fix: quality-adjusted SM-2 first intervals and review UX freeze

apps/api/app/algorithms/sm2.py

@@ -44,7 +44,10 @@ def sm2_schedule(
         new_repetitions = repetitions + 1
 
         if repetitions == 0:
-            new_interval = 1
+            # Quality-adjusted first interval: Easy gets 4 days, Hard gets 2 days.
+            # Standard SM-2 fixes this at 1, but that makes every first review
+            # feel identical regardless of confidence — poor UX.
+            new_interval = 4 if quality >= 4 else 2
         elif repetitions == 1:
             new_interval = 6
         else:

apps/api/tests/test_sm2.py

@@ -8,10 +8,17 @@
 # Basic scheduling progression
 # ---------------------------------------------------------------------------
 
-def test_first_review_easy_interval_is_one():
-    """First review (repetitions=0) always produces interval=1 regardless of quality."""
+def test_first_review_easy_gives_four_day_interval():
+    """First review (repetitions=0) with quality>=4 (Easy) gives interval=4."""
     interval, reps, ef = sm2_schedule(quality=5, repetitions=0, ease_factor=2.5, interval=1)
-    assert interval == 1
+    assert interval == 4
+    assert reps == 1
+
+
+def test_first_review_hard_gives_two_day_interval():
+    """First review (repetitions=0) with quality==3 (Hard) gives interval=2."""
+    interval, reps, ef = sm2_schedule(quality=3, repetitions=0, ease_factor=2.5, interval=1)
+    assert interval == 2
     assert reps == 1
 
 
@@ -111,7 +118,7 @@ def test_simulate_30_days_of_reviews():
         assert ease_factor >= 1.3, f"EF below minimum at step {step}"
         assert repetitions == step + 1, f"Unexpected reps at step {step}"
 
-        # After the fixed steps (1 and 6), each interval must grow
+        # After the quality-adjusted first step (4) and the fixed second step (6), intervals grow
         if step >= 2:
             assert interval >= prev_interval, (
                 f"Interval did not grow at step {step}: {interval} < {prev_interval}"

apps/web/components/review-card.tsx

@@ -13,10 +13,11 @@ interface ReviewCardProps {
   index: number
   total: number
   onRate: (rating: 1 | 3 | 5) => void
-  isSubmitting: boolean
+  submittingRating: 1 | 3 | 5 | null
 }
 
-export function ReviewCard({ snippet, index, total, onRate, isSubmitting }: ReviewCardProps) {
+export function ReviewCard({ snippet, index, total, onRate, submittingRating }: ReviewCardProps) {
+  const isSubmitting = submittingRating !== null
   const [revealed, setReveal] = useState(false)
 
   return (
@@ -120,20 +121,23 @@ export function ReviewCard({ snippet, index, total, onRate, isSubmitting }: Revi
               sublabel="Start over"
               onClick={() => onRate(1)}
               disabled={isSubmitting}
+              isActive={submittingRating === 1}
               variant="forgot"
             />
             <RatingButton
               label="Hard"
               sublabel="Got it, barely"
               onClick={() => onRate(3)}
               disabled={isSubmitting}
+              isActive={submittingRating === 3}
               variant="hard"
             />
             <RatingButton
               label="Easy"
               sublabel="Got it!"
               onClick={() => onRate(5)}
               disabled={isSubmitting}
+              isActive={submittingRating === 5}
               variant="easy"
             />
           </div>
@@ -148,12 +152,14 @@ function RatingButton({
   sublabel,
   onClick,
   disabled,
+  isActive,
   variant,
 }: {
   label: string
   sublabel: string
   onClick: () => void
   disabled: boolean
+  isActive: boolean
   variant: "forgot" | "hard" | "easy"
 }) {
   const styles = {
@@ -170,12 +176,29 @@ function RatingButton({
       className={cn(
         "flex flex-col items-center gap-0.5 rounded-xl border px-3 py-3.5",
         "active:scale-[0.96] transition-[transform,background-color,opacity] duration-100",
-        "disabled:pointer-events-none disabled:opacity-50",
+        "disabled:pointer-events-none",
+        isActive ? "opacity-100" : "disabled:opacity-40",
         styles[variant],
       )}
     >
-      <span className="text-sm font-semibold">{label}</span>
-      <span className="text-[11px] opacity-70">{sublabel}</span>
+      {isActive ? (
+        <svg
+          className="size-4 animate-spin"
+          viewBox="0 0 24 24"
+          fill="none"
+          aria-label="Processing"
+        >
+          <circle className="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" strokeWidth="2.5" />
+          <path
+            className="opacity-75"
+            fill="currentColor"
+            d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4z"
+          />
+        </svg>
+      ) : (
+        <span className="text-sm font-semibold">{label}</span>
+      )}
+      <span className="text-[11px] opacity-70">{isActive ? "Saving…" : sublabel}</span>
     </button>
   )
 }

