Lofi_Generator/lib/audio/drumMachine.ts

import * as Tone from 'tone';
import { DrumPattern } from '@/types/audio';
import { getRandomPattern, generateRandomPattern } from './patterns';

export class DrumMachine {
  private kick: Tone.MembraneSynth;
  private snare: Tone.NoiseSynth;
  private hihat: Tone.NoiseSynth;
  private openhat: Tone.NoiseSynth;
  private sequence: Tone.Sequence | null = null;
  private pattern: DrumPattern;
  private output: Tone.Gain;
  private lowpass: Tone.Filter;

  constructor(destination: Tone.InputNode) {
    this.output = new Tone.Gain(0.8);
    this.lowpass = new Tone.Filter({
      frequency: 8000,
      type: 'lowpass',
      rolloff: -12,
    });

    // Kick drum - deep and punchy
    this.kick = new Tone.MembraneSynth({
      pitchDecay: 0.05,
      octaves: 6,
      oscillator: { type: 'sine' },
      envelope: {
        attack: 0.001,
        decay: 0.4,
        sustain: 0.01,
        release: 0.4,
      },
    });

    // Snare - filtered noise
    this.snare = new Tone.NoiseSynth({
      noise: { type: 'white' },
      envelope: {
        attack: 0.001,
        decay: 0.2,
        sustain: 0,
        release: 0.1,
      },
    });
    const snareFilter = new Tone.Filter({
      frequency: 5000,
      type: 'bandpass',
      Q: 1,
    });
    this.snare.connect(snareFilter);
    snareFilter.connect(this.lowpass);

    // Closed hi-hat - high filtered noise
    this.hihat = new Tone.NoiseSynth({
      noise: { type: 'white' },
      envelope: {
        attack: 0.001,
        decay: 0.05,
        sustain: 0,
        release: 0.02,
      },
    });
    const hihatFilter = new Tone.Filter({
      frequency: 10000,
      type: 'highpass',
    });
    this.hihat.connect(hihatFilter);
    hihatFilter.connect(this.lowpass);

    // Open hi-hat
    this.openhat = new Tone.NoiseSynth({
      noise: { type: 'white' },
      envelope: {
        attack: 0.001,
        decay: 0.3,
        sustain: 0,
        release: 0.15,
      },
    });
    const openhatFilter = new Tone.Filter({
      frequency: 8000,
      type: 'highpass',
    });
    this.openhat.connect(openhatFilter);
    openhatFilter.connect(this.lowpass);

    // Connect kick directly to lowpass
    this.kick.connect(this.lowpass);

    // Chain: lowpass -> output -> destination
    this.lowpass.connect(this.output);
    this.output.connect(destination);

    // Initialize with a random pattern
    this.pattern = getRandomPattern();
  }

  createSequence(onStep?: (step: number) => void): void {
    if (this.sequence) {
      this.sequence.dispose();
    }

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

    this.sequence = new Tone.Sequence(
      (time, step) => {
        if (this.pattern.kick[step]) {
          this.kick.triggerAttackRelease('C1', '8n', time, 0.8);
        }
        if (this.pattern.snare[step]) {
          this.snare.triggerAttackRelease('8n', time, 0.5);
        }
        if (this.pattern.hihat[step]) {
          this.hihat.triggerAttackRelease('32n', time, 0.3);
        }
        if (this.pattern.openhat[step]) {
          this.openhat.triggerAttackRelease('16n', time, 0.25);
        }

        // Call step callback on main thread
        if (onStep) {
          Tone.getDraw().schedule(() => {
            onStep(step);
          }, time);
        }
      },
      steps,
      '16n'
    );

    this.sequence.start(0);
  }

  setPattern(pattern: DrumPattern): void {
    this.pattern = pattern;
  }

  randomize(): DrumPattern {
    this.pattern = Math.random() > 0.5 ? getRandomPattern() : generateRandomPattern();
    return this.pattern;
  }

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

  mute(muted: boolean): void {
    this.output.gain.rampTo(muted ? 0 : 0.8, 0.1);
  }

  getPattern(): DrumPattern {
    return this.pattern;
  }

  dispose(): void {
    this.sequence?.dispose();
    this.kick.dispose();
    this.snare.dispose();
    this.hihat.dispose();
    this.openhat.dispose();
    this.lowpass.dispose();
    this.output.dispose();
  }
}