DMNerd · DMNerd · Nov 23, 2025
diff --git a/src/app/App.jsx b/src/app/App.jsx
@@ -165,17 +165,16 @@ export default function App() {
     tuning,
     setTuning,
     presetMap,
-    presetMetaMap,
     presetNames,
     saveDefault,
     savedExists,
+    savedMeta,
     defaultForCount,
   } = useDefaultTuning({
     systemId,
     strings,
     DEFAULT_TUNINGS,
     PRESET_TUNINGS,
-    PRESET_TUNING_META,
   });
 
   const [stringMeta, setStringMeta] = useState(null);
@@ -257,8 +256,9 @@ export default function App() {
     queuePresetByName,
   } = useMergedPresets({
     presetMap,
-    presetMetaMap,
     presetNames,
+    presetMetaSource: PRESET_TUNING_META,
+    savedMeta,
     customTunings,
     setTuning,
     setStringMeta,

diff --git a/src/hooks/useDefaultTuning.js b/src/hooks/useDefaultTuning.js
@@ -32,7 +32,6 @@ export function useDefaultTuning({
   strings,
   DEFAULT_TUNINGS,
   PRESET_TUNINGS,
-  PRESET_TUNING_META = {},
 }) {
   const storeKey = keyOf(systemId, strings);
 
@@ -94,28 +93,6 @@ export function useDefaultTuning({
     return m;
   }, [factory, savedExists, saved, systemId, strings, PRESET_TUNINGS]);
 
-  const presetMetaMap = useMemo(() => {
-    const metaForGroup = PRESET_TUNING_META?.[systemId]?.[strings] || {};
-    const out = Object.create(null);
-    out["Factory default"] = null;
-    if (presetMap["Saved default"]) {
-      out["Saved default"] = savedMeta ? { ...savedMeta } : null;
-    }
-
-    for (const name of Object.keys(presetMap)) {
-      if (name === "Factory default" || name === "Saved default") continue;
-      out[name] = normalizePresetMeta(metaForGroup[name], {
-        stringMetaFormat: "array",
-      });
-    }
-    return out;
-  }, [PRESET_TUNING_META, systemId, strings, presetMap, savedMeta]);
-
-  const getPresetMeta = useCallback(
-    (name) => (name in presetMetaMap ? presetMetaMap[name] : null),
-    [presetMetaMap],
-  );
-
   const saveDefault = useCallback(
     (stringMeta, boardMeta) => {
       const isFactory =
@@ -191,10 +168,9 @@ export function useDefaultTuning({
       tuning,
       setTuning,
       presetMap,
-      presetMetaMap,
-      getPresetMeta,
       presetNames: Object.keys(presetMap),
       savedExists,
+      savedMeta,
       saveDefault,
       loadSavedDefault,
       resetFactoryDefault,
@@ -204,9 +180,8 @@ export function useDefaultTuning({
       tuning,
       setTuning,
       presetMap,
-      presetMetaMap,
-      getPresetMeta,
       savedExists,
+      savedMeta,
       saveDefault,
       loadSavedDefault,
       resetFactoryDefault,

diff --git a/src/hooks/useMergedPresets.js b/src/hooks/useMergedPresets.js
@@ -5,7 +5,7 @@ import {
   useLatest,
   useMountedState,
 } from "react-use";
-import { normalizePresetMeta } from "@/lib/meta/meta";
+import { usePresetMeta } from "@/hooks/usePresetMeta";
 import { isPlainObject } from "@/utils/object";
 
 function coerceTuningArray(strings) {
@@ -37,8 +37,9 @@ function coerceAnyTuning(value) {
 
 export function useMergedPresets({
   presetMap,
-  presetMetaMap,
   presetNames,
+  presetMetaSource,
+  savedMeta,
   customTunings,
   setTuning,
   setStringMeta,
@@ -94,30 +95,22 @@ export function useMergedPresets({
     return out;
   }, [compatibleCustoms]);
 
-  const customPresetMetaMap = useMemo(() => {
-    if (!compatibleCustoms.length) return {};
-    const out = {};
-    for (const pack of compatibleCustoms) {
-      const name = typeof pack?.name === "string" ? pack.name : null;
-      const meta = normalizePresetMeta(pack?.meta, { stringMetaFormat: "map" });
-      if (!name || !meta) continue;
-      out[name] = meta;
-    }
-    return out;
-  }, [compatibleCustoms]);
-
   const mergedPresetMap = useMemo(
     () => ({ ...presetMap, ...customPresetMap }),
     [presetMap, customPresetMap],
   );
 
