import jwt
import os
import requests
import unicodedata
from datetime import datetime, timedelta, UTC
from functools import lru_cache
from iqpilot.system.hardware.hw import Paths
from iqpilot.system.version import get_version

KEYS = {"id_rsa": "RS256",
        "id_ecdsa": "ES256"}

_CUSTODIAN_KEY = object()
_IQKEEPER_SOCKET = "/run/iqkeeper/iqkeeper.sock"


def _custodian_available() -> bool:
  import stat
  try:
    return stat.S_ISSOCK(os.stat(_IQKEEPER_SOCKET).st_mode)
  except OSError:
    return False


def _custodian_sign_jwt(dongle_id: str, payload: dict, alg: str) -> str:
  import base64
  import json
  import socket
  nonce = base64.b64encode(os.urandom(16)).decode()
  packet = json.dumps({
    "v": 1,
    "op": "sign",
    "dongle_id": dongle_id,
    "payload": payload,
    "alg": alg,
    "nonce": nonce,
  }).encode()
  with socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET) as sock:
    sock.settimeout(25.0)
    sock.connect(_IQKEEPER_SOCKET)
    sock.send(packet)
    reply_data = sock.recv(8192)
  reply = json.loads(reply_data) if reply_data else {}
  if reply.get("nonce") != nonce or not reply.get("ok"):
    raise PermissionError(f"custodian sign failed: {reply.get('error', 'unknown')}")
  return reply["token"]


@lru_cache(maxsize=4)
def load_signing_key(private_key: str):
  # PyJWT re-parses a PEM string on every encode; an RSA parse is ~40ms, so cache the key object
  try:
    from cryptography.hazmat.primitives.serialization import load_pem_private_key
    return load_pem_private_key(private_key.encode(), password=None)
  except Exception:
    return private_key


class BaseApi:
  def __init__(self, dongle_id, api_host, user_agent="openpilot-", *, transport=None):
    self.dongle_id = dongle_id
    self.api_host = api_host
    self.user_agent = user_agent
    self._transport = requests if transport is None else transport
    self.jwt_algorithm, self.private_key, _ = self.get_key_pair()

  def get(self, *args, **kwargs):
    return self.request('GET', *args, **kwargs)

  def post(self, *args, **kwargs):
    return self.request('POST', *args, **kwargs)

  def request_options(self, method, endpoint, *, timeout=None, access_token=None, json=None, **params):
    identity = unicodedata.normalize('NFD', f'{self.user_agent}{get_version()}')
    headers = {'User-Agent': ''.join(character for character in identity if 32 <= ord(character) <= 126)}
    if access_token is not None:
      headers['Authorization'] = f'JWT {access_token}'
    return {'method': method, 'url': f"{self.api_host.rstrip('/')}/{endpoint.lstrip('/')}",
            'timeout': timeout, 'headers': headers, 'json': json, 'params': params}

  def request(self, method, endpoint, timeout=None, access_token=None, *, session=None, json=None, **params):
    options = self.request_options(method, endpoint, timeout=timeout, access_token=access_token, json=json, **params)
    transport = self._transport if session is None else session
    return transport.request(**options)

  def _get_token(self, payload_extra=None, expiry_hours=1, **extra_payload):
    now = datetime.now(UTC).replace(tzinfo=None)
    payload = {
      'identity': self.dongle_id,
      'nbf': now,
      'iat': now,
      'exp': now + timedelta(hours=expiry_hours),
      **extra_payload
    }
    if payload_extra is not None:
      payload.update(payload_extra)
    if self.private_key is _CUSTODIAN_KEY:
      serializable = {k: int(v.timestamp()) if isinstance(v, datetime) else v for k, v in payload.items()}
      return _custodian_sign_jwt(self.dongle_id, serializable, self.jwt_algorithm)
    key = load_signing_key(self.private_key) if self.private_key else self.private_key
    token = jwt.encode(payload, key, algorithm=self.jwt_algorithm)
    if isinstance(token, bytes):
      token = token.decode('utf8')
    return token

  def get_token(self, payload_extra=None, expiry_hours=1):
    return self._get_token(payload_extra, expiry_hours)

  def api_get(self, endpoint, method='GET', timeout=None, access_token=None, session=None, json=None, **params):
    return self.request(method, endpoint, timeout, access_token, session=session, json=json, **params)

  @staticmethod
  def get_key_pair() -> tuple[str, str | object, str] | tuple[None, None, None]:
    for key in KEYS:
      priv_path = Paths.persist_root() + f'/comma/{key}'
      pub_path = priv_path + '.pub'
      if not os.path.isfile(priv_path) or not os.path.isfile(pub_path):
        continue
      try:
        with open(pub_path) as public:
          pub = public.read()
      except OSError:
        continue
      try:
        with open(priv_path) as private:
          return KEYS[key], private.read(), pub
      except PermissionError:
        import time
        for _attempt in range(10):
          if _custodian_available():
            return KEYS[key], _CUSTODIAN_KEY, pub
          time.sleep(0.5)
        continue
    return None, None, None