feat: implemented drag-n-drop to import KGOne generated audio/MIDI file feature

src/core/commands/region/ImportMidiClipCommand.ts

@@ -0,0 +1,113 @@
+import { KGCommand } from '../KGCommand';
+import { KGCore } from '../../KGCore';
+import { KGMidiRegion } from '../../region/KGMidiRegion';
+import { KGMidiNote } from '../../midi/KGMidiNote';
+import { generateUniqueId } from '../../../util/miscUtil';
+import type { RawMidiNote } from '../../../util/midiUtil';
+
+/**
+ * Command to insert a MIDI clip (from K.G.One generation) into a MIDI track.
+ * All note data is stored so that redo recreates the full region with notes.
+ */
+export class ImportMidiClipCommand extends KGCommand {
+  private trackId: string;
+  private trackIndex: number;
+  private regionId: string;
+  private regionName: string;
+  private startBeat: number;
+  private lengthInBeats: number;
+  private rawNotes: RawMidiNote[];
+  private createdRegion: KGMidiRegion | null = null;
+
+  constructor(
+    trackId: string,
+    trackIndex: number,
+    startBeat: number,
+    lengthInBeats: number,
+    rawNotes: RawMidiNote[],
+    regionName?: string,
+    regionId?: string
+  ) {
+    super();
+    this.trackId = trackId;
+    this.trackIndex = trackIndex;
+    this.startBeat = startBeat;
+    this.lengthInBeats = lengthInBeats;
+    this.rawNotes = rawNotes;
+    this.regionId = regionId || generateUniqueId('KGMidiRegion');
+    this.regionName = regionName || 'KGOne Clip';
+  }
+
+  execute(): void {
+    const core = KGCore.instance();
+    const currentProject = core.getCurrentProject();
+    const track = currentProject.getTracks().find(t => t.getId().toString() === this.trackId);
+    if (!track) {
+      throw new Error(`Track ${this.trackId} not found`);
+    }
+
+    // Create the region
+    this.createdRegion = new KGMidiRegion(
+      this.regionId,
+      this.trackId,
+      this.trackIndex,
+      this.regionName,
+      this.startBeat,
+      this.lengthInBeats
+    );
+
+    // Populate notes
+    for (const raw of this.rawNotes) {
+      const note = new KGMidiNote(
+        generateUniqueId('KGMidiNote'),
+        raw.startBeat,
+        raw.endBeat,
+        raw.pitch,
+        raw.velocity
+      );
+      this.createdRegion.addNote(note);
+    }
+
+    track.addRegion(this.createdRegion);
+    console.log(`Imported MIDI clip "${this.regionName}" (${this.rawNotes.length} notes) at beat ${this.startBeat}`);
+  }
+
+  undo(): void {
+    const core = KGCore.instance();
+    const currentProject = core.getCurrentProject();
+    const track = currentProject.getTracks().find(t => t.getId().toString() === this.trackId);
+    if (track) {
+      track.removeRegion(this.regionId);
+    }
+    console.log(`Undid MIDI clip import "${this.regionName}"`);
+  }
+
+  getDescription(): string {
+    return `Import MIDI clip "${this.regionName}"`;
+  }
+
+  getCreatedRegion(): KGMidiRegion | null {
+    return this.createdRegion;
+  }
+
+  /**
+   * Factory from bar-based coordinates (common UI pattern).
+   */
+  static fromBarCoordinates(
+    trackId: string,
+    trackIndex: number,
+    barNumber: number,
+    lengthInBars: number,
+    beatsPerBar: number,
+    rawNotes: RawMidiNote[],
+    regionName?: string,
+    regionId?: string
+  ): ImportMidiClipCommand {
+    const startBeat = (barNumber - 1) * beatsPerBar;
+    const lengthInBeats = lengthInBars * beatsPerBar;
+    return new ImportMidiClipCommand(
+      trackId, trackIndex, startBeat, lengthInBeats,
+      rawNotes, regionName, regionId
+    );
+  }
+}