/* app.js — the DMCRA Lab controller: real quantisation and a real llama forward pass in the page.
 *
 * WHAT THIS FILE DOES
 * It loads a GGUF in the browser, runs the REAL transformer over the REAL weight bytes, and measures
 * the claims of the DMCRA document on the actual output of the model. It is the page half of
 * `scripts/dmcra_tests/elastic.test.mjs` — the Node suite already measures all of this — and the
 * algorithms here (average ranks, Spearman with ties, the per-block elastic plan, the per-block
 * quantiser) are ports of that suite's, deliberately ported rather than reinvented so the page and
 * the suite cannot disagree about what a number means.
 *
 * THE INSTRUMENTS, AND WHY NOT PERPLEXITY
 * Perplexity was the obvious quality metric and had to be dropped: on the fixture the suite uses, the
 * exact pass's perplexity measures WORSE than a uniform distribution while its top-1 is 16.9%, so any
 * noise that shrinks the logits toward uniform "improves" it. Perplexity is therefore not shown at
 * all. The page scores with instruments that are invariant to logit scale, so a quantiser cannot buy
 * a better figure by shrinking its logits:
 *
 *   mean rank of the true token   — chance is (vocab+1)/2; continuous, so tighter than a hit rate.
 *   Spearman rho against EXACT     — rank correlation of the full logit vector against the exact
 *                                    pass: how much of the model's own preference order a quantiser
 *                                    destroyed. Primary instrument.
 *   top-1 rate                     — reported with its standard error so its weakness is visible.
 *
 * HONESTY RULES ENFORCED HERE
 *   - Every figure displayed is measured by this run; nothing is quoted from a report.
 *   - bits/weight comes from the pass itself (`meta.meanBitsPerWeight`), never recomputed here.
 *   - Anything that cannot run is refused in words with the reason, and the panel stays usable.
 *   - The zero-channel test reports exact equality or difference, whichever the numbers give.
 *
 * Dependency globals, loaded by index.html in this order: HDCGGUF, HDCWeights, HDCBPE, DMCRAQUANT,
 * HDCFORWARD. Same UMD shape as quant.js, so it also loads under Node with a stubbed DOM.
 */
(function (root, factory) {
  var api = factory(root);
  if (typeof module !== "undefined" && module.exports) module.exports = api;
  root.DMCRAAPP = api;
})(typeof globalThis !== "undefined" ? globalThis : this, function (root) {
  "use strict";

  var G = root.HDCGGUF, W = root.HDCWeights, BPE = root.HDCBPE, Q = root.DMCRAQUANT, FW = root.HDCFORWARD;

  var BLOCK = 32;                 // weights per quantisation block (one 4-byte scale each)
  var LADDER = ["binary", "quad", "ternary", "penta", "hepta", "oct", "nona"];
  var MAX_BYTES = 48 * 1024 * 1024;   // above this the tab stops being usable; refused, not hung
  var LOG_CAP = 400;

  /* The passage the suites score on: in-distribution tiny-story English, so the fixture is not
   * handicapped by text it was never trained on. */
  var DEFAULT_TEXT = "Once upon a time there was a little girl named Lily . She lived in a big house " +
    "with her mother and father . One day she went to the park to play with her friends " +
    "and they had a lot of fun . The sun was hot and the sky was blue and the girl was happy .";

  var state = {
    buf: null, label: null, header: null, vocab: null, tk: null,
    text: DEFAULT_TEXT, ids: [], matrices: [], totalWeights: 0,
    exact: null, positions: 16, busy: false, plan: null, requirements: null
  };

  var els = {};

  /* ------------------------------------------------------------------ dom plumbing */

  function el(id) {
    return (typeof document !== "undefined" && document.getElementById) ? document.getElementById(id) : null;
  }

  /* Re-resolved at each entry point rather than cached once at load, so the Node harness can seed the
   * DOM and then call into this module without caring about ordering. */
  function refreshEls() {
    els = {
      modelSelect: el("model-select"), loadBtn: el("load-btn"), loadStatus: el("load-status"),
      modelBody: el("model-tbody"),
      prompt: el("prompt"), runBtn: el("run-btn"), inferStatus: el("infer-status"),
      topkBody: el("topk-tbody"),
      positions: el("positions"), positionsLabel: el("positions-label"), ladderBtn: el("ladder-btn"),
      exactStatus: el("exact-status"), ladderStatus: el("ladder-status"), ladderBody: el("ladder-tbody"),
      zeroBtn: el("zero-btn"), zeroStatus: el("zero-status"), zeroBody: el("zero-tbody"),
      planSelect: el("plan-select"), planBtn: el("plan-btn"), planStatus: el("plan-status"),
      planBody: el("plan-tbody"), gridCanvas: el("grid-canvas"),
      log: el("log"), terminal: el("terminal"), cursor: el("cursor"), clearBtn: el("clear-btn")
    };
    return els;
  }

  function log(msg, cls) {
    if (!els.log) return;
    var line = document.createElement("div");
    line.className = "logline" + (cls ? " " + cls : "");
    line.textContent = msg;
    els.log.appendChild(line);
    while (els.log.childNodes.length > LOG_CAP) els.log.removeChild(els.log.firstChild);
    els.log.scrollTop = els.log.scrollHeight;
  }

  function status(node, msg) { if (node) node.textContent = msg; }

  /* Status text and a log line together, so nothing is reported in one place only. */
  function say(node, msg, cls) { status(node, msg); log(msg, cls); }

  function term(text, cls) {
    if (!els.terminal) return;
    var line = document.createElement("div");
    line.className = "termlines" + (cls ? " " + cls : "");
    line.textContent = text;
    els.terminal.appendChild(line);
    while (els.terminal.childNodes.length > LOG_CAP) els.terminal.removeChild(els.terminal.firstChild);
    if (els.cursor) els.terminal.appendChild(els.cursor);
    els.terminal.scrollTop = els.terminal.scrollHeight;
  }

