/**
 * Small pure helpers for combining traces from different renderers at
 * different rates. Resampling is linear interpolation, which is adequate
 * here because the instrawave traces arrive oversampled (the solver rate,
 * around 114 kHz) and the content sits far below either rate.
 */
export function resampleLinear(x: Float32Array, srFrom: number, srTo: number): Float32Array {
  if (x.length === 0) return new Float32Array(0);
  const n = Math.max(1, Math.round((x.length * srTo) / srFrom));
  const out = new Float32Array(n);
  for (let i = 0; i < n; i++) {
    const s = (i * srFrom) / srTo;
    const k = Math.min(x.length - 2, Math.floor(s));
    const f = Math.min(1, Math.max(0, s - k));
    out[i] = (1 - f) * x[k] + f * x[Math.min(x.length - 1, k + 1)];
  }
  return out;
}

export function peak(x: Float32Array): number {
  let p = 0;
  for (let i = 0; i < x.length; i++) {
    const a = Math.abs(x[i]);
    if (a > p) p = a;
  }
  return p;
}

/** dst += src * gain, clipped to dst's length. */
export function mixInto(dst: Float32Array, src: Float32Array, gain = 1): void {
  const n = Math.min(dst.length, src.length);
  for (let i = 0; i < n; i++) dst[i] += src[i] * gain;
}