"""Install the pinned embedded fx runtime; no user-level fx configuration is written."""
import hashlib
import io
import os
from pathlib import Path
import platform
import shutil
import subprocess
import tarfile
import urllib.request

ROOT = Path(__file__).resolve().parents[1]
NODE_VERSION = 'v24.21.0'
NODE_SHA256 = 'fd8e59d5a511510f6a298afb548f18c7d2b1be404d8b4a27d94fbe49f56cb2d6'


def prepare():
    runtime = ROOT / '.runtime'
    runtime.mkdir(exist_ok=True)
    if platform.system() == 'Linux' and platform.machine() == 'x86_64':
        node_root = runtime / f'node-{NODE_VERSION}-linux-x64'
        node = node_root / 'bin/node'
        if not node.is_file():
            url = f'https://nodejs.org/dist/{NODE_VERSION}/node-{NODE_VERSION}-linux-x64.tar.xz'
            with urllib.request.urlopen(url, timeout=120) as response:
                data = response.read()
            if hashlib.sha256(data).hexdigest() != NODE_SHA256:
                raise RuntimeError('Node runtime checksum mismatch')
            with tarfile.open(fileobj=io.BytesIO(data), mode='r:xz') as archive:
                archive.extractall(runtime, filter='data')
        os.environ['PATH'] = str(node_root / 'bin') + os.pathsep + os.environ.get('PATH', '')
    node = shutil.which('node')
    npm = shutil.which('npm')
    if not node or not npm:
        raise RuntimeError('Node 20+ and npm are required for isolated fx refinement')
    major = int(subprocess.check_output([node, '--version'], text=True).strip().lstrip('v').split('.')[0])
    if major < 20:
        raise RuntimeError('Node 20+ is required for isolated fx refinement')
    folder = ROOT / 'studio/fx_runtime'
    lock_hash = hashlib.sha256((folder / 'package-lock.json').read_bytes()).hexdigest()
    marker = folder / 'node_modules/.studio-lock'
    if not marker.is_file() or marker.read_text() != lock_hash:
        subprocess.run([npm, 'ci', '--ignore-scripts', '--no-audit', '--no-fund'], cwd=folder,
                       check=True, timeout=300)
        marker.write_text(lock_hash)