import asyncio
import stripe

from app.config import get_settings
from app.exceptions import PaymentError

_stripe_initialized = False


def _init_stripe():
    global _stripe_initialized
    if not _stripe_initialized:
        stripe.api_key = get_settings().STRIPE_SECRET_KEY
        _stripe_initialized = True


async def create_payment_intent(
    amount: float,
    metadata: dict,
    description: str = "",
) -> stripe.PaymentIntent:
    _init_stripe()
    settings = get_settings()
    try:
        intent = await asyncio.to_thread(
            stripe.PaymentIntent.create,
            amount=int(round(amount * 100)),
            currency=settings.STRIPE_CURRENCY,
            metadata=metadata,
            description=description,
            automatic_payment_methods={"enabled": True},
        )
        return intent
    except stripe.StripeError as e:
        raise PaymentError(str(e))


async def create_refund(
    payment_intent_id: str,
    amount: float | None = None,
    reason: str | None = None,
) -> stripe.Refund:
    _init_stripe()
    try:
        kwargs: dict = {"payment_intent": payment_intent_id}
        if amount is not None:
            kwargs["amount"] = int(round(amount * 100))
        if reason:
            kwargs["reason"] = reason
        return await asyncio.to_thread(stripe.Refund.create, **kwargs)
    except stripe.StripeError as e:
        raise PaymentError(str(e))


def verify_webhook(payload: bytes, sig_header: str) -> stripe.Event:
    _init_stripe()
    settings = get_settings()
    try:
        return stripe.Webhook.construct_event(payload, sig_header, settings.STRIPE_WEBHOOK_SECRET)
    except stripe.SignatureVerificationError:
        raise PaymentError("Invalid webhook signature")