From 70a6d58b8432e455ab1443d45bc23dd70b363bea Mon Sep 17 00:00:00 2001
From: Maze Winther <mazewinther@gmail.com>
Date: Tue, 31 Mar 2026 15:47:30 +0200
Subject: refactor: centralize track placement into its own module

---
 apps/web/src/lib/timeline/track-utils.ts | 235 -------------------------------
 1 file changed, 235 deletions(-)

(limited to 'apps/web/src/lib/timeline/track-utils.ts')

diff --git a/apps/web/src/lib/timeline/track-utils.ts b/apps/web/src/lib/timeline/track-utils.ts
index 0034c72e..cc9e67c4 100644
--- a/apps/web/src/lib/timeline/track-utils.ts
+++ b/apps/web/src/lib/timeline/track-utils.ts
@@ -1,21 +1,17 @@
 import type {
 	TrackType,
 	TimelineTrack,
-	ElementType,
 	VideoTrack,
 	AudioTrack,
 	GraphicTrack,
 	TextTrack,
 	EffectTrack,
-	TimelineElement,
 } from "@/lib/timeline";
 import {
-	ELEMENT_TRACK_MAP,
 	TRACK_CONFIG,
 	ELEMENT_TYPE_CONFIG,
 	TRACK_GAP,
 } from "@/constants/timeline-constants";
-import { generateUUID } from "@/utils/id";
 
 export function canTracktHaveAudio(
 	track: TimelineTrack,
@@ -64,234 +60,3 @@ export function getTotalTracksHeight({
 	const gapsHeight = Math.max(0, tracks.length - 1) * TRACK_GAP;
 	return tracksHeight + gapsHeight;
 }
-
-export function buildEmptyTrack({
-	id,
-	type,
-	name,
-}: {
-	id: string;
-	type: TrackType;
-	name?: string;
-}): TimelineTrack {
-	const trackName = name ?? TRACK_CONFIG[type].defaultName;
-
-	switch (type) {
-		case "video":
-			return {
-				id,
-				name: trackName,
-				type: "video",
-				elements: [],
-				hidden: false,
-				muted: false,
-				isMain: false,
-			};
-		case "text":
-			return {
-				id,
-				name: trackName,
-				type: "text",
-				elements: [],
-				hidden: false,
-			};
-		case "graphic":
-			return {
-				id,
-				name: trackName,
-				type: "graphic",
-				elements: [],
-				hidden: false,
-			};
-		case "audio":
-			return {
-				id,
-				name: trackName,
-				type: "audio",
-				elements: [],
-				muted: false,
-			};
-		case "effect":
-			return {
-				id,
-				name: trackName,
-				type: "effect",
-				elements: [],
-				hidden: false,
-			};
-		default:
-			throw new Error(`Unsupported track type: ${type}`);
-	}
-}
-
-export function getDefaultInsertIndexForTrack({
-	tracks,
-	trackType,
-}: {
-	tracks: TimelineTrack[];
-	trackType: TrackType;
-}): number {
-	if (trackType === "audio") {
-		return tracks.length;
-	}
-
-	if (trackType === "effect") {
-		return 0;
-	}
-
-	const mainTrackIndex = tracks.findIndex((track) => isMainTrack(track));
-	if (mainTrackIndex >= 0) {
-		return mainTrackIndex;
-	}
-
-	const firstAudioTrackIndex = tracks.findIndex(
-		(track) => track.type === "audio",
-	);
-	if (firstAudioTrackIndex >= 0) {
-		return firstAudioTrackIndex;
-	}
-
-	return tracks.length;
-}
-
-export function getHighestInsertIndexForTrack({
-	tracks,
-	trackType,
-}: {
-	tracks: TimelineTrack[];
-	trackType: TrackType;
-}): number {
-	const mainTrackIndex = tracks.findIndex((track) => isMainTrack(track));
-
-	if (trackType === "audio") {
-		return mainTrackIndex >= 0 ? mainTrackIndex + 1 : tracks.length;
-	}
-
-	return 0;
-}
-
-export function isMainTrack(track: TimelineTrack): track is VideoTrack {
-	return track.type === "video" && track.isMain === true;
-}
-
-export function getMainTrack({
-	tracks,
-}: {
-	tracks: TimelineTrack[];
-}): TimelineTrack | null {
-	return tracks.find((track) => isMainTrack(track)) ?? null;
-}
-
-export function ensureMainTrack({
-	tracks,
-}: {
-	tracks: TimelineTrack[];
-}): TimelineTrack[] {
-	const hasMainTrack = tracks.some((track) => isMainTrack(track));
-
-	if (!hasMainTrack) {
-		const mainTrack: TimelineTrack = {
-			id: generateUUID(),
-			name: "Main Track",
-			type: "video",
-			elements: [],
-			muted: false,
-			isMain: true,
-			hidden: false,
-		};
-		return [mainTrack, ...tracks];
-	}
-
-	return tracks;
-}
-
-export function canElementGoOnTrack({
-	elementType,
-	trackType,
-}: {
-	elementType: ElementType;
-	trackType: TrackType;
-}): boolean {
-	return ELEMENT_TRACK_MAP[elementType] === trackType;
-}
-
-export function validateElementTrackCompatibility({
-	element,
-	track,
-}: {
-	element: { type: ElementType };
-	track: { type: TrackType };
-}): { isValid: boolean; errorMessage?: string } {
-	const isValid = canElementGoOnTrack({
-		elementType: element.type,
-		trackType: track.type,
-	});
-
-	if (!isValid) {
-		return {
-			isValid: false,
-			errorMessage: `${element.type} elements cannot be placed on ${track.type} tracks`,
-		};
-	}
-
-	return { isValid: true };
-}
-
-export function getEarliestMainTrackElement({
-	tracks,
-	excludeElementId,
-}: {
-	tracks: TimelineTrack[];
-	excludeElementId?: string;
-}): TimelineElement | null {
-	const mainTrack = getMainTrack({ tracks });
-	if (!mainTrack) {
-		return null;
-	}
-
-	const elements = mainTrack.elements.filter(
-		(element) => !excludeElementId || element.id !== excludeElementId,
-	);
-
-	if (elements.length === 0) {
-		return null;
-	}
-
-	return elements.reduce((earliest, element) =>
-		element.startTime < earliest.startTime ? element : earliest,
-	);
-}
-
-export function enforceMainTrackStart({
-	tracks,
-	targetTrackId,
-	requestedStartTime,
-	excludeElementId,
-}: {
-	tracks: TimelineTrack[];
-	targetTrackId: string;
-	requestedStartTime: number;
-	excludeElementId?: string;
-}): number {
-	const mainTrack = getMainTrack({ tracks });
-	if (!mainTrack || mainTrack.id !== targetTrackId) {
-		return requestedStartTime;
-	}
-
-	const earliestElement = getEarliestMainTrackElement({
-		tracks,
-		excludeElementId,
-	});
-
-	if (!earliestElement) {
-		return 0;
-	}
-
-	// main track must always start at time 0; if this element would
-	// become the earliest, pin it to the start
-	if (requestedStartTime <= earliestElement.startTime) {
-		return 0;
-	}
-
-	return requestedStartTime;
-}
-- 
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