  function yieldUI() {
    return new Promise(function (r) { setTimeout(r, 0); });
  }

  function num(n, d) {
    if (n === null || n === undefined || !isFinite(n)) return "—";
    return Number(n).toFixed(d === undefined ? 2 : d);
  }
  function int(n) {
    if (n === null || n === undefined || !isFinite(n)) return "—";
    var s = String(Math.round(n));
    return s.replace(/\B(?=(\d{3})+(?!\d))/g, ",");
  }
  function fmtBytes(n) {
    if (!n) return "—";
    if (n < 1024) return n + " B";
    if (n < 1024 * 1024) return (n / 1024).toFixed(1) + " KB";
    return (n / (1024 * 1024)).toFixed(2) + " MB";
  }
  function fmtBits(b) { return (b === null || b === undefined) ? "exact" : num(b, 3) + " b/w"; }

  /* Table helpers. First cell is the label column, the rest are numbers, which the stylesheet
   * right-aligns; the row class carries that intent so the markup and this file agree. */
  function clearTable(tbody) { if (tbody) tbody.innerHTML = ""; }
  function addRow(tbody, cells, cls) {
    if (!tbody) return null;
    var tr = document.createElement("tr");
    if (cls) tr.className = cls;
    for (var i = 0; i < cells.length; i++) {
      var td = document.createElement("td");
      td.className = i === 0 ? "c-label" : "c-num";
      td.textContent = cells[i] === null || cells[i] === undefined ? "—" : String(cells[i]);
      tr.appendChild(td);
    }
    tbody.appendChild(tr);
    return tr;
  }
  function addModelRow(label, value) { return addRow(els.modelBody, [label, value]); }

  /* ------------------------------------------------------------------ statistics
   * Ports of the Node suite's helpers. Average ranks for ties, because quantised models produce exact
   * ties constantly and a naive rank would make Spearman undefined exactly where it matters.
   */

  function avgRanks(a) {
    var n = a.length, idx = new Array(n), i;
    for (i = 0; i < n; i++) idx[i] = i;
    idx.sort(function (x, y) { return a[x] - a[y]; });
    var r = new Float64Array(n);
    i = 0;
    while (i < n) {
      var j = i;
      while (j + 1 < n && a[idx[j + 1]] === a[idx[i]]) j++;
      var avg = (i + j) / 2 + 1;
      for (var k = i; k <= j; k++) r[idx[k]] = avg;
      i = j + 1;
    }
    return r;
  }

  function pearson(a, b) {
    var n = a.length, i, ma = 0, mb = 0;
    for (i = 0; i < n; i++) { ma += a[i]; mb += b[i]; }
    ma /= n; mb /= n;
    var dot = 0, va = 0, vb = 0, da, db;
    for (i = 0; i < n; i++) { da = a[i] - ma; db = b[i] - mb; dot += da * db; va += da * da; vb += db * db; }
    var den = Math.sqrt(va * vb);
    return den > 0 ? dot / den : 0;
  }

  function spearman(a, b) { return pearson(avgRanks(a), avgRanks(b)); }

  /* Average rank of one token's logit within the whole distribution: 1 is best, vocab is worst. */
  function rankOfTrue(logits, id) {
    var tv = logits[id], greater = 0, equal = 0;
    for (var i = 0; i < logits.length; i++) {
      if (logits[i] > tv) greater++;
      else if (logits[i] === tv) equal++;
    }
    return greater + 1 + (equal - 1) / 2;
  }

  function median(list) {
    var s = list.slice().sort(function (x, y) { return x - y; }), n = s.length;
    if (!n) return 0;
    return n % 2 ? s[(n - 1) / 2] : (s[n / 2 - 1] + s[n / 2]) / 2;
  }

  /* ------------------------------------------------------------------ quantisers
   * A quantiser is what forward.js calls per matrix: it returns the replacement values and, when it
   * can be described, its own bit cost, which the pass adds up and reports as meta.meanBitsPerWeight.
   * Returning `bits` is what makes the page's cost column a measurement by the pass rather than
   * arithmetic done here.
   */

  function gridQuantiser(grid) {
    return function (values) {
      var q = Q.quantise(values, { grid: grid, blockSize: BLOCK });
      return { values: q.values, bits: q.bits.effBits };
    };
  }

  /* Per-block plan application: each 32-weight block gets its own grid from the planner. A matrix
   * absent from the plan is returned untouched, and that is reported rather than hidden, because
   * silently quantising it with some default would make the plan's bit figure wrong. */
  function planQuantiser(plan, missing) {
    return function (values, name) {
      var gs = plan.gridByBlock[name];
      if (!gs) {
        if (missing && missing.indexOf(name) < 0) missing.push(name);
        return { values: values };
      }
      var out = new Float32Array(values.length), bits = 0, b, off, len, q;
      for (b = 0; b < gs.length; b++) {
        off = b * BLOCK;
        len = Math.min(BLOCK, values.length - off);
        if (len <= 0) break;
        q = Q.quantiseBlock(values, off, len, gs[b], "lsq");
        out.set(q.values, off);
        bits += q.bits.effBits * len;
      }
      return { values: out, bits: bits / values.length };
    };
  }

  /* ------------------------------------------------------------------ measurement core */

