refactor: centralize track placement into its own module

1 files changed, 40 insertions, 0 deletions

diff --git a/apps/web/src/lib/timeline/placement/overlap.ts b/apps/web/src/lib/timeline/placement/overlap.ts
new file mode 100644
index 00000000..e5f95fa9
--- /dev/null
+++ b/apps/web/src/lib/timeline/placement/overlap.ts
@@ -0,0 +1,40 @@
+import type { TimelineElement, TimelineTrack } from "@/lib/timeline";
+import type { PlacementTimeSpan } from "./types";
+
+function wouldElementOverlap({
+	elements,
+	startTime,
+	endTime,
+	excludeElementId,
+}: {
+	elements: TimelineElement[];
+	startTime: number;
+	endTime: number;
+	excludeElementId?: string;
+}): boolean {
+	return elements.some((element) => {
+		if (excludeElementId && element.id === excludeElementId) {
+			return false;
+		}
+
+		const elementEnd = element.startTime + element.duration;
+		return startTime < elementEnd && endTime > element.startTime;
+	});
+}
+
+export function canPlaceTimeSpansOnTrack({
+	track,
+	timeSpans,
+}: {
+	track: TimelineTrack;
+	timeSpans: PlacementTimeSpan[];
+}): boolean {
+	return timeSpans.every(({ startTime, duration, excludeElementId }) => {
+		return !wouldElementOverlap({
+			elements: track.elements,
+			startTime,
+			endTime: startTime + duration,
+			excludeElementId,
+		});
+	});
+}