From eea6d43c82e1fd09d94d73001090dad205b1f1d2 Mon Sep 17 00:00:00 2001
From: Maze Winther <mazewinther@gmail.com>
Date: Sun, 26 Apr 2026 02:50:04 +0200
Subject: fix: model editor time as wasm MediaTime ticks end-to-end

---
 .../commands/timeline/clipboard/paste-keyframes.ts | 24 ++++++++----
 apps/web/src/commands/timeline/clipboard/paste.ts  | 45 ++++++++++++++++------
 2 files changed, 51 insertions(+), 18 deletions(-)

(limited to 'apps/web/src/commands/timeline/clipboard')

diff --git a/apps/web/src/commands/timeline/clipboard/paste-keyframes.ts b/apps/web/src/commands/timeline/clipboard/paste-keyframes.ts
index e05b49fa..c1127921 100644
--- a/apps/web/src/commands/timeline/clipboard/paste-keyframes.ts
+++ b/apps/web/src/commands/timeline/clipboard/paste-keyframes.ts
@@ -10,6 +10,13 @@ import type { KeyframeClipboardItem } from "@/clipboard";
 import type { SceneTracks, TimelineElement } from "@/timeline";
 import { updateElementInSceneTracks } from "@/timeline";
 import { generateUUID } from "@/utils/id";
+import {
+	addMediaTime,
+	type MediaTime,
+	maxMediaTime,
+	minMediaTime,
+	ZERO_MEDIA_TIME,
+} from "@/wasm";
 
 function pasteKeyframesIntoElement({
 	element,
@@ -17,7 +24,7 @@ function pasteKeyframesIntoElement({
 	clipboardItems,
 }: {
 	element: TimelineElement;
-	time: number;
+	time: MediaTime;
 	clipboardItems: KeyframeClipboardItem[];
 }): TimelineElement {
 	let nextElement = element;
@@ -31,10 +38,13 @@ function pasteKeyframesIntoElement({
 			continue;
 		}
 
-		const keyframeTime = Math.max(
-			0,
-			Math.min(time + item.timeOffset, nextElement.duration),
-		);
+		const keyframeTime = maxMediaTime({
+			a: ZERO_MEDIA_TIME,
+			b: minMediaTime({
+				a: addMediaTime({ a: time, b: item.timeOffset }),
+				b: nextElement.duration,
+			}),
+		});
 		const nextAnimations = upsertPathKeyframe({
 			animations: nextElement.animations,
 			propertyPath: item.propertyPath,
@@ -79,7 +89,7 @@ export class PasteKeyframesCommand extends Command {
 	private savedState: SceneTracks | null = null;
 	private readonly trackId: string;
 	private readonly elementId: string;
-	private readonly time: number;
+	private readonly time: MediaTime;
 	private readonly clipboardItems: KeyframeClipboardItem[];
 
 	constructor({
@@ -90,7 +100,7 @@ export class PasteKeyframesCommand extends Command {
 	}: {
 		trackId: string;
 		elementId: string;
-		time: number;
+		time: MediaTime;
 		clipboardItems: KeyframeClipboardItem[];
 	}) {
 		super();
diff --git a/apps/web/src/commands/timeline/clipboard/paste.ts b/apps/web/src/commands/timeline/clipboard/paste.ts
index 4523566e..be0c2b91 100644
--- a/apps/web/src/commands/timeline/clipboard/paste.ts
+++ b/apps/web/src/commands/timeline/clipboard/paste.ts
@@ -13,18 +13,25 @@ import {
 	enforceMainTrackStart,
 } from "@/timeline/placement";
 import { cloneAnimations } from "@/animation";
+import {
+	addMediaTime,
+	type MediaTime,
+	maxMediaTime,
+	subMediaTime,
+	ZERO_MEDIA_TIME,
+} from "@/wasm";
 
 export class PasteCommand extends Command {
 	private savedState: SceneTracks | null = null;
 	private pastedElements: { trackId: string; elementId: string }[] = [];
-	private readonly time: number;
+	private readonly time: MediaTime;
 	private readonly clipboardItems: ElementClipboardItem[];
 
 	constructor({
 		time,
 		clipboardItems,
 	}: {
-		time: number;
+		time: MediaTime;
 		clipboardItems: ElementClipboardItem[];
 	}) {
 		super();
@@ -39,8 +46,12 @@ export class PasteCommand extends Command {
 		this.savedState = editor.scenes.getActiveScene().tracks;
 		this.pastedElements = [];
 
-		const minStart = Math.min(
-			...this.clipboardItems.map((item) => item.element.startTime),
+		const minStart = this.clipboardItems.reduce(
+			(earliestStartTime, item) =>
+				item.element.startTime < earliestStartTime
+					? item.element.startTime
+					: earliestStartTime,
+			this.clipboardItems[0].element.startTime,
 		);
 
 		let updatedTracks = this.savedState;
@@ -97,12 +108,18 @@ export class PasteCommand extends Command {
 						targetTrackId: targetTrack.id,
 						requestedStartTime: earliestElement.startTime,
 					});
-					const delta = adjustedEarliestStartTime - earliestElement.startTime;
+					const delta = subMediaTime({
+						a: adjustedEarliestStartTime,
+						b: earliestElement.startTime,
+					});
 
-					if (delta !== 0) {
+					if (delta !== ZERO_MEDIA_TIME) {
 						elementsForPlacement = elementsToAdd.map((element) => ({
 							...element,
-							startTime: Math.max(0, element.startTime + delta),
+							startTime: maxMediaTime({
+								a: ZERO_MEDIA_TIME,
+								b: addMediaTime({ a: element.startTime, b: delta }),
+							}),
 						}));
 					}
 				}
@@ -168,14 +185,20 @@ function buildPastedElements({
 	time,
 }: {
 	items: ElementClipboardItem[];
-	minStart: number;
-	time: number;
+	minStart: MediaTime;
+	time: MediaTime;
 }): TimelineElement[] {
 	const elementsToAdd: TimelineElement[] = [];
 
 	for (const item of items) {
-		const relativeOffset = item.element.startTime - minStart;
-		const startTime = Math.max(0, time + relativeOffset);
+		const relativeOffset = subMediaTime({
+			a: item.element.startTime,
+			b: minStart,
+		});
+		const startTime = maxMediaTime({
+			a: ZERO_MEDIA_TIME,
+			b: addMediaTime({ a: time, b: relativeOffset }),
+		});
 		const newElementId = generateUUID();
 
 		elementsToAdd.push({
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