const Order = require('../models/orderModel');
const {
  initiatePayment: initiatePaymobPayment,
  verifyPayment: verifyPaymobPayment,
  refundTransaction: refundPaymobTransaction,
} = require('../utils/paymobService');
const { sendOrderConfirmationEmail } = require('../utils/emailService');
const {
  notifyOrderCreated,
  notifyAdminsNewOrder,
  notifyVendorNewOrder,
  emitOrderUpdate,
} = require('../utils/notificationService');

/**
 * Initiate Paymob payment for an order
 * This should be called after creating an order with payment method 'visa'
 */
exports.initiatePayment = async (req, res) => {
  try {
    const { orderId, frontendUrl } = req.body;

    if (!orderId) {
      return res.status(400).json({
        status: 'fail',
        message: 'Order ID is required',
      });
    }

    const order = await Order.findById(orderId).populate('items.product');

    if (!order) {
      return res.status(404).json({
        status: 'fail',
        message: 'Order not found',
      });
    }

    // Verify that the order belongs to the user (if not admin)
    if (req.user && order.user && String(order.user) !== String(req.user._id)) {
      return res.status(403).json({
        status: 'fail',
        message: 'Not authorized to access this order',
      });
    }

    // Check if payment method is visa
    if (order.payment.method !== 'visa') {
      return res.status(400).json({
        status: 'fail',
        message: 'This order does not require online payment',
      });
    }

    // Check if already paid
    if (order.payment.status === 'paid') {
      return res.status(400).json({
        status: 'fail',
        message: 'This order has already been paid',
      });
    }

    // Prepare billing data
    const nameParts = order.name.split(' ');
    const billingData = {
      firstName: nameParts[0] || order.name,
      lastName: nameParts.slice(1).join(' ') || nameParts[0],
      email: req.user ? req.user.email : 'guest@samoulla.com',
      phone: order.mobile,
      street: order.address.street,
      city: order.address.city,
      state: order.address.governorate,
      country: 'EG',
      apartment: 'NA',
      floor: 'NA',
      building: 'NA',
      postalCode: 'NA',
    };

    // Prepare order data for Paymob
    const orderData = {
      amount: order.totalPrice,
      items: order.items.map((item) => ({
        name: item.name,
        quantity: item.quantity,
        unitPrice: item.unitPrice,
        description: item.name,
      })),
      billingData,
    };

    // Initiate payment with Paymob
    const paymentResult = await initiatePaymobPayment(orderData);

    if (!paymentResult.success) {
      return res.status(500).json({
        status: 'error',
        message: 'Failed to initiate payment',
        error: paymentResult.error,
      });
    }

    // Update order with Paymob data
    order.payment.paymobOrderId = paymentResult.paymobOrderId;
    order.payment.paymentKey = paymentResult.paymentKey;
    if (frontendUrl) {
      order.payment.frontendUrl = frontendUrl;
    }
    await order.save();

    res.status(200).json({
      status: 'success',
      data: {
        paymentKey: paymentResult.paymentKey,
        iframeUrl: paymentResult.iframeUrl,
        paymobOrderId: paymentResult.paymobOrderId,
      },
    });
  } catch (error) {
    console.error('Payment initiation error:', error);
    res.status(500).json({
      status: 'error',
      message: error.message,
    });
  }
};

const { restoreOrderStock } = require('../utils/orderUtils');
const Promo = require('../models/promoCodeModel');

/**
 * Paymob callback handler
 * This endpoint receives payment status updates from Paymob
 */
exports.paymobCallback = async (req, res) => {
  let order;
  try {
    // Combine body and query for consistent data access
    const transactionData = { ...req.query, ...req.body };

    console.log(
      'Paymob callback received:',
      JSON.stringify(transactionData, null, 2),
    );

    // Verify payment using HMAC
    const verificationResult = await verifyPaymobPayment(transactionData);

    // TRY TO FIND ORDER EARLY (to get frontendUrl for redirects)
    if (verificationResult.orderId) {
      order = await Order.findOne({
        'payment.paymobOrderId': String(verificationResult.orderId),
      }).populate('user', 'name email');
    }

    const fallbackUrl = process.env.FRONTEND_URL || 'http://localhost:5173';
    const frontendUrl =
      (order && order.payment && order.payment.frontendUrl) || fallbackUrl;

    // 1. VERIFICATION CHECK
    if (!verificationResult.hmacVerified) {
      console.error('Payment verification failed: Invalid HMAC signature');
      if (req.method === 'GET') {
        return res.redirect(
          `${frontendUrl}/checkout?error=verification_failed`,
        );
      }
      return res
        .status(200)
        .json({ message: 'Callback received but verification failed' });
    }