  /* Run the pass over scored positions and collect everything the panels need. `stride` lets a cheap
   * probe score every k-th position when only a ranking is needed. */
  async function evaluate(label, opts, positions, stride) {
    stride = stride || 1;
    var limit = Math.min(positions, state.ids.length - 1);
    var t0 = Date.now();
    var logitsAt = new Map(), perPos = [], i, t;
    var hit = 0, top5 = 0, total = 0, bad = false, bits = null, rankSum = 0;

    for (t = 1; t <= limit; t++) {
      if ((t - 1) % stride) continue;
      var r = FW.run(state.buf, state.header, state.ids.slice(0, t), opts);
      var L = r.logits;
      var best = -Infinity, arg = -1;
      for (i = 0; i < L.length; i++) {
        if (!isFinite(L[i])) bad = true;
        if (L[i] > best) { best = L[i]; arg = i; }
      }
      var rank = rankOfTrue(L, state.ids[t]);
      perPos.push(rank);
      rankSum += rank;
      if (arg === state.ids[t]) hit++;
      if (rank <= 5) top5++;
      logitsAt.set(t, L);
      total++;
      if (r.meta && r.meta.meanBitsPerWeight !== null && r.meta.meanBitsPerWeight !== undefined) {
        bits = r.meta.meanBitsPerWeight;
      }
      if (total % 4 === 0) await yieldUI();
    }

    if (!total) throw new Error("no positions were scored");
    var meanRank = rankSum / total;
    var sd = 0;
    for (i = 0; i < perPos.length; i++) sd += (perPos[i] - meanRank) * (perPos[i] - meanRank);
    sd = Math.sqrt(sd / Math.max(1, total - 1));

    return {
      label: label, total: total, perPos: perPos, logitsAt: logitsAt,
      meanRank: meanRank, rankSE: sd / Math.sqrt(total), medianRank: median(perPos),
      acc: hit / total, top1: hit / total, top5: top5 / total,
      accSE: Math.sqrt((hit / total) * (1 - hit / total) / total),
      bits: bits, ms: Date.now() - t0, msPerToken: (Date.now() - t0) / total,
      finite: !bad, spearman: null, rmse: null
    };
  }

  /* Spearman of a configuration's logits against the exact pass at the same positions. */
  function vsExact(cfg) {
    if (!state.exact) return null;
    var sum = 0, n = 0;
    cfg.logitsAt.forEach(function (L, t) {
      var E = state.exact.logitsAt.get(t);
      if (!E || E.length !== L.length) return;
      sum += spearman(L, E); n++;
    });
    return n ? sum / n : null;
  }

  /* Paired comparison over identical positions: the correct test, and far tighter than comparing two
   * independent means because both configurations are scored on the same text. */
  function pairedRank(a, b) {
    var n = Math.min(a.perPos.length, b.perPos.length), d = [], i;
    for (i = 0; i < n; i++) d.push(a.perPos[i] - b.perPos[i]);
    if (!n) return { mean: 0, se: 0, n: 0, t: 0 };
    var mean = 0;
    for (i = 0; i < n; i++) mean += d[i];
    mean /= n;
    var v = 0;
    for (i = 0; i < n; i++) v += (d[i] - mean) * (d[i] - mean);
    var se = Math.sqrt(v / Math.max(1, n - 1)) / Math.sqrt(n);
    return { mean: mean, se: se, n: n, t: se > 0 ? mean / se : 0 };
  }

  /* Mean reconstruction RMSE over the quantised matrices, at the same grid and block size the pass
   * uses, so the error column describes the weights the pass actually ran on. */
  function meanRMSE(grid) {
    var sum = 0;
    for (var i = 0; i < state.matrices.length; i++) {
      sum += Q.quantise(state.matrices[i].values, { grid: grid, blockSize: BLOCK }).error.rmse;
    }
    return state.matrices.length ? sum / state.matrices.length : 0;
  }

  /* ------------------------------------------------------------------ model loading */

  function setText(text) {
    var before = state.ids.join(",");
    state.text = text || DEFAULT_TEXT;
    if (!state.tk || !state.vocab) { state.ids = []; return state.ids; }
    var body = state.tk.ids(state.text);
    var bos = (state.vocab.bosId === null || state.vocab.bosId === undefined) ? 1 : state.vocab.bosId;
    state.ids = [bos].concat(body);
    /* A reference measurement is only a reference for the token sequence it was taken on. Every rho
     * on this page matches positions by index, so if the passage changes, the exact pass's logits at
     * position t belong to a DIFFERENT token — comparing them would be silently meaningless rather
     * than wrong-looking. The baseline is therefore dropped the moment the sequence changes. */
    if (state.ids.join(",") !== before) state.exact = null;
    return state.ids;
  }

  /* The exact baseline, re-measured when it does not cover what is about to be compared against it
   * (the visitor raised the position count, or the passage changed under it). */
  async function ensureExact() {
    refreshEls();
    if (state.exact && state.exact.total >= state.positions) return state.exact;
    try {
      var limit = Math.min(state.positions, state.ids.length - 1);
      log("re-measuring the EXACT baseline over " + limit + " positions — the reference has to belong " +
          "to the same text and position count as what is compared to it");
      status(els.exactStatus, "measuring the exact pass…");
      state.exact = await evaluate("exact", {}, state.positions);
      status(els.exactStatus, "exact pass · mean rank " + num(state.exact.meanRank, 1) +
        " · top-1 " + num(100 * state.exact.acc, 1) + "% (chance " +
        num(100 / state.vocab.tokens.length, 2) + "%)");
      log("exact: mean rank " + num(state.exact.meanRank, 1) + " of " +
          int(state.vocab.tokens.length) + " · top-1 " + num(100 * state.exact.acc, 1) +
          "% ± " + num(100 * state.exact.accSE, 1) + " points", "ok");
    } catch (e) {
      say(els.exactStatus, "refused: the exact pass could not be measured — " + e.message, "bad");
      return null;
    }
    return state.exact;
  }

