// fallow-ignore-file code-duplication
import { execSync, spawnSync } from "node:child_process";
import { existsSync, mkdirSync, readdirSync, rmSync, statSync, utimesSync } from "node:fs";
import { basename } from "node:path";
import { homedir } from "node:os";
import { join } from "node:path";
import { normalizeErrorMessage } from "../utils/errorMessage.js";

type PuppeteerBrowsers = typeof import("@puppeteer/browsers");

async function loadPuppeteerBrowsers(): Promise<PuppeteerBrowsers> {
  try {
    return await import("@puppeteer/browsers");
  } catch (err) {
    const cause = normalizeErrorMessage(err);
    throw new Error(
      `Failed to load @puppeteer/browsers: ${cause}\n` +
        `Fix: run \`npm install\` or \`bun install\` to restore missing packages, then retry.`,
    );
  }
}

// Bumped from 152.0.7928.2 on 2026-08-10 to pick up crbug 522872457's fix
// (CL 8032671, "Force-merge PendingLayer for canvas child descendant", merged
// 2026-07-07 — after the 152.0.7935.0 canary cut, so the old pin predated it).
//
// Measured on the shipping headless-shell binary, drawElementImage vs a CDP
// screenshot of the identical state:
//   sibling content dropped from 3D captures  — FIXED
//   background lost from 3D captures          — FIXED
//   backface-visibility:hidden ignored        — STILL BROKEN (1.4 dB -> 14.8 dB;
//                                               better, still far under the
//                                               32 dB floor)
// So the 3D compile gate must stay. See PRINFRA-486.
//
// Deliberately Beta, not Canary. 153.0.8000.0 measured identical to this build
// on every probe variant, so crossing a major buys nothing measurable.
const CHROME_VERSION = "152.0.7977.30";
const CACHE_ROOT_DIR = join(homedir(), ".cache", "hyperframes");
const CACHE_DIR = join(homedir(), ".cache", "hyperframes", "chrome");
// Puppeteer's managed cache — where `@puppeteer/browsers install
// chrome-headless-shell` (and `puppeteer install`) drop binaries. The engine's
// `resolveHeadlessShellPath` scans the same directory; the CLI must look here
// too or it silently picks system Chrome over a perfectly good headless-shell.
const PUPPETEER_CACHE_DIR = join(homedir(), ".cache", "puppeteer", "chrome-headless-shell");

// `@puppeteer/browsers`' downloadFile() (lib/httpUtil.js) opens a bare
// node:http(s) request with no AbortController/timeout anywhere in the chain
// (confirmed by source read of the resolved 3.x package) — a connection that
// never gets a response (e.g. a network that only egresses through an
// HTTP(S)_PROXY, which downloadFile's own proxy-agent support silently no-ops
// on: `proxy-agent` is only an *optional peer* dependency, so the package's
// dynamic import of it throws, is caught, and the request falls back to a
// bare agent that never reads proxy env vars) just hangs at "Downloading
// Chrome... 0%" forever. See PRINFRA-682. This is a stall watchdog, not a
// total-download-duration cap: it resets on every progress tick, so a
// slow-but-actually-progressing download (large binary over a slow line)
// never trips it — only a connection that stops producing any bytes for this
// long does.
const DOWNLOAD_STALL_TIMEOUT_MS = 45_000;

// `@puppeteer/browsers`' install() has no concurrency guard of its own — two
// CLI invocations that both miss the cache at the same time both extract into
// the same target directory simultaneously. A killed/interrupted extraction
// from that race can leave a binary that merely *exists* (so doctor/lint/
// validate all report healthy) while missing bits a clean install sets (e.g.
// macOS Gatekeeper/quarantine + GPU/Metal entitlements) — reported as headless
// GPU frame capture silently returning all-black frames despite --browser-gpu
// auto/hardware, invisible until someone inspects the actual pixels.
//
// mkdirSync is atomic (EEXIST if another process already holds it), so it
// doubles as a zero-dependency cross-process mutex — no lockfile library needed.
const INSTALL_LOCK_DIR = join(CACHE_ROOT_DIR, ".chrome.install.lock");
const INSTALL_RECLAIM_LOCK_DIR = join(CACHE_ROOT_DIR, ".chrome.install.reclaim.lock");
const INSTALL_LOCK_TIMINGS = {
  staleMs: 120_000,
  pollMs: 200,
  heartbeatMs: 15_000,
  waitNoticeMs: 10_000,
};

interface InstallLockTimings {
  staleMs: number;
  pollMs: number;
  heartbeatMs: number;
  waitNoticeMs: number;
}

function isErrno(err: unknown, code: string): boolean {
  return (err as NodeJS.ErrnoException).code === code;
}

function sleep(ms: number): Promise<void> {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