    // 2. FIND AND UPDATE ORDER (If not already found)
    if (!order) {
      console.error(
        'Order not found for Paymob order ID:',
        verificationResult.orderId,
      );
      if (req.method === 'GET') {
        // If it's a redirect and order is gone (maybe deleted by POST already),
        // We still want to go back to checkout with a status if possible
        const status = verificationResult.success ? 'success' : 'failed';
        if (status === 'failed') {
          return res.redirect(`${frontendUrl}/checkout?status=failed`);
        }
        return res.redirect(`${frontendUrl}/checkout?error=order_not_found`);
      }
      return res.status(200).json({ message: 'Order not found' });
    }

    // IDEMPOTENCY CHECK: Skip if already processed (paid or explicitly cancelled)
    const isAlreadyPaid = order.payment.status === 'paid';
    const isAlreadyCancelled = order.orderStatus === 'cancelled';

    if (!isAlreadyPaid && !isAlreadyCancelled) {
      if (verificationResult.success) {
        // SUCCESSFUL TRANSACTION
        order.payment.status = 'paid';
        order.payment.paidAt = new Date();
        order.payment.paymobTransactionId = String(
          verificationResult.transactionId,
        );

        // Ensure orderStatus is 'created' or 'processing' if paid
        if (order.orderStatus === 'cancelled') order.orderStatus = 'created';

        await order.save();

        // Send confirmation email and notifications
        try {
          // Notify the user
          if (order.user) {
            await notifyOrderCreated(order, order.user._id || order.user);
          }

          // Notify admins
          await notifyAdminsNewOrder(order);

          // Notify vendors
          const uniqueProviderIds = new Set();
          // We need items available here. Let's populate them if needed or use the existing ones.
          // The order already has items array but products might not be populated with provider.
          const orderWithProducts = await Order.findById(order._id).populate(
            'items.product',
          );
          orderWithProducts.items.forEach((item) => {
            if (item.product && item.product.provider) {
              uniqueProviderIds.add(item.product.provider.toString());
            }
          });

          for (const pId of uniqueProviderIds) {
            await notifyVendorNewOrder(order, pId);
          }

          // Send Email
          if (order.user) {
            // Populate for email (fully)
            const populatedOrderForEmail = await Order.findById(
              order._id,
            ).populate({
              path: 'items.product',
              select: 'nameAr price imageCover',
              populate: { path: 'provider', select: 'storeName' },
            });

            const emailOrderData = {
              orderNumber: order._id.toString().slice(-8).toUpperCase(),
              items: populatedOrderForEmail.items.map((item) => ({
                product: {
                  nameAr: (item.product && item.product.nameAr) || item.name,
                  imageCover: (item.product && item.product.imageCover) || null,
                  provider: (item.product && item.product.provider) || null,
                },
                quantity: item.quantity,
                price: item.unitPrice,
              })),
              subtotal:
                order.totalPrice -
                (order.shippingPrice || 0) +
                (order.discountAmount || 0),
              discount: order.discountAmount || 0,
              shippingCost: order.shippingPrice || 0,
              total: order.totalPrice,
              paymentMethod: order.payment.method,
              shippingAddress: {
                street: order.address.street,
                city: order.address.city,
                governorate: order.address.governorate,
                phone: order.mobile,
              },
            };

            await sendOrderConfirmationEmail(emailOrderData, order.user);
          }
        } catch (notifErr) {
          console.error('Notification/Email error:', notifErr);
        }

        emitOrderUpdate(order, 'payment_completed');
        console.log(`✅ Payment successful for order ${order._id}`);
      } else {
        // FAILED TRANSACTION
        // Per user request: Don't place (keep) the order if payment failed.
        // We delete it instead of marking as cancelled.

        // 1. RESTORE STOCK
        try {
          await restoreOrderStock(order.items);
          console.log(
            `📦 Stock restored for deleted (previously failed) order ${order._id}`,
          );
        } catch (stockErr) {
          console.error('Failed to restore stock:', stockErr);
        }

        // 2. RESTORE PROMO (if any)
        if (order.promo) {
          try {
            await Promo.findByIdAndUpdate(order.promo, {
              $inc: { usedCount: -1 },
            });
            console.log(`🏷️ Promo usage rolled back for order ${order._id}`);
          } catch (promoErr) {
            console.error('Failed to restore promo usage:', promoErr);
          }
        }

        // 3. EMIT FAILURE EVENT (before delete)
        emitOrderUpdate(order, 'payment_failed');

        // 4. DELETE THE ORDER
        const orderId = order._id;
        await Order.findByIdAndDelete(orderId);
        console.log(`🗑️ Failed order ${orderId} deleted from database`);
      }
    } else {
      console.log(
        `ℹ️ Order ${order._id} already processed. Status: ${order.payment.status}, OrderStatus: ${order.orderStatus}`,
      );
    }

