/** The GPU device, requested the same way everywhere (app and scripts). */
export async function requestAcousticDevice(): Promise<GPUDevice> {
  if (!navigator.gpu) {
    throw new Error(
      'this browser has no WebGPU. Chrome and Edge 113+, Safari 26+, and ' +
        'Firefox 141+ on Windows have it; on Linux Firefox and Chrome may need ' +
        'it enabled explicitly.',
    );
  }
  const adapter = await navigator.gpu.requestAdapter({ powerPreference: 'high-performance' });
  if (!adapter) throw new Error('WebGPU found no adapter on this machine.');

  // A field of 192^3 f32 is 28 MB and there are four of them, so the default
  // 128 MB buffer limit and 256 MB total are both too small at the top grid
  // size. Ask for what the adapter will give.
  const lim = adapter.limits;
  return adapter.requestDevice({
    requiredLimits: {
      maxStorageBufferBindingSize: lim.maxStorageBufferBindingSize,
      maxBufferSize: lim.maxBufferSize,
    },
  });
}

/** Largest cube side this device can hold four fields of. */
export function maxGridSide(device: GPUDevice): number {
  const perField = device.limits.maxStorageBufferBindingSize;
  for (const n of [192, 160, 128, 96, 64]) {
    if (4 * n * n * n <= perField) return n;
  }
  return 64;
}