/*
    *  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.mina.filter.reqres;
  
  import java.util.NoSuchElementException;
  import java.util.concurrent.BlockingQueue;
  import java.util.concurrent.LinkedBlockingQueue;
  import java.util.concurrent.ScheduledFuture;
  import java.util.concurrent.TimeUnit;
  
  /**
   * TODO Add documentation
   * 
   * @author The Apache MINA Project (dev@mina.apache.org)
   */
  public class Request {
      private final Object id;
  
      private final Object message;
  
      private final long timeoutMillis;
  
      private volatile Runnable timeoutTask;
  
      private volatile ScheduledFuture<?> timeoutFuture;
  
      private final BlockingQueue<Object> responses;
  
      private volatile boolean endOfResponses;
  
      public Request(Object id, Object message, long timeoutMillis) {
          this(id, message, true, timeoutMillis);
      }
  
      public Request(Object id, Object message, boolean useResponseQueue,
                     long timeoutMillis) {
          this(id, message, useResponseQueue, timeoutMillis,
                  TimeUnit.MILLISECONDS);
      }
  
      public Request(Object id, Object message, long timeout, TimeUnit unit) {
          this(id, message, true, timeout, unit);
      }
  
      public Request(Object id, Object message, boolean useResponseQueue,
                     long timeout, TimeUnit unit) {
          if (id == null) {
              throw new NullPointerException("id");
          }
          if (message == null) {
              throw new NullPointerException("message");
          }
          if (timeout < 0) {
              throw new IllegalArgumentException("timeout: " + timeout
                      + " (expected: 0+)");
          } else if (timeout == 0) {
              timeout = Long.MAX_VALUE;
          }
  
          if (unit == null) {
              throw new NullPointerException("unit");
          }
  
          this.id = id;
          this.message = message;
          this.responses = useResponseQueue ? new LinkedBlockingQueue<Object>() : null;
          this.timeoutMillis = unit.toMillis(timeout);
      }
  
      public Object getId() {
          return id;
      }
  
      public Object getMessage() {
          return message;
      }
  
      public long getTimeoutMillis() {
          return timeoutMillis;
      }
  
      public boolean isUseResponseQueue() {
         return responses != null;
     }
 
     public boolean hasResponse() {
         checkUseResponseQueue();
         return !responses.isEmpty();
     }
 
     public Response awaitResponse() throws RequestTimeoutException,
             InterruptedException {
         checkUseResponseQueue();
         chechEndOfResponses();
         return convertToResponse(responses.take());
     }
 
     public Response awaitResponse(long timeout, TimeUnit unit)
             throws RequestTimeoutException, InterruptedException {
         checkUseResponseQueue();
         chechEndOfResponses();
         return convertToResponse(responses.poll(timeout, unit));
     }
 
     private Response convertToResponse(Object o) {
         if (o instanceof Response) {
             return (Response) o;
         }
 
         if (o == null) {
             return null;
         }
 
         throw (RequestTimeoutException) o;
     }
 
     public Response awaitResponseUninterruptibly()
             throws RequestTimeoutException {
         for (; ;) {
             try {
                 return awaitResponse();
             } catch (InterruptedException e) {
                 // Do nothing
             }
         }
     }
 
     private void chechEndOfResponses() {
         if (responses != null && endOfResponses && responses.isEmpty()) {
             throw new NoSuchElementException(
                     "All responses has been retrieved already.");
         }
     }
 
     private void checkUseResponseQueue() {
         if (responses == null) {
             throw new UnsupportedOperationException(
                     "Response queue is not available; useResponseQueue is false.");
         }
     }
 
     void signal(Response response) {
         signal0(response);
         if (response.getType() != ResponseType.PARTIAL) {
             endOfResponses = true;
         }
     }
 
     void signal(RequestTimeoutException e) {
         signal0(e);
         endOfResponses = true;
     }
 
     private void signal0(Object answer) {
         if (responses != null) {
             responses.add(answer);
         }
     }
 
     @Override
     public int hashCode() {
         return getId().hashCode();
     }
 
     @Override
     public boolean equals(Object o) {
         if (o == this) {
             return true;
         }
 
         if (o == null) {
             return false;
         }
 
         if (!(o instanceof Request)) {
             return false;
         }
 
         Request that = (Request) o;
         return this.getId().equals(that.getId());
     }
 
     @Override
     public String toString() {
         String timeout = getTimeoutMillis() == Long.MAX_VALUE ? "max"
                 : String.valueOf(getTimeoutMillis());
 
         return "request: { id=" + getId() + ", timeout=" + timeout
                 + ", message=" + getMessage() + " }";
     }
 
     Runnable getTimeoutTask() {
         return timeoutTask;
     }
 
     void setTimeoutTask(Runnable timeoutTask) {
         this.timeoutTask = timeoutTask;
     }
 
     ScheduledFuture<?> getTimeoutFuture() {
         return timeoutFuture;
     }
 
     void setTimeoutFuture(ScheduledFuture<?> timeoutFuture) {
         this.timeoutFuture = timeoutFuture;
     }
 }