"""Heleket payment integration."""

import base64
import hashlib
import json
import logging
from typing import Optional

import aiohttp

from config.settings import settings

logger = logging.getLogger(__name__)


def _make_sign(body_bytes: bytes, api_key: str) -> str:
    """Генерирует подпись запроса: md5(base64(body) + api_key)."""
    b64 = base64.b64encode(body_bytes).decode("utf-8")
    return hashlib.md5((b64 + api_key).encode("utf-8")).hexdigest()


class HelketPayment:
    """Heleket payment gateway. Принимает сумму в рублях напрямую."""

    BASE_URL = "https://api.heleket.com/v1"

    def __init__(self):
        self.api_key = settings.HELEKET_API_KEY

    def _post_headers(self, body_bytes: bytes) -> dict:
        """Заголовки для POST-запроса с подписью."""
        return {
            "merchant": self.api_key,
            "sign": _make_sign(body_bytes, self.api_key),
            "Content-Type": "application/json",
        }

    def _get_headers(self) -> dict:
        """Заголовки для GET-запроса (тело пустое)."""
        return {
            "merchant": self.api_key,
            "sign": _make_sign(b"", self.api_key),
        }

    async def create_invoice(self, amount_rub: int, order_id: str) -> Optional[dict]:
        """
        Создаёт счёт на сумму в рублях.
        Возвращает dict: payment_id, address, url.  None при ошибке.
        """
        if not self.api_key:
            logger.error("HELEKET_API_KEY не задан")
            return None

        payload = {
            "amount": str(amount_rub),
            "currency": "RUB",
            "order_id": order_id,
            "url_callback": settings.HELEKET_WEBHOOK_URL,
        }
        body = json.dumps(payload, separators=(",", ":")).encode("utf-8")

        try:
            async with aiohttp.ClientSession() as session:
                async with session.post(
                    f"{self.BASE_URL}/payment",
                    data=body,
                    headers=self._post_headers(body),
                    timeout=aiohttp.ClientTimeout(total=15),
                ) as resp:
                    data = await resp.json()
                    if data.get("state") == 0:
                        r = data.get("result", {})
                        return {
                            "payment_id": r.get("uuid"),
                            "address": r.get("address"),
                            "url": r.get("url"),
                            "mock": False,
                        }
                    logger.error(f"Heleket create error: {data}")
                    return None
        except Exception as e:
            logger.error(f"Heleket request error: {e}")
            return None

    async def check_status(self, payment_id: str) -> str:
        """Возвращает: 'paid' | 'pending' | 'expired' | 'error'"""
        try:
            async with aiohttp.ClientSession() as session:
                async with session.get(
                    f"{self.BASE_URL}/payment/info/{payment_id}",
                    headers=self._get_headers(),
                    timeout=aiohttp.ClientTimeout(total=15),
                ) as resp:
                    data = await resp.json()
                    if data.get("state") == 0:
                        status = data.get("result", {}).get("status", "")
                        if status in ("paid", "paid_over"):
                            return "paid"
                        if status in ("cancel", "expired", "fail", "wrong_amount"):
                            return "expired"
                        return "pending"
                    return "error"
        except Exception as e:
            logger.error(f"Heleket check error: {e}")
            return "error"