initial public release.

src/core/track/KGMidiTrack.ts

@@ -0,0 +1,56 @@
+import { Expose, Type, Transform } from 'class-transformer';
+import { KGTrack, TrackType } from './KGTrack';
+import { KGMidiRegion } from '../region/KGMidiRegion';
+import { KGRegion } from '../region/KGRegion';
+import { FLUIDR3_INSTRUMENT_MAP } from '../../constants/generalMidiConstants';
+import { AUDIO_INTERFACE_CONSTANTS } from '../../constants/coreConstants';
+
+export type InstrumentType = keyof typeof FLUIDR3_INSTRUMENT_MAP;
+
+export class KGMidiTrack extends KGTrack {
+  @Expose()
+  protected override __type: string = 'KGMidiTrack';
+  
+  @Expose()
+  @Transform(({ value }) => value || 'acoustic_grand_piano', { toClassOnly: true })
+  protected instrument: InstrumentType = 'acoustic_grand_piano';
+  
+  @Expose()
+  @Type(() => KGRegion, {
+    discriminator: {
+      property: '__type',
+      subTypes: [
+        { value: KGRegion, name: 'KGRegion' },
+        { value: KGMidiRegion, name: 'KGMidiRegion' },
+      ],
+    },
+  })
+  protected override regions: KGMidiRegion[] = [];
+
+  constructor(name: string = 'Untitled MIDI Track', id: number = 0, instrument: InstrumentType = 'acoustic_grand_piano', volume: number = AUDIO_INTERFACE_CONSTANTS.DEFAULT_TRACK_VOLUME) {
+    super(name, id, TrackType.MIDI);
+    this.__type = 'KGMidiTrack';
+    this.instrument = instrument;
+    this.volume = volume;
+  }
+
+  // Override parent setRegions to enforce KGMidiRegion type
+  public override setRegions(regions: KGMidiRegion[]): void {
+    this.regions = regions;
+  }
+
+  // Instrument getters and setters
+  public getInstrument(): InstrumentType {
+    // Backward compatibility: default to acoustic_grand_piano if undefined
+    return this.instrument || 'acoustic_grand_piano';
+  }
+
+  public setInstrument(instrument: InstrumentType): void {
+    this.instrument = instrument;
+  }
+
+  // Override getCurrentType to return specific subclass type
+  public override getCurrentType(): string {
+    return 'KGMidiTrack';
+  }
+}