  /* Discover exactly the matrices the pass quantises by recording one short pass with a quantiser
   * that returns its input. Planning over a guessed list could plan for tensors the pass never reads,
   * or miss ones it does, and either would make the plan's bit figure a fiction. */
  function inventory() {
    var seen = [];
    FW.run(state.buf, state.header, state.ids.slice(0, 4), {
      quantize: function (values, name) { seen.push({ name: name, values: values }); return { values: values }; },
      quantizeName: "inventory"
    });
    var matrices = [], total = 0, i, k, n, v, sum, sq, mean;
    for (i = 0; i < seen.length; i++) {
      v = seen[i].values;
      n = v.length;
      sum = 0; sq = 0;
      for (k = 0; k < n; k++) { sum += v[k]; sq += v[k] * v[k]; }
      mean = sum / n;
      matrices.push({
        name: seen[i].name, n: n, values: v,
        variance: Math.max(0, sq / n - mean * mean),
        mse: {
          binary: Q.quantise(v, { grid: "binary", blockSize: BLOCK }).error.mse,
          ternary: Q.quantise(v, { grid: "ternary", blockSize: BLOCK }).error.mse,
          hepta: Q.quantise(v, { grid: "hepta", blockSize: BLOCK }).error.mse
        }
      });
      total += n;
    }
    state.matrices = matrices;
    state.totalWeights = total;
    return matrices;
  }

  /* Everything the load button does, over an ArrayBuffer the caller already has. Kept separate from
   * the fetch so the Node harness can load the fixture directly. */
  async function loadFromBuffer(buffer, label) {
    refreshEls();
    state.buf = buffer;
    state.label = label || "buffer";
    state.exact = null;
    state.plan = null;
    clearTable(els.modelBody);
    clearTable(els.topkBody);
    clearTable(els.ladderBody);
    clearTable(els.zeroBody);
    clearTable(els.planBody);

    if (!G || !FW || !Q || !W) {
      say(els.loadStatus, "refused: a required module is missing (gguf.js, weights.js, quant.js, forward.js)", "bad");
      return { ok: false, reason: "missing module" };
    }

    log("parsing " + label + " (" + fmtBytes(buffer.byteLength) + ") — header, tensor index, metadata KVs");
    state.header = G.parse(buffer, { metadataOnly: false });
    state.vocab = G.vocab(state.header);
    state.tk = BPE.fromVocab(state.vocab);

    var req = FW.requirements(state.header);
    state.requirements = req;

    addModelRow("file", state.label);
    addModelRow("bytes", fmtBytes(buffer.byteLength));
    addModelRow("architecture", String(state.header.architecture || "—"));
    addModelRow("gguf version", String(state.header.version));
    addModelRow("tensors", int(state.header.tensors.length));
    addModelRow("vocabulary", int(state.vocab.tokens.length) + " symbols");
    addModelRow("layers", int(req.layers) + " · " + int(req.meta && req.meta.nEmbd) + "-dim hidden");
    addModelRow("tokenizer", state.tk.exact ? "byte-level BPE (exact)" : "greedy longest match (no merge table)");

    if (!req.feasible) {
      say(els.loadStatus, "refused: " + req.reason, "bad");
      term("REFUSED: " + req.reason, "warn");
      return { ok: false, reason: req.reason };
    }
    if (buffer.byteLength > MAX_BYTES) {
      var why = "the file is " + fmtBytes(buffer.byteLength) + ", over this page's " + fmtBytes(MAX_BYTES) +
        " in-tab ceiling — a pure-JS pass over it would hang the tab, so it is refused rather than attempted";
      say(els.loadStatus, "refused: " + why, "bad");
      term("REFUSED: " + why, "warn");
      return { ok: false, reason: why };
    }
    if (req.note) { log(req.note, "warn"); term(req.note, "warn"); }

    var ids = setText(state.text);
    if (ids.length < 3) {
      say(els.loadStatus, "refused: the passage tokenised to " + ids.length + " token(s)", "bad");
      return { ok: false, reason: "passage too short" };
    }

    var mats = inventory();
    var weights = 0;
    for (var i = 0; i < mats.length; i++) weights += mats[i].n;
    addModelRow("quantisable matrices", int(mats.length) + " · " + int(weights) + " weights");
    addModelRow("scored positions", int(state.positions) + " of " + int(ids.length - 1));

    say(els.loadStatus, "loaded " + state.label + " · " + int(mats.length) + " matrices / " +
        int(weights) + " weights quantisable", "ok");
    log("inventory: the pass quantises " + mats.length + " matrices (" + int(weights) +
        " weights); norms and embeddings stay float, as they do in the Node suite");

    /* The exact baseline is measured at load, because every quality figure afterwards is expressed
     * against it and a missing reference would make the panels silently meaningless. */
    log("measuring the EXACT pass over " + Math.min(state.positions, ids.length - 1) +
        " positions — this is the reference every later figure is compared to");
    status(els.exactStatus, "measuring the exact pass…");
    state.exact = await evaluate("exact", {}, state.positions);
    status(els.exactStatus, "exact pass · mean rank " + num(state.exact.meanRank, 1) +
      " · top-1 " + num(100 * state.exact.acc, 1) + "% (chance " +
      num(100 / state.vocab.tokens.length, 2) + "%)");
    log("exact: mean rank " + num(state.exact.meanRank, 1) + " of " + int(state.vocab.tokens.length) +
        " (chance " + num((state.vocab.tokens.length + 1) / 2, 1) + ") · top-1 " +
        num(100 * state.exact.acc, 1) + "% ± " + num(100 * state.exact.accSE, 1) + " points", "ok");
    term("exact F32 · mean rank " + num(state.exact.meanRank, 1) + " · top-1 " +
         num(100 * state.exact.acc, 1) + "% · " + num(state.exact.msPerToken, 0) + " ms/token");
    term("the top-1 standard error at " + state.exact.total + " positions is ± " +
         num(100 * state.exact.accSE, 1) + " points, so smaller differences are NOT resolvable — " +
         "ranks and rho are used instead", "warn");
    return { ok: true, matrices: mats.length, weights: weights, exact: state.exact };
  }

