fix(chapters): sync race-story titles after conflict trim

resolveConflicts already clips a still-open safety car so finish can
keep the last laps, but Title and EndTime stayed on the pre-trim
range. Rebuild range-bearing titles from the final laps and point
EndTime at the trimmed lap-index end.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/chapters/chapters.go

@@ -72,7 +72,7 @@ func Detect(rc []RaceControl, positions []PositionSample, laps []Lap, totalLaps
 	chapters = append(chapters, detectDecisiveSwings(positions, lapIndex, totalLaps)...)
 	chapters = append(chapters, detectFinish(rc, lapIndex, totalLaps))
 
-	return resolveConflicts(chapters)
+	return resolveConflicts(chapters, lapIndex)
 }
 
 func normalizeTotalLaps(totalLaps int, laps []Lap, rc []RaceControl) int {
@@ -321,7 +321,7 @@ func detectPitPhases(laps []Lap, idx lapIndex) []Chapter {
 		}
 		ch := Chapter{
 			Kind:          KindPitPhase,
-			Title:         fmt.Sprintf("Pit phase (L%d-L%d)", start, end),
+			Title:         pitPhaseTitle(start, end),
 			StartLap:      start,
 			EndLap:        end,
 			StartTime:     idx.lapStart(start),
@@ -339,7 +339,7 @@ func detectPitPhases(laps []Lap, idx lapIndex) []Chapter {
 				drivers[driver] = true
 			}
 			last.DriverNumbers = sortedDriverNumbers(drivers)
-			last.Title = fmt.Sprintf("Pit phase (L%d-L%d)", last.StartLap, last.EndLap)
+			last.Title = pitPhaseTitle(last.StartLap, last.EndLap)
 			continue
 		}
 		windows = append(windows, ch)
@@ -479,7 +479,7 @@ func detectFinish(rc []RaceControl, idx lapIndex, totalLaps int) Chapter {
 	}
 	return Chapter{
 		Kind:      KindFinish,
-		Title:     fmt.Sprintf("Finish (L%d-L%d)", startLap, finishLap),
+		Title:     finishTitle(startLap, finishLap),
 		StartLap:  startLap,
 		EndLap:    finishLap,
 		StartTime: idx.lapStart(startLap),
@@ -487,7 +487,31 @@ func detectFinish(rc []RaceControl, idx lapIndex, totalLaps int) Chapter {
 	}
 }
 
-func resolveConflicts(chapters []Chapter) []Chapter {
+func pitPhaseTitle(startLap, endLap int) string {
+	return fmt.Sprintf("Pit phase (L%d-L%d)", startLap, endLap)
+}
+
+func finishTitle(startLap, endLap int) string {
+	return fmt.Sprintf("Finish (L%d-L%d)", startLap, endLap)
+}
+
+// titleForResolved rebuilds range-bearing titles from the final StartLap/EndLap
+// after conflict resolution. Flag and pit-phase formatters are reused so stale
+// pre-trim strings are never parsed.
+func titleForResolved(ch Chapter) string {
+	switch ch.Kind {
+	case KindSafetyCar, KindVirtualSafetyCar, KindRedFlag:
+		return flagTitle(ch.Kind, ch.StartLap, ch.EndLap)
+	case KindPitPhase:
+		return pitPhaseTitle(ch.StartLap, ch.EndLap)
+	case KindFinish:
+		return finishTitle(ch.StartLap, ch.EndLap)
+	default:
+		return ch.Title
+	}
+}
+
+func resolveConflicts(chapters []Chapter, idx lapIndex) []Chapter {
 	normalized := make([]Chapter, 0, len(chapters))
 	for _, ch := range chapters {
 		if ch.StartLap <= 0 {
@@ -528,6 +552,7 @@ func resolveConflicts(chapters []Chapter) []Chapter {
 		if priority(ch.Kind) > priority(last.Kind) {
 			if last.StartLap < ch.StartLap {
 				last.EndLap = ch.StartLap - 1
+				last.EndTime = idx.lapEnd(last.EndLap)
 				out = append(out, ch)
 			} else {
 				*last = ch
@@ -541,6 +566,9 @@ func resolveConflicts(chapters []Chapter) []Chapter {
 			}
 		}
 	}
+	for i := range out {
+		out[i].Title = titleForResolved(out[i])
+	}
 	return out
 }
 

internal/chapters/chapters_test.go

@@ -125,6 +125,42 @@ func TestDetectDecisiveSwingPersistsToFinish(t *testing.T) {
 	}
 }
 
+func TestDetectSafetyCarTrimmedForFinishRewritesTitle(t *testing.T) {
+	rcs := []RaceControl{
+		rc(3, models.CategorySafetyCar, "", "SAFETY CAR DEPLOYED"),
+		rc(72, models.CategoryFlag, models.FlagChequered, "CHEQUERED FLAG"),
+	}
+
+	got := Detect(rcs, nil, testLaps(72, nil), 72)
+
+	sc := findKind(got, KindSafetyCar)
+	if sc == nil {
+		t.Fatalf("chapters = %+v, want safety car", got)
+	}
+	if sc.StartLap != 3 || sc.EndLap != 70 || sc.Title != "Safety Car (L3-L70)" {
+		t.Fatalf("safety car = %+v, want StartLap=3 EndLap=70 Title=%q", *sc, "Safety Car (L3-L70)")
+	}
+	if wantEnd := lapTime(71); sc.EndTime != wantEnd {
+		t.Fatalf("safety car EndTime = %q, want lap-index end of L70 (%q)", sc.EndTime, wantEnd)
+	}
+
+	fin := findKind(got, KindFinish)
+	if fin == nil || fin.StartLap != 71 || fin.EndLap != 72 {
+		t.Fatalf("finish = %+v, want L71-L72", got)
+	}
+
+	for i := 1; i < len(got); i++ {
+		if got[i].StartLap <= got[i-1].EndLap {
+			t.Fatalf("chapters overlap at %d: %+v then %+v", i, got[i-1], got[i])
+		}
+	}
+
+	headed := ApplyHeadlines(got, nil, rcs, 0)
+	if scH := findKind(headed, KindSafetyCar); scH == nil || scH.Headline != "Safety Car (L3-L70)" {
+		t.Fatalf("headline = %+v, want fallback to resolved title Safety Car (L3-L70)", headed)
+	}
+}
+
 func TestDetectFlagPeriodsWinOverConflictingChapters(t *testing.T) {
 	pitOuts := map[int][]int{
 		12: {1, 2},