# wav.ludic - a PCM WAV's length from its own header (the sample rate at byte 24, the data length at
# 40), so a loop re-triggered before its clip ends follows whatever the fetcher wrote
export function aud_wav_seconds(path: string, fallback: float) -> float {
  let hdr = Fs.read_bytes(path)
  if hdr == null { return fallback }
  if len(hdr) < 44 { return fallback }
  let rate = hdr[24] | (hdr[25] << 8) | (hdr[26] << 16) | (hdr[27] << 24)
  let bps = hdr[34]
  let ch = hdr[22]
  let data = hdr[40] | (hdr[41] << 8) | (hdr[42] << 16) | (hdr[43] << 24)
  if rate <= 0 or bps <= 0 or ch <= 0 { return fallback }
  let frames = data / (ch * (bps / 8))
  let secs = float(frames) / float(rate)
  if secs < 0.2 { return fallback }
  return secs
}