-  const mergedPresetMetaMap = useMemo(() => {
-    const merged = { ...presetMetaMap };
-    for (const [k, v] of Object.entries(customPresetMetaMap)) {
-      merged[k] = v;
-    }
-    return merged;
-  }, [presetMetaMap, customPresetMetaMap]);
+  const { mergedPresetMetaMap, applyPresetMeta, resetMetaForInstrumentChange } =
+    usePresetMeta({
+      presetNames,
+      presetMetaSource,
+      savedMeta,
+      customTunings: compatibleCustoms,
+      systemId,
+      strings,
+      setStringMeta,
+      setBoardMeta,
+    });
 
   const mergedPresetNames = useMemo(() => {
     const names = new Set([
@@ -175,26 +168,15 @@ export function useMergedPresets({
         return;
       }
       setTuning(coerced);
-      const meta =
-        normalizePresetMeta(mergedPresetMetaMap?.[name]) ||
-        normalizePresetMeta(
-          (compatibleCustoms.find((p) => p?.name === name) || {})?.meta,
-        );
-      if (meta?.stringMeta) setStringMeta(meta.stringMeta);
-      else setStringMeta(null);
-      if (meta?.board) setBoardMeta(meta.board);
-      else setBoardMeta(null);
+      applyPresetMeta(name);
       queuedPresetRef.current = null;
     },
     [
       isMounted,
       resolveTuningByName,
-      mergedPresetMetaMap,
-      compatibleCustoms,
       setTuning,
-      setStringMeta,
-      setBoardMeta,
       currentStrings,
+      applyPresetMeta,
     ],
   );
 
@@ -271,8 +253,7 @@ export function useMergedPresets({
     const instrumentChanged =
       prevSystemId !== systemId || prevStrings !== strings;
     if (!instrumentChanged) return;
-    setStringMeta(null);
-    setBoardMeta(null);
+    resetMetaForInstrumentChange();
     if (typeof onInstrumentChangeRef.current === "function") {
       onInstrumentChangeRef.current({
         queuePresetByName,
@@ -293,8 +274,7 @@ export function useMergedPresets({
     queuePresetByName,
     resetSelection,
     defaultPresetName,
-    setStringMeta,
-    setBoardMeta,
+    resetMetaForInstrumentChange,
     onInstrumentChangeRef,
   ]);
 

diff --git a/src/hooks/usePresetMeta.js b/src/hooks/usePresetMeta.js
@@ -0,0 +1,110 @@
+import { useCallback, useMemo } from "react";
+import { normalizePresetMeta } from "@/lib/meta/meta";
+
+function normalizeBaseMeta({
+  presetNames,
+  presetMetaSource,
+  savedMeta,
+  systemId,
+  strings,
+}) {
+  const metaForGroup = presetMetaSource?.[systemId]?.[strings] || {};
+  const normalized = Object.create(null);
+
+  (Array.isArray(presetNames) ? presetNames : []).forEach((name) => {
+    if (name === "Saved default") {
+      const normalizedSaved = normalizePresetMeta(savedMeta, {
+        stringMetaFormat: "map",
+      });
+      if (normalizedSaved) normalized[name] = normalizedSaved;
+      return;
+    }
+
+    const meta = normalizePresetMeta(metaForGroup?.[name], {
+      stringMetaFormat: "map",
+    });
+    if (meta) normalized[name] = meta;
+  });
+
+  return normalized;
+}
+
+function normalizeCustomMeta(customTunings) {
+  if (!Array.isArray(customTunings) || !customTunings.length) return {};
+  const out = {};
+  for (const pack of customTunings) {
+    const name = typeof pack?.name === "string" ? pack.name : null;
+    if (!name) continue;
+    const meta = normalizePresetMeta(pack?.meta, { stringMetaFormat: "map" });
+    if (meta) out[name] = meta;
+  }
+  return out;
+}
+
+export function usePresetMeta({
+  presetNames = [],
+  presetMetaSource,
+  savedMeta,
+  customTunings,
+  systemId,
+  strings,
+  setStringMeta,
+  setBoardMeta,
+}) {
+  const basePresetMetaMap = useMemo(
+    () =>
+      normalizeBaseMeta({
+        presetNames,
+        presetMetaSource,
+        savedMeta,
+        systemId,
+        strings,
+      }),
+    [presetNames, presetMetaSource, savedMeta, systemId, strings],
+  );
+
+  const customPresetMetaMap = useMemo(
+    () => normalizeCustomMeta(customTunings),
+    [customTunings],
+  );
+
+  const mergedPresetMetaMap = useMemo(() => {
+    const merged = { ...basePresetMetaMap };
+    for (const [name, meta] of Object.entries(customPresetMetaMap)) {
+      merged[name] = meta;
+    }
+    return merged;
+  }, [basePresetMetaMap, customPresetMetaMap]);
+
+  const getPresetMeta = useCallback(
+    (name) => (name in mergedPresetMetaMap ? mergedPresetMetaMap[name] : null),
+    [mergedPresetMetaMap],
+  );
+
+  const applyPresetMeta = useCallback(
+    (name) => {
+      const meta = getPresetMeta(name);
+      if (meta?.stringMeta) setStringMeta?.(meta.stringMeta);
+      else setStringMeta?.(null);
+      if (meta?.board) setBoardMeta?.(meta.board);
+      else setBoardMeta?.(null);
+      return meta ?? null;
+    },
+    [getPresetMeta, setStringMeta, setBoardMeta],
+  );
+
+  const resetMetaForInstrumentChange = useCallback(() => {
+    setStringMeta?.(null);
+    setBoardMeta?.(null);
+  }, [setStringMeta, setBoardMeta]);
+
+  return useMemo(
+    () => ({
+      mergedPresetMetaMap,
+      getPresetMeta,
+      applyPresetMeta,
+      resetMetaForInstrumentChange,
+    }),
+    [mergedPresetMetaMap, getPresetMeta, applyPresetMeta, resetMetaForInstrumentChange],
+  );
+}
diff --git a/src/hooks/useTuningIO.js b/src/hooks/useTuningIO.js
@@ -11,6 +11,7 @@ import {
 import { buildTuningPack, downloadJsonFile } from "@/lib/export/tuningIO";
 import { withToastPromise } from "@/utils/toast";
 import { isPlainObject } from "@/utils/object";
+import { normalizePresetMeta } from "@/lib/meta/meta";
 
