// Groups failures from a judge --list tsv by machine state and source context.
// Usage: node classify.mjs fails.tsv [kindFilter] [max]
import fs from "node:fs";
import { createRequire } from "node:module";
const root = new URL("../..", import.meta.url).pathname.replace(/\/$/, "");
const ts = createRequire(root + "/package.json")("typescript");
process.env.TYPESTRIP_ERASE_WASM ??= "build/erase.wasm";
const { blankSourceFile } = await import(root + "/vendor/ts-blank-space/out/index.js");
const { transformSync, engine } = await import(root + "/src/index.js");
const rows = fs.readFileSync(process.argv[2], "utf8").trim().split("\n").map((l) => l.split("\t"));
const filter = process.argv[3] ?? "";
const max = Number(process.argv[4] ?? 400);
const d = (i) => engine().dbg?.(i); // only build/downlevel-debug.wasm has the probe

function* parts(src) {
  let seed = src.length;
  for (let i = 0; i < src.length; ) {
    seed = (seed * 1103515245 + 12345) & 0x7fffffff;
    const n = 1 + (seed % 4096);
    yield src.slice(i, i + n);
    i += n;
  }
}
function chunked(src) {
  let out = "";
  for (const piece of transformSync(parts(src))) out += piece;
  return out;
}
// First index where got differs from want other than a `;` where want has a space, or vice versa.
function sigDiff(want, got) {
  const n = Math.min(want.length, got.length);
  for (let i = 0; i < n; i++) {
    if (want[i] === got[i]) continue;
    if ((want[i] === " " && got[i] === ";") || (want[i] === ";" && got[i] === " ")) continue;
    return i;
  }
  return want.length === got.length ? -1 : n;
}
const groups = new Map();
let shown = 0;
for (const [kind, name, problem] of rows) {
  if (filter && !kind.includes(filter)) continue;
  if (shown++ >= max) break;
  let src;
  try { src = fs.readFileSync(name, "utf8"); } catch { continue; }
  let key, ctx;
  if (kind.startsWith("threw")) {
    const bytes = Buffer.from(src, "utf8");
    try {
      if (kind === "threw whole") transformSync(src); else chunked(src);
      key = "no longer throws";
      ctx = "";
    } catch {
      const tsb = d(4);
      const at = bytes.subarray(Math.max(0, tsb - 70), tsb).toString() + "⟨⟩" + bytes.subarray(tsb, tsb + Number(process.env.AFTER ?? 30)).toString();
      key = `${kind}: state=${d(0)} c=${d(1)} tt=${d(5)}`;
      ctx = JSON.stringify(at);
    }
  } else {
    const sf = ts.createSourceFile("input.ts", src, ts.ScriptTarget.ESNext, false, ts.ScriptKind.TS);
    const want = blankSourceFile(sf, () => {});
    let got;
    try { got = transformSync(src); } catch { key = kind + " (now throws)"; ctx = ""; }
    if (got !== undefined) {
      const i = sigDiff(want, got);
      key = kind;
      ctx = i < 0 ? "only ; differences" : `@${i} src=${JSON.stringify(src.slice(Math.max(0, i - 60), i + 40))}\n      want=${JSON.stringify(want.slice(Math.max(0, i - 60), i + 40))}\n      got =${JSON.stringify(got.slice(Math.max(0, i - 60), i + 40))}`;
    }
  }
  if (!groups.has(key)) groups.set(key, []);
  groups.get(key).push({ name, ctx, problem });
}
for (const [key, items] of [...groups.entries()].sort((a, b) => b[1].length - a[1].length)) {
  console.log(`\n## ${key} (${items.length})`);
  for (const it of items.slice(0, Number(process.env.PER ?? 3))) console.log(`  ${it.name}\n    ${it.ctx}`);
}