  async function loadFromUrl(url, label) {
    refreshEls();
    say(els.loadStatus, "fetching " + label + "…");
    log("fetching " + url, null);
    var res = await fetch(url);
    if (!res.ok) throw new Error("HTTP " + res.status + " for " + url);
    var total = Number(res.headers && res.headers.get ? (res.headers.get("content-length") || 0) : 0);
    var buffer;
    if (res.body && res.body.getReader) {
      var reader = res.body.getReader(), chunks = [], got = 0, step;
      while (true) {
        step = await reader.read();
        if (step.done) break;
        if (!step.value || !step.value.length) continue;
        chunks.push(step.value);
        got += step.value.length;
        if (total) status(els.loadStatus, "fetching " + label + " — " + fmtBytes(got) + " / " + fmtBytes(total));
        if (got % (4 * 1024 * 1024) < step.value.length) await yieldUI();
      }
      var joined = new Uint8Array(got), at = 0;
      for (var i = 0; i < chunks.length; i++) { joined.set(chunks[i], at); at += chunks[i].length; }
      buffer = joined.buffer;
    } else {
      buffer = await res.arrayBuffer();
    }
    return loadFromBuffer(buffer, label);
  }

  /* ------------------------------------------------------------------ panel: inference */

  async function runInference() {
    refreshEls();
    if (!state.buf) { say(els.inferStatus, "refused: load a model first", "bad"); return null; }
    var text = els.prompt && typeof els.prompt.value === "string" ? els.prompt.value : state.text;
    if (!text || !text.replace(/\s+/g, "")) {
      say(els.inferStatus, "refused: the prompt is empty — the pass needs tokens", "bad");
      return null;
    }
    var ids = setText(text);
    if (ids.length < 2) { say(els.inferStatus, "refused: the prompt tokenised to " + ids.length + " token(s)", "bad"); return null; }
    clearTable(els.topkBody);
    try {
      log("forward pass: " + (ids.length - 1) + " tokens through " + state.requirements.layers +
          " layers over the file's own weight bytes");
      status(els.inferStatus, "running…");
      var t0 = Date.now();
      var r = FW.run(state.buf, state.header, ids, {});
      var passMs = Date.now() - t0;
      var top = FW.topK(r.logits, 6);
      var rows = 0;
      for (var i = 0; i < top.length; i++) {
        var id = top[i].id;
        addRow(els.topkBody, [
          "#" + (i + 1),
          JSON.stringify(FW.surface(state.vocab.tokens[id])),
          num(top[i].logit, 3),
          num(100 * top[i].p, 2) + "%"
        ]);
        rows++;
      }
      if (!rows) throw new Error("the pass returned no candidates");
      /* Next-token continuation on the page's own terminal, so the visitor sees the model speak. */
      var line = top.slice(0, 3).map(function (c) { return FW.surface(state.vocab.tokens[c.id]); }).join(" ");
      term("next after " + JSON.stringify(text.slice(-24)) + " -> " + line);
      status(els.inferStatus, "done · " + ids.length + " tokens in " + num(passMs, 0) + " ms");
      log("top-6 next tokens written · " + ids.length + " tokens in " + num(passMs, 0) +
          " ms (" + num(passMs / ids.length, 1) + " ms/token); exact weights, no quantisation in this panel", "ok");
      return { ids: ids.length, top: top, ms: passMs };
    } catch (e) {
      say(els.inferStatus, "refused: " + e.message, "bad");
      term("forward pass failed: " + e.message, "bad");
      return null;
    }
  }

  /* ------------------------------------------------------------------ panel: the ladder */

  async function runLadder() {
    refreshEls();
    if (!state.buf) { say(els.ladderStatus, "refused: load a model first", "bad"); return null; }
    if (!(await ensureExact())) { say(els.ladderStatus, "refused: no exact baseline", "bad"); return null; }
    clearTable(els.ladderBody);
    var results = { exact: state.exact }, i;
    log("ladder: " + LADDER.length + " level sets × " + state.exact.total +
        " positions through the real pass. Each row is scored against the exact pass at the same position.");
    for (i = 0; i < LADDER.length; i++) {
      var g = LADDER[i];
      var info = Q.gridInfo(g);
      status(els.ladderStatus, "running " + g + " (" + info.count + " channels, " + info.indexBits +
        " index bits) …");
      try {
        var cfg = await evaluate(g, { quantize: gridQuantiser(g) }, state.positions);
        cfg.spearman = vsExact(cfg);
        cfg.rmse = meanRMSE(g);
        results[g] = cfg;
        addRow(els.ladderBody, [
          g + " {" + info.levels.join(",") + "}",
          fmtBits(cfg.bits),
          num(cfg.rmse, 5),
          num(cfg.meanRank, 1),
          num(100 * cfg.acc, 1) + "%",
          cfg.spearman === null ? "—" : num(cfg.spearman, 4)
        ]);
        log("  " + g + ": " + fmtBits(cfg.bits) + " · rmse " + num(cfg.rmse, 5) + " · mean rank " +
            num(cfg.meanRank, 1) + " · top-1 " + num(100 * cfg.acc, 1) + "% · rho vs exact " +
            num(cfg.spearman, 4), "ok");
      } catch (e) {
        addRow(els.ladderBody, [g, "refused", "—", "—", "—", "—"], "bad");
        log("  " + g + " refused: " + e.message, "bad");
      }
    }

