import hashlib

from aiohttp import web

from config import KASSAI_SECRET_KEY
from database import add_payment, async_session_maker, update_balance
from handlers.payments.utils import send_payment_success_notification
from logger import logger


processed_payments = set()


async def kassai_payment_webhook(request: web.Request):
    """
    Обработчик вебхука от KassaAI для подтверждения оплаты
    """
    try:
        data = await request.post()
        data_dict = dict(data)

        logger.info(f"KassaAI webhook received from {request.remote}")

        signature = data_dict.get("SIGN")
        if not signature:
            logger.error("KassaAI: Missing SIGN in request")
            return web.Response(status=400, text="Signature missing")

        if not verify_kassai_webhook_signature(data_dict, signature):
            logger.error("KassaAI: Invalid signature")
            return web.Response(status=400, text="Invalid signature")

        merchant_order_id = data_dict.get("MERCHANT_ORDER_ID")
        amount = data_dict.get("AMOUNT")
        p_email = data_dict.get("P_EMAIL")
        intid = data_dict.get("intid")

        logger.info(f"KassaAI payment: intid={intid}, MERCHANT_ORDER_ID={merchant_order_id}, amount={amount}")

        if not amount or not intid:
            logger.error("KassaAI: Missing AMOUNT or intid")
            return web.Response(status=400, text="Missing required fields")

        if intid in processed_payments:
            logger.warning(f"KassaAI: Duplicate payment intid={intid}")
            return web.Response(status=200, text="YES")

        if merchant_order_id and merchant_order_id in processed_payments:
            logger.warning(f"KassaAI: Duplicate payment MERCHANT_ORDER_ID={merchant_order_id}")
            return web.Response(status=200, text="YES")

        try:
            if p_email and "@" in p_email:
                tg_id = int(p_email.split("@")[0])
            else:
                logger.error(f"KassaAI: Invalid email format: {p_email}")
                return web.Response(status=400, text="Invalid email format")

            amount_float = float(amount)
        except (ValueError, TypeError) as e:
            logger.error(f"KassaAI: Invalid data format: {e}")
            return web.Response(status=400, text="Invalid data format")

        async with async_session_maker() as session:
            await update_balance(session, tg_id, amount_float)
            await add_payment(session, tg_id, amount_float, "kassai")
            await send_payment_success_notification(tg_id, amount_float, session)

        processed_payments.add(intid)
        if merchant_order_id:
            processed_payments.add(merchant_order_id)

        logger.info(
            f"✅ KassaAI: Payment processed for user {tg_id}, amount {amount_float}, intid={intid}, MERCHANT_ORDER_ID={merchant_order_id}"
        )
        return web.Response(status=200, text="YES")

    except Exception as e:
        logger.error(f"KassaAI webhook error: {e}")
        return web.Response(status=500, text="Internal server error")


def verify_kassai_webhook_signature(data: dict, signature: str) -> bool:
    """
    Проверка подписи вебхука KassaAI согласно документации FreeKassa
    """
    try:
        sign_string = (
            f"{data.get('MERCHANT_ID', '')}:"
            f"{data.get('AMOUNT', '')}:"
            f"{KASSAI_SECRET_KEY}:"
            f"{data.get('MERCHANT_ORDER_ID', '')}"
        )

        expected_signature = hashlib.md5(sign_string.encode("utf-8")).hexdigest()
        result = signature.upper() == expected_signature.upper()

        if not result:
            logger.error("KassaAI webhook signature mismatch")

        return result

    except Exception as e:
        logger.error(f"KassaAI signature verification error: {e}")
        return False