lnbits-legend/lnbits/extensions/scrub/tasks.py

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

import httpx
from fastapi import HTTPException

from lnbits import bolt11
from lnbits.core.models import Payment
from lnbits.core.services import pay_invoice
from lnbits.helpers import get_current_extension_name
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, get_current_extension_name())

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


async def on_invoice_paid(payment: Payment):
    # (avoid loops)
    if payment.extra and payment.extra.get("tag") == "scrubed":
        # already scrubbed
        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):
            raise HTTPException(
                status_code=HTTPStatus.BAD_REQUEST,
                detail=f"Failed to connect to {domain}.",
            )

    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"])

    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}.",
        )

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

    return {
        "payment_hash": payment_hash,
        # maintain backwards compatibility with API clients:
        "checking_id": payment_hash,
    }