Equalizer

interface EqualizerBand {
  band: number;  // Band index (0-14)
  gain: number;  // Gain multiplier
}

const bands: EqualizerBand[] = [
  { band: 0, gain: 0.25 },   // 25 Hz
  { band: 1, gain: 0.40 },   // 40 Hz
  { band: 2, gain: 0.63 },   // 63 Hz
  { band: 3, gain: 0.10 },   // 100 Hz
  { band: 4, gain: 0.16 },   // 160 Hz
  { band: 5, gain: 0.25 },   // 250 Hz
  { band: 6, gain: 0.40 },   // 400 Hz
  { band: 7, gain: 0.63 },   // 630 Hz
  { band: 8, gain: 0.10 },   // 1 kHz
  { band: 9, gain: 0.16 },   // 1.6 kHz
  { band: 10, gain: 0.25 },  // 2.5 kHz
  { band: 11, gain: 0.40 },  // 4 kHz
  { band: 12, gain: 0.63 },  // 6.3 kHz
  { band: 13, gain: 0.10 },  // 10 kHz
  { band: 14, gain: 0.16 }   // 16 kHz
];

await queue.filters.equalizer?.setEQ(bands);

import { EqualizerConfigurationPreset } from 'discord-player';

// Apply rock preset
await queue.filters.equalizer?.setEQ(
  EqualizerConfigurationPreset.Rock
);

// Create custom EQ curve
const customEQ: EqualizerBand[] = Array.from(
  { length: 15 },
  (_, i) => ({
    band: i,
    gain: i < 5 ? 0.8 : 0.2  // Boost bass, reduce treble
  })
);

await queue.filters.equalizer?.setEQ(customEQ);

const currentEQ = queue.filters.equalizer?.getEQ();
console.log(currentEQ);
// [
//   { band: 0, gain: 0.25 },
//   { band: 1, gain: 0.40 },
//   ...
// ]

const multipliers = queue.filters.equalizer?.bandMultipliers;
console.log(multipliers); // [0.25, 0.40, 0.63, ...]

const queue = player.queues.create(guild, {
  disableEqualizer: true  // Disable 15-band EQ
});

const makeBands = (arr: number[]) => {
  return Array.from(
    { length: 15 },  // 15 bands
    (_, i) => ({
      band: i,
      gain: arr[i] ? arr[i] / 30 : 0  // Normalize gain
    })
  );
};

// Example: Create bass-heavy preset
const heavyBass = makeBands([
  12.0, 10.0, 8.0, 6.0, 4.0,  // High bass
  2.0, 0, 0, 0, 0,            // Neutral mids
  0, 0, 0, 0, 0               // Neutral highs
]);

// All presets are available on the filters object
const presets = queue.filters.equalizerPresets;

// Access any preset
const rockPreset = presets.Rock;
const popPreset = presets.Pop;
const flatPreset = presets.Flat;

// Apply EQ preset
await queue.filters.equalizer?.setEQ(
  EqualizerConfigurationPreset.Rock
);

// Add FFmpeg filters on top
await queue.filters.ffmpeg.setFilters(['bassboost', 'normalizer']);

// Set EQ
await queue.filters.equalizer?.setEQ(
  EqualizerConfigurationPreset.FullBass
);

// Adjust volume to compensate
queue.node.setVolume(80);

// EQ changes are applied in real-time without interruption
const eqPresets = [
  'Rock', 'Pop', 'Dance', 'Classical'
] as const;

let currentIndex = 0;

setInterval(() => {
  const presetName = eqPresets[currentIndex];
  queue.filters.equalizer?.setEQ(
    EqualizerConfigurationPreset[presetName]
  );
  
  currentIndex = (currentIndex + 1) % eqPresets.length;
}, 10000); // Change preset every 10 seconds

queue.on('eqBands', (filters) => {
  console.log('Equalizer bands updated:', filters);
});

const graph = queue.filters.graph.dump();

console.log('Equalizer:', graph.equalizer);
// [
//   { band: 0, gain: 0.267 },
//   { band: 1, gain: 0.160 },
//   ...
// ]

const allPresets = [
  'Flat',
  'Classical',
  'Club',
  'Dance',
  'FullBass',
  'FullBassTreble',
  'FullTreble',
  'Headphones',
  'LargeHall',
  'Live',
  'Party',
  'Pop',
  'Reggae',
  'Rock',
  'Ska',
  'Soft',
  'SoftRock',
  'Techno'
];