function tryAcquireDirLock(lockDir: string): boolean {
  try {
    // recursive:false is load-bearing: it's what makes this throw EEXIST
    // (and therefore act as a mutex) instead of silently no-op'ing like
    // `mkdir -p` when the lock dir already exists.
    mkdirSync(lockDir, { recursive: false });
    return true;
  } catch (err) {
    if (!isErrno(err, "EEXIST")) throw err;
    return false;
  }
}

function isDirLockStale(lockDir: string, timeoutMs: number): boolean {
  try {
    return Date.now() - statSync(lockDir).mtimeMs > timeoutMs;
  } catch (err) {
    if (isErrno(err, "ENOENT")) return false;
    throw err;
  }
}

function reclaimStaleInstallLock(timeoutMs: number): void {
  if (!tryAcquireDirLock(INSTALL_RECLAIM_LOCK_DIR)) return;
  try {
    const mtimeMs = statSync(INSTALL_LOCK_DIR).mtimeMs;
    if (Date.now() - mtimeMs > timeoutMs) {
      rmSync(INSTALL_LOCK_DIR, { recursive: true, force: true });
    }
  } catch (err) {
    if (!isErrno(err, "ENOENT")) throw err;
  } finally {
    rmSync(INSTALL_RECLAIM_LOCK_DIR, { recursive: true, force: true });
  }
}

function reclaimAbandonedReclaimLock(timeoutMs: number): void {
  try {
    if (isDirLockStale(INSTALL_RECLAIM_LOCK_DIR, timeoutMs)) {
      rmSync(INSTALL_RECLAIM_LOCK_DIR, { recursive: true, force: true });
    }
  } catch (err) {
    if (!isErrno(err, "ENOENT")) throw err;
  }
}

function touchInstallLock(): void {
  try {
    const now = new Date();
    utimesSync(INSTALL_LOCK_DIR, now, now);
  } catch {
    // ponytail: heartbeat is best-effort; stale-lock reclaim remains the fallback.
  }
}

export async function withInstallLock<T>(
  fn: () => Promise<T>,
  timings: InstallLockTimings = INSTALL_LOCK_TIMINGS,
): Promise<T> {
  // recursive:false below needs the parent to already exist (unlike `mkdir -p`).
  // Keep lock dirs outside CACHE_DIR so force-clearing the Chrome cache cannot
  // delete another installer's in-flight lock.
  if (!existsSync(CACHE_ROOT_DIR)) mkdirSync(CACHE_ROOT_DIR, { recursive: true });
  let deadline = Date.now() + timings.staleMs;
  const waitStart = Date.now();
  let lastNoticeMs = 0;
  for (;;) {
    if (existsSync(INSTALL_RECLAIM_LOCK_DIR)) {
      // A process can die after acquiring the reclaim gate but before its
      // synchronous cleanup runs. Without aging out that gate, every future
      // installer sleeps here forever and never reaches the install-lock
      // timeout/reclaim path below.
      reclaimAbandonedReclaimLock(timings.staleMs);
      await sleep(timings.pollMs);
      continue;
    }
    if (tryAcquireDirLock(INSTALL_LOCK_DIR)) {
      rmSync(INSTALL_RECLAIM_LOCK_DIR, { recursive: true, force: true });
      break;
    }
    const waitedMs = Date.now() - waitStart;
    if (waitedMs - lastNoticeMs >= timings.waitNoticeMs) {
      lastNoticeMs = waitedMs;
      console.warn(
        `[browser] Waiting for another hyperframes process to finish installing chrome-headless-shell (${Math.round(waitedMs / 1000)}s elapsed)...`,
      );
    }
    if (isDirLockStale(INSTALL_LOCK_DIR, timings.staleMs) || Date.now() > deadline) {
      // The reclaim gate matters when multiple waiters cross the timeout at
      // once: without it, waiter A can delete the stale lock and acquire a
      // fresh one, then waiter B (whose old deadline also expired) can delete
      // A's fresh lock. The gate serializes reclaimers, and the mtime re-check
      // after the gate prevents deleting a fresh lock another waiter just won.
      reclaimStaleInstallLock(timings.staleMs);
      deadline = Date.now() + timings.staleMs;
      continue;
    }
    await sleep(timings.pollMs);
  }
  const heartbeat = setInterval(touchInstallLock, timings.heartbeatMs);
  if (typeof heartbeat.unref === "function") heartbeat.unref();
  try {
    return await fn();
  } finally {
    clearInterval(heartbeat);
    rmSync(INSTALL_LOCK_DIR, { recursive: true, force: true });
  }
}

export type BrowserSource = "env" | "cache" | "system" | "download";

export interface BrowserResult {
  executablePath: string;
  source: BrowserSource;
}

