From f5f31b43df9ef46f1afdd63ba759b2f9bd80e7a3 Mon Sep 17 00:00:00 2001
From: Maze Winther <mazewinther@gmail.com>
Date: Wed, 22 Apr 2026 02:41:18 +0200
Subject: refactor: migration run() and pure v1-to-v2 transform

---
 .../storage/migrations/transformers/v17-to-v18.ts  | 218 +++++++++++----------
 1 file changed, 113 insertions(+), 105 deletions(-)

(limited to 'apps/web/src/services/storage/migrations/transformers/v17-to-v18.ts')

diff --git a/apps/web/src/services/storage/migrations/transformers/v17-to-v18.ts b/apps/web/src/services/storage/migrations/transformers/v17-to-v18.ts
index 3ef6cde9..660d91ee 100644
--- a/apps/web/src/services/storage/migrations/transformers/v17-to-v18.ts
+++ b/apps/web/src/services/storage/migrations/transformers/v17-to-v18.ts
@@ -1,105 +1,113 @@
-import type { MigrationResult, ProjectRecord } from "./types";
-import { VOLUME_DB_MIN } from "@/timeline/audio-constants";
-import { clampDb } from "@/timeline/audio-state";
-import { getProjectId, isRecord } from "./utils";
-
-export function transformProjectV17ToV18({
-	project,
-}: {
-	project: ProjectRecord;
-}): MigrationResult<ProjectRecord> {
-	if (!getProjectId({ project })) {
-		return { project, skipped: true, reason: "no project id" };
-	}
-
-	if (typeof project.version === "number" && project.version >= 18) {
-		return { project, skipped: true, reason: "already v18" };
-	}
-
-	return {
-		project: {
-			...migrateElementVolumes({ project }),
-			version: 18,
-		},
-		skipped: false,
-	};
-}
-
-function migrateElementVolumes({
-	project,
-}: {
-	project: ProjectRecord;
-}): ProjectRecord {
-	const scenesValue = project.scenes;
-	if (!Array.isArray(scenesValue)) {
-		return project;
-	}
-
-	const migratedScenes = scenesValue.map((scene) => {
-		if (!isRecord(scene)) {
-			return scene;
-		}
-
-		const tracksValue = scene.tracks;
-		if (!Array.isArray(tracksValue)) {
-			return scene;
-		}
-
-		const migratedTracks = tracksValue.map((track) => {
-			if (!isRecord(track)) {
-				return track;
-			}
-
-			const elementsValue = track.elements;
-			if (!Array.isArray(elementsValue)) {
-				return track;
-			}
-
-			const migratedElements = elementsValue.map((element) => {
-				if (!isRecord(element)) {
-					return element;
-				}
-
-				if (element.type !== "audio" && element.type !== "video") {
-					return element;
-				}
-
-				const legacyVolume = element.volume;
-				return {
-					...element,
-					volume:
-						typeof legacyVolume === "number"
-							? linearGainToDb(legacyVolume)
-							: 0,
-				};
-			});
-
-			return {
-				...track,
-				elements: migratedElements,
-			};
-		});
-
-		return {
-			...scene,
-			tracks: migratedTracks,
-		};
-	});
-
-	return {
-		...project,
-		scenes: migratedScenes,
-	};
-}
-
-function linearGainToDb(gain: number): number {
-	if (!Number.isFinite(gain)) {
-		return 0;
-	}
-
-	if (gain <= 0) {
-		return VOLUME_DB_MIN;
-	}
-
-	return clampDb(20 * Math.log10(gain));
-}
+import type { MigrationResult, ProjectRecord } from "./types";
+import { getProjectId, isRecord } from "./utils";
+
+// Frozen snapshots of v18-era volume bounds. See ./README.md.
+const VOLUME_DB_MIN = -60;
+const VOLUME_DB_MAX = 20;
+
+export function transformProjectV17ToV18({
+	project,
+}: {
+	project: ProjectRecord;
+}): MigrationResult<ProjectRecord> {
+	if (!getProjectId({ project })) {
+		return { project, skipped: true, reason: "no project id" };
+	}
+
+	if (typeof project.version === "number" && project.version >= 18) {
+		return { project, skipped: true, reason: "already v18" };
+	}
+
+	return {
+		project: {
+			...migrateElementVolumes({ project }),
+			version: 18,
+		},
+		skipped: false,
+	};
+}
+
+function migrateElementVolumes({
+	project,
+}: {
+	project: ProjectRecord;
+}): ProjectRecord {
+	const scenesValue = project.scenes;
+	if (!Array.isArray(scenesValue)) {
+		return project;
+	}
+
+	const migratedScenes = scenesValue.map((scene) => {
+		if (!isRecord(scene)) {
+			return scene;
+		}
+
+		const tracksValue = scene.tracks;
+		if (!Array.isArray(tracksValue)) {
+			return scene;
+		}
+
+		const migratedTracks = tracksValue.map((track) => {
+			if (!isRecord(track)) {
+				return track;
+			}
+
+			const elementsValue = track.elements;
+			if (!Array.isArray(elementsValue)) {
+				return track;
+			}
+
+			const migratedElements = elementsValue.map((element) => {
+				if (!isRecord(element)) {
+					return element;
+				}
+
+				if (element.type !== "audio" && element.type !== "video") {
+					return element;
+				}
+
+				const legacyVolume = element.volume;
+				return {
+					...element,
+					volume:
+						typeof legacyVolume === "number" ? linearGainToDb(legacyVolume) : 0,
+				};
+			});
+
+			return {
+				...track,
+				elements: migratedElements,
+			};
+		});
+
+		return {
+			...scene,
+			tracks: migratedTracks,
+		};
+	});
+
+	return {
+		...project,
+		scenes: migratedScenes,
+	};
+}
+
+function linearGainToDb(gain: number): number {
+	if (!Number.isFinite(gain)) {
+		return 0;
+	}
+
+	if (gain <= 0) {
+		return VOLUME_DB_MIN;
+	}
+
+	return clampDb(20 * Math.log10(gain));
+}
+
+function clampDb(value: number): number {
+	if (!Number.isFinite(value)) {
+		return 0;
+	}
+
+	return Math.min(VOLUME_DB_MAX, Math.max(VOLUME_DB_MIN, value));
+}
-- 
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