    // simple SRS, so any other mode keeps whatever the list already stored
+    // rather than writing NULL over it.
+    let newPerSession: number | null = list?.newPerSession ?? null;
+    if (mode === "simple_srs") {
+      newPerSession = null;
+      if (newPerSessionText.trim()) {
+        const parsed = Number(newPerSessionText.trim());
+        if (!Number.isInteger(parsed) || parsed < 1 || parsed > 500) {
+          alert("Invalid number", "New cards per session must be a whole number from 1 to 500.");
+          return;
+        }
+        newPerSession = parsed;
+      }
+    }
+
     // Validate learning steps if provided
     let learningSteps: string[] | null = null;
     let relearningSteps: string[] | null = null;
@@ -159,7 +179,8 @@ export function FlashcardSettingsModal({
         typingMode === (list.typingMode ?? false) &&
         mnemonicCloze === (list.mnemonicCloze ?? false) &&
         arrEq(learningSteps, list.learningSteps) &&
-        arrEq(relearningSteps, list.relearningSteps);
+        arrEq(relearningSteps, list.relearningSteps) &&
+        newPerSession === (list.newPerSession ?? null);
       if (unchanged) {
         onClose(false);
         return;
@@ -168,7 +189,7 @@ export function FlashcardSettingsModal({
 
     const now = new Date().toISOString();
     await userDb.runAsync(
-      "UPDATE lists SET flashcard_mode = ?, front_faces = ?, back_faces = ?, auto_play_audio = ?, confusion_detection = ?, voice_mode = ?, typing_mode = ?, mnemonic_cloze = ?, learning_steps = ?, relearning_steps = ?, configured = 1, updated_at = ? WHERE id = ?",
+      "UPDATE lists SET flashcard_mode = ?, front_faces = ?, back_faces = ?, auto_play_audio = ?, confusion_detection = ?, voice_mode = ?, typing_mode = ?, mnemonic_cloze = ?, learning_steps = ?, relearning_steps = ?, new_per_session = ?, configured = 1, updated_at = ? WHERE id = ?",
       [
         mode,
         JSON.stringify(frontFaces),
@@ -180,6 +201,7 @@ export function FlashcardSettingsModal({
         mnemonicCloze ? 1 : 0,
         learningSteps ? JSON.stringify(learningSteps) : null,
         relearningSteps ? JSON.stringify(relearningSteps) : null,
+        newPerSession,
         now,
         listId,
       ],
@@ -196,13 +218,17 @@ export function FlashcardSettingsModal({
       mnemonicCloze,
       learningSteps,
       relearningSteps,
+      newPerSession,
       updatedAt: now,
     });
     markDirty();
     if (onStartStudy) {
       onStartStudy();
     } else {
-      onClose(mode !== list?.flashcardMode);
+      // The queue is rebuilt for a changed mode and for a changed new-card cap:
+      // the cap decides how many cards the session loads, so leaving it until
+      // the next session means the setting looks ignored.
+      onClose(mode !== list?.flashcardMode || newPerSession !== (list?.newPerSession ?? null));
     }
   }
 
@@ -297,6 +323,28 @@ export function FlashcardSettingsModal({
               </View>
             )}
 
+            {/* New cards per session (simple SRS only) */}
+            {mode === "simple_srs" && (
+              <View className="mb-4">
+                <Text className="text-sm font-medium text-muted-foreground mb-2">
+                  New cards per session
+                </Text>
+                <TextInput
+                  value={newPerSessionText}
+                  onChangeText={setNewPerSessionText}
+                  placeholder={String(DEFAULT_NEW_PER_SESSION)}
+                  placeholderTextColor="#999"
+                  keyboardType="number-pad"
+                  className="border border-border rounded-lg px-3 py-2 text-sm text-foreground"
+                  autoCapitalize="none"
+                  autoCorrect={false}
+                />
+                <Text className="text-xs text-muted-foreground mt-2">
+                  Each new card costs about ten reviews a day once it settles in.
+                </Text>
+              </View>
+            )}
+
             {/* Front faces */}
             <Text className="text-sm font-medium text-muted-foreground mb-2">Front</Text>
             <View className="flex-row flex-wrap gap-2 mb-4">

components/StudyStatisticsModal.tsx

@@ -39,7 +39,8 @@ export function StudyStatisticsModal({
     if (flashcardMode === "simple_srs") {
       const now = new Date().toISOString();
       await userDb.runAsync(
-        "UPDATE srs_cards SET simple_stage = NULL, simple_n = NULL, simple_interval = NULL, updated_at = ? WHERE list_id = ?",
+        `UPDATE srs_cards SET simple_stage = NULL, simple_n = NULL, simple_interval = NULL,
+          simple_relearning = 0, simple_run = 0, updated_at = ? WHERE list_id = ?`,
         [now, listId],
       );
     } else if (flashcardMode === "srs") {

db/schema.ts

@@ -118,6 +118,7 @@ export const lists = sqliteTable("lists", {
   voiceMode: integer("voice_mode").notNull().default(0),
   typingMode: integer("typing_mode").notNull().default(0),
   mnemonicCloze: integer("mnemonic_cloze").notNull().default(0),
+  newPerSession: integer("new_per_session").default(10),
   disableFlipAnimation: integer("disable_flip_animation").notNull().default(0),
   disableSwipeAnimation: integer("disable_swipe_animation").notNull().default(0),
   isDefault: integer("is_default").notNull().default(0),
@@ -161,6 +162,8 @@ export const srsCards = sqliteTable("srs_cards", {
   simpleStage: integer("simple_stage"),
   simpleN: real("simple_n"),
   simpleInterval: real("simple_interval"),
+  simpleRelearning: integer("simple_relearning").default(0),
+  simpleRun: integer("simple_run").default(0),
   lastConfusionCheck: text("last_confusion_check"),
   deletedAt: text("deleted_at"),
   learningSteps: integer("learning_steps").notNull().default(0),