export interface EnsureBrowserOptions {
  onProgress?: (downloadedBytes: number, totalBytes: number) => void;
  // Purge any cached HF-managed download before resolving, so a stale or
  // partially-extracted install can't make the retry look like a no-op.
  force?: boolean;
  // Always resolve to OUR pinned `CHROME_VERSION` build (cached, or freshly
  // downloaded) — skip both the shared puppeteer-cache preference (some other
  // tool's install, arbitrary version) and system Chrome (tracks Stable,
  // arbitrary version, doesn't get updated in lockstep with this codebase).
  // Rendering behavior should not vary with whatever Chrome happens to be
  // sitting on the machine: it's the version we've actually tested against,
  // and the one that implements `canvas.drawElementImage` (Dev/Canary-only —
  // Stable doesn't have it, so system Chrome used to crash drawElement-
  // eligible renders outright; HF#2060). `HYPERFRAMES_BROWSER_PATH` still
  // wins over this — an explicit override is still an explicit override.
  preferManagedChrome?: boolean;
}

interface CacheLookupResult {
  result?: BrowserResult;
  staleHyperframesCachePath?: string;
  // Root install-folder path for the stale entry (InstalledBrowser#path), NOT
  // the missing executablePath above — this is what actually needs deleting.
  staleInstallPath?: string;
}

/**
 * Remove one browser version's install directory (not the whole CACHE_DIR).
 * @puppeteer/browsers' install() treats an existing-but-incomplete directory
 * as already installed and throws "folder exists but executable is missing"
 * rather than re-extracting — so an extraction interrupted by a Windows AV
 * lock, a sleep/wake cycle, or ctrl-C (left with only alphabetically-early
 * files like ABOUT/LICENSE, no exe) wedges every subsequent ensure/render
 * with the same error until someone manually deletes the directory. Purging
 * it first makes the retry actually retry.
 */
function purgeStaleInstall(installPath: string): void {
  rmSync(installPath, { recursive: true, force: true });
}

// --- Internal helpers -------------------------------------------------------

const SYSTEM_CHROME_PATHS: ReadonlyArray<string> =
  process.platform === "darwin"
    ? ["/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"]
    : process.platform === "win32"
      ? [
          join(
            process.env["ProgramW6432"] ?? process.env["PROGRAMFILES"] ?? "C:\\Program Files",
            "Google",
            "Chrome",
            "Application",
            "chrome.exe",
          ),
          join(
            process.env["PROGRAMFILES(X86)"] ?? "C:\\Program Files (x86)",
            "Google",
            "Chrome",
            "Application",
            "chrome.exe",
          ),
          ...(process.env["LOCALAPPDATA"]
            ? [join(process.env["LOCALAPPDATA"], "Google", "Chrome", "Application", "chrome.exe")]
            : []),
        ]
      : [
          "/usr/bin/google-chrome",
          "/usr/bin/google-chrome-stable",
          "/usr/bin/chromium",
          "/usr/bin/chromium-browser",
        ];

function whichBinary(name: string): string | undefined {
  try {
    const cmd = process.platform === "win32" ? `where ${name}` : `which ${name}`;
    const output = execSync(cmd, {
      encoding: "utf-8",
      stdio: ["pipe", "pipe", "pipe"],
      timeout: 5000,
      windowsHide: true,
    });
    const first = output
      .split(/\r?\n/)
      .map((s) => s.trim())
      .find(Boolean);
    return first || undefined;
  } catch {
    return undefined;
  }
}

// Env-var aliases for a caller-supplied browser executable path. The CLI-native
// name `HYPERFRAMES_BROWSER_PATH` is the canonical spelling (documented via the
// download-failure hint added in #2443). `PRODUCER_HEADLESS_SHELL_PATH` is the
// engine-side name that per-worker render launches already honor (see
// `packages/engine/src/services/browserManager.ts` and `render.ts` which even
// propagates the CLI-resolved executable into it). Docs in
// `skills/hyperframes-animation/adapters/typegpu.md`,
// `packages/gcp-cloud-run/Dockerfile`, and `examples/k8s-jobs/Dockerfile.example`
// all instruct users to set `PRODUCER_HEADLESS_SHELL_PATH`, so field reports
// (e.g. `#hyperframes-cli-feedback` ts=1784095034 on win32/x64) hit the case
// where `render` completes via that env var while `check`, `snapshot`, and
// `compare` all ignore it and crash on the cached headless-shell instead.
// Alias them here so every consumer of `openSettledCompositionPage` (which
// calls `ensureBrowser` → `findFromEnv`) picks up the same escape hatch.
// Tiebreak: HYPERFRAMES_BROWSER_PATH wins when both are set, matching the
// CLI-native canonicalization in `render.ts` (which only sets
// `PRODUCER_HEADLESS_SHELL_PATH` if not already present).
function findFromEnv(): BrowserResult | undefined {
  const envPath =
    process.env["HYPERFRAMES_BROWSER_PATH"] ?? process.env["PRODUCER_HEADLESS_SHELL_PATH"];
  if (envPath && existsSync(envPath)) {
    return { executablePath: envPath, source: "env" };
  }
  return undefined;
}

