"""Shared `httpx.Client` helper.

Creating short-lived httpx clients disables connection pooling and costs extra CPU.
This module provides a small singleton client for callers that just need basic
GETs without the full HTTPClient wrapper.
"""

from __future__ import annotations

import threading
from typing import Dict, Optional

import httpx

from API.ssl_certs import resolve_verify_value

_DEFAULT_USER_AGENT = (
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
    "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/121.0 Safari/537.36"
)

_lock = threading.Lock()
_shared_client: Optional[httpx.Client] = None


def get_shared_httpx_client(
    *,
    timeout: float = 30.0,
    verify_ssl: bool = True,
    headers: Optional[Dict[str, str]] = None,
) -> httpx.Client:
    """Return a process-wide shared synchronous httpx.Client."""

    global _shared_client
    if _shared_client is None:
        with _lock:
            if _shared_client is None:
                base_headers = {"User-Agent": _DEFAULT_USER_AGENT}
                if headers:
                    base_headers.update({str(k): str(v) for k, v in headers.items()})
                _shared_client = httpx.Client(
                    timeout=timeout,
                    verify=resolve_verify_value(verify_ssl),
                    headers=base_headers,
                )

    return _shared_client


def close_shared_httpx_client() -> None:
    global _shared_client
    client = _shared_client
    _shared_client = None
    if client is not None:
        try:
            client.close()
        except Exception:
            pass