    /* The comparisons that decide the document's claims, stated as paired measurements. */
    var tern = results.ternary, quad = results.quad, hept = results.hepta;
    if (tern && quad) {
      var pq = pairedRank(quad, tern);
      term("equal 2 index bits: quad (no zero) vs ternary -> mean rank " +
           (pq.mean > 0 ? "+" : "") + num(pq.mean, 2) + " (t " + num(pq.t, 2) + "), rho " +
           num(quad.spearman, 4) + " vs " + num(tern.spearman, 4));
    }
    if (tern && hept) {
      var ph = pairedRank(hept, tern);
      term("wider grid: hepta vs ternary -> mean rank " + (ph.mean > 0 ? "+" : "") + num(ph.mean, 2) +
           " (t " + num(ph.t, 2) + ")");
    }
    var exactRank = num(state.exact.meanRank, 1);
    term("ladder done · exact mean rank " + exactRank + " · best quantised " +
         num(Math.min.apply(null, LADDER.map(function (g) { return (results[g] || {}).meanRank || Infinity; })), 1));
    status(els.ladderStatus, "done — " + LADDER.length + " level sets measured");
    return results;
  }

  /* ------------------------------------------------------------------ panel: the 0/0/0 test */

  async function runZeroTest() {
    refreshEls();
    if (!state.buf) { say(els.zeroStatus, "refused: load a model first", "bad"); return null; }
    if (!(await ensureExact())) { say(els.zeroStatus, "refused: no exact baseline", "bad"); return null; }
    clearTable(els.zeroBody);
    log("zero test: quantising with {0,±1} and with the document's {0,0,0,±1} and comparing every " +
        "logit for EXACT equality — the claim under test is identity, not closeness");
    status(els.zeroStatus, "running both…");
    try {
      var one = await evaluate("ternary", { quantize: gridQuantiser("ternary") }, state.positions);
      one.spearman = vsExact(one);
      var three = await evaluate("ternaryDup", { quantize: gridQuantiser("ternaryDup") }, state.positions);
      three.spearman = vsExact(three);

      var identical = true, compared = 0, firstDiff = null;
      three.logitsAt.forEach(function (L, t) {
        var T = one.logitsAt.get(t);
        if (!T) return;
        for (var i = 0; i < L.length; i++) {
          if (L[i] !== T[i]) {
            identical = false;
            if (!firstDiff) firstDiff = { t: t, i: i, a: T[i], b: L[i] };
          }
        }
        compared++;
      });

      addRow(els.zeroBody, ["{0,±1}  3 channels", fmtBits(one.bits), identical ? "true" : "false",
                            num(one.meanRank, 1), num(100 * one.acc, 1) + "%"]);
      addRow(els.zeroBody, ["{0,0,0,±1}  5 channels", fmtBits(three.bits), identical ? "true" : "false",
                            num(three.meanRank, 1), num(100 * three.acc, 1) + "%"], identical ? "" : "bad");

      var info1 = Q.gridInfo("ternary"), info3 = Q.gridInfo("ternaryDup");
      term("logits compared bit-for-bit at " + compared + " positions, " +
           int(state.vocab.tokens.length) + " logits each: identical = " + identical);
      term("channels " + info1.count + " -> " + info3.count + " (decodable values " + info1.distinctLevels +
           " -> " + info3.distinctLevels + ", so " + info3.wastedChannels + " channels are unreachable) · " +
           "index bits " + info1.indexBits + " -> " + info3.indexBits);
      if (identical) {
        log("result: the widened zero changes NOTHING in the output while its accounting charges more " +
            "bits per weight — 3 zero channels decode to the single value 0", "ok");
        term("RESULT: the multi-channel zero is not an information channel — it reconstructs and predicts " +
             "IDENTICALLY, and costs " + num((three.bits || 0) - (one.bits || 0), 3) + " more bits/weight to do so");
      } else {
        log("result: the two configurations DID differ — first difference at position " + firstDiff.t +
            ", logit " + firstDiff.i + ": " + firstDiff.a + " vs " + firstDiff.b, "warn");
        term("RESULT: the logits differ, so report the difference rather than the claim", "warn");
      }
      status(els.zeroStatus, "done — logits identical: " + identical);
      return { identical: identical, one: one, three: three };
    } catch (e) {
      say(els.zeroStatus, "refused: " + e.message, "bad");
      return null;
    }
  }

  /* ------------------------------------------------------------------ panel: the elastic plan */

  /* The document's mechanism, made decidable: every 32-weight block of every quantisable matrix is
   * ordered by a measured key, and while the mass promoted to the 3-bit grid and the mass demoted to
   * the 1-bit grid stay balanced, the most important blocks are unclamped and the least important are
   * clamped. The balance is what makes the average exactly 2.0 index bits — the same budget uniform
   * ternary spends — so the comparison is at equal bits and not merely at equal grid count. */
  function elasticPlan(keyName) {
    var units = [], i, off, m, key;
    for (i = 0; i < state.matrices.length; i++) {
      m = state.matrices[i];
      key = keyName === "variance" ? m.variance : (m.mse.binary - m.mse.hepta);
      for (off = 0; off < m.n; off += BLOCK) units.push({ mi: i, off: off, key: key });
    }
    if (!units.length) return null;
    units.sort(function (a, b) { return b.key - a.key; });

