// `archilyzer mcp` starts the real MCP server, and stdout stays JSON-RPC.
//
// Run with:
//   pnpm --filter yt-dlp-transcript-common test
//
// Spawns the CLI the way `claude mcp add … -- <command>` would, sends the 2025
// initialize request, and reads the answer. The arguments after `mcp` reach the
// server untouched (the `--local` dir comes back in its stderr banner), and the
// FIRST line on stdout is the server's JSON-RPC answer: anything the CLI printed
// before it would break every MCP client.

import { test, after } from "node:test";
import assert from "node:assert/strict";
import { spawn } from "node:child_process";
import { mkdtempSync, rmSync } from "node:fs";
import os from "node:os";
import path from "node:path";
import { fileURLToPath } from "node:url";

const HERE = path.dirname(fileURLToPath(import.meta.url));
const TSX = path.join(HERE, "..", "node_modules", ".bin", "tsx");
const DIR = mkdtempSync(path.join(os.tmpdir(), "archilyzer-mcp-"));
after(() => rmSync(DIR, { recursive: true, force: true }));

test("archilyzer mcp answers initialize on stdout, with its argv passed through", { timeout: 60_000 }, async () => {
  const child = spawn(TSX, [path.join(HERE, "archilyzer.ts"), "mcp", "--local", DIR], {
    stdio: ["pipe", "pipe", "pipe"],
  });
  // Listened for from the start: a CLI that refuses at once exits before any
  // later listener could see it.
  const exited = new Promise<number | null>((r) => child.on("exit", (c) => r(c)));
  let stdout = "";
  let stderr = "";
  child.stdout.on("data", (b) => (stdout += b));
  child.stderr.on("data", (b) => (stderr += b));
  child.stdin.write(
    `${JSON.stringify({
      jsonrpc: "2.0",
      id: 1,
      method: "initialize",
      params: { protocolVersion: "2025-06-18", capabilities: {}, clientInfo: { name: "test", version: "0" } },
    })}\n`,
  );
  const deadline = Date.now() + 30_000;
  let ended = false;
  void exited.then(() => (ended = true));
  while (!stdout.includes("\n") && !ended && Date.now() < deadline) {
    await new Promise((r) => setTimeout(r, 50));
  }
  child.stdin.end();
  const code = await exited;
  const first = stdout.split("\n")[0];
  const msg = JSON.parse(first) as { id: number; result?: { serverInfo?: { name?: string } } };
  assert.equal(msg.id, 1);
  assert.equal(msg.result?.serverInfo?.name, "yt-dlp-transcript-mcp");
  assert.match(stderr, new RegExp(`default corpus: local:${DIR.replace(/[.*+?^${}()|[\]\\]/g, "\\$&")}`));
  // stdin closed: the server ends, and the CLI ends with it.
  assert.equal(code, 0);
});