import test from "node:test";
import assert from "node:assert/strict";
import { mkdtemp, writeFile, symlink, rm } from "node:fs/promises";
import { join } from "node:path";
import { tmpdir } from "node:os";
import { CandidateMetadataBudget, readCandidateMetadata } from "../src/execution-world/metadata.js";

test("concurrent candidate reservations enforce aggregate and owner limits and release exactly once", () => {
  const budget = new CandidateMetadataBudget({ bytes: 1000, ownerBytes: 600, candidates: 3 });
  const first = budget.acquire("a"),
    second = budget.acquire("a"),
    third = budget.acquire("b");
  assert.throws(() => budget.acquire("c"), /CANDIDATE_METADATA_LIMIT/);
  first.charge(400);
  second.charge(200);
  third.charge(400);
  assert.throws(() => second.charge(1), /CANDIDATE_METADATA_LIMIT/);
  assert.throws(() => third.charge(1), /CANDIDATE_METADATA_LIMIT/);
  assert.equal(budget.snapshot().bytes, 1000);
  second.release();
  second.release();
  assert.equal(budget.snapshot().bytes, 800);
  assert.throws(() => second.charge(1), /CANDIDATE_METADATA_CLOSED/);
  first.release();
  third.release();
  assert.deepEqual(budget.snapshot(), { bytes: 0, candidates: 0, owners: 0, limits: budget.limits });
});

test("metadata files reserve parse/index space before allocation and refuse oversized or linked inputs", async () => {
  const root = await mkdtemp(join(tmpdir(), "qx-metadata-budget-"));
  const budget = new CandidateMetadataBudget({ bytes: 512, ownerBytes: 512, candidates: 2 });
  const scope = budget.acquire("workspace");
  try {
    const file = join(root, "metadata.json");
    await writeFile(file, '{"ok":true}');
    assert.equal(new TextDecoder().decode(await readCandidateMetadata(file, scope, 100)), '{"ok":true}');
    assert.equal(scope.bytes, 12 * 32);
    await assert.rejects(readCandidateMetadata(file, scope, 100), /CANDIDATE_METADATA_LIMIT/);
    assert.equal(scope.bytes, 12 * 32);
    await assert.rejects(readCandidateMetadata(file, scope, 5), /CANDIDATE_METADATA_FILE_LIMIT/);
    await symlink(file, join(root, "linked"));
    await assert.rejects(readCandidateMetadata(join(root, "linked"), scope, 100), { code: "ELOOP" });
    await assert.rejects(readCandidateMetadata(root, scope, 100), /CANDIDATE_METADATA_FILE_LIMIT/);
    assert.equal(scope.bytes, 12 * 32);
  } finally {
    scope.release();
    await rm(root, { recursive: true, force: true });
  }
  assert.equal(budget.snapshot().bytes, 0);
});