Subversion Repositories SmartDukaan

package in.shop2020.serving.services;

import in.shop2020.model.v1.catalog.Item;
import in.shop2020.model.v1.catalog.InventoryService.Client;
import in.shop2020.model.v1.order.LineItem;
import in.shop2020.model.v1.order.Order;
import in.shop2020.model.v1.order.Transaction;
import in.shop2020.model.v1.order.TransactionServiceException;
import in.shop2020.model.v1.order.TransactionStatus;
import in.shop2020.model.v1.user.Cart;
import in.shop2020.model.v1.user.Line;
import in.shop2020.model.v1.user.PromotionException;
import in.shop2020.model.v1.user.ShoppingCartException;
import in.shop2020.payments.Payment;
import in.shop2020.payments.PaymentException;
import in.shop2020.thrift.clients.CatalogClient;
import in.shop2020.thrift.clients.PaymentClient;
import in.shop2020.thrift.clients.PromotionClient;
import in.shop2020.thrift.clients.TransactionClient;
import in.shop2020.thrift.clients.UserClient;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.log4j.Logger;
import org.apache.thrift.TException;

/**
 * This class has methods to be used to process non-gateway-specific aspects of
 * payments and transactions.
 * 
 * @author Chandranshu
 * 
 */
public class CommonPaymentService {

        private static final boolean PAYMENT_NOT_CREATED = false;
        
        private static Logger log = Logger.getLogger(Class.class);
        
        private long paymentId;
        private double amount;

        public long getPaymentId() {
                return paymentId;
        }

        public double getAmount() {
                return amount;
        }

        /**
         * Creates a payment for the given cart of the given user for the given
         * transaction. Stores the id of the newly created payment and the amount
         * for which this payment was created. They can be retrieved later on using
         * {@link #getPaymentId()}getPaymentId() and {@link #getAmount()}getAmount()
         * methods respectively later on.
         * 
         * @param currentCartId
         *            The cart for which the payment object has to be created.
         * @param userId
         *            The user for whom the payment has to be created.
         * @param txnId
         *            The transaction against which the payment has to be created.
         * @param gatewayId
         * @return True if the payment object is successfully created, False
         *         otherwise.
         */
        public boolean createPayment(long currentCartId, long userId, long txnId, int gatewayId, long sourceId){
                PaymentClient paymentServiceClient = null;
                try {
                        paymentServiceClient = new PaymentClient();
                } catch (Exception e) {
                        log.error("Error while getting payment client", e);
                        return PAYMENT_NOT_CREATED;
                }
                
                try {
                        amount = calculatePaymentAmount(currentCartId, sourceId);
                } catch (ShoppingCartException e1) {
                        log.error("Unable to fetch payment amount from cart id.", e1);
                        return PAYMENT_NOT_CREATED;
                } catch (TException e1) {
                        log.error("Unable to fetch payment amount.", e1);
                        return PAYMENT_NOT_CREATED;
                }
                
                try {
                        paymentId = paymentServiceClient.getClient().createPayment(userId, amount, gatewayId, txnId);
                        // This is being done to ensure that the amount which we pass on to
                        // the PGs is same as what we have in the database.
                        Payment payment = paymentServiceClient.getClient().getPayment(paymentId);
                        amount = payment.getAmount();
                } catch (PaymentException e1) {
                        log.error("Unable to create payment object.", e1);
                        return PAYMENT_NOT_CREATED;
                } catch (TException e) {
                        log.error("Not able to create payment object.", e);
                        return PAYMENT_NOT_CREATED;
                }
                
                return true;
        }

        // TODO: The service client parameters in the processSuccessfulTxn et al are
        // unnecessary but initializing them again when the caller has the necessary
        // references has a performance overhead. Need to think more about this.