/**
 * Hyperframes-managed cache only (populated by `ensureBrowser` as a
 * download-of-last-resort, pinned to `CHROME_VERSION`).
 */
async function findFromHyperframesCache(): Promise<CacheLookupResult> {
  if (!existsSync(CACHE_DIR)) return {};
  const { Browser, detectBrowserPlatform, getInstalledBrowsers } = await loadPuppeteerBrowsers();
  // A corrupt cache (stub file where a browser dir is expected, malformed
  // metadata) makes getInstalledBrowsers throw. Treat that as "no cached
  // browser" so resolution falls through to system/download instead of
  // crashing every caller.
  let installed: Awaited<ReturnType<typeof getInstalledBrowsers>>;
  try {
    installed = await getInstalledBrowsers({ cacheDir: CACHE_DIR });
  } catch (err) {
    const code = (err as NodeJS.ErrnoException | undefined)?.code;
    const suffix = code ? ` (${code})` : "";
    console.warn(
      `[hyperframes] Browser cache read failed${suffix}: ${normalizeErrorMessage(err)}. Falling back to system Chrome or a fresh download.`,
    );
    installed = [];
  }
  // Match on buildId too, not just browser type — an install left over from
  // an older hyperframes version (this pin has moved 131 → 151 → 152 across
  // releases) must NOT satisfy resolution, or an upgrade silently keeps
  // running whatever build happened to be cached instead of ever fetching
  // the version this release actually needs (HF#2060 review). Match platform
  // as well so a shared/migrated cache cannot return a foreign executable.
  const hostPlatform = detectBrowserPlatform();
  const match = installed.find(
    (b) =>
      b.browser === Browser.CHROMEHEADLESSSHELL &&
      b.buildId === CHROME_VERSION &&
      b.platform === hostPlatform,
  );
  if (match && existsSync(match.executablePath)) {
    return { result: { executablePath: match.executablePath, source: "cache" } };
  }
  if (match) {
    return { staleHyperframesCachePath: match.executablePath, staleInstallPath: match.path };
  }
  return {};
}

async function findFromCache(): Promise<CacheLookupResult> {
  // 1) Puppeteer's managed cache — where `npx @puppeteer/browsers install
  // chrome-headless-shell` lands, and where `puppeteer install` from a project
  // depending on full `puppeteer` (not `puppeteer-core`) lands. The engine's
  // `resolveHeadlessShellPath` reads from here and selects newest-version-
  // first; the CLI must match that semantic or it will silently hand the
  // engine an older binary than the engine itself would pick.
  //
  // We intentionally check puppeteer BEFORE the hyperframes-managed cache:
  // this is the non-`preferManagedChrome` path, which exists so a user who
  // installed chrome-headless-shell separately (via `@puppeteer/browsers
  // install`) keeps using that binary instead of being silently switched to
  // the HF-pinned one. Note `CHROME_VERSION` (above) is a pre-Stable pin
  // that may be NEWER than a user's puppeteer-cache Stable build — this is
  // about respecting an explicit prior choice, not "newest wins".
  const fromPuppeteer = findFromPuppeteerCache();
  if (fromPuppeteer) {
    return { result: fromPuppeteer };
  }

  // 2) Hyperframes-managed cache. This is the fallback path: only reached
  // when no puppeteer-cache binary exists.
  return findFromHyperframesCache();
}

/**
 * Parse a puppeteer-cache version directory name (`linux-148.0.7778.97`,
 * `mac_arm-131.0.6778.85`, etc.) into a numeric tuple for ordering.
 *
 * Lexicographic sort on these strings is buggy because `"99"` > `"148"` (the
 * `9` outranks the `1` character-wise), so a 99-era binary would beat a
 * 148-era binary in `.sort().reverse()`. We split on `-` to drop the platform
 * prefix, then on `.` to get integer segments. Returns `undefined` for names
 * that don't have at least one parseable numeric segment so they sort last.
 */
function parseVersionSegments(versionDir: string): number[] | undefined {
  const dashIdx = versionDir.indexOf("-");
  const versionPart = dashIdx >= 0 ? versionDir.slice(dashIdx + 1) : versionDir;
  const segments = versionPart.split(".");
  const parsed: number[] = [];
  for (const seg of segments) {
    const n = parseInt(seg, 10);
    if (!Number.isFinite(n)) {
      // Stop at the first non-numeric segment but keep what we've collected.
      break;
    }
    parsed.push(n);
  }
  return parsed.length > 0 ? parsed : undefined;
}