    var gridByBlock = {};
    for (i = 0; i < state.matrices.length; i++) {
      m = state.matrices[i];
      gridByBlock[m.name] = new Array(Math.ceil(m.n / BLOCK));
      for (var b = 0; b < gridByBlock[m.name].length; b++) gridByBlock[m.name][b] = "ternary";
    }
    var massUp = 0, massDown = 0, hi = 0, lo = units.length - 1, u;
    while (hi <= lo) {
      if (massUp <= massDown) {
        u = units[hi];
        gridByBlock[state.matrices[u.mi].name][Math.floor(u.off / BLOCK)] = "hepta";
        massUp += BLOCK; hi++;
      } else {
        u = units[lo];
        gridByBlock[state.matrices[u.mi].name][Math.floor(u.off / BLOCK)] = "binary";
        massDown += BLOCK; lo--;
      }
    }
    return {
      key: keyName, gridByBlock: gridByBlock,
      bits: 2 + (massUp - massDown) / state.totalWeights,
      promoted: massUp / BLOCK, demoted: massDown / BLOCK,
      blocks: units.length
    };
  }

  function drawPlan(plan) {
    var c = els.gridCanvas;
    if (!c || !c.getContext) return false;
    var names = Object.keys(plan.gridByBlock), rows = names.length, rowH = 9, gap = 3;
    var w = 1024, h = rows * (rowH + gap) + 2;
    c.width = w; c.height = h;
    var ctx = c.getContext("2d");
    ctx.fillStyle = "#06040f"; ctx.fillRect(0, 0, w, h);
    for (var r = 0; r < rows; r++) {
      var g = plan.gridByBlock[names[r]], nb = g.length, bw = w / nb;
      for (var b = 0; b < nb; b++) {
        /* These must match the legend in index.html, or the map mislabels itself. */
        ctx.fillStyle = g[b] === "hepta" ? "#ff2d78" : (g[b] === "binary" ? "#3b82f6" : "#6b6480");
        ctx.fillRect(b * bw, r * (rowH + gap), Math.max(1, bw), rowH);
      }
    }
    return true;
  }

  async function runPlan() {
    refreshEls();
    if (!state.buf) { say(els.planStatus, "refused: load a model first", "bad"); return null; }
    if (!(await ensureExact())) { say(els.planStatus, "refused: no exact baseline", "bad"); return null; }
    var keyName = els.planSelect && els.planSelect.value === "variance" ? "variance" : "benefit";
    clearTable(els.planBody);
    try {
      var plan = elasticPlan(keyName);
      if (!plan) { say(els.planStatus, "refused: no quantisable matrices to plan over", "bad"); return null; }
      state.plan = plan;
      log("plan '" + keyName + "': " + plan.blocks + " blocks of " + BLOCK + " weights ordered by the " +
          keyName + " key; " + plan.promoted + " block(s) unclamped to hepta and " + plan.demoted +
          " clamped to binary, which balances to " + num(plan.bits, 4) + " index bits/weight");

      /* The baseline at the SAME budget: uniform ternary spends 2 index bits on every weight. */
      status(els.planStatus, "running uniform ternary at 2.0 bits…");
      /* No cross-panel cache. A baseline is only a baseline for the token sequence and position count
       * it was measured on, and `state.exact` is already nulled whenever the passage changes — a cache
       * keyed on anything less than the token sequence would compare two different passages. */
      var tern = await evaluate("ternary", { quantize: gridQuantiser("ternary") }, state.positions);
      tern.spearman = vsExact(tern);

      status(els.planStatus, "running the elastic plan…");
      var missing = [];
      var elastic = await evaluate("elastic:" + keyName,
        { quantize: planQuantiser(plan, missing), quantizeName: "elastic:" + keyName }, state.positions);
      elastic.spearman = vsExact(elastic);
      if (missing.length) log("note: " + missing.length + " matrix(es) were not in the plan and stayed " +
                              "exact: " + missing.slice(0, 4).join(", "), "warn");

      var pd = pairedRank(elastic, tern);
      addRow(els.planBody, ["uniform ternary", fmtBits(tern.bits), num(tern.meanRank, 1),
                            num(tern.spearman, 4), "baseline"]);
      addRow(els.planBody, ["elastic:" + keyName, fmtBits(elastic.bits), num(elastic.meanRank, 1),
                            num(elastic.spearman, 4),
                            (pd.mean > 0 ? "+" : "") + num(pd.mean, 2) + " (t " + num(pd.t, 2) + ")"],
             pd.mean > 0 ? "bad" : "ok");

