/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.activemq.transport.amqp.client;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;

import org.apache.activemq.transport.amqp.client.util.AsyncResult;
import org.apache.activemq.transport.amqp.client.util.ClientFuture;
import org.apache.activemq.transport.amqp.client.util.UnmodifiableSession;
import org.apache.qpid.proton.amqp.Symbol;
import org.apache.qpid.proton.amqp.messaging.Source;
import org.apache.qpid.proton.amqp.messaging.Target;
import org.apache.qpid.proton.engine.Connection;
import org.apache.qpid.proton.engine.Session;

/**
 * Session class that manages a Proton session endpoint.
 */
public class AmqpSession extends AmqpAbstractResource<Session> {

   private final AtomicLong receiverIdGenerator = new AtomicLong();
   private final AtomicLong senderIdGenerator = new AtomicLong();

   private final AmqpConnection connection;
   private final String sessionId;
   private final AmqpTransactionContext txContext;
   private final AtomicBoolean closed = new AtomicBoolean();

   /**
    * Create a new session instance.
    *
    * @param connection The parent connection that created the session.
    * @param sessionId  The unique ID value assigned to this session.
    */
   public AmqpSession(AmqpConnection connection, String sessionId) {
      this.connection = connection;
      this.sessionId = sessionId;
      this.txContext = new AmqpTransactionContext(this);
   }

   /**
    * Close the receiver, a closed receiver will throw exceptions if any further send
    * calls are made.
    *
    * @throws IOException if an error occurs while closing the receiver.
    */
   public void close() throws IOException {
      if (closed.compareAndSet(false, true)) {
         final ClientFuture request = new ClientFuture();
         getScheduler().execute(new Runnable() {

            @Override
            public void run() {
               checkClosed();
               close(request);
               pumpToProtonTransport(request);
            }
         });

         request.sync();
      }
   }

   /**
    * Create an anonymous sender.
    *
    * @return a newly created sender that is ready for use.
    *
    * @throws Exception if an error occurs while creating the sender.
    */
   public AmqpSender createSender() throws Exception {
      return createSender(null, false);
   }

   /**
    * Create a sender instance using the given address
    *
    * @param address the address to which the sender will produce its messages.
    * @return a newly created sender that is ready for use.
    * @throws Exception if an error occurs while creating the sender.
    */
   public AmqpSender createSender(final String address) throws Exception {
      return createSender(address, false);
   }

   /**
    * Create a sender instance using the given address
    *
    * @param address the address to which the sender will produce its messages.
    * @param desiredCapabilities the capabilities that the caller wants the remote to support.
    * @return a newly created sender that is ready for use.
    * @throws Exception if an error occurs while creating the sender.
    */
   public AmqpSender createSender(final String address, Symbol[] desiredCapabilities) throws Exception {
      return createSender(address, false, desiredCapabilities, null, null);
   }


   /**
    * Create a sender instance using the given address
    *
    * @param address   the address to which the sender will produce its messages.
    * @param presettle controls if the created sender produces message that have already been marked settled.
    * @return a newly created sender that is ready for use.
    * @throws Exception if an error occurs while creating the sender.
    */
   public AmqpSender createSender(final String address, boolean presettle) throws Exception {
      return createSender(address, presettle, null, null, null);
   }

   /**
    * Create a sender instance using the given address
    *
    * @param address   the address to which the sender will produce its messages.
    * @param presettle controls if the created sender produces message that have already been marked settled.
    * @param desiredCapabilities the capabilities that the caller wants the remote to support.
    * @param offeredCapabilities the capabilities that the caller wants the advertise support for.
    * @param properties the properties to send as part of the sender open.
    * @return a newly created sender that is ready for use.
    * @throws Exception if an error occurs while creating the sender.
    */
   public AmqpSender createSender(final String address, boolean presettle, Symbol[] desiredCapabilities, Symbol[] offeredCapabilities, Map<Symbol, Object> properties) throws Exception {
      checkClosed();

      final AmqpSender sender = new AmqpSender(AmqpSession.this, address, getNextSenderId());
      sender.setPresettle(presettle);
      sender.setDesiredCapabilities(desiredCapabilities);
      sender.setOfferedCapabilities(offeredCapabilities);
      sender.setProperties(properties);
      final ClientFuture request = new ClientFuture();

      connection.getScheduler().execute(new Runnable() {

         @Override
         public void run() {
            checkClosed();
            sender.setStateInspector(getStateInspector());
            sender.open(request);
            pumpToProtonTransport(request);
         }
      });

      request.sync();

      return sender;
   }

   /**
    * Create a sender instance using the given Target
    *
    * @param target the caller created and configured Traget used to create the sender link.
    * @return a newly created sender that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpSender createSender(Target target) throws Exception {
      return createSender(target, getNextSenderId());
   }

   /**
    * Create a sender instance using the given Target
    *
    * @param target the caller created and configured Traget used to create the sender link.
    * @param senderId the sender ID to assign to the newly created Sender.
    * @return a newly created sender that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpSender createSender(Target target, String senderId) throws Exception {
      return createSender(target, senderId, null, null, null);
   }