    // 3. FINAL RESPONSE
    if (req.method === 'GET') {
      const status = verificationResult.success ? 'success' : 'failed';
      console.log(
        `Redirecting user for order ${order._id} with status ${status} to ${frontendUrl}`,
      );

      if (status === 'success') {
        return res.redirect(
          `${frontendUrl}/order-confirmation/${order._id}?status=success`,
        );
      }
      return res.redirect(
        `${frontendUrl}/checkout?status=failed&orderId=${order._id}`,
      );
    }

    res.status(200).json({
      status: 'success',
      message: 'Callback processed successfully',
    });
  } catch (error) {
    console.error('Callback processing error:', error);
    if (req.method === 'GET') {
      const fallbackUrlCatch =
        process.env.FRONTEND_URL || 'http://localhost:5173';
      const frontendUrlCatch =
        (order && order.payment && order.payment.frontendUrl) ||
        fallbackUrlCatch;
      return res.redirect(
        `${frontendUrlCatch}/checkout?error=internal_server_error`,
      );
    }
    res
      .status(200)
      .json({ message: 'Callback received but processing failed' });
  }
};

/**
 * Check payment status for an order
 */
exports.checkPaymentStatus = async (req, res) => {
  try {
    const { orderId } = req.params;

    const order = await Order.findById(orderId);

    if (!order) {
      return res.status(404).json({
        status: 'fail',
        message: 'Order not found',
      });
    }

    // Verify that the order belongs to the user (if not admin)
    if (req.user && order.user && String(order.user) !== String(req.user._id)) {
      return res.status(403).json({
        status: 'fail',
        message: 'Not authorized to access this order',
      });
    }

    res.status(200).json({
      status: 'success',
      data: {
        paymentStatus: order.payment.status,
        paymentMethod: order.payment.method,
        paidAt: order.payment.paidAt,
        transactionId: order.payment.paymobTransactionId,
      },
    });
  } catch (error) {
    console.error('Payment status check error:', error);
    res.status(500).json({
      status: 'error',
      message: error.message,
    });
  }
};

/**
 * Refund a payment (Admin only)
 */
exports.refundPayment = async (req, res) => {
  try {
    const { orderId } = req.params;
    const { amount } = req.body;

    const order = await Order.findById(orderId);

    if (!order) {
      return res.status(404).json({
        status: 'fail',
        message: 'Order not found',
      });
    }

    // Check if order was paid
    if (order.payment.status !== 'paid') {
      return res.status(400).json({
        status: 'fail',
        message: 'Cannot refund an unpaid order',
      });
    }

    // Check if transaction ID exists
    if (!order.payment.paymobTransactionId) {
      return res.status(400).json({
        status: 'fail',
        message: 'No Paymob transaction found for this order',
      });
    }

    // Determine refund amount
    const refundAmount = amount || order.totalPrice;

    if (refundAmount > order.totalPrice) {
      return res.status(400).json({
        status: 'fail',
        message: 'Refund amount cannot exceed order total',
      });
    }

    // Process refund with Paymob
    const refundResult = await refundPaymobTransaction(
      order.payment.paymobTransactionId,
      refundAmount,
    );

    if (!refundResult.success) {
      return res.status(500).json({
        status: 'error',
        message: 'Failed to process refund',
        error: refundResult.error,
      });
    }

    // Update order
    order.payment.refundedAt = new Date();
    order.payment.refundAmount = refundAmount;
    order.payment.status = 'failed'; // Mark as failed after refund
    await order.save();

    // Broadcast order update
    emitOrderUpdate(order, 'payment_refunded');

    res.status(200).json({
      status: 'success',
      data: {
        message: 'Refund processed successfully',
        refundAmount,
        order,
      },
    });
  } catch (error) {
    console.error('Refund processing error:', error);
    res.status(500).json({
      status: 'error',
      message: error.message,
    });
  }
};

/**
 * Paymob transaction processed callback (Alternative callback endpoint)
 */
exports.paymobTransactionCallback = async (req, res) => {
  try {
    // Extract data from query parameters (Paymob sends some data via GET)
    const transactionData = {
      ...req.query,
      ...req.body,
    };

    console.log(
      'Transaction callback received:',
      JSON.stringify(transactionData, null, 2),
    );

    // Forward to main callback handler
    req.body = transactionData;
    return exports.paymobCallback(req, res);
  } catch (error) {
    console.error('Transaction callback error:', error);
    res.status(200).json({ message: 'Callback received' });
  }
};

module.exports = exports;