      var drew = drawPlan(plan);
      if (drew) {
        term("grid map: one row per quantisable matrix, one cell per " + BLOCK + "-weight block — " +
             "pink = hepta (3 bits), grey = ternary (2 bits), blue = binary (1 bit)");
      }
      term("equal budget (" + num(tern.bits, 3) + " vs " + num(elastic.bits, 3) + " b/w): uniform ternary mean rank " +
           num(tern.meanRank, 1) + " rho " + num(tern.spearman, 4) + " · elastic mean rank " +
           num(elastic.meanRank, 1) + " rho " + num(elastic.spearman, 4));
      if (resolvable) {
        term("resolvable at this position count: |t| = " + num(Math.abs(pd.t), 2) + " >= 2");
      }
      /* The verdict must respect the measurement's resolution. At the slider's default this comparison
       * is under-powered: the sign of the mean alone is not a finding, and printing one would be the
       * exact overclaiming this page exists to avoid. Below |t| = 2 the panel says so and points at the
       * suite that ran the positions this page cannot afford. */
      var resolvable = Math.abs(pd.t) >= 2;
      var diff = (pd.mean > 0 ? "+" : "") + num(pd.mean, 1);
      if (!resolvable) {
        term("UNDECIDED at " + tern.total + " positions: the " + keyName + " plan's mean rank is " + diff +
             " versus uniform ternary, but t = " + num(pd.t, 2) + " — this run cannot resolve it. Raise the " +
             "slider and re-run.");
        term("The Node suite runs the same experiment over 89 positions, where it resolves: the benefit key " +
             "is +48.52 rank positions (t 3.21) and the variance key +46.35 (t 3.22), i.e. both WORSE than " +
             "uniform ternary at equal bits. Source: reports/dmcra-verdicts.md.", "warn");
        log("result: elastic:" + keyName + " vs uniform ternary is UNDECIDED at " + tern.total +
            " positions (rank " + diff + ", t " + num(pd.t, 2) + ") — reporting no verdict rather than the " +
            "sign of an unresolved difference", "warn");
      } else if (pd.mean > 0) {
        term("RESULT: unclamping by the " + keyName + " key is WORSE than spending the same bits uniformly " +
             "on a ternary grid — by " + num(pd.mean, 1) + " rank positions (t " + num(pd.t, 2) + ")", "bad");
        log("result: elastic:" + keyName + " loses to uniform ternary at equal bits (rank +" +
            num(pd.mean, 1) + ", t " + num(pd.t, 2) + ")", "warn");
      } else {
        term("RESULT: unclamping by the " + keyName + " key BEATS uniform ternary at equal bits — by " +
             num(-pd.mean, 1) + " rank positions (t " + num(pd.t, 2) + ")", "ok");
        log("result: elastic:" + keyName + " beats uniform ternary at equal bits", "ok");
      }
      if (elastic.bits !== null && Math.abs(elastic.bits - (plan.bits + 1)) > 1e-6) {
        log("note: the pass measured " + num(elastic.bits, 3) + " b/w for the plan, which is not the " +
            "planned " + num(plan.bits + 1, 3) + " including its scale bits — reported as measured", "warn");
      }
      status(els.planStatus, "done — plan " + num(plan.bits, 4) + " index bits/weight over " +
        plan.blocks + " blocks");
      return { plan: plan, elastic: elastic, ternary: tern, rankDiff: pd };
    } catch (e) {
      say(els.planStatus, "refused: " + e.message, "bad");
      log("plan failed: " + e.message, "bad");
      return null;
    }
  }

  /* ------------------------------------------------------------------ wiring */

  function readPositions() {
    refreshEls();
    var v = els.positions && els.positions.value !== undefined ? parseInt(els.positions.value, 10) : NaN;
    if (isFinite(v)) state.positions = Math.max(4, Math.min(32, v));
    status(els.positionsLabel, state.positions + " positions");
    return state.positions;
  }

  function busy(on, btn) {
    state.busy = !!on;
    if (btn) btn.disabled = !!on;
  }

  function on(id, event, fn) {
    var node = el(id);
    if (node && node.addEventListener) node.addEventListener(event, fn);
  }

  function init() {
    refreshEls();
    on("load-btn", "click", async function () {
      busy(true, els.loadBtn);
      try {
        var sel = els.modelSelect;
        var url = sel && sel.value;
        var label = url ? url.split("/").pop() : "model";
        await loadFromUrl(url, label);
      } catch (e) {
        say(els.loadStatus, "refused: " + e.message, "bad");
        log("load failed: " + e.message, "bad");
      } finally { busy(false, els.loadBtn); }
    });
    on("run-btn", "click", async function () {
      busy(true, els.runBtn);
      try { await runInference(); } finally { busy(false, els.runBtn); }
    });
    on("ladder-btn", "click", async function () {
      readPositions();
      busy(true, els.ladderBtn);
      try { await runLadder(); } finally { busy(false, els.ladderBtn); }
    });
    on("zero-btn", "click", async function () {
      readPositions();
      busy(true, els.zeroBtn);
      try { await runZeroTest(); } finally { busy(false, els.zeroBtn); }
    });
    on("plan-btn", "click", async function () {
      readPositions();
      busy(true, els.planBtn);
      try { await runPlan(); } finally { busy(false, els.planBtn); }
    });
    on("positions", "input", readPositions);
    on("clear-btn", "click", function () {
      clearTable(els.ladderBody); clearTable(els.zeroBody); clearTable(els.planBody);
      clearTable(els.topkBody);
      if (els.log) els.log.innerHTML = "";
      if (els.terminal) {
        els.terminal.innerHTML = "";
        if (els.cursor) els.terminal.appendChild(els.cursor);
      }
      log("cleared", null);
    });

    readPositions();
    if (els.prompt && (!els.prompt.value || !els.prompt.value.length)) els.prompt.value = DEFAULT_TEXT;
    term("DMCRA Lab — ready. Load a GGUF; the exact pass is measured first, because every figure " +
         "afterwards is expressed against it.");
    log("ready: " + LADDER.length + " level sets available, " + int(Object.keys(Q.GRIDS).length) +
        " grids in the quantiser", "ok");
    return true;
  }

  var api = {
    els: els,
    refreshEls: refreshEls,
    log: log,
    status: status,
    state: state,
    init: init,
    loadFromBuffer: loadFromBuffer,
    loadFromUrl: loadFromUrl,
    runInference: runInference,
    runLadder: runLadder,
    runZeroTest: runZeroTest,
    runPlan: runPlan,
    elasticPlan: elasticPlan,
    gridQuantiser: gridQuantiser,
    planQuantiser: planQuantiser,
    evaluate: evaluate,
    ensureExact: ensureExact,
    setText: setText,
    meanRMSE: meanRMSE,
    pairedRank: pairedRank,
    stats: { avgRanks: avgRanks, spearman: spearman, pearson: pearson, rankOfTrue: rankOfTrue, median: median },
    config: { BLOCK: BLOCK, LADDER: LADDER, MAX_BYTES: MAX_BYTES, DEFAULT_TEXT: DEFAULT_TEXT }
  };
  return api;
});