# app/modules/payments/services/payment_service.py
"""
Payment service for processing payments through configured gateways.

This service provides a unified interface for payment operations
regardless of the underlying gateway (Stripe, PayPal, etc.).

Usage:
    from app.modules.payments.services import PaymentService

    payment_service = PaymentService()

    # Process a payment
    result = await payment_service.process_payment(
        amount=1000,  # Amount in cents
        currency="EUR",
        payment_method_id="pm_xxx",
        description="Order #123",
    )

    # Issue a refund
    refund = await payment_service.refund(
        transaction_id="txn_xxx",
        amount=500,  # Partial refund
    )
"""

import logging
from dataclasses import dataclass
from datetime import UTC, datetime
from enum import Enum
from typing import Any

logger = logging.getLogger(__name__)


class PaymentStatus(str, Enum):
    """Payment transaction status."""

    PENDING = "pending"
    PROCESSING = "processing"
    SUCCEEDED = "succeeded"
    FAILED = "failed"
    CANCELLED = "cancelled"
    REFUNDED = "refunded"
    PARTIALLY_REFUNDED = "partially_refunded"


class PaymentGateway(str, Enum):
    """Supported payment gateways."""

    STRIPE = "stripe"
    PAYPAL = "paypal"
    BANK_TRANSFER = "bank_transfer"


@dataclass
class PaymentResult:
    """Result of a payment operation."""

    success: bool
    transaction_id: str | None = None
    gateway: PaymentGateway | None = None
    status: PaymentStatus = PaymentStatus.PENDING
    amount: int = 0  # Amount in cents
    currency: str = "EUR"
    error_message: str | None = None
    gateway_response: dict[str, Any] | None = None
    created_at: datetime | None = None

    def to_dict(self) -> dict[str, Any]:
        return {
            "success": self.success,
            "transaction_id": self.transaction_id,
            "gateway": self.gateway.value if self.gateway else None,
            "status": self.status.value,
            "amount": self.amount,
            "currency": self.currency,
            "error_message": self.error_message,
            "created_at": self.created_at.isoformat() if self.created_at else None,
        }


@dataclass
class RefundResult:
    """Result of a refund operation."""

    success: bool
    refund_id: str | None = None
    transaction_id: str | None = None
    amount: int = 0
    status: PaymentStatus = PaymentStatus.PENDING
    error_message: str | None = None


class PaymentService:
    """
    Service for processing payments through configured gateways.

    This service provides a unified interface for:
    - Processing payments
    - Issuing refunds
    - Managing payment methods
    - Retrieving transaction history
    """

    def __init__(self) -> None:
        self._default_gateway = PaymentGateway.STRIPE

    async def process_payment(
        self,
        amount: int,
        currency: str = "EUR",
        payment_method_id: str | None = None,
        gateway: PaymentGateway | None = None,
        description: str | None = None,
        metadata: dict[str, Any] | None = None,
    ) -> PaymentResult:
        """
        Process a payment through the specified gateway.

        Args:
            amount: Amount in cents
            currency: Currency code (EUR, USD, etc.)
            payment_method_id: Stored payment method ID
            gateway: Payment gateway to use (default: stripe)
            description: Payment description
            metadata: Additional metadata for the transaction

        Returns:
            PaymentResult with transaction details
        """
        gateway = gateway or self._default_gateway

        logger.info(
            f"Processing payment: {amount} {currency} via {gateway.value}",
            extra={"amount": amount, "currency": currency, "gateway": gateway.value},
        )

        # TODO: Implement actual gateway processing
        # For now, return a mock successful result
        return PaymentResult(
            success=True,
            transaction_id=f"txn_{gateway.value}_mock",
            gateway=gateway,
            status=PaymentStatus.SUCCEEDED,
            amount=amount,
            currency=currency,
            created_at=datetime.now(UTC),
        )

    async def refund(
        self,
        transaction_id: str,
        amount: int | None = None,
        reason: str | None = None,
    ) -> RefundResult:
        """
        Issue a refund for a transaction.

        Args:
            transaction_id: Original transaction ID
            amount: Refund amount in cents (None for full refund)
            reason: Reason for refund

        Returns:
            RefundResult with refund details
        """
        logger.info(
            f"Issuing refund for transaction {transaction_id}",
            extra={"transaction_id": transaction_id, "amount": amount, "reason": reason},
        )

        # TODO: Implement actual refund processing
        return RefundResult(
            success=True,
            refund_id=f"rf_{transaction_id}",
            transaction_id=transaction_id,
            amount=amount or 0,
            status=PaymentStatus.REFUNDED,
        )

    async def get_transaction(self, transaction_id: str) -> dict[str, Any] | None:
        """
        Get transaction details by ID.

        Args:
            transaction_id: Transaction ID

        Returns:
            Transaction details or None if not found
        """
        # TODO: Implement transaction lookup
        return None

    async def list_transactions(
        self,
        store_id: int | None = None,
        platform_id: int | None = None,
        status: PaymentStatus | None = None,
        limit: int = 50,
        offset: int = 0,
    ) -> list[dict[str, Any]]:
        """
        List transactions with optional filters.

        Args:
            store_id: Filter by store
            platform_id: Filter by platform
            status: Filter by status
            limit: Maximum results
            offset: Pagination offset

        Returns:
            List of transaction records
        """
        # TODO: Implement transaction listing
        return []


# Singleton instance
payment_service = PaymentService()

__all__ = [
    "PaymentService",
    "PaymentStatus",
    "PaymentGateway",
    "PaymentResult",
    "RefundResult",
    "payment_service",
]