From ac43a5a73fa905cdac905bc956763b6093d6738e Mon Sep 17 00:00:00 2001
From: Maze Winther <mazewinther@gmail.com>
Date: Wed, 15 Apr 2026 05:43:29 +0200
Subject: feat: move/resize multiple elements

---
 .../src/lib/timeline/group-move/track-placement.ts | 83 ++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 apps/web/src/lib/timeline/group-move/track-placement.ts

(limited to 'apps/web/src/lib/timeline/group-move/track-placement.ts')

diff --git a/apps/web/src/lib/timeline/group-move/track-placement.ts b/apps/web/src/lib/timeline/group-move/track-placement.ts
new file mode 100644
index 00000000..d301e5ef
--- /dev/null
+++ b/apps/web/src/lib/timeline/group-move/track-placement.ts
@@ -0,0 +1,83 @@
+import type { SceneTracks, TimelineTrack } from "@/lib/timeline";
+import type { GroupTrackSection } from "./types";
+
+export interface TrackPlacement {
+	trackId: string;
+	trackType: TimelineTrack["type"];
+	section: GroupTrackSection;
+	sectionIndex: number;
+	displayIndex: number;
+}
+
+export function getDisplayTracks({
+	tracks,
+}: {
+	tracks: SceneTracks;
+}): TimelineTrack[] {
+	return [...tracks.overlay, tracks.main, ...tracks.audio];
+}
+
+export function getTrackPlacementById({
+	tracks,
+	trackId,
+}: {
+	tracks: SceneTracks;
+	trackId: string;
+}): TrackPlacement | null {
+	if (tracks.main.id === trackId) {
+		return {
+			trackId,
+			trackType: tracks.main.type,
+			section: "main",
+			sectionIndex: -1,
+			displayIndex: tracks.overlay.length,
+		};
+	}
+
+	const overlayTrackIndex = tracks.overlay.findIndex(
+		(track) => track.id === trackId,
+	);
+	if (overlayTrackIndex >= 0) {
+		return {
+			trackId,
+			trackType: tracks.overlay[overlayTrackIndex].type,
+			section: "overlay",
+			sectionIndex: overlayTrackIndex,
+			displayIndex: overlayTrackIndex,
+		};
+	}
+
+	const audioTrackIndex = tracks.audio.findIndex(
+		(track) => track.id === trackId,
+	);
+	if (audioTrackIndex >= 0) {
+		return {
+			trackId,
+			trackType: tracks.audio[audioTrackIndex].type,
+			section: "audio",
+			sectionIndex: audioTrackIndex,
+			displayIndex: tracks.overlay.length + 1 + audioTrackIndex,
+		};
+	}
+
+	return null;
+}
+
+export function getTrackPlacementByDisplayIndex({
+	tracks,
+	displayIndex,
+}: {
+	tracks: SceneTracks;
+	displayIndex: number;
+}): TrackPlacement | null {
+	const displayTracks = getDisplayTracks({ tracks });
+	const track = displayTracks[displayIndex];
+	if (!track) {
+		return null;
+	}
+
+	return getTrackPlacementById({
+		tracks,
+		trackId: track.id,
+	});
+}
-- 
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