feat: added global chord region to MIDI region conversion feature

2026-05-25 16:25:43 -07:00
parent e49b675985
commit 8aa36d2368
12 changed files with 941 additions and 16 deletions
@@ -0,0 +1,130 @@
+import { Chord, Note } from 'tonal';
+import { KGChordRegion } from '../core/region/KGChordRegion';
+import { getChordMidiPitches, parseChordSymbol } from './chordUtil';
+
+export const CHORD_REGION_IMPORT_MIME_TYPE = 'application/kgstudio-chord-region';
+export const CHORD_REGION_IMPORT_VELOCITY = 127;
+export const CHORD_REGION_IMPORT_REGION_NAME = 'Chord Progression';
+
+export interface ChordRegionImportPayload {
+  draggedRegionId: string;
+  selectedRegionIds: string[];
+}
+
+export interface ImportedChordMidiNoteData {
+  startBeat: number;
+  endBeat: number;
+  pitch: number;
+  velocity: number;
+}
+
+export interface ChordRegionImportPlan {
+  sourceRegionIds: string[];
+  startBeat: number;
+  lengthInBeats: number;
+  notes: ImportedChordMidiNoteData[];
+}
+
+export interface ChordRegionImportError {
+  message: string;
+}
+
+export type ChordRegionImportPlanResult =
+  | { ok: true; plan: ChordRegionImportPlan }
+  | { ok: false; error: ChordRegionImportError };
+
+export function resolveChordRegionImportSelection(
+  draggedRegionId: string,
+  selectedRegionIds: string[],
+): string[] {
+  return selectedRegionIds.includes(draggedRegionId)
+    ? selectedRegionIds
+    : [draggedRegionId];
+}
+
+function getBaseRootMidi(symbol: string): number | null {
+  const descriptor = parseChordSymbol(symbol);
+  if (!descriptor) {
+    return null;
+  }
+
+  const rootLetter = descriptor.root.charAt(0).toUpperCase();
+  const octave = ['F', 'G', 'A', 'B'].includes(rootLetter) ? 3 : 4;
+  return Note.midi(`${descriptor.root}${octave}`);
+}
+
+export function convertChordSymbolToMidiPitches(symbol: string): number[] | null {
+  const descriptor = parseChordSymbol(symbol);
+  if (!descriptor) {
+    return null;
+  }
+
+  const tonalChord = Chord.get(descriptor.symbol);
+  if (tonalChord.empty) {
+    return null;
+  }
+
+  const rootMidi = getBaseRootMidi(descriptor.symbol);
+  if (rootMidi === null) {
+    return null;
+  }
+
+  const midiPitches = getChordMidiPitches(descriptor.symbol, rootMidi);
+  if (midiPitches.length === 0) {
+    return null;
+  }
+
+  return [rootMidi - 12, ...midiPitches];
+}
+
+export function buildChordRegionImportPlan(
+  chordRegions: KGChordRegion[],
+): ChordRegionImportPlanResult {
+  if (chordRegions.length === 0) {
+    return {
+      ok: false,
+      error: { message: 'No chord regions were available to import.' },
+    };
+  }
+
+  const sortedRegions = [...chordRegions].sort((left, right) => (
+    left.getStartFromBeat() - right.getStartFromBeat()
+  ));
+  const firstRegion = sortedRegions[0];
+  const lastRegion = sortedRegions[sortedRegions.length - 1];
+  const startBeat = firstRegion.getStartFromBeat();
+  const endBeat = lastRegion.getStartFromBeat() + lastRegion.getLength();
+  const notes: ImportedChordMidiNoteData[] = [];
+
+  for (const region of sortedRegions) {
+    const midiPitches = convertChordSymbolToMidiPitches(region.getSymbol());
+    if (!midiPitches) {
+      return {
+        ok: false,
+        error: { message: `Unable to import chord "${region.getSymbol()}". Please update the chord symbol and try again.` },
+      };
+    }
+
+    const noteStartBeat = region.getStartFromBeat() - startBeat;
+    const noteEndBeat = noteStartBeat + region.getLength();
+
+    midiPitches.forEach(pitch => {
+      notes.push({
+        startBeat: noteStartBeat,
+        endBeat: noteEndBeat,
+        pitch,
+        velocity: CHORD_REGION_IMPORT_VELOCITY,
+      });
+    });
+  }
+
+  return {
+    ok: true,
+    plan: {
+      sourceRegionIds: sortedRegions.map(region => region.getId()),
+      startBeat,
+      lengthInBeats: endBeat - startBeat,
+      notes,
+    },
+  };
+}