// Shared by the scene gate, the clip recorder, and the card cutter: the
// Playwright chromium they all drive, a private game server on a
// throwaway data dir, ffmpeg with the flags they all want, and the
// reel's rewind. Run from the repo root after `npx vite build` in
// packages/web.
import { execFileSync, spawn } from "node:child_process";
import { existsSync, mkdtempSync, readdirSync, rmSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";

/** The Playwright chromium executable: $WIZWAR_CHROME, else the newest
 * build in the ms-playwright cache. */
export function chromiumExe() {
  if (process.env.WIZWAR_CHROME) return process.env.WIZWAR_CHROME;
  const cache = join(process.env.HOME ?? "", "Library", "Caches", "ms-playwright");
  const builds = existsSync(cache)
    ? readdirSync(cache).filter((d) => /^chromium-\d+$/.test(d)).sort()
    : [];
  for (const build of builds.reverse()) {
    const exe = join(cache, build, "chrome-mac-arm64",
      "Google Chrome for Testing.app", "Contents", "MacOS", "Google Chrome for Testing");
    if (existsSync(exe)) return exe;
  }
  throw new Error("no Playwright chromium found — run: npx playwright-core install chromium (or set WIZWAR_CHROME)");
}

/** A game server on `port` with its own empty data dir. `up()` resolves
 * once it answers; `stop()` kills it and removes the dir. */
export function startServer(port, label = "wizwar-harness") {
  const dataDir = mkdtempSync(join(tmpdir(), `${label}-`));
  const server = spawn("npx", ["tsx", "src/index.ts"], {
    cwd: join(import.meta.dirname, "..", "..", "packages", "server"),
    env: { ...process.env, PORT: String(port), WIZWAR_DATA_DIR: join(dataDir, "rooms") },
    stdio: "ignore",
  });
  const up = async () => {
    for (let i = 0; i < 60; i++) {
      try { if ((await fetch(`http://127.0.0.1:${port}/`)).ok) return; } catch { /* not yet */ }
      await new Promise((r) => setTimeout(r, 500));
    }
    throw new Error("server never came up");
  };
  const stop = () => { server.kill(); rmSync(dataDir, { recursive: true, force: true }); };
  return { up, stop };
}

/** ffmpeg, quiet and overwriting. */
export const ff = (...args) => execFileSync("ffmpeg", ["-loglevel", "error", "-y", ...args]);

/** Pause the reel and step it back to its first move. */
export async function rewindReel(page) {
  await page.locator("button", { hasText: "❚❚" }).click();
  const count = Number((await page.locator(".replay-count").textContent()).match(/of (\d+)/)[1]);
  for (let i = 0; i < count; i++) await page.locator("button", { hasText: "◀" }).click();
  return count;
}