Add system (curated) vs. user-uploaded flashcards

System decks/notes are owned by a reserved sentinel user id, reusing all existing per-user store/index plumbing unchanged. Regular users see them under a separate "Official Decks" section, can study them with fully independent per-user FSRS progress (lazily materialized on first visit), but can never edit or archive them - enforced both in the client (no Edit/Archive controls) and server-side (ownership guard on every mutating endpoint). Includes a small idempotent seed command (`dotnet run -- seed-flashcards`) for testing, since there's no in-app authoring UI yet.
2026-07-22 15:52:19 -05:00
parent 3a01e9156c
commit 7f76ca0fdc
13 changed files with 444 additions and 31 deletions
@@ -81,6 +81,44 @@ public sealed class FlashcardScheduleStore
        }
    }

+    // Sibling of SyncVariantsAsync: materializes this note's variant schedule rows under a
+    // DIFFERENT user's ownership (the studying user, not the note's own owner). Used only for
+    // system notes, so a regular user studying shared content gets independent, per-user FSRS
+    // state. Deliberately duplicated rather than sharing a parameterized private helper with
+    // SyncVariantsAsync, which is called eagerly on every regular note save and must stay
+    // untouched/low-risk.
+    public async Task SyncVariantsForStudyingUserAsync(string studyingUserId, FlashcardNote note)
+    {
+        var desiredVariants = note.Type == FlashcardTypes.Cloze
+            ? FlashcardClozeParser.DistinctClozeNumbers(note.Prompt)
+            : [0];
+        if (desiredVariants.Count == 0) return;
+
+        var existing = await GetByNoteIdAsync(studyingUserId, note.Id!);
+        var existingVariants = existing.Select(v => v.Variant).ToHashSet();
+        var now = DateTime.UtcNow;
+        foreach (var variant in desiredVariants.Where(v => !existingVariants.Contains(v)))
+        {
+            var schedule = new FlashcardSchedule
+            {
+                UserId = studyingUserId,
+                NoteId = note.Id!,
+                Variant = variant,
+                State = FlashcardScheduleStates.New,
+                DueUtc = now,
+                CreatedUtc = now
+            };
+            try
+            {
+                await _schedules.InsertOneAsync(schedule);
+            }
+            catch (MongoWriteException exception) when (exception.WriteError?.Category == ServerErrorCategory.DuplicateKey)
+            {
+                // Concurrent save already created this variant.
+            }
+        }
+    }
+
    public async Task<FlashcardSchedule?> GetAsync(string userId, string cardId) =>
        await _schedules.Find(v => v.UserId == userId && v.Id == cardId).FirstOrDefaultAsync();