Lofi_Generator/lib/audio/brassEngine.ts

import * as Tone from 'tone';
import { BrassType, Genre } from '@/types/audio';
import { getRandomBrassPattern } from './patterns';

export class BrassEngine {
  private synth: Tone.Synth | null = null;
  private sequence: Tone.Sequence | null = null;
  private pattern: (string | null)[];
  private output: Tone.Gain;
  private filter: Tone.Filter;
  private reverb: Tone.Reverb;
  private currentType: BrassType = 'trumpet';
  private genre: Genre = 'hiphop';

  constructor(destination: Tone.InputNode) {
    this.output = new Tone.Gain(0.4);
    this.filter = new Tone.Filter({
      frequency: 3000,
      type: 'lowpass',
      rolloff: -12,
    });
    this.reverb = new Tone.Reverb({
      decay: 2,
      wet: 0.3,
    });

    this.filter.connect(this.reverb);
    this.reverb.connect(this.output);
    this.output.connect(destination);

    this.pattern = getRandomBrassPattern(this.genre);
    this.createSynth('trumpet');
  }

  private createSynth(type: BrassType): void {
    if (this.synth) {
      this.synth.dispose();
    }

    const configs: Record<BrassType, Partial<Tone.SynthOptions>> = {
      trumpet: {
        oscillator: { type: 'sawtooth' },
        envelope: { attack: 0.05, decay: 0.2, sustain: 0.6, release: 0.3 },
      },
      horn: {
        oscillator: { type: 'sine' },
        envelope: { attack: 0.1, decay: 0.3, sustain: 0.7, release: 0.5 },
      },
      'synth-brass': {
        oscillator: { type: 'fatsawtooth', spread: 20, count: 3 } as Tone.OmniOscillatorOptions,
        envelope: { attack: 0.02, decay: 0.3, sustain: 0.5, release: 0.2 },
      },
      orchestra: {
        oscillator: { type: 'sawtooth' },
        envelope: { attack: 0.15, decay: 0.4, sustain: 0.8, release: 0.6 },
      },
    };

    this.synth = new Tone.Synth(configs[type]);
    this.synth.volume.value = -8;
    this.synth.connect(this.filter);
    this.currentType = type;
  }

  setInstrument(type: BrassType): void {
    this.createSynth(type);
  }

  setGenre(genre: Genre): void {
    this.genre = genre;
    this.pattern = getRandomBrassPattern(genre);
    if (this.sequence) {
      this.createSequence();
    }
  }

  createSequence(): void {
    if (this.sequence) {
      this.sequence.dispose();
    }

    const steps = Array.from({ length: 16 }, (_, i) => i);

    this.sequence = new Tone.Sequence(
      (time, step) => {
        const note = this.pattern[step];
        if (note && this.synth) {
          this.synth.triggerAttackRelease(note, '8n', time, 0.6);
        }
      },
      steps,
      '16n'
    );

    this.sequence.start(0);
  }

  randomize(): void {
    this.pattern = getRandomBrassPattern(this.genre);
    if (this.sequence) {
      this.createSequence();
    }
  }

  setVolume(volume: number): void {
    this.output.gain.rampTo(volume, 0.1);
  }

  mute(muted: boolean): void {
    this.output.gain.rampTo(muted ? 0 : 0.4, 0.1);
  }

  dispose(): void {
    this.sequence?.dispose();
    this.synth?.dispose();
    this.filter.dispose();
    this.reverb.dispose();
    this.output.dispose();
  }
}