audio-ui/lib/history/commands/effect-command.ts

/**
 * Effect commands for undo/redo system
 */

import { BaseCommand } from '../command';

export class EffectCommand extends BaseCommand {
  private originalBuffer: AudioBuffer;
  private modifiedBuffer: AudioBuffer;
  private applyCallback: (buffer: AudioBuffer) => void;
  private description: string;

  constructor(
    originalBuffer: AudioBuffer,
    modifiedBuffer: AudioBuffer,
    applyCallback: (buffer: AudioBuffer) => void,
    description: string
  ) {
    super();
    this.originalBuffer = originalBuffer;
    this.modifiedBuffer = modifiedBuffer;
    this.applyCallback = applyCallback;
    this.description = description;
  }

  getDescription(): string {
    return this.description;
  }

  execute(): void {
    this.applyCallback(this.modifiedBuffer);
  }

  undo(): void {
    this.applyCallback(this.originalBuffer);
  }

  redo(): void {
    this.execute();
  }
}

/**
 * Factory function to create effect commands
 */
export function createEffectCommand(
  originalBuffer: AudioBuffer,
  effectFunction: (buffer: AudioBuffer) => AudioBuffer | Promise<AudioBuffer>,
  applyCallback: (buffer: AudioBuffer) => void,
  description: string
): EffectCommand {
  const result = effectFunction(originalBuffer);
  const modifiedBuffer = result instanceof Promise ? originalBuffer : result;
  return new EffectCommand(originalBuffer, modifiedBuffer, applyCallback, description);
}

/**
 * Factory function to create async effect commands
 */
export async function createAsyncEffectCommand(
  originalBuffer: AudioBuffer,
  effectFunction: (buffer: AudioBuffer) => Promise<AudioBuffer>,
  applyCallback: (buffer: AudioBuffer) => void,
  description: string
): Promise<EffectCommand> {
  const modifiedBuffer = await effectFunction(originalBuffer);
  return new EffectCommand(originalBuffer, modifiedBuffer, applyCallback, description);
}

/**
 * Factory for gain effect command
 */
export function createGainCommand(
  buffer: AudioBuffer,
  gainValue: number,
  applyCallback: (buffer: AudioBuffer) => void
): EffectCommand {
  return createEffectCommand(
    buffer,
    (buf) => {
      // Import will happen at runtime
      const { applyGain } = require('@/lib/audio/effects/gain');
      return applyGain(buf, gainValue);
    },
    applyCallback,
    `Apply Gain (${gainValue.toFixed(2)}x)`
  );
}

/**
 * Factory for normalize peak command
 */
export function createNormalizePeakCommand(
  buffer: AudioBuffer,
  targetPeak: number,
  applyCallback: (buffer: AudioBuffer) => void
): EffectCommand {
  return createEffectCommand(
    buffer,
    (buf) => {
      const { normalizePeak } = require('@/lib/audio/effects/normalize');
      return normalizePeak(buf, targetPeak);
    },
    applyCallback,
    `Normalize to Peak (${targetPeak.toFixed(2)})`
  );
}

/**
 * Factory for normalize RMS command
 */
export function createNormalizeRMSCommand(
  buffer: AudioBuffer,
  targetRMS: number,
  applyCallback: (buffer: AudioBuffer) => void
): EffectCommand {
  return createEffectCommand(
    buffer,
    (buf) => {
      const { normalizeRMS } = require('@/lib/audio/effects/normalize');
      return normalizeRMS(buf, targetRMS);
    },
    applyCallback,
    `Normalize to RMS (${targetRMS.toFixed(2)})`
  );
}

/**
 * Factory for fade in command
 */
export function createFadeInCommand(
  buffer: AudioBuffer,
  duration: number,
  applyCallback: (buffer: AudioBuffer) => void
): EffectCommand {
  return createEffectCommand(
    buffer,
    (buf) => {
      const { applyFadeIn } = require('@/lib/audio/effects/fade');
      return applyFadeIn(buf, duration);
    },
    applyCallback,
    `Fade In (${duration.toFixed(2)}s)`
  );
}

/**
 * Factory for fade out command
 */
export function createFadeOutCommand(
  buffer: AudioBuffer,
  duration: number,
  applyCallback: (buffer: AudioBuffer) => void
): EffectCommand {
  return createEffectCommand(
    buffer,
    (buf) => {
      const { applyFadeOut } = require('@/lib/audio/effects/fade');
      return applyFadeOut(buf, duration);
    },
    applyCallback,
    `Fade Out (${duration.toFixed(2)}s)`
  );
}

/**
 * Factory for reverse command
 */
export function createReverseCommand(
  buffer: AudioBuffer,
  applyCallback: (buffer: AudioBuffer) => void
): EffectCommand {
  return createEffectCommand(
    buffer,
    (buf) => {
      const { reverseAudio } = require('@/lib/audio/effects/reverse');
      return reverseAudio(buf);
    },
    applyCallback,
    'Reverse Audio'
  );
}

/**
 * Factory for low-pass filter command
 */
export async function createLowPassFilterCommand(
  buffer: AudioBuffer,
  frequency: number,
  Q: number,
  applyCallback: (buffer: AudioBuffer) => void
): Promise<EffectCommand> {
  return createAsyncEffectCommand(
    buffer,
    async (buf) => {
      const { applyLowPassFilter } = require('@/lib/audio/effects/filters');
      return await applyLowPassFilter(buf, frequency, Q);
    },
    applyCallback,
    `Low-Pass Filter (${frequency}Hz)`
  );
}

/**
 * Factory for high-pass filter command
 */
export async function createHighPassFilterCommand(
  buffer: AudioBuffer,
  frequency: number,
  Q: number,
  applyCallback: (buffer: AudioBuffer) => void
): Promise<EffectCommand> {
  return createAsyncEffectCommand(
    buffer,
    async (buf) => {
      const { applyHighPassFilter } = require('@/lib/audio/effects/filters');
      return await applyHighPassFilter(buf, frequency, Q);
    },
    applyCallback,
    `High-Pass Filter (${frequency}Hz)`
  );
}

/**
 * Factory for band-pass filter command
 */
export async function createBandPassFilterCommand(
  buffer: AudioBuffer,
  frequency: number,
  Q: number,
  applyCallback: (buffer: AudioBuffer) => void
): Promise<EffectCommand> {
  return createAsyncEffectCommand(
    buffer,
    async (buf) => {
      const { applyBandPassFilter } = require('@/lib/audio/effects/filters');
      return await applyBandPassFilter(buf, frequency, Q);
    },
    applyCallback,
    `Band-Pass Filter (${frequency}Hz)`
  );
}