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

// **Every open pull request's new head is announced, however many are open** (novox/hq issue 579). A pass asked the
// forge for the 20 most recently updated open pull requests of a repository, so a new head on the 21st or later was
// not announced and its merge check never started. A pass now pages through the open pull requests updated since its
// last look — every page on a sweep or the first pass — and stops at the first page that reaches back past the floor.

const HOUR = 3600_000;
const T0 = Date.parse("2026-10-12T12:00:00Z");
const sha = (n: number, v: string) => `${v}${String(n).padStart(4, "0")}`.padEnd(40, "0");

/** A forge holding `count` open pull requests of novox/hq, #n updated n hours after T0 (#count the newest), paged and
 *  sorted the way gitea answers `sort=recentupdate`: by update time, newest first. */
function forge(count: number, heads: Record<number, string>) {
  const asked: URLSearchParams[] = [];
  const server = createServer((req, res) => {
    const url = new URL(req.url ?? "", "http://x");
    if (url.pathname !== "/api/v1/repos/novox/hq/pulls") {
      res.statusCode = 404;
      return res.end("{}");
    }
    asked.push(url.searchParams);
    const limit = Number(url.searchParams.get("limit") ?? 30);
    const page = Number(url.searchParams.get("page") ?? 1);
    const all = Array.from({ length: count }, (_, i) => count - i).map((n) => ({
      number: n, state: "open", base: { ref: "main" }, head: { ref: `b${n}`, sha: heads[n] ?? sha(n, "a") },
      updated_at: new Date(T0 + n * HOUR).toISOString(), html_url: `h/${n}`,
    }));
    res.end(JSON.stringify(all.slice((page - 1) * limit, page * limit)));
  });
  return { server, asked };
}

async function serve(count: number, heads: Record<number, string>) {
  const { GiteaClient } = await import("../client.ts");
  const f = forge(count, heads);
  await new Promise<void>((r) => f.server.listen(0, r));
  const client = new GiteaClient(`http://127.0.0.1:${(f.server.address() as any).port}`, "t");
  return { client, ...f };
}

test("a new head beyond the newest 20 open pull requests is announced, exactly once", async () => {
  const { headsToAnnounce } = await import("../pulls.ts");
  // 25 open, every head announced before; #3 — the 23rd most recently updated — got a new head.
  const announced: Record<string, string> = {};
  for (let n = 1; n <= 25; n++) announced[`novox/hq#${n}`] = sha(n, "a");
  const { client, server, asked } = await serve(25, { 3: sha(3, "b") });
  try {
    // The fault: the newest 20 alone do not hold it.
    const newest = await client.listPullRequests("novox", "hq", { state: "open", sort: "recentupdate", limit: "20" });
    assert.deepEqual(headsToAnnounce("novox/hq", newest, announced), [], "the newest 20 miss #3's new head");
    asked.length = 0;
    const said: string[] = [];
    for (let pass = 0; pass < 2; pass++) {
      // The sweep, as index.ts's pollPulls asks: no floor, every page.
      const open = await client.listOpenPullsSince("novox", "hq", "");
      for (const p of headsToAnnounce("novox/hq", open, announced)) {
        said.push(`#${p.number}@${p.head_sha}`);
        announced[`novox/hq#${p.number}`] = String(p.head_sha);
      }
    }
    assert.deepEqual(said, [`#3@${sha(3, "b")}`], "the new head past the newest 20, announced once over two passes");
    assert.ok(asked.every((q) => q.get("state") === "open" && q.get("sort") === "recentupdate"), "asked newest first");
  } finally {
    server.close();
  }
});

test("a pass pages until it reaches back past its floor, and no further", async () => {
  // 130 open pull requests, #n updated n hours after T0: page 1 holds #130–#81, page 2 #80–#31, page 3 #30–#1.
  const { client, server, asked } = await serve(130, {});
  try {
    // A floor between #60 and #61: page 2 reaches back past it, so page 3 is never asked.
    const floor = new Date(T0 + 60.5 * HOUR).toISOString();
    const open = await client.listOpenPullsSince("novox", "hq", floor);
    assert.deepEqual(asked.map((q) => q.get("page")), ["1", "2"]);
    assert.equal(open.length, 100);
    assert.ok(open.some((p) => p.number === 61), "every one updated since the floor is read");
    // A floor no page reaches past: the last short page ends it.
    asked.length = 0;
    assert.equal((await client.listOpenPullsSince("novox", "hq", "")).length, 130);
    assert.deepEqual(asked.map((q) => q.get("page")), ["1", "2", "3"]);
    // Every page holds fewer than 50 updated since a recent floor: one page.
    asked.length = 0;
    await client.listOpenPullsSince("novox", "hq", new Date(T0 + 129 * HOUR).toISOString());
    assert.deepEqual(asked.map((q) => q.get("page")), ["1"]);
  } finally {
    server.close();
  }
});