        /**
         * Processes a successful transaction by:
         * <ol>
         * <li>Marking the given transaction as 'authorized'.</li>
         * <li>Removing the items in the cart for which the given transaction was
         * processed.</li>
         * <li>Marking the coupon associated with this transaction, if any, as used
         * for this user.</li>
         * <li>Queuing the transaction successful email, containing transaction
         * info, to be sent later by a batch job.</li>
         * </ol>
         * <br>
         * Please note that it's possible that a user has added items to the cart
         * and so it's not possible to simply wipe out their cart. Therefore, it's
         * important to ensure that we remove only as much quantity of items as for
         * which the order was processed.
         * 
         * @param txnId
         *            The transaction which should be marked as successful.
         * @param userServiceClient
         *            A user context service client to use.
         * @param transactionServiceClient
         *            A transaction service client to use.
         * @param isFlagged
         *                        If payment is flagged it will be true else false 
         */
        public static void processSuccessfulTxn(long txnId, UserClient userServiceClient, TransactionClient transactionServiceClient, boolean isFlagged) {
                Transaction transaction = null;
                TransactionStatus tStatus = TransactionStatus.AUTHORIZED;
        String description = "Payment authorized for the order";
                // if flag is set, status to be changed to flagged
                if(isFlagged){
                        tStatus = TransactionStatus.FLAGGED;
                        description = "Payment flagged for the order";
                }
                try {
                        in.shop2020.model.v1.order.TransactionService.Client transactionClient = transactionServiceClient.getClient();
                        transactionClient.changeTransactionStatus(txnId, tStatus, description);
                        transaction = transactionClient.getTransaction(txnId);
                        transactionClient.enqueueTransactionInfoEmail(txnId);
                } catch (TException e1) {
                        log.error("Unable to update status of transaction. Thrift Exception:", e1);
                } catch (TransactionServiceException e) {
                        log.error("Unable to update status of transaction. Thrift Exception: ", e);
                }
                trackCouponUsage(transaction);
        resetCart(transaction, userServiceClient);
        }

        /**
         * Marks a transaction as well as all its orders as failed.
         * 
         * @param txnId
         *            The id of the transaction which has to be marked as failed.
         * @param transactionServiceClient
         */
        public static void processFailedTxn(long txnId, TransactionClient transactionServiceClient) {
                try {
                        in.shop2020.model.v1.order.TransactionService.Client transactionClient = transactionServiceClient.getClient();
                        transactionClient.changeTransactionStatus(txnId, TransactionStatus.FAILED, "Payment failed for the transaction.");
                } catch(TException e){
                        log.error("Thrift exception while getting information from transaction service.", e);
                } catch (TransactionServiceException e) {
                        log.error("Error while updating status information in transaction database.", e);
                }
        }

    /**
     * Processes a COD transaction by:
     * <ol>
     * <li>Setting the COD flag of all the orders and moving them to the INIT
     * state.
     * <li>Marking the given transaction to be in COD_IN_PROCESS state
     * <li>Marking the coupon associated with this transaction, if any, as used
     * for this user.</li>
     * <li>Queuing the transaction successful email, containing transaction
     * info, to be sent later by a batch job.</li>
     * </ol>
     * <br>
     * Please note that it's possible that a user has added items to the cart
     * and so it's not possible to simply wipe out their cart. Therefore, it's
     * important to ensure that we remove only as much quantity of items as for
     * which the order was processed.
     * 
     * @param txnId
     *            The COD transaction which should be marked as verification
     *            pending.
     */
        public static void processCodTxn(long txnId){
        try {            
            TransactionClient transactionServiceClient = new TransactionClient();
            in.shop2020.model.v1.order.TransactionService.Client transactionClient = transactionServiceClient.getClient();
            transactionClient.changeTransactionStatus(txnId, TransactionStatus.COD_IN_PROCESS, "COD payment awaited");
            Transaction transaction = transactionClient.getTransaction(txnId);
            transactionClient.enqueueTransactionInfoEmail(txnId);
            
            UserClient userServiceClient = new UserClient();
            trackCouponUsage(transaction);
            resetCart(transaction, userServiceClient);
        } catch (TException e1) {
            log.error("Unable to update status of transaction. Thrift Exception:", e1);
        } catch (TransactionServiceException e) {
            log.error("Unable to update status of transaction. Thrift Exception: ", e);
        } catch (Exception e) {
            log.error("Unable to update status of transaction. Thrift Exception: ", e);
        }
        }
        
