export interface CachedFloat32BufferWrite {
  hasValue: boolean;
  previous: Float32Array;
}

export const createCachedFloat32BufferWrite = (
  length: number
): CachedFloat32BufferWrite => ({
  hasValue: false,
  previous: new Float32Array(length),
});

export const writeFloat32BufferIfChanged = (
  device: GPUDevice,
  buffer: GPUBuffer,
  values: Float32Array,
  cache: CachedFloat32BufferWrite
): boolean => {
  if (values.length !== cache.previous.length) {
    throw new Error('Cached buffer write length mismatch');
  }

  let hasChanged = !cache.hasValue;
  for (let i = 0; i < values.length && !hasChanged; i++) {
    hasChanged = !Object.is(values[i], cache.previous[i]);
  }

  if (!hasChanged) {
    return false;
  }

  cache.previous.set(values);
  cache.hasValue = true;
  device.queue.writeBuffer(buffer, 0, values);
  return true;
};