import assert from "node:assert/strict";
import { test } from "node:test";

// **A pending check says where it is, and the verdict lands last** (novox/hq issue 446). This module is the one writer
// of a head's mesh/merge-gate: the announcement's pending words, "building on <machine> since …" when the build seat
// says a machine took the check, and the verdict. The forge keeps the newest status of a context, so a pending word
// written after the verdict hides it — a pass reads pending, a failure hides under "building".

const SHA = "a6b08de8507c1703528277e5cefc80548dbc9bb3";

// The build seat's `started` as a machine said it for novox/hq#309's check on 2026-10-11 (its log, read with the
// controller's `builds --log build-1791680941048622697`, opens at 03:09:01 on shanks); only the forge's address
// replaced. The shape is mesh-controller's link.BuildStart.
const startedOnShanks = { id: "build-1791680941048622697", repository: "http://127.0.0.1:20000/novox/hq.git",
  ref: SHA, on: "shanks", at: "2026-10-11T01:09:01.204319Z" };

/** A forge that keeps the newest status per context, as gitea does, and whose writes take as long as a test says. */
function aForge() {
  const kept: Record<string, { state: string; description: string; updated_at: string }> = {};
  const written: string[] = [];
  let hold: Promise<void> | null = null;
  let release = () => {};
  let readHold: Promise<void> | null = null;
  let readRelease = () => {};
  return {
    kept, written,
    /** The next writes wait until released: a request in flight. */
    holdWrites() {
      hold = new Promise<void>((r) => (release = r));
    },
    release() {
      hold = null;
      release();
    },
    async setCommitStatus(_o: string, _r: string, _sha: string, s: { state: string; context: string; description: string }) {
      if (hold) await hold;
      kept[s.context] = { state: s.state, description: s.description, updated_at: new Date().toISOString() };
      written.push(`${s.state} ${s.description}`);
    },
    /** Reads answer what the forge held when asked, as late as the reads are held: the answer of a request in flight. */
    holdReads() {
      readHold = new Promise<void>((r) => (readRelease = r));
    },
    releaseReads() {
      readHold = null;
      readRelease();
    },
    async gateOf(_o: string, _r: string, _sha: string) {
      const held = kept["mesh/merge-gate"] ? { ...kept["mesh/merge-gate"] } : undefined;
      if (readHold) await readHold;
      return held;
    },
  };
}

/** The clock of the test: the head announced at 01:08:50Z. */
const announcedAt = () => new Date("2026-10-11T01:08:50Z");

test("a build machine taking the check is said on the head: building on which machine, since the local time", async () => {
  const { GateWriter, buildingWords } = await import("../gate.ts");
  const forge = aForge();
  const gates = new GateWriter(forge, announcedAt);
  await gates.pending("novox", "hq", SHA);
  assert.equal(await gates.started("novox", "hq", SHA, startedOnShanks), true);
  assert.equal(forge.kept["mesh/merge-gate"].state, "pending");
  assert.equal(forge.kept["mesh/merge-gate"].description, buildingWords("shanks", new Date(startedOnShanks.at)));
  assert.equal(buildingWords("shanks", new Date(2026, 9, 11, 3, 9, 1)), "building on shanks since 03:09");
});

test("the verdict heard while a 'building' write is in flight lands last and stays", async () => {
  const { GateWriter } = await import("../gate.ts");
  const forge = aForge();
  const gates = new GateWriter(forge, announcedAt);
  await gates.pending("novox", "hq", SHA);
  forge.holdWrites(); // the 'building' request is in flight when the verdict comes
  const building = gates.started("novox", "hq", SHA, startedOnShanks);
  await new Promise((r) => setImmediate(r));
  const verdict = gates.verdict("novox", "hq", SHA, () =>
    forge.setCommitStatus("novox", "hq", SHA, { state: "success", context: "mesh/merge-gate", description: "pass" }));
  forge.release();
  await Promise.all([building, verdict]);
  assert.equal(`${forge.kept["mesh/merge-gate"].state} ${forge.kept["mesh/merge-gate"].description}`, "success pass",
    `the verdict is not the newest status: ${forge.written.join(" | ")}`);
});

