Lofi_Generator/lib/audio/chordEngine.ts

import * as Tone from 'tone';
import { ChordProgression, ChordType, Genre } from '@/types/audio';
import { getRandomProgression } from './patterns';

export class ChordEngine {
  private synth: Tone.PolySynth | null = null;
  private sequence: Tone.Sequence | null = null;
  private progression: ChordProgression;
  private output: Tone.Gain;
  private filter: Tone.Filter;
  private reverb: Tone.Reverb;
  private chorus: Tone.Chorus;
  private currentType: ChordType = 'pad';
  private genre: Genre = 'hiphop';

  constructor(destination: Tone.InputNode) {
    this.output = new Tone.Gain(0.6);

    this.filter = new Tone.Filter({
      frequency: 2000,
      type: 'lowpass',
      rolloff: -24,
    });

    this.reverb = new Tone.Reverb({
      decay: 3,
      wet: 0.4,
    });

    this.chorus = new Tone.Chorus({
      frequency: 0.5,
      delayTime: 3.5,
      depth: 0.5,
      wet: 0.3,
    }).start();

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

    this.progression = getRandomProgression(this.genre);
    this.createSynth('pad');
  }

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

    const configs: Record<ChordType, { synth: typeof Tone.Synth | typeof Tone.FMSynth; options: object }> = {
      pad: {
        synth: Tone.FMSynth,
        options: {
          harmonicity: 2,
          modulationIndex: 1.5,
          oscillator: { type: 'sine' },
          envelope: { attack: 0.3, decay: 0.3, sustain: 0.8, release: 1.5 },
          modulation: { type: 'sine' },
          modulationEnvelope: { attack: 0.5, decay: 0.2, sustain: 0.5, release: 0.5 },
        },
      },
      strings: {
        synth: Tone.Synth,
        options: {
          oscillator: { type: 'sawtooth' },
          envelope: { attack: 0.4, decay: 0.3, sustain: 0.9, release: 2 },
        },
      },
      organ: {
        synth: Tone.Synth,
        options: {
          oscillator: { type: 'sine' },
          envelope: { attack: 0.01, decay: 0.1, sustain: 0.9, release: 0.3 },
        },
      },
      synth: {
        synth: Tone.Synth,
        options: {
          oscillator: { type: 'fatsawtooth', spread: 30, count: 3 },
          envelope: { attack: 0.1, decay: 0.2, sustain: 0.6, release: 0.8 },
        },
      },
    };

    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 = -12;
    this.synth.connect(this.filter);
    this.currentType = type;
  }

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

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

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

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

    this.sequence = new Tone.Sequence(
      (time, step) => {
        const chord = this.progression.chords[step];
        const duration = this.progression.durations[step];

        if (this.synth) {
          this.synth.releaseAll(time);
          this.synth.triggerAttackRelease(chord, duration, time, 0.5);
        }
      },
      steps,
      '2n'
    );

    this.sequence.start(0);
  }

  setProgression(progression: ChordProgression): void {
    this.progression = progression;
    if (this.sequence) {
      this.createSequence();
    }
  }

  randomize(): ChordProgression {
    this.progression = getRandomProgression(this.genre);
    if (this.sequence) {
      this.createSequence();
    }
    return this.progression;
  }

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

  mute(muted: boolean): void {
    this.output.gain.rampTo(muted ? 0 : 0.6, 0.1);
  }

  setFilterFrequency(freq: number): void {
    this.filter.frequency.rampTo(freq, 0.1);
  }

  getProgression(): ChordProgression {
    return this.progression;
  }

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