import os
from dataclasses import dataclass
from typing import Optional

import requests


class PaymentGatewayError(RuntimeError):
    def __init__(self, message: str, status_code: Optional[int] = None, payload: Optional[dict] = None) -> None:
        super().__init__(message)
        self.status_code = status_code
        self.payload = payload or {}


@dataclass
class PaymentInitResult:
    external_id: str
    status: Optional[str]
    redirect_url: Optional[str]
    payload: dict


class BasePaymentGateway:
    def create_payment(
        self,
        amount: int,
        currency: str,
        description: str,
        source: dict,
        callback_url: Optional[str],
        given_id: str,
        metadata: dict,
    ) -> PaymentInitResult:
        raise NotImplementedError

    def capture_payment(self, external_id: str, amount: Optional[int] = None) -> None:
        """Capture an authorized payment. Amount in minor units; omit for full capture."""
        raise NotImplementedError

    def refund_payment(self, external_id: str, amount: Optional[int] = None) -> None:
        """Refund a paid/captured payment. Amount in minor units; omit for full refund."""
        raise NotImplementedError


class MoyasarGateway(BasePaymentGateway):
    def __init__(self) -> None:
        self.secret_key = os.getenv("MOYASAR_SECRET_KEY")
        self.publishable_key = os.getenv("MOYASAR_PUBLISHABLE_KEY")
        self.base_url = os.getenv("MOYASAR_BASE_URL", "https://api.moyasar.com")

    def _assert_config(self) -> None:
        if not self.secret_key or not self.publishable_key:
            raise ValueError("Moyasar credentials are not configured")

    def create_payment(
        self,
        amount: int,
        currency: str,
        description: str,
        source: dict,
        callback_url: Optional[str],
        given_id: str,
        metadata: dict,
    ) -> PaymentInitResult:
        self._assert_config()
        url = f"{self.base_url}/v1/payments"
        payload = {
            "amount": amount,
            "currency": currency,
            "description": description,
            "source": source,
            "given_id": given_id,
            "metadata": metadata,
        }
        if callback_url:
            payload["callback_url"] = callback_url

        try:
            response = requests.post(url, json=payload, auth=(self.secret_key, ""), timeout=10)
        except requests.RequestException as exc:
            raise PaymentGatewayError("Failed to reach Moyasar") from exc

        try:
            data = response.json() if response.content else {}
        except ValueError as exc:
            raise PaymentGatewayError("Invalid response from Moyasar") from exc

        if response.status_code not in (200, 201):
            raise PaymentGatewayError(
                "Moyasar returned an error",
                status_code=response.status_code,
                payload=data,
            )
        redirect_url = None
        source_payload = data.get("source") or {}
        if isinstance(source_payload, dict):
            redirect_url = source_payload.get("transaction_url")

        return PaymentInitResult(
            external_id=data.get("id"),
            status=data.get("status"),
            redirect_url=redirect_url,
            payload=data,
        )

    def capture_payment(self, external_id: str, amount: Optional[int] = None) -> None:
        """Capture an authorized payment. Amount in minor units; omit for full capture."""
        self._assert_config()
        url = f"{self.base_url}/v1/payments/{external_id}/capture"
        payload = {} if amount is None else {"amount": amount}
        try:
            response = requests.post(url, json=payload, auth=(self.secret_key, ""), timeout=10)
        except requests.RequestException as exc:
            raise PaymentGatewayError("Failed to reach Moyasar for capture") from exc
        if response.status_code not in (200, 201):
            data = response.json() if response.content else {}
            raise PaymentGatewayError(
                "Moyasar capture failed",
                status_code=response.status_code,
                payload=data,
            )

    def refund_payment(self, external_id: str, amount: Optional[int] = None) -> None:
        """Refund a paid/captured payment. Amount in minor units; omit for full refund."""
        self._assert_config()
        url = f"{self.base_url}/v1/payments/{external_id}/refund"
        payload = {} if amount is None else {"amount": amount}
        try:
            response = requests.post(url, json=payload, auth=(self.secret_key, ""), timeout=10)
        except requests.RequestException as exc:
            raise PaymentGatewayError("Failed to reach Moyasar for refund") from exc
        if response.status_code not in (200, 201):
            data = response.json() if response.content else {}
            raise PaymentGatewayError(
                "Moyasar refund failed",
                status_code=response.status_code,
                payload=data,
            )