refactor: unify element updates into pipeline and centralize ripple

1 files changed, 65 insertions, 0 deletions

diff --git a/apps/web/src/lib/ripple/apply.ts b/apps/web/src/lib/ripple/apply.ts
new file mode 100644
index 00000000..098a0247
--- /dev/null
+++ b/apps/web/src/lib/ripple/apply.ts
@@ -0,0 +1,65 @@
+import type { TimelineTrack } from "@/lib/timeline/types";
+import { rippleShiftElements } from "./shift";
+
+export interface RippleAdjustment {
+	trackId: string;
+	afterTime: number;
+	shiftAmount: number;
+}
+
+export function applyRippleAdjustments({
+	tracks,
+	adjustments,
+}: {
+	tracks: TimelineTrack[];
+	adjustments: RippleAdjustment[];
+}): TimelineTrack[] {
+	if (adjustments.length === 0) {
+		return tracks;
+	}
+
+	const adjustmentsByTrack = new Map<string, RippleAdjustment[]>();
+	for (const adjustment of adjustments) {
+		const trackAdjustments = adjustmentsByTrack.get(adjustment.trackId) ?? [];
+		trackAdjustments.push(adjustment);
+		adjustmentsByTrack.set(adjustment.trackId, trackAdjustments);
+	}
+
+	return tracks.map((track) =>
+		applyTrackRippleAdjustments({
+			track,
+			adjustments: adjustmentsByTrack.get(track.id) ?? [],
+		}),
+	);
+}
+
+function applyTrackRippleAdjustments<
+	TElement extends TimelineTrack["elements"][number],
+	TTrack extends TimelineTrack & { elements: TElement[] },
+>({
+	track,
+	adjustments,
+}: {
+	track: TTrack;
+	adjustments: RippleAdjustment[];
+}): TTrack {
+	if (adjustments.length === 0) {
+		return track;
+	}
+
+	const sortedAdjustments = [...adjustments].sort(
+		(firstAdjustment, secondAdjustment) =>
+			secondAdjustment.afterTime - firstAdjustment.afterTime,
+	);
+
+	let elements: TElement[] = track.elements;
+	for (const adjustment of sortedAdjustments) {
+		elements = rippleShiftElements({
+			elements,
+			afterTime: adjustment.afterTime,
+			shiftAmount: adjustment.shiftAmount,
+		});
+	}
+
+	return { ...track, elements };
+}