   /**
    * Create a sender instance using the given Target
    *
    * @param target the caller created and configured Traget used to create the sender link.
    * @param senderId the sender ID to assign to the newly created Sender.
    * @param desiredCapabilities the capabilities that the caller wants the remote to support.
    * @param offeredCapabilities the capabilities that the caller wants the advertise support for.
    * @param properties the properties to send as part of the sender open.
    * @return a newly created sender that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpSender createSender(Target target, String senderId, Symbol[] desiredCapabilities, Symbol[] offeredCapabilities, Map<Symbol, Object> properties) throws Exception {
      checkClosed();

      final AmqpSender sender = new AmqpSender(AmqpSession.this, target, senderId);
      sender.setDesiredCapabilities(desiredCapabilities);
      sender.setOfferedCapabilities(offeredCapabilities);
      sender.setProperties(properties);
      final ClientFuture request = new ClientFuture();

      connection.getScheduler().execute(new Runnable() {

         @Override
         public void run() {
            checkClosed();
            sender.setStateInspector(getStateInspector());
            sender.open(request);
            pumpToProtonTransport(request);
         }
      });

      request.sync();

      return sender;
   }

   /**
    * Create a receiver instance using the given address
    *
    * @param address the address to which the receiver will subscribe for its messages.
    * @return a newly created receiver that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver createReceiver(String address) throws Exception {
      return createReceiver(address, null, false);
   }

   /**
    * Create a receiver instance using the given address
    *
    * @param address  the address to which the receiver will subscribe for its messages.
    * @param selector the JMS selector to use for the subscription
    * @return a newly created receiver that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver createReceiver(String address, String selector) throws Exception {
      return createReceiver(address, selector, false);
   }

   /**
    * Create a receiver instance using the given address
    *
    * @param address  the address to which the receiver will subscribe for its messages.
    * @param selector the JMS selector to use for the subscription
    * @param noLocal  should the subscription have messages from its connection filtered.
    * @return a newly created receiver that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver createReceiver(String address, String selector, boolean noLocal) throws Exception {
      return createReceiver(address, selector, noLocal, false);
   }

   /**
    * Create a receiver instance using the given address
    *
    * @param address   the address to which the receiver will subscribe for its messages.
    * @param selector  the JMS selector to use for the subscription
    * @param noLocal   should the subscription have messages from its connection filtered.
    * @param presettle should the receiver be created with a settled sender mode.
    * @return a newly created receiver that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver createReceiver(String address,
                                      String selector,
                                      boolean noLocal,
                                      boolean presettle) throws Exception {
      checkClosed();

      final ClientFuture request = new ClientFuture();
      final AmqpReceiver receiver = new AmqpReceiver(AmqpSession.this, address, getNextReceiverId());

      receiver.setNoLocal(noLocal);
      receiver.setPresettle(presettle);
      if (selector != null && !selector.isEmpty()) {
         receiver.setSelector(selector);
      }

      connection.getScheduler().execute(new Runnable() {

         @Override
         public void run() {
            checkClosed();
            receiver.setStateInspector(getStateInspector());
            receiver.open(request);
            pumpToProtonTransport(request);
         }
      });

      request.sync();

      return receiver;
   }

   /**
    * Create a receiver instance using the given Source
    *
    * @param source the caller created and configured Source used to create the receiver link.
    * @return a newly created receiver that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver createReceiver(Source source) throws Exception {
      return createReceiver(source, getNextReceiverId());
   }

   /**
    * Create a receiver instance using the given Source
    *
    * @param source the caller created and configured Source used to create the receiver link.
    * @param receiverId the receiver id to use.
    * @return a newly created receiver that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver createReceiver(Source source, String receiverId) throws Exception {
      checkClosed();

      final ClientFuture request = new ClientFuture();
      final AmqpReceiver receiver = new AmqpReceiver(AmqpSession.this, source, getNextReceiverId());

      connection.getScheduler().execute(new Runnable() {

         @Override
         public void run() {
            checkClosed();
            receiver.setStateInspector(getStateInspector());
            receiver.open(request);
            pumpToProtonTransport(request);
         }
      });

      request.sync();

      return receiver;
   }

   /**
    * Create a receiver instance using the given address that creates a durable subscription.
    *
    * @param address          the address to which the receiver will subscribe for its messages.
    * @param subscriptionName the name of the subscription that is being created.
    * @return a newly created receiver that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver createDurableReceiver(String address, String subscriptionName) throws Exception {
      return createDurableReceiver(address, subscriptionName, null, false);
   }

   /**
    * Create a receiver instance using the given address that creates a durable subscription.
    *
    * @param address          the address to which the receiver will subscribe for its messages.
    * @param subscriptionName the name of the subscription that is being created.
    * @param selector         the JMS selector to use for the subscription
    * @return a newly created receiver that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver createDurableReceiver(String address,
                                             String subscriptionName,
                                             String selector) throws Exception {
      return createDurableReceiver(address, subscriptionName, selector, false);
   }

