1 files changed, 32 insertions, 29 deletions
diff --git a/apps/web/src/timeline/index.ts b/apps/web/src/timeline/index.ts
index 5ee079b1..3775e006 100644
--- a/apps/web/src/timeline/index.ts
+++ b/apps/web/src/timeline/index.ts
@@ -1,29 +1,32 @@
-import type { SceneTracks } from "./types";
-
-export * from "./types";
-export * from "./drag";
-export * from "./track-capabilities";
-export * from "./track-element-update";
-export * from "./element-utils";
-export * from "./audio-separation";
-export * from "./zoom-utils";
-export * from "./ruler-utils";
-export * from "./pixel-utils";
-
-export function calculateTotalDuration({
-	tracks,
-}: {
-	tracks: SceneTracks;
-}): number {
-	const orderedTracks = [...tracks.overlay, tracks.main, ...tracks.audio];
-	if (orderedTracks.length === 0) return 0;
-
-	const trackEndTimes = orderedTracks.map((track) =>
-		track.elements.reduce((maxEnd, element) => {
-			const elementEnd = element.startTime + element.duration;
-			return Math.max(maxEnd, elementEnd);
-		}, 0),
-	);
-
-	return Math.max(...trackEndTimes, 0);
-}
+import { type MediaTime, ZERO_MEDIA_TIME } from "@/wasm";
+import type { SceneTracks } from "./types";
+
+export * from "./types";
+export * from "./drag";
+export * from "./track-capabilities";
+export * from "./track-element-update";
+export * from "./element-utils";
+export * from "./audio-separation";
+export * from "./zoom-utils";
+export * from "./ruler-utils";
+export * from "./pixel-utils";
+
+export function calculateTotalDuration({
+	tracks,
+}: {
+	tracks: SceneTracks;
+}): MediaTime {
+	const orderedTracks = [...tracks.overlay, tracks.main, ...tracks.audio];
+	if (orderedTracks.length === 0) return ZERO_MEDIA_TIME;
+
+	let maxEnd: MediaTime = ZERO_MEDIA_TIME;
+	for (const track of orderedTracks) {
+		for (const element of track.elements) {
+			// `startTime + duration` is integer-by-construction (both `MediaTime`),
+			// so the cast re-establishes the brand without runtime work.
+			const elementEnd = (element.startTime + element.duration) as MediaTime;
+			if (elementEnd > maxEnd) maxEnd = elementEnd;
+		}
+	}
+	return maxEnd;
+}