// The runner's git tools (src/git-tools.mjs) against a fake git socket that
// records the request line. The review loop over the real host's socket is in
// packages/cli/tests/git-socket.test.mjs.

import { test } from "node:test";
import assert from "node:assert/strict";
import { spawnSync } from "node:child_process";
import { existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
import { createServer } from "node:net";
import { join } from "node:path";
import { fetchReview, git as runnerGit, HAVE_MAX } from "../src/git-tools.mjs";
import { scratch } from "./helpers.mjs";

const ENV = { PATH: process.env.PATH, HOME: "/nonexistent", GIT_CONFIG_NOSYSTEM: "1", GIT_CONFIG_GLOBAL: "/dev/null", LC_ALL: "C" };

function git(cwd, args, extra = {}) {
  const r = spawnSync("git", ["-c", "user.name=t", "-c", "user.email=t@example.invalid", "-C", cwd, ...args], { env: { ...ENV, ...extra }, encoding: "utf8" });
  assert.equal(r.status, 0, `git ${args.join(" ")}: ${r.stderr}`);
  return r.stdout.trim();
}

// A clone at `dir` with `refs` (name -> commit time) pointing at commits of
// their own.
function clone(dir, refs) {
  mkdirSync(dir, { recursive: true });
  git(dir, ["init", "-q"]);
  const tree = git(dir, ["mktree"]);
  const oids = {};
  for (const [name, time] of Object.entries(refs)) {
    const date = `${time} +0000`;
    oids[name] = git(dir, ["commit-tree", tree, "-m", name], { GIT_AUTHOR_DATE: date, GIT_COMMITTER_DATE: date });
    git(dir, ["update-ref", name, oids[name]]);
  }
  return oids;
}

// A socket that keeps each request line and refuses it.
async function fakeHost(t, dir) {
  const path = join(dir, "git.sock");
  const lines = [];
  const server = createServer((s) => {
    let buf = "";
    s.on("data", (b) => {
      buf += b;
      if (!buf.includes("\n")) return;
      lines.push(JSON.parse(buf.split("\n")[0]));
      s.end(`${JSON.stringify({ ok: false, error: "request-not-found" })}\n`);
    });
  });
  await new Promise((r) => server.listen(path, r));
  t.after(() => new Promise((r) => server.close(r)));
  return { path, lines };
}

test("fetch_review's have lists the working refs before origin's, and no more than HAVE_MAX", async (t) => {
  const dir = scratch(t);
  const workspace = join(dir, "ws");
  // 40 origin refs, newer than every working ref, and 13 working refs in two
  // clones: 53 in all.
  const stack = {};
  for (let i = 0; i < 40; i++) stack[`refs/remotes/origin/b${i}`] = 1_800_000_000 + i;
  for (let i = 1; i <= 10; i++) stack[`refs/remotes/working/work/vikunja-1-${i}`] = 1_700_000_000 + i;
  const other = {};
  for (let i = 1; i <= 3; i++) other[`refs/remotes/working/work/vikunja-2-${i}`] = 1_700_000_000 + i;
  const a = clone(join(workspace, "stack"), stack);
  const b = clone(join(workspace, "other"), other);
  const host = await fakeHost(t, dir);
  await assert.rejects(fetchReview({ path: host.path, cap: "c".repeat(64), workspace, task_ref: "vikunja:1/2", request: "r1", tmp: dir, env: ENV }), (e) => e.code === "request-not-found");
  const [req] = host.lines;
  assert.equal(req.op, "fetch");
  assert.equal(HAVE_MAX, 32);
  assert.equal(req.have.length, HAVE_MAX);
  assert.equal(new Set(req.have).size, HAVE_MAX);
  const working = [...Object.entries(a), ...Object.entries(b)].filter(([n]) => n.startsWith("refs/remotes/working/")).map(([, oid]) => oid);
  assert.equal(working.length, 13);
  // Every working ref, ahead of any of origin's.
  assert.deepEqual(new Set(req.have.slice(0, 13)), new Set(working));
  const origin = new Set(Object.entries(a).filter(([n]) => n.startsWith("refs/remotes/origin/")).map(([, oid]) => oid));
  for (const oid of req.have.slice(13)) assert.ok(origin.has(oid), oid);
});