   /**
    * Create a receiver instance using the given address that creates a durable subscription.
    *
    * @param address          the address to which the receiver will subscribe for its messages.
    * @param subscriptionName the name of the subscription that is being created.
    * @param selector         the JMS selector to use for the subscription
    * @param noLocal          should the subscription have messages from its connection filtered.
    * @return a newly created receiver that is ready for use.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver createDurableReceiver(String address,
                                             String subscriptionName,
                                             String selector,
                                             boolean noLocal) throws Exception {
      checkClosed();

      if (subscriptionName == null || subscriptionName.isEmpty()) {
         throw new IllegalArgumentException("subscription name must not be null or empty.");
      }

      final ClientFuture request = new ClientFuture();
      final AmqpReceiver receiver = new AmqpReceiver(AmqpSession.this, address, getNextReceiverId());
      receiver.setSubscriptionName(subscriptionName);
      receiver.setNoLocal(noLocal);
      if (selector != null && !selector.isEmpty()) {
         receiver.setSelector(selector);
      }

      connection.getScheduler().execute(new Runnable() {

         @Override
         public void run() {
            checkClosed();
            receiver.setStateInspector(getStateInspector());
            receiver.open(request);
            pumpToProtonTransport(request);
         }
      });

      request.sync();

      return receiver;
   }

   /**
    * Create a receiver instance using the given address that creates a durable subscription.
    *
    * @param subscriptionName the name of the subscription that should be queried for on the remote..
    * @return a newly created receiver that is ready for use if the subscription exists.
    * @throws Exception if an error occurs while creating the receiver.
    */
   public AmqpReceiver lookupSubscription(String subscriptionName) throws Exception {
      checkClosed();

      if (subscriptionName == null || subscriptionName.isEmpty()) {
         throw new IllegalArgumentException("subscription name must not be null or empty.");
      }

      final ClientFuture request = new ClientFuture();
      final AmqpReceiver receiver = new AmqpReceiver(AmqpSession.this, (String) null, getNextReceiverId());
      receiver.setSubscriptionName(subscriptionName);

      connection.getScheduler().execute(new Runnable() {

         @Override
         public void run() {
            checkClosed();
            receiver.setStateInspector(getStateInspector());
            receiver.open(request);
            pumpToProtonTransport(request);
         }
      });

      request.sync();

      return receiver;
   }

   /**
    * @return this session's parent AmqpConnection.
    */
   public AmqpConnection getConnection() {
      return connection;
   }

   public Session getSession() {
      return new UnmodifiableSession(getEndpoint());
   }

   public boolean isInTransaction() {
      return txContext.isInTransaction();
   }

   @Override
   public String toString() {
      return "AmqpSession { " + sessionId + " }";
   }

   //----- Session Transaction Methods --------------------------------------//

   /**
    * Starts a new transaction associated with this session.
    *
    * @throws Exception if an error occurs starting a new Transaction.
    */
   public void begin() throws Exception {
      if (txContext.isInTransaction()) {
         throw new javax.jms.IllegalStateException("Session already has an active transaction");
      }

      txContext.begin();
   }

   /**
    * Commit the current transaction associated with this session.
    *
    * @throws Exception if an error occurs committing the Transaction.
    */
   public void commit() throws Exception {
      if (!txContext.isInTransaction()) {
         throw new javax.jms.IllegalStateException("Commit called on Session that does not have an active transaction");
      }

      txContext.commit();
   }

   /**
    * Roll back the current transaction associated with this session.
    *
    * @throws Exception if an error occurs rolling back the Transaction.
    */
   public void rollback() throws Exception {
      if (!txContext.isInTransaction()) {
         throw new javax.jms.IllegalStateException("Rollback called on Session that does not have an active transaction");
      }

      txContext.rollback();
   }

   //----- Internal access used to manage resources -------------------------//

   ScheduledExecutorService getScheduler() {
      return connection.getScheduler();
   }

   Connection getProtonConnection() {
      return connection.getProtonConnection();
   }

   void pumpToProtonTransport(AsyncResult request) {
      connection.pumpToProtonTransport(request);
   }

   public AmqpTransactionId getTransactionId() {
      if (txContext != null && txContext.isInTransaction()) {
         return txContext.getTransactionId();
      }

      return null;
   }

   AmqpTransactionContext getTransactionContext() {
      return txContext;
   }

   //----- Private implementation details -----------------------------------//

   @Override
   protected void doOpenInspection() {
      try {
         getStateInspector().inspectOpenedResource(getSession());
      } catch (Throwable error) {
         getStateInspector().markAsInvalid(error.getMessage());
      }
   }

   @Override
   protected void doClosedInspection() {
      try {
         getStateInspector().inspectClosedResource(getSession());
      } catch (Throwable error) {
         getStateInspector().markAsInvalid(error.getMessage());
      }
   }

   private String getNextSenderId() {
      return sessionId + ":" + senderIdGenerator.incrementAndGet();
   }

   private String getNextReceiverId() {
      return sessionId + ":" + receiverIdGenerator.incrementAndGet();
   }

   private void checkClosed() {
      if (isClosed() || connection.isClosed()) {
         throw new IllegalStateException("Session is already closed");
      }
   }
}