Lofi_Generator/lib/audio/pianoEngine.ts

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

export class PianoEngine {
  private synth: Tone.PolySynth | 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: PianoType = 'grand';
  private genre: Genre = 'hiphop';

  constructor(destination: Tone.InputNode) {
    this.output = new Tone.Gain(0.5);
    this.filter = new Tone.Filter({
      frequency: 5000,
      type: 'lowpass',
      rolloff: -12,
    });
    this.reverb = new Tone.Reverb({
      decay: 2.5,
      wet: 0.25,
    });

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

    this.pattern = getRandomPianoPattern(this.genre);
    this.createSynth('grand');
  }

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

    const configs: Record<PianoType, { synth: typeof Tone.Synth; options: object }> = {
      grand: {
        synth: Tone.Synth,
        options: {
          oscillator: { type: 'triangle' },
          envelope: { attack: 0.005, decay: 0.8, sustain: 0.2, release: 1.2 },
        },
      },
      electric: {
        synth: Tone.Synth,
        options: {
          oscillator: { type: 'sine' },
          envelope: { attack: 0.01, decay: 0.5, sustain: 0.3, release: 0.8 },
        },
      },
      rhodes: {
        synth: Tone.FMSynth,
        options: {
          harmonicity: 3,
          modulationIndex: 1,
          oscillator: { type: 'sine' },
          envelope: { attack: 0.01, decay: 0.6, sustain: 0.3, release: 1 },
          modulation: { type: 'sine' },
          modulationEnvelope: { attack: 0.01, decay: 0.3, sustain: 0.5, release: 0.5 },
        },
      },
      synth: {
        synth: Tone.Synth,
        options: {
          oscillator: { type: 'sawtooth' },
          envelope: { attack: 0.02, decay: 0.3, sustain: 0.4, release: 0.5 },
        },
      },
    };

    const config = configs[type];
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    this.synth = new Tone.PolySynth(config.synth as any, config.options);
    this.synth.volume.value = -10;
    this.synth.connect(this.filter);
    this.currentType = type;
  }

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

  setGenre(genre: Genre): void {
    this.genre = genre;
    this.pattern = getRandomPianoPattern(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 notes = this.pattern[step];
        if (notes && this.synth) {
          this.synth.triggerAttackRelease(notes, '8n', time, 0.5);
        }
      },
      steps,
      '16n'
    );

    this.sequence.start(0);
  }

  randomize(): void {
    this.pattern = getRandomPianoPattern(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 : 0.5, 0.1);
  }

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