const [directory, output] = Deno.args;
if (!directory || !output) throw new Error("Expected EVIDENCE_DIR and OUTPUT.");
const root = await Deno.realPath(directory);
const variants = ["recorded-source/seed-check.ts.txt", "seed-check.ts.txt"];
const AsyncFunction = Object.getPrototypeOf(async function () {}).constructor;
const rows = [];
for (const file of variants) {
  const bytes = await Deno.readFile(`${root}/${file}`);
  const source = new TextDecoder().decode(bytes);
  const hash = Array.from(
    new Uint8Array(await crypto.subtle.digest("SHA-256", bytes)),
    (b) => b.toString(16).padStart(2, "0"),
  ).join("");
  const enforceValidation = file === "seed-check.ts.txt";
  const countStart = source.indexOf("const topicCount =");
  if (enforceValidation && countStart < 0) {
    throw new Error("Replay source is missing its topic-count declaration.");
  }
  const countCode = countStart < 0
    ? 'return Number(Deno.env.get("CF_TOPIC_BOARD_TOPICS") ?? 5);'
    : source.slice(countStart, source.indexOf("const identity =", countStart)) +
      "return topicCount;";
  for (
    const configured of [undefined, "0", "-1", "1.5", "NaN", "", "1", "2", "5"]
  ) {
    let result, error;
    try {
      result = await new AsyncFunction("Deno", countCode)({
        env: { get: () => configured },
      });
    } catch (e) {
      error = e instanceof Error ? e.message : String(e);
    }
    rows.push({ file, hash, case: "topicCount", configured, result, error });
    const expectedCount = Number(configured ?? 5);
    const valid = Number.isInteger(expectedCount) && expectedCount > 0;
    if (
      enforceValidation &&
      (valid !== (error === undefined) || (valid && result !== expectedCount))
    ) {
      throw new Error(`Wrong validation for ${configured}`);
    }
  }
  const afterFixture = source.indexOf("JSON.stringify(fixture));") +
    "JSON.stringify(fixture));".length;
  const statsCode = source.slice(
    afterFixture,
    source.indexOf("const reader =", afterFixture),
  );
  for (const status of [200, 503]) {
    const writes: unknown[] = [];
    let error;
    try {
      await new AsyncFunction(
        "Deno",
        "fetch",
        "apiUrl",
        "runDir",
        "join",
        statsCode,
      )(
        { writeTextFile: (...args: unknown[]) => writes.push(args) },
        () =>
          Promise.resolve({
            ok: status === 200,
            status,
            text: () => Promise.resolve(JSON.stringify({ status })),
          }),
        "http://synthetic.invalid",
        "capture",
        (...parts: string[]) => parts.join("/"),
      );
    } catch (e) {
      error = e instanceof Error ? e.message : String(e);
    }
    rows.push({ file, hash, case: "stats", status, writes, error });
    if (
      enforceValidation &&
      (status === 503
        ? error === undefined || writes.length !== 0
        : error !== undefined || writes.length !== 1)
    ) throw new Error(`Wrong statistics validation for ${status}`);
  }
}
await Deno.writeTextFile(
  output,
  JSON.stringify(
    {
      mode: "source-fragment input controls, no network or pattern workload",
      rows,
    },
    null,
    2,
  ) + "\n",
);
console.log("Replay input controls passed.");