 function normalizePackName(value) {
   return typeof value === "string" ? value.trim() : "";
@@ -266,33 +267,37 @@ export function useTuningIO({ systemId, strings, TUNINGS }) {
   const getCurrentTuningPack = useCallback(
     (tuning, stringMeta = null, boardMeta = null) => {
       const sys = TUNINGS[systemId];
-      const cleanStringMeta = Array.isArray(stringMeta) ? stringMeta : null;
-      const cleanBoardMeta =
-        boardMeta && typeof boardMeta === "object" && !Array.isArray(boardMeta)
-          ? boardMeta
-          : null;
+
+      const normalizedMeta = normalizePresetMeta(
+        { stringMeta, board: boardMeta },
+        { stringMetaFormat: "map" },
+      );
+
+      const metaStringArray =
+        normalizedMeta?.stringMeta instanceof Map
+          ? Array.from(normalizedMeta.stringMeta.values())
+          : Array.isArray(normalizedMeta?.stringMeta)
+            ? normalizedMeta.stringMeta
+            : null;
 
       const pack = buildTuningPack({
         systemDivisions: sys.divisions,
         systemId,
         stringsCount: strings,
         tuning,
-        stringMeta: cleanStringMeta ?? undefined,
+        stringMeta: metaStringArray ?? undefined,
       });
 
-      const meta = { ...(pack.meta || {}) };
-      if (cleanStringMeta && cleanStringMeta.length) {
-        meta.stringMeta = cleanStringMeta;
-      }
-      if (cleanBoardMeta && Object.keys(cleanBoardMeta).length) {
-        meta.board = { ...cleanBoardMeta };
-      }
-
-      const hasMeta = Object.keys(meta).length > 0;
+      const meta = normalizedMeta
+        ? {
+            ...(metaStringArray?.length ? { stringMeta: metaStringArray } : {}),
+            ...(normalizedMeta?.board ? { board: normalizedMeta.board } : {}),
+          }
+        : undefined;
 
       return {
         ...pack,
-        ...(hasMeta ? { meta } : { meta: undefined }),
+        ...(meta ? { meta } : {}),
       };
     },
     [systemId, strings, TUNINGS],
@@ -381,7 +386,23 @@ export function useTuningIO({ systemId, strings, TUNINGS }) {
         const uniqueName = ensureUniqueName(label, takenNames);
         const { system, ...rest } = p;
         const cleanSystem = { edo: system.edo };
-        return { ...rest, system: cleanSystem, name: uniqueName };
+        const normalizedMeta = normalizePresetMeta(rest?.meta, {
+          stringMetaFormat: "array",
+        });
+        const meta = normalizedMeta
+          ? {
+              ...(normalizedMeta?.stringMeta?.length
+                ? { stringMeta: normalizedMeta.stringMeta }
+                : {}),
+              ...(normalizedMeta?.board ? { board: normalizedMeta.board } : {}),
+            }
+          : undefined;
+        return {
+          ...rest,
+          ...(meta ? { meta } : {}),
+          system: cleanSystem,
+          name: uniqueName,
+        };
       });
 
       const nextTunings = [...existing, ...newTunings];