/** Numeric semver-style descending comparator for puppeteer cache dirs. */
function compareVersionDirsDescending(a: string, b: string): number {
  const pa = parseVersionSegments(a);
  const pb = parseVersionSegments(b);
  // Unparseable names sort after parseable ones (so we still try them, just last).
  if (!pa && !pb) return 0;
  if (!pa) return 1;
  if (!pb) return -1;
  const len = Math.max(pa.length, pb.length);
  for (let i = 0; i < len; i += 1) {
    const av = pa[i] ?? 0;
    const bv = pb[i] ?? 0;
    if (av !== bv) return bv - av; // descending (newest first)
  }
  return 0;
}

const CACHED_HEADLESS_SHELL_EXECUTABLES: Readonly<
  Record<string, readonly [directory: string, executable: string]>
> = {
  "darwin/arm64": ["chrome-headless-shell-mac-arm64", "chrome-headless-shell"],
  "darwin/x64": ["chrome-headless-shell-mac-x64", "chrome-headless-shell"],
  "linux/x64": ["chrome-headless-shell-linux64", "chrome-headless-shell"],
  "win32/ia32": ["chrome-headless-shell-win32", "chrome-headless-shell.exe"],
  "win32/x64": ["chrome-headless-shell-win64", "chrome-headless-shell.exe"],
};

function cachedHeadlessShellExecutable(
  hostPlatform = process.platform,
  hostArch = process.arch,
): readonly [directory: string, executable: string] | undefined {
  // Chrome for Testing cache entries are host-specific. Resolve exactly one
  // platform/architecture directory so a foreign binary cannot win by probe order.
  // Chrome for Testing does not publish Linux ARM64 binaries. Windows ARM64 can
  // emulate x64 only on supported Windows 11 builds, which this platform/arch-only
  // resolver cannot prove, so both hosts deliberately fall through to system
  // browser discovery instead of attempting a potentially foreign cached binary.
  return CACHED_HEADLESS_SHELL_EXECUTABLES[`${hostPlatform}/${hostArch}`];
}

function findFromPuppeteerCache(): BrowserResult | undefined {
  if (!existsSync(PUPPETEER_CACHE_DIR)) return undefined;
  const executable = cachedHeadlessShellExecutable();
  if (!executable) return undefined;
  let versions: string[];
  try {
    // Numeric semver-style sort, newest first. Lexicographic `.sort().reverse()`
    // (the previous implementation, still in engine `resolveHeadlessShellPath`)
    // mis-orders `linux-99...` ahead of `linux-148...` because character `'9'`
    // outranks `'1'`. See `parseVersionSegments` above.
    versions = [...readdirSync(PUPPETEER_CACHE_DIR)].sort(compareVersionDirsDescending);
  } catch {
    return undefined;
  }
  for (const version of versions) {
    // Same shape as `resolveHeadlessShellPath` in engine/browserManager.ts —
    // keep them aligned. If puppeteer ever changes the on-disk layout the two
    // need to move together.
    const binary = join(PUPPETEER_CACHE_DIR, version, ...executable);
    if (existsSync(binary)) {
      return { executablePath: binary, source: "cache" };
    }
  }
  return undefined;
}

/**
 * True iff the binary at `executablePath` is `chrome-headless-shell` (i.e. the
 * Chromium build that still exposes `HeadlessExperimental.enable` /
 * `beginFrame`). Regular Chrome and `chromium` have dropped those domains, so
 * the engine's perf-optimized BeginFrame capture path silently degrades to
 * screenshot mode when those are used.
 */
function isHeadlessShellBinary(executablePath: string): boolean {
  const name = basename(executablePath).toLowerCase();
  return name === "chrome-headless-shell" || name === "chrome-headless-shell.exe";
}

/**
 * Emit a one-time warning when the CLI selects a non-headless-shell binary on
 * Linux. Idempotent across repeated `findBrowser()` calls so a long-running
 * `hyperframes studio` process doesn't get spammed.
 */
let _warnedSystemFallback = false;
function warnSystemFallbackOnce(executablePath: string): void {
  if (_warnedSystemFallback) return;
  if (process.platform !== "linux") return;
  if (isHeadlessShellBinary(executablePath)) return;
  _warnedSystemFallback = true;
  console.warn(
    `[hyperframes] Using system Chrome at ${executablePath}; HeadlessExperimental.beginFrame is unavailable in regular Chrome builds, so the perf-optimized capture path falls back to screenshot mode. Install chrome-headless-shell for the optimized path:\n  npx @puppeteer/browsers install chrome-headless-shell\n(Or set HYPERFRAMES_BROWSER_PATH to point at an existing chrome-headless-shell binary.)`,
  );
}

