2 files changed, 69 insertions, 9 deletions
diff --git a/server/internal/skips/kinds.go b/server/internal/skips/kinds.go
index e70ce05..e2518dd 100644
--- a/server/internal/skips/kinds.go
+++ b/server/internal/skips/kinds.go
@@ -38,10 +38,10 @@ const (
 // confirm anything until a second fetch occasion has passed.
 func Classify(breaks []AdBreak, servedMs, declaredMs int64) []AdBreak {
 	out := make([]AdBreak, 0, len(breaks))
-	// If there's no declared length, we can't compare, so treat conservatively as inserted ads.
+	// If we can't judge (missing served or declared length), treat conservatively as inserted ads.
 	// If both lengths are known and the file is longer than declared by more than encoding slop,
 	// it contains inserted ads.
-	inserted := declaredMs <= 0 || (servedMs > 0 && declaredMs > 0 && servedMs-declaredMs > durationSlopMs)
+	inserted := servedMs <= 0 || declaredMs <= 0 || (servedMs > 0 && declaredMs > 0 && servedMs-declaredMs > durationSlopMs)
 
 	for _, b := range breaks {
 		b.Kind = KindAd
@@ -53,15 +53,48 @@ func Classify(breaks []AdBreak, servedMs, declaredMs int64) []AdBreak {
 	return out
 }
 
-// furnitureKindAt names a break by where it sits. Opening first: a very short episode could
-// satisfy both tests, and its first break is its opening.
+// furnitureKindAt names a break by where it sits.
+//
+// For normal-length episodes, the opening and closing windows don't overlap. For very short
+// episodes, they do: a break may be close to both the start and the end. In that case, classify
+// by the nearest edge.
 func furnitureKindAt(b AdBreak, servedMs int64) BreakKind {
-	switch {
-	case b.StartMs <= edgeWindowMs:
+	if servedMs <= 0 {
+		return KindCue // shouldn't happen but be safe
+	}
+
+	// Use a window size proportional to the episode length for very short episodes.
+	// For long episodes (>= 240s), use the fixed edgeWindowMs (120s).
+	// For short episodes, use a quarter of the episode length as the window.
+	windowMs := int64(edgeWindowMs)
+	if servedMs < 2*edgeWindowMs {
+		// For short episodes (< 240s), use a quarter of the episode as the window
+		windowMs = servedMs / 4
+	}
+
+	distToStart := b.StartMs
+	distToEnd := servedMs - b.EndMs
+
+	inOpeningWindow := distToStart <= windowMs
+	inClosingWindow := distToEnd <= windowMs
+
+	if inOpeningWindow && inClosingWindow {
+		// In the overlap - use nearest edge
+		if distToStart < distToEnd {
+			return KindIntro
+		} else if distToEnd < distToStart {
+			return KindOutro
+		} else {
+			// Exactly in the middle - treat as cue (interior break)
+			return KindCue
+		}
+	}
+
+	if inOpeningWindow {
 		return KindIntro
-	case servedMs > 0 && servedMs-b.EndMs <= edgeWindowMs:
+	}
+	if inClosingWindow {
 		return KindOutro
-	default:
-		return KindCue
 	}
+	return KindCue
 }
diff --git a/server/internal/skips/kinds_test.go b/server/internal/skips/kinds_test.go
index f9fc6f0..544b9ea 100644
--- a/server/internal/skips/kinds_test.go
+++ b/server/internal/skips/kinds_test.go
@@ -109,3 +109,30 @@ func TestClassifyLeavesEverythingButTheKindAlone(t *testing.T) {
 		t.Errorf("classify altered the range: %+v, want %+v with only Kind set", got, in)
 	}
 }
+
+// Finding 1: A zero or invalid servedMs falls through to furniture instead of the mandated "ad" fallback.
+func TestAZeroServedLengthIsTreatedAsAdvertising(t *testing.T) {
+	got := Classify([]AdBreak{{StartMs: 50_000, EndMs: 55_000}}, 0, 100_000)
+
+	if got[0].Kind != KindAd {
+		t.Errorf("kind %q, want %q when served length is zero", got[0].Kind, KindAd)
+	}
+}
+
+// Finding 2: In a short episode, interior and closing breaks are misclassified as "intro".
+func TestAShortEpisodeClassifiesBreaksByPosition(t *testing.T) {
+	// Episode is 100 seconds (less than 2*edgeWindowMs = 240s).
+	// With breaks at 0s, 50s, and 90s, they should be distinguished as intro, cue, and outro.
+	got := Classify([]AdBreak{
+		{StartMs: 0, EndMs: 5_000},
+		{StartMs: 50_000, EndMs: 55_000},
+		{StartMs: 90_000, EndMs: 95_000},
+	}, 100_000, 100_000)
+
+	want := []BreakKind{KindIntro, KindCue, KindOutro}
+	for i, k := range kindsOf(got) {
+		if k != want[i] {
+			t.Errorf("break %d at %dms is %q, want %q in short episode", i, got[i].StartMs, k, want[i])
+		}
+	}
+}