tasks.py

import asyncio
import json
from http import HTTPStatus
from math import floor
from urllib.parse import urlparse

import bolt11
import httpx
from fastapi import HTTPException
from lnbits.core.crud import get_standalone_payment
from lnbits.core.models import Payment
from lnbits.core.services import pay_invoice
from lnbits.tasks import register_invoice_listener

from .crud import get_scrub_by_wallet


async def wait_for_paid_invoices():
    invoice_queue = asyncio.Queue()
    register_invoice_listener(invoice_queue, "ext_scrub")

    while True:
        payment = await invoice_queue.get()
        await on_invoice_paid(payment)


async def on_invoice_paid(payment: Payment):
    if payment.extra and payment.extra.get("tag") == "scrubed":
        return

    scrub_link = await get_scrub_by_wallet(payment.wallet_id)
    if not scrub_link:
        return

    from lnbits.core.views.api import api_lnurlscan

    # DECODE LNURLP OR LNADDRESS
    data = await api_lnurlscan(scrub_link.payoraddress)

    # I REALLY HATE THIS DUPLICATION OF CODE!! CORE/VIEWS/API.PY, LINE 267
    domain = urlparse(data["callback"]).netloc
    rounded_amount = floor(payment.amount / 1000) * 1000

    async with httpx.AsyncClient() as client:
        try:
            r = await client.get(
                data["callback"],
                params={"amount": rounded_amount},
                timeout=40,
            )
            if r.is_error:
                raise httpx.ConnectError("issue with scrub callback")
        except (httpx.ConnectError, httpx.RequestError) as exc:
            raise HTTPException(
                status_code=HTTPStatus.BAD_REQUEST,
                detail=f"Failed to connect to {domain}.",
            ) from exc

    params = json.loads(r.text)
    if params.get("status") == "ERROR":
        raise HTTPException(
            status_code=HTTPStatus.BAD_REQUEST,
            detail=f"{domain} said: '{params.get('reason', '')}'",
        )

    invoice = bolt11.decode(params["pr"])

    lnurlp_payment = await get_standalone_payment(invoice.payment_hash)
    # (avoid loops)
    # do not scrub yourself! :)
    if lnurlp_payment and lnurlp_payment.wallet_id == payment.wallet_id:
        return

    if invoice.amount_msat != rounded_amount:
        raise HTTPException(
            status_code=HTTPStatus.BAD_REQUEST,
            detail=f"""
            {domain} returned an invalid invoice.
            Expected {payment.amount} msat, got {invoice.amount_msat}.
            """,
        )

    await pay_invoice(
        wallet_id=payment.wallet_id,
        payment_request=params["pr"],
        description=data["description"],
        extra={"tag": "scrubed"},
    )