        /**
         * Calculates the amount for the payment required for the given cart.
         * 
         * @param cartId
         *            Id of the cart for which this payment amount has to be
         *            calculated.
         * @return The total amount for which a payment should be created.
         * @throws ShoppingCartException
         *             If no cart can be found for the given id.
         * @throws TException
         */
        private double calculatePaymentAmount(long cartId, long sourceId) throws ShoppingCartException, TException{
                double totalAmount = 0;
                Cart cart;
                UserClient userContextServiceClient = null;
                try {
                        userContextServiceClient = new UserClient();
                } catch (Exception e) {
                        log.error("Unable to initialize user context service client", e);
                        throw new ShoppingCartException(100, "Unable to initialize the user service client");
                }
                in.shop2020.model.v1.user.UserContextService.Client userClient = userContextServiceClient.getClient();
                cart = userClient.getCart(cartId);
                
                if(cart.getCouponCode() == null)  {
                    List<Line> lineItems = cart.getLines(); 
                    
                for (Line line : lineItems) {
                    long productId = line.getItemId();
                    // FIXME: It's expensive to get the price of each item from the
                    // catalog service. We maintain the pricing info in the line items
                    // themselves now.
                    totalAmount =  totalAmount + line.getQuantity() * getItemPrice(productId, sourceId);
                }
                } else {
                    totalAmount = cart.getDiscountedPrice();
                }
                
                return totalAmount;
        }

        
        private double getItemPrice(long itemId, long sourceId){
                CatalogClient catalogClient = null;
                Client client = null;
                Double itemPrice = 0.0;
                try {
                        catalogClient = new CatalogClient();
                        client = catalogClient.getClient();
                        Item item = client.getItemForSource(itemId, sourceId);
                        itemPrice = item.getSellingPrice();
                        
                } catch(Exception e){
                        log.error("Unable to get the item price because of:", e);
                }
                return itemPrice;
        }


        /**
         * Removes the items processed through the given transaction from the
         * shopping cart.
         * 
         * @param transaction
         *            The transaction whose items have to be removed from the
         *            shopping cart.
         * @param userServiceClient
         */
        private static void resetCart(Transaction transaction, UserClient userServiceClient) {
                Map<Long, Double> items = new HashMap<Long, Double>();
                for(Order order: transaction.getOrders()){
                        for(LineItem lineitem: order.getLineitems()){
                                Long itemId = lineitem.getItem_id();
                                Double quantity = items.get(itemId);
                                if(quantity==null){
                                        quantity = lineitem.getQuantity();
                                } else {
                                        quantity= quantity + lineitem.getQuantity();
                                }
                                items.put(itemId, quantity);
                        }
                }
                
                log.debug("Items to reset in cart are: " + items);
                
                try {
                        //TODO Optimize the function to send less data over the wire
            userServiceClient.getClient().resetCart(transaction.getShoppingCartid(), items);
                }catch (TException e) {
                        log.error("Error while updating information in payment database.", e);
                } catch (ShoppingCartException e) {
                        log.error("Error while reseting the cart in cart database.", e);
                }catch (Exception e) {
                        log.error("Unexpected exception", e);
        }
        }

        /**
         * Mark the coupon associated with the given transaction as used.
         * 
         * @param transaction
         *            The transaction to track coupon for.
         * 
         * @param userServiceClient
         *            The user service client instance to use.
         */
        private static void trackCouponUsage(Transaction transaction) {
        try {
            String couponCode = transaction.getCoupon_code();
            
            if (couponCode != null && !couponCode.isEmpty()) {
                PromotionClient promotionServiceClient = new PromotionClient();
                promotionServiceClient.getClient().trackCouponUsage(couponCode, transaction.getId(), transaction.getCustomer_id());
            }
        } catch (PromotionException e) {
            log.error("Promotion Exception: " + e);
        } catch (TException e)  {
            log.error("Transport from Promotion Service failed:", e);
        } catch (Exception e) {
            log.error("Unexpected exception:", e);
        }
        }
}