// The race the review of mesh-catalog#202 reproduced: a writer reads the forge's gate (pending), the verdict is written,
// then the writer writes "building" — and the pass reads pending until the next push. A head this process did not
// announce is the one case where the forge is read before writing.
test("the verdict written while a start's read of the forge is in flight stays the newest status", async () => {
  const { GateWriter } = await import("../gate.ts");
  const forge = aForge();
  forge.kept["mesh/merge-gate"] = { state: "pending", description: "waiting", updated_at: "2026-10-11T01:08:50Z" };
  const gates = new GateWriter(forge, announcedAt);
  forge.holdReads();
  const building = gates.started("novox", "hq", SHA, startedOnShanks);
  await new Promise((r) => setImmediate(r));
  const verdict = gates.verdict("novox", "hq", SHA, () =>
    forge.setCommitStatus("novox", "hq", SHA, { state: "success", context: "mesh/merge-gate", description: "pass" }));
  await new Promise((r) => setImmediate(r));
  forge.releaseReads();
  await Promise.all([building, verdict]);
  assert.equal(`${forge.kept["mesh/merge-gate"].state} ${forge.kept["mesh/merge-gate"].description}`, "success pass",
    `the verdict is not the newest status: ${forge.written.join(" | ")}`);
});

test("the verdict heard while a 'building' write still waits its turn: the 'building' is never written", async () => {
  const { GateWriter } = await import("../gate.ts");
  const forge = aForge();
  const gates = new GateWriter(forge, announcedAt);
  forge.holdWrites(); // the pending words are still being written
  const pending = gates.pending("novox", "hq", SHA);
  const building = gates.started("novox", "hq", SHA, startedOnShanks);
  const verdict = gates.verdict("novox", "hq", SHA, () =>
    forge.setCommitStatus("novox", "hq", SHA, { state: "failure", context: "mesh/merge-gate", description: "fail: 0 of 4 compose" }));
  forge.release();
  await Promise.all([pending, verdict]);
  assert.equal(await building, false);
  assert.equal(forge.kept["mesh/merge-gate"].state, "failure");
  assert.ok(!forge.written.some((w) => w.includes("building")), forge.written.join(" | "));
});

test("a start heard after the verdict writes nothing", async () => {
  const { GateWriter } = await import("../gate.ts");
  const forge = aForge();
  const gates = new GateWriter(forge, announcedAt);
  await gates.pending("novox", "hq", SHA);
  await gates.verdict("novox", "hq", SHA, () =>
    forge.setCommitStatus("novox", "hq", SHA, { state: "success", context: "mesh/merge-gate", description: "pass" }));
  assert.equal(await gates.started("novox", "hq", SHA, startedOnShanks), false);
  assert.equal(forge.kept["mesh/merge-gate"].state, "success");
});

test("a start from before the check now pending (a run before a recheck, the stream's history) writes nothing", async () => {
  const { GateWriter } = await import("../gate.ts");
  const forge = aForge();
  let now = announcedAt();
  const gates = new GateWriter(forge, () => now);
  await gates.pending("novox", "hq", SHA);
  await gates.verdict("novox", "hq", SHA, () =>
    forge.setCommitStatus("novox", "hq", SHA, { state: "failure", context: "mesh/merge-gate", description: "error" }));
  now = new Date("2026-10-11T01:30:00Z"); // checked again: pending once more
  await gates.pending("novox", "hq", SHA);
  assert.equal(await gates.started("novox", "hq", SHA, startedOnShanks), false, "the first run's start");
  assert.match(forge.kept["mesh/merge-gate"].description, /^waiting in the build queue since /);
  assert.equal(await gates.started("novox", "hq", SHA, { ...startedOnShanks, at: "2026-10-11T01:31:00Z" }), true,
    "the second run's start");
});

test("a head this process did not announce (it restarted) is said only while the forge holds its gate pending", async () => {
  const { GateWriter } = await import("../gate.ts");
  const forge = aForge();
  forge.kept["mesh/merge-gate"] = { state: "success", description: "pass", updated_at: "2026-10-11T01:20:00Z" };
  const gates = new GateWriter(forge, announcedAt);
  assert.equal(await gates.started("novox", "hq", SHA, startedOnShanks), false);
  forge.kept["mesh/merge-gate"] = { state: "pending", description: "waiting", updated_at: "2026-10-11T01:08:50Z" };
  assert.equal(await gates.started("novox", "hq", SHA, startedOnShanks), true);
});

test("a repository as the mesh clones it is told from another", async () => {
  const { clonedAs } = await import("../gate.ts");
  assert.equal(clonedAs("http://127.0.0.1:20000/novox/hq.git", "novox", "hq"), true);
  assert.equal(clonedAs("http://127.0.0.1:20000/novox/mesh-hq.git", "novox", "hq"), false);
  assert.equal(clonedAs("http://127.0.0.1:20000/novox/mesh-controller.git", "novox", "hq"), false);
});