// Past HAVE_MAX the order is per clone: each clone's working refs newest
// first, one clone after another, so an earlier clone's older refs come
// ahead of a later clone's newer ones. The clones' order is the workspace's
// directory order, so the test takes it from the request.
test("fetch_review's have orders the working refs newest first within each clone, one clone after another", async (t) => {
  const dir = scratch(t);
  const workspace = join(dir, "ws");
  // 20 working refs in each clone; beta's are all newer than alpha's.
  // Created in a shuffled order, so the name order isn't the date order.
  const order = [7, 2, 15, 0, 11, 19, 4, 9, 13, 1, 17, 6, 3, 18, 10, 5, 14, 8, 16, 12];
  const refs = (task, base) => Object.fromEntries(order.map((i) => [`refs/remotes/working/work/vikunja-${task}-${i + 1}`, base + i * 60]));
  const alpha = clone(join(workspace, "alpha"), refs(1, 1_700_000_000));
  const beta = clone(join(workspace, "beta"), refs(2, 1_750_000_000));
  const host = await fakeHost(t, dir);
  await assert.rejects(fetchReview({ path: host.path, cap: "c".repeat(64), workspace, task_ref: "vikunja:1/2", request: "r1", tmp: dir, env: ENV }), (e) => e.code === "request-not-found");
  const [req] = host.lines;
  // Newest first: the ref for i = 19 first, i = 0 last.
  const newest = (oids, task) => order.slice().sort((x, y) => y - x).map((i) => oids[`refs/remotes/working/work/vikunja-${task}-${i + 1}`]);
  const [first, second] = new Set(Object.values(alpha)).has(req.have[0]) ? [newest(alpha, 1), newest(beta, 2)] : [newest(beta, 2), newest(alpha, 1)];
  assert.deepEqual(req.have, [...first, ...second].slice(0, HAVE_MAX));
});

// A git on PATH that runs `body` in place of the real one.
function fakeGit(dir, body) {
  const bin = join(dir, "bin");
  mkdirSync(bin);
  writeFileSync(join(bin, "git"), `#!/bin/bash\n${body}\n`, { mode: 0o755 });
  return { ...ENV, PATH: `${bin}:${process.env.PATH}` };
}

// True once `pid` has gone, or is a zombie waiting to be reaped.
async function gone(pid, ms) {
  const end = Date.now() + ms;
  for (;;) {
    let stat = null;
    try {
      stat = readFileSync(`/proc/${pid}/stat`, "utf8");
    } catch {}
    if (stat === null || stat.slice(stat.lastIndexOf(")") + 2)[0] === "Z") return true;
    if (Date.now() > end) return false;
    await new Promise((r) => setTimeout(r, 50));
  }
}

async function pidIn(file) {
  for (let i = 0; i < 100 && !existsSync(file); i++) await new Promise((r) => setTimeout(r, 20));
  return Number(readFileSync(file, "utf8").trim());
}

const kill = (pid) => {
  try {
    process.kill(pid, "SIGKILL");
  } catch {}
};

// git ignores SIGTERM and waits on a sleep it started. SIGTERM goes to the
// group, so the sleep dies at the timeout; git itself lasts until SIGKILL.
test("a runner git past its time: SIGTERM reaches its process group, and SIGKILL follows after the grace period", { timeout: 20000 }, async (t) => {
  const dir = scratch(t);
  const file = join(dir, "child.pid");
  const env = fakeGit(dir, `sleep 30 </dev/null >/dev/null 2>&1 &\necho $! > '${file}'\ntrap '' TERM\nwait $!\nexec sleep 30`);
  const started = Date.now();
  const run = runnerGit(["fetch"], env, { timeoutMs: 300, graceMs: 1500 });
  const pid = await pidIn(file);
  t.after(() => kill(pid));
  assert.equal(await gone(pid, 800), true, "the sleep git started died at SIGTERM");
  assert.ok(Date.now() - started < 1500, "before the grace period was over");
  const r = await run;
  assert.equal(r.why, "killed by SIGKILL");
  assert.ok(Date.now() - started >= 1800, "SIGKILL waited out the grace period");
});

// git dies at SIGTERM; a process it started ignores SIGTERM and holds none
// of git's output. Once git has closed, its group gets SIGKILL.
test("once a signalled runner git has closed, its group gets SIGKILL, so a process that ignored SIGTERM dies too", { timeout: 20000 }, async (t) => {
  const dir = scratch(t);
  const file = join(dir, "child.pid");
  const env = fakeGit(dir, `(trap '' TERM; exec sleep 30) </dev/null >/dev/null 2>&1 &\necho $! > '${file}'\nexec sleep 30`);
  const r = await runnerGit(["fetch"], env, { timeoutMs: 300, graceMs: 20000 });
  assert.equal(r.why, "killed by SIGTERM");
  const pid = await pidIn(file);
  t.after(() => kill(pid));
  assert.equal(await gone(pid, 1500), true, "the sleep that ignored SIGTERM is gone well inside the grace period");
});