/** Test-only: reset the one-shot warn latch. */
export function _resetSystemFallbackWarnForTests(): void {
  _warnedSystemFallback = false;
}

export function findSystemBrowser(): BrowserResult | undefined {
  for (const p of SYSTEM_CHROME_PATHS) {
    if (existsSync(p)) {
      return { executablePath: p, source: "system" };
    }
  }

  const fromWhich = whichBinary("google-chrome") ?? whichBinary("chromium");
  if (fromWhich) {
    return { executablePath: fromWhich, source: "system" };
  }

  return undefined;
}

// --- Public API -------------------------------------------------------------

/**
 * Find an existing browser without downloading.
 * Resolution: env var -> cached download -> system Chrome.
 */
export async function findBrowser(): Promise<BrowserResult | undefined> {
  const fromEnv = findFromEnv();
  if (fromEnv) return fromEnv;

  const fromCache = await findFromCache();
  if (fromCache.result) return fromCache.result;
  if (fromCache.staleHyperframesCachePath) {
    console.warn(
      `[browser] Cached binary missing at ${fromCache.staleHyperframesCachePath} — re-downloading...`,
    );
    try {
      return await withInstallLock(async () => {
        if (fromCache.staleInstallPath) purgeStaleInstall(fromCache.staleInstallPath);
        return downloadBrowser();
      });
    } catch (err) {
      const cause = normalizeErrorMessage(err);
      throw new Error(
        `Cached Chrome binary was missing at ${fromCache.staleHyperframesCachePath}, and re-download failed: ${cause}\n` +
          `Run \`hyperframes browser ensure --force\` to re-download.`,
      );
    }
  }

  const fromSystem = findSystemBrowser();
  if (fromSystem) {
    warnSystemFallbackOnce(fromSystem.executablePath);
  }
  return fromSystem;
}

/**
 * On Linux ARM64, attempt to auto-install system Chromium if not found.
 * This makes `hyperframes render` work out-of-the-box on DGX Spark / GB10 / Jetson.
 */
async function ensureLinuxArmBrowser(options?: EnsureBrowserOptions): Promise<BrowserResult> {
  void options;

  // If already available (env var or system path), use it directly.
  const existing = await findBrowser();
  if (existing) return existing;

  // Try auto-installing via apt (common on Ubuntu-based ARM systems).
  const hasApt = existsSync("/usr/bin/apt-get");
  if (hasApt) {
    console.error(
      "\n🔍 Linux ARM64 detected — Chrome Headless Shell is not available for this platform.",
    );
    console.error("📦 Auto-installing system Chromium via apt-get (this only happens once)...\n");

    // Use spawnSync so output streams to the terminal in real time.
    const result = spawnSync("apt-get", ["install", "-y", "chromium-browser"], {
      stdio: "inherit",
      timeout: 120_000,
    });

    if (result.status === 0) {
      const afterInstall = await findBrowser();
      if (afterInstall) {
        console.error(`\n✅ Chromium installed at ${afterInstall.executablePath}\n`);
        return afterInstall;
      }
    } else {
      // apt succeeded but binary not found, or apt failed — fall through to helpful error.
      console.error("\n⚠️  apt-get exited with errors. Trying anyway...\n");
      const afterAttempt = await findBrowser();
      if (afterAttempt) return afterAttempt;
    }
  }

  // Could not auto-install — give clear manual instructions.
  throw new Error(
    `Chrome Headless Shell is not available for Linux ARM64 (DGX Spark, GB10, Jetson).\n\n` +
      `Install Chromium manually and point hyperframes to it:\n\n` +
      `  sudo apt-get install -y chromium-browser\n` +
      `  export HYPERFRAMES_BROWSER_PATH=$(which chromium-browser)\n\n` +
      `Then re-run your command. The HYPERFRAMES_BROWSER_PATH env var persists for the session.`,
  );
}

/**
 * Find or download a browser.
 * Resolution: env var -> cached download -> system Chrome -> auto-download.
 * With `preferManagedChrome`: env var -> OUR pinned cache -> auto-download
 * (puppeteer-cache preference and system Chrome are both skipped).
 */
export async function ensureBrowser(options?: EnsureBrowserOptions): Promise<BrowserResult> {
  const fromEnv = findFromEnv();
  if (fromEnv) return fromEnv;

  if (!options?.force) {
    const fromCache = await (options?.preferManagedChrome
      ? findFromHyperframesCache()
      : findFromCache());
    if (fromCache.result) return fromCache.result;
    if (fromCache.staleHyperframesCachePath) {
      console.warn(
        `[browser] Cached binary missing at ${fromCache.staleHyperframesCachePath} — re-downloading...`,
      );
      return withInstallLock(async () => {
        if (fromCache.staleInstallPath) purgeStaleInstall(fromCache.staleInstallPath);
        return downloadBrowser(options);
      });
    }

    if (!options?.preferManagedChrome) {
      const fromSystem = findSystemBrowser();
      if (fromSystem) {
        warnSystemFallbackOnce(fromSystem.executablePath);
        return fromSystem;
      }
    }
  }

  return withInstallLock(async () => {
    if (options?.force) {
      // `--force` means "always get a fresh managed download" — purging the
      // whole HF-managed cache after acquiring the install lock keeps two
      // concurrent force retries from deleting each other's in-flight lock or
      // partially extracted install.
      clearBrowser();
    }

