from __future__ import annotations

import logging
import secrets
import time
from collections import OrderedDict

logger = logging.getLogger(__name__)

id_label = "matrixUserId"

_pairing_codes: OrderedDict[str, tuple[str, float]] = OrderedDict()
_PAIRING_MAX_SIZE = 10000
_PAIRING_TTL_SECONDS = 600


async def generate_code(peer_id: str, config: dict = None, account_id: str = None) -> str:
    alphabet = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789"
    code = "".join(secrets.choice(alphabet) for _ in range(8))
    _evict_expired()
    _pairing_codes[peer_id] = (code, time.monotonic() + _PAIRING_TTL_SECONDS)
    if len(_pairing_codes) > _PAIRING_MAX_SIZE:
        _pairing_codes.popitem(last=False)
    logger.info("Generated pairing code for peer %s", peer_id)
    return code


async def verify_code(peer_id: str, code: str, config: dict = None, account_id: str = None) -> bool:
    _evict_expired()
    stored = _pairing_codes.get(peer_id)
    if stored is None:
        logger.info("Pairing verify failed: no code for peer %s", peer_id)
        return False
    stored_code, expires_at = stored
    if time.monotonic() > expires_at:
        del _pairing_codes[peer_id]
        logger.info("Pairing verify failed: code expired for peer %s", peer_id)
        return False
    if code.upper() != stored_code:
        logger.info("Pairing verify failed: code mismatch for peer %s", peer_id)
        return False
    del _pairing_codes[peer_id]
    logger.info("Pairing verified for peer %s", peer_id)
    return True


def _evict_expired() -> None:
    now = time.monotonic()
    expired = [k for k, (_, exp) in _pairing_codes.items() if now > exp]
    for k in expired:
        del _pairing_codes[k]


def normalize_allow_entry(entry: str) -> str:
    return entry.strip().lower()


async def notify_approval(config: dict, peer_id: str, account_id: str | None = None) -> None:
    logger.info("Matrix pairing approved for %s", peer_id)