// Print a high-band / low-band energy trace so events can be READ off the audio.
// node env-dump.mjs <wav> <startSec> [lo] [hi] [hopMs]
import { readFileSync } from "node:fs";

function readWav(file) {
  const b = readFileSync(file);
  let p = 12, fmt = null, data = null;
  while (p + 8 <= b.length) {
    const id = b.toString("latin1", p, p + 4), sz = b.readUInt32LE(p + 4), body = p + 8;
    if (id === "fmt ") fmt = { ch: b.readUInt16LE(body + 2), sr: b.readUInt32LE(body + 4), bits: b.readUInt16LE(body + 14) };
    if (id === "data") { data = b.subarray(body, body + sz); break; }
    p = body + sz + (sz & 1);
  }
  const by = fmt.bits / 8, n = Math.floor(data.length / by / fmt.ch), x = new Float32Array(n);
  for (let i = 0; i < n; i += 1) { let s = 0; for (let c = 0; c < fmt.ch; c += 1) s += data.readInt16LE((i * fmt.ch + c) * by) / 32768; x[i] = s / fmt.ch; }
  return { x, sr: fmt.sr };
}
function fft(re, im) {
  const N = re.length;
  for (let i = 1, j = 0; i < N; i += 1) { let bit = N >> 1; for (; j & bit; bit >>= 1) j ^= bit; j ^= bit; if (i < j) { [re[i], re[j]] = [re[j], re[i]]; [im[i], im[j]] = [im[j], im[i]]; } }
  for (let len = 2; len <= N; len <<= 1) { const ang = -2 * Math.PI / len;
    for (let i = 0; i < N; i += len) for (let k = 0; k < len / 2; k += 1) {
      const wr = Math.cos(ang * k), wi = Math.sin(ang * k), ur = re[i + k], ui = im[i + k];
      const vr = re[i + k + len / 2] * wr - im[i + k + len / 2] * wi, vi = re[i + k + len / 2] * wi + im[i + k + len / 2] * wr;
      re[i + k] = ur + vr; im[i + k] = ui + vi; re[i + k + len / 2] = ur - vr; im[i + k + len / 2] = ui - vi;
    } }
}
const [f, startArg, loArg, hiArg, hopArg] = process.argv.slice(2);
const start = Number(startArg ?? 0), lo = Number(loArg ?? 2000), hi = Number(hiArg ?? 9000), hop = Number(hopArg ?? 20) / 1000;
const { x, sr } = readWav(f);
const N = 1024, HOP = Math.round(hop * sr);
const bin = sr / N;
const kLo = [Math.max(1, Math.floor(lo / bin)), Math.min(N / 2 - 1, Math.ceil(hi / bin))];
const rows = [];
for (let off = 0; off + N <= x.length; off += HOP) {
  const re = new Float64Array(N), im = new Float64Array(N);
  for (let i = 0; i < N; i += 1) re[i] = x[off + i] * (0.5 - 0.5 * Math.cos(2 * Math.PI * i / (N - 1)));
  fft(re, im);
  let hiE = 0, loE = 0, best = 0, bestK = 0;
  for (let k = 1; k < N / 2; k += 1) {
    const m = re[k] * re[k] + im[k] * im[k];
    if (k >= kLo[0] && k <= kLo[1]) hiE += m; else if (k * bin < lo) loE += m;
    if (m > best) { best = m; bestK = k; }
  }
  rows.push({ t: start + off / sr, hi: hiE, lo: loE, peakHz: bestK * bin, peakMag: best });
}
const mx = Math.max(...rows.map((r) => r.hi));
for (const r of rows) {
  const db = 10 * Math.log10(r.hi / mx + 1e-12);
  const bar = "#".repeat(Math.max(0, Math.round((db + 60) / 2)));
  console.log(`${r.t.toFixed(3)}  hi ${db.toFixed(1).padStart(6)}dB  ratio ${(r.hi / (r.lo + 1e-12)).toFixed(2).padStart(7)}  peak ${r.peakHz.toFixed(0).padStart(5)}Hz  ${bar}`);
}