    // Re-check after acquiring the lock: a concurrent invocation may have
    // finished installing while we were waiting, in which case reuse its
    // result instead of downloading and extracting a second time. Skipped
    // under --force, which already purged and always wants a fresh download.
    if (!options?.force) {
      const afterLock = await (options?.preferManagedChrome
        ? findFromHyperframesCache()
        : findFromCache());
      if (afterLock.result) return afterLock.result;
      if (afterLock.staleInstallPath) purgeStaleInstall(afterLock.staleInstallPath);
    }
    return downloadBrowser(options);
  });
}

/**
 * True when `err` is a corrupt/truncated-archive extraction failure, as opposed
 * to a network error or a genuine platform problem. A partially-downloaded or
 * interrupted browser archive left in the cache makes `install()`'s extraction
 * throw "invalid end-of-central-directory" (a zip whose central directory is
 * missing/truncated). Left unhandled, that hard-blocks every render on the box
 * until the user manually clears the cache — so we detect it and re-download.
 */
export function isCorruptArchiveError(err: unknown): boolean {
  const msg = normalizeErrorMessage(err).toLowerCase();
  return (
    msg.includes("end of central directory") ||
    msg.includes("end-of-central-directory") ||
    msg.includes("invalid or corrupt") ||
    msg.includes("corrupt zip") ||
    msg.includes("not a zip") ||
    msg.includes("unexpected end of") ||
    msg.includes("corrupted")
  );
}

/**
 * Run a browser install; if it fails because the cached archive is corrupt,
 * clear the cache (dropping the bad archive) and retry the download exactly
 * once. Non-corruption errors propagate unchanged, and a second corruption
 * propagates too (no infinite retry).
 */
export async function installWithCorruptArchiveRecovery<T>(
  runInstall: () => Promise<T>,
  clearCache: () => void,
  onRecover?: (err: unknown) => void,
): Promise<T> {
  try {
    return await runInstall();
  } catch (err) {
    if (!isCorruptArchiveError(err)) throw err;
    onRecover?.(err);
    clearCache();
    return await runInstall();
  }
}

/**
 * Race an install-style call against a "no progress" watchdog instead of a
 * total-duration cap. The timer (re)arms on every progress tick — and once
 * before the first one, since a connection that never gets a response never
 * ticks at all — so a download that is merely slow keeps resetting it
 * indefinitely, while one that has truly stalled (no bytes, ever, or bytes
 * that stop arriving mid-stream) trips it after `timeoutMs` of silence.
 *
 * This cannot abort the underlying socket (`@puppeteer/browsers` exposes no
 * `AbortSignal`), so a stalled connection lingers until the OS reclaims it —
 * but the CLI's root exit handler calls `process.exit()` unconditionally once
 * a command settles (see `cli.ts`'s `registerRootExitRequester`), so
 * rejecting here still unblocks the process instead of leaving it hung.
 */
export function withDownloadStallGuard<T>(
  run: (onProgress: (downloadedBytes: number, totalBytes: number) => void) => Promise<T>,
  options: {
    timeoutMs: number;
    onProgress?: (downloadedBytes: number, totalBytes: number) => void;
  },
): Promise<T> {
  return new Promise((resolve, reject) => {
    let settled = false;
    let timer: ReturnType<typeof setTimeout>;
    const armTimer = () => {
      clearTimeout(timer);
      timer = setTimeout(() => {
        if (settled) return;
        settled = true;
        reject(
          new Error(`Download stalled: no progress for ${Math.round(options.timeoutMs / 1000)}s.`),
        );
      }, options.timeoutMs);
    };
    armTimer();
    run((downloadedBytes, totalBytes) => {
      if (settled) return;
      armTimer();
      options.onProgress?.(downloadedBytes, totalBytes);
    }).then(
      (result) => {
        if (settled) return;
        settled = true;
        clearTimeout(timer);
        resolve(result);
      },
      (err: unknown) => {
        if (settled) return;
        settled = true;
        clearTimeout(timer);
        reject(err);
      },
    );
  });
}

