import httpx
import hashlib
import hmac
import logging

logger = logging.getLogger(__name__)

_META_API = "https://graph.facebook.com/v19.0"


async def send_message(phone_number_id: str, to: str, text: str, access_token: str) -> bool:
    try:
        async with httpx.AsyncClient(timeout=10) as client:
            r = await client.post(
                f"{_META_API}/{phone_number_id}/messages",
                headers={"Authorization": f"Bearer {access_token}"},
                json={
                    "messaging_product": "whatsapp",
                    "to": to,
                    "type": "text",
                    "text": {"body": text},
                },
            )
            return r.status_code == 200
    except Exception as e:
        logger.error(f"WhatsApp send error: {e}")
        return False


def verify_signature(payload: bytes, signature: str, app_secret: str) -> bool:
    expected = "sha256=" + hmac.new(
        app_secret.encode("utf-8"),
        payload,
        hashlib.sha256,
    ).hexdigest()
    return hmac.compare_digest(expected, signature)