package com.paymentlink.service;

import com.stripe.exception.StripeException;
import com.stripe.model.PaymentIntent;
import com.stripe.model.checkout.Session;
import com.stripe.param.PaymentIntentCreateParams;
import com.stripe.param.checkout.SessionCreateParams;
import com.paymentlink.model.entity.Order;
import com.paymentlink.model.entity.Product;
import com.paymentlink.repository.OrderRepository;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

@Service
public class StripePaymentService {

    private static final Logger logger = LoggerFactory.getLogger(StripePaymentService.class);

    private final CurrencyService currencyService;
    private final OrderRepository orderRepository;

    @Value("${stripe.publishable.key}")
    private String publishableKey;

    @Value("${stripe.success.url:http://localhost:8080/order-confirmation}")
    private String successUrl;

    @Value("${stripe.cancel.url:http://localhost:8080/checkout}")
    private String cancelUrl;

    public StripePaymentService(CurrencyService currencyService, OrderRepository orderRepository) {
        this.currencyService = currencyService;
        this.orderRepository = orderRepository;
    }

    /**
     * Create a PaymentIntent for a payment (legacy method)
     */
    public PaymentIntent createPaymentIntent(long amount, String currency) throws StripeException {
        logger.info("Creating Stripe PaymentIntent: amount={}, currency={}", amount, currency);

        PaymentIntentCreateParams params = PaymentIntentCreateParams.builder()
                .setAmount(amount)
                .setCurrency(currency.toLowerCase())
                .addPaymentMethodType("card")
                .build();

        PaymentIntent paymentIntent = PaymentIntent.create(params);
        logger.info("Created PaymentIntent: {}", paymentIntent.getId());
        
        return paymentIntent;
    }

    /**
     * Create a Checkout Session with multi-currency support
     * CRITICAL: Charges in target currency, not USD
     */
    public String createCheckoutSession(Order order, String targetCurrency) throws StripeException {
        // Validate currency is supported by Stripe
        if (!currencyService.isCurrencySupported(targetCurrency)) {
            logger.warn("Currency {} not supported by Stripe, falling back to USD", targetCurrency);
            targetCurrency = "USD";
        }

        // Make targetCurrency effectively final for lambda usage
        final String finalTargetCurrency = targetCurrency;

        // Convert total to target currency
        Long convertedAmount = currencyService.convertPrice(
                order.getTotal(),
                order.getCurrency() != null ? order.getCurrency() : "USD",
                finalTargetCurrency
        );

        // Store conversion details in order
        order.setCurrency(finalTargetCurrency);
        order.setOriginalCurrency(order.getCurrency() != null ? order.getCurrency() : "USD");
        order.setOriginalAmount(order.getTotal());
        order.setExchangeRate(currencyService.getRate(
                order.getOriginalCurrency(),
                finalTargetCurrency
        ));
        orderRepository.save(order);

        // Build line items from order items
        SessionCreateParams.Builder paramsBuilder = SessionCreateParams.builder()
                .setMode(SessionCreateParams.Mode.PAYMENT)
                .setSuccessUrl(successUrl + "?orderId=" + order.getOrderId())
                .setCancelUrl(cancelUrl + "?orderId=" + order.getOrderId())
                .putMetadata("orderId", order.getOrderId())
                .putMetadata("originalCurrency", order.getOriginalCurrency())
                .putMetadata("originalAmount", String.valueOf(order.getOriginalAmount()));

        // Add line items for each product in the order
        order.getItems().forEach(item -> {
            // Convert item price to target currency
            Long itemPrice = currencyService.convertPrice(
                    item.getPrice(),
                    order.getOriginalCurrency(),
                    finalTargetCurrency
            );

            SessionCreateParams.LineItem lineItem = SessionCreateParams.LineItem.builder()
                    .setPriceData(
                            SessionCreateParams.LineItem.PriceData.builder()
                                    .setCurrency(finalTargetCurrency.toLowerCase()) // Stripe requires lowercase
                                    .setUnitAmount(itemPrice) // Amount in cents
                                    .setProductData(
                                            SessionCreateParams.LineItem.PriceData.ProductData.builder()
                                                    .setName(item.getProductName() != null ? item.getProductName() : "Product")
                                                    .build()
                                    )
                                    .build()
                    )
                    .setQuantity((long) item.getQuantity())
                    .build();

            paramsBuilder.addLineItem(lineItem);
        });

        SessionCreateParams params = paramsBuilder.build();
        Session session = Session.create(params);

        logger.info("Created Stripe Checkout Session: {} for order: {} in currency: {} (converted from {} {})",
                session.getId(), order.getOrderId(), finalTargetCurrency, order.getOriginalAmount(), order.getOriginalCurrency());

        return session.getUrl();
    }

    /**
     * Retrieve a PaymentIntent
     */
    public PaymentIntent retrievePaymentIntent(String paymentIntentId) throws StripeException {
        return PaymentIntent.retrieve(paymentIntentId);
    }

    /**
     * Get publishable key (for frontend)
     */
    public String getPublishableKey() {
        return publishableKey;
    }

    /**
     * Check if payment intent is successful
     */
    public boolean isPaymentSuccessful(PaymentIntent paymentIntent) {
        return "succeeded".equals(paymentIntent.getStatus());
    }
}