/**
 * When `@puppeteer/browsers`' install() rejects for any reason the corrupt-
 * archive recovery path can't handle (all CDN providers rejected — the
 * `All providers failed for chrome-headless-shell <ver>` case reported from the
 * field on darwin/arm64 with CLI 0.7.57; DNS/network failure; a macOS Gatekeeper
 * quarantine that blocks the pinned Dev-channel binary from launching a probe;
 * a second corruption that trips the retry gate), the raw error names none of
 * the escape hatches that would unblock the user. Rewrap it in one that does:
 * `HYPERFRAMES_BROWSER_PATH` wins over both the managed download and system
 * lookup (see `findFromEnv` above), so pointing it at an already-installed
 * Chrome renders successfully via the screenshot fallback while the pinned
 * chrome-headless-shell download is broken. Sibling failure mode: #2078
 * (SIGTRAP at launch), same remediation, different trigger.
 */
function browserPathHintForPlatform(): string {
  if (process.platform === "darwin") {
    return "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome";
  }
  if (process.platform === "win32") {
    return "C:\\Program Files\\Google\\Chrome\\Application\\chrome.exe";
  }
  return "/usr/bin/google-chrome";
}

/**
 * `@puppeteer/browsers`' download request does attempt real proxy support
 * (a dynamic import of the `proxy-agent` package), but that package is only
 * an *optional peer* dependency that a normal hyperframes install never
 * pulls in — so the import throws, is caught silently, and the request falls back
 * to a bare node:http(s) agent that never reads HTTP_PROXY/HTTPS_PROXY on
 * its own. On a network that only egresses through that proxy, the direct
 * connection attempt doesn't fail fast; it stalls, which is what
 * `withDownloadStallGuard` above catches. Naming the proxy as the likely
 * cause (when one is actually configured) turns "download stalled, no idea
 * why" into an actionable diagnosis instead of just repeating the same
 * escape hatch with no context.
 */
function proxyDownloadStallHint(): string {
  const proxyConfigured = ["HTTPS_PROXY", "HTTP_PROXY", "https_proxy", "http_proxy"].some((key) =>
    Boolean(process.env[key]?.trim()),
  );
  if (!proxyConfigured) return "";
  return (
    `\n\nHTTP_PROXY/HTTPS_PROXY is set in this environment, but chrome-headless-shell's ` +
    `download does not honor it (the proxy support it depends on is an optional ` +
    `dependency hyperframes does not install) — on a network that requires the proxy for ` +
    `internet access, the download attempts a direct connection and stalls instead of ` +
    `failing fast. Use HYPERFRAMES_BROWSER_PATH above to skip the download entirely.`
  );
}

function wrapDownloadFailureWithBrowserPathHint(cause: unknown): Error {
  const original = normalizeErrorMessage(cause);
  const example = browserPathHintForPlatform();
  const message =
    `Failed to download chrome-headless-shell ${CHROME_VERSION}: ${original}\n\n` +
    `Point hyperframes at an already-installed Chrome/Chromium instead:\n\n` +
    `  export HYPERFRAMES_BROWSER_PATH="${example}"\n\n` +
    `Then re-run your command. Any Chrome build works for the screenshot ` +
    `capture path; install a real chrome-headless-shell later if you need the ` +
    `perf-optimized BeginFrame path. Alternatively, run inside the hyperframes ` +
    `Docker image which ships a compatible headless-shell.` +
    proxyDownloadStallHint();
  return new Error(message, { cause: cause instanceof Error ? cause : undefined });
}

async function downloadBrowser(options?: EnsureBrowserOptions): Promise<BrowserResult> {
  if (isLinuxArm()) {
    return ensureLinuxArmBrowser(options);
  }

  const { Browser, detectBrowserPlatform, install } = await loadPuppeteerBrowsers();

  const platform = detectBrowserPlatform();
  if (!platform) {
    throw new Error(`Unsupported platform: ${process.platform} ${process.arch}`);
  }

  const runInstall = () =>
    withDownloadStallGuard(
      (onProgress) =>
        install({
          cacheDir: CACHE_DIR,
          browser: Browser.CHROMEHEADLESSSHELL,
          buildId: CHROME_VERSION,
          platform,
          downloadProgressCallback: onProgress,
        }),
      { timeoutMs: DOWNLOAD_STALL_TIMEOUT_MS, onProgress: options?.onProgress },
    );

  let installed;
  try {
    installed = await installWithCorruptArchiveRecovery(
      runInstall,
      () => {
        rmSync(CACHE_DIR, { recursive: true, force: true });
        mkdirSync(CACHE_DIR, { recursive: true });
      },
      (err) =>
        console.warn(
          `[hyperframes] Cached browser archive was corrupt (${normalizeErrorMessage(err)}); clearing the cache and re-downloading.`,
        ),
    );
  } catch (err) {
    throw wrapDownloadFailureWithBrowserPathHint(err);
  }

  return { executablePath: installed.executablePath, source: "download" };
}

/**
 * Remove the cached Chrome download directory.
 * Returns true if anything was removed.
 */
export function clearBrowser(): boolean {
  if (!existsSync(CACHE_DIR)) {
    return false;
  }
  rmSync(CACHE_DIR, { recursive: true, force: true });
  return true;
}

export function isLinuxArm(): boolean {
  return process.platform === "linux" && process.arch === "arm64";
}

export { CHROME_VERSION, CACHE_DIR };