apps/web/components/review-session.tsx

@@ -13,20 +13,29 @@ export function ReviewSession() {
 
   const [index, setIndex] = useState(0)
   const [done, setDone] = useState(false)
+  const [submittingRating, setSubmittingRating] = useState<1 | 3 | 5 | null>(null)
+  const [submitError, setSubmitError] = useState<string | null>(null)
 
   const handleRate = async (snippet: Snippet, rating: 1 | 3 | 5) => {
-    await submitReview.mutateAsync({
-      snippetId: snippet.id,
-      rating,
-      currentEase: snippet.ease_factor,
-      currentInterval: snippet.interval_days,
-      currentReps: snippet.repetitions,
-    })
-
-    if (index + 1 >= due.length) {
-      setDone(true)
-    } else {
-      setIndex((i) => i + 1)
+    setSubmittingRating(rating)
+    setSubmitError(null)
+    try {
+      await submitReview.mutateAsync({
+        snippetId: snippet.id,
+        rating,
+        currentEase: snippet.ease_factor,
+        currentInterval: snippet.interval_days,
+        currentReps: snippet.repetitions,
+      })
+      if (index + 1 >= due.length) {
+        setDone(true)
+      } else {
+        setIndex((i) => i + 1)
+      }
+    } catch (err) {
+      setSubmitError(err instanceof Error ? err.message : "Something went wrong. Try again.")
+    } finally {
+      setSubmittingRating(null)
     }
   }
 
@@ -98,13 +107,19 @@ export function ReviewSession() {
         </p>
       </div>
 
+      {submitError && (
+        <div className="rounded-xl border border-destructive/30 bg-destructive/8 px-4 py-3 text-sm text-destructive">
+          {submitError}
+        </div>
+      )}
+
       <ReviewCard
         key={current.id}
         snippet={current}
         index={index}
         total={due.length}
         onRate={(rating) => handleRate(current, rating)}
-        isSubmitting={submitReview.isPending}
+        submittingRating={submittingRating}
       />
     </div>
   )

apps/web/hooks/use-review.ts

@@ -1,6 +1,7 @@
 "use client"
 
 import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query"
+import { useAuth } from "@clerk/nextjs"
 import { createClient } from "@/lib/supabase/client"
 import { snippetKeys } from "@/hooks/use-snippets"
 import { useSupabaseUserId } from "@/hooks/use-user"
@@ -32,7 +33,9 @@ export function useReviewLogs() {
 }
 
 export function useSubmitReview() {
-  const { data: userId } = useSupabaseUserId()
+  // clerkId must match the key used by useDueSnippets — they both use snippetKeys.due(clerkId)
+  const { userId: clerkId } = useAuth()
+  const { data: supabaseUserId } = useSupabaseUserId()
   const queryClient = useQueryClient()
 
   return useMutation({
@@ -60,8 +63,10 @@ export function useSubmitReview() {
       }
     },
     onSuccess: () => {
-      queryClient.invalidateQueries({ queryKey: snippetKeys.due(userId ?? "") })
-      queryClient.invalidateQueries({ queryKey: reviewKeys.logs(userId ?? "") })
+      queryClient.invalidateQueries({ queryKey: snippetKeys.due(clerkId ?? "") })
+      if (supabaseUserId) {
+        queryClient.invalidateQueries({ queryKey: reviewKeys.logs(supabaseUserId) })
+      }
     },
   })
 }