/*
 *
 *   Copyright (c) 1999 - 2011 my-Channels Ltd
 *   Copyright (c) 2012 - 2017 Software AG, Darmstadt, Germany and/or Software AG USA Inc., Reston, VA, USA, and/or its subsidiaries and/or its affiliates and/or their licensors.
 *
 *   Use, reproduction, transfer, publication or disclosure is prohibited except as specifically provided for in your License Agreement with Software AG.
 *
 */
package com.pcbsys.nirvana.apps;

import com.pcbsys.nirvana.client.*;

import java.io.IOException;

/**
 * Creates an asynchronous queue listener using a queue reader
 */
public class QSubscriber extends nSampleApp implements nEventListener {

  static String selector = null;

  private long lastEID = 0;
  private long startTime = 0;
  private long byteCount = 0;

  private int logLevel = 0;
  private int count = -1;
  private int totalMsgs = 0;
  private int reportCount = 1000;

  private nQueue myQueue;
  private static QSubscriber mySelf = null;

  /**
   * This method demonstrates the Nirvana API calls necessary to create an
   * asynchronous listener on a queue
   * It is called after all command line arguments have been received and
   * validated
   *
   * @param realmDetails a String[] containing the possible RNAME values
   * @param aqueueName the queue name to pop
   * @param selector the pop selector filter
   * @param loglvl the specified log level
   * @param repCount the specified report count
   */
  private void doit(String[] realmDetails, String aqueueName, int loglvl, int repCount, String selector) {
    logLevel = loglvl;
    reportCount = repCount;

    mySelf.constructSession(realmDetails);

    // Subscribes to the specified queue
    try {
      // Create a channel attributes object
      nChannelAttributes nca = new nChannelAttributes();
      nca.setName(aqueueName);

      // Obtain the queue reference
      myQueue = mySession.findQueue(nca);
      // output queue details
      nQueueDetails details = myQueue.getDetails();
      System.out.println("Current queue size = " + details.getNoOfEvents());
      System.out.println("Current queue age  = " + (details.getLastEventTime() - details.getFirstEventTime()));
      System.out.println("Current storage size = " + details.getTotalMemorySize());
      System.out.println("Current readers    = " + details.getNoOfReaders());
      // create the queue reader

      nQueueAsyncReader reader = myQueue.createAsyncReader(new nQueueReaderContext(this, selector));
      // Stay subscribed until the user presses any key
      System.in.read();

      System.out.println("Finished. Consumed total of " + totalMsgs);
      // Destroy the queue reader
      nQueue.destroyReader(reader);
    }
    // Handle errors
    catch (nChannelNotFoundException cnfe) {
      System.out.println("The queue specified could not be found.");
      System.out.println("Please ensure that the queue exists in the REALM you connect to.");
      cnfe.printStackTrace();
      System.exit(1);
    } catch (nSecurityException se) {
      System.out.println("Insufficient permissions for the requested operation.");
      System.out.println("Please check the ACL settings on the server.");
      se.printStackTrace();
      System.exit(1);
    } catch (nSessionNotConnectedException snce) {
      System.out.println("The session object used is not physically connected to the Nirvana realm.");
      System.out.println("Please ensure the realm is up and check your RNAME value.");
      snce.printStackTrace();
      System.exit(1);
    } catch (nUnexpectedResponseException ure) {
      System.out.println("The Nirvana REALM has returned an unexpected response.");
      System.out.println("Please ensure the Nirvana REALM and client API used are compatible.");
      ure.printStackTrace();
      System.exit(1);
    } catch (nUnknownRemoteRealmException urre) {
      System.out.println("The queue specified resided in a remote realm which could not be found.");
      System.out.println("Please ensure the queue name specified is correct.");
      urre.printStackTrace();
      System.exit(1);
    } catch (nRequestTimedOutException rtoe) {
      System.out.println("The requested operation has timed out waiting for a response from the REALM.");
      System.out.println("If this is a very busy REALM ask your administrator to increase the client timeout values.");
      rtoe.printStackTrace();
      System.exit(1);
    } catch (nBaseClientException nbce) {
      System.out.println("An error occured while creating the Channel Attributes object.");
      nbce.printStackTrace();
      System.exit(1);
    } catch (IOException e) {
      e.printStackTrace();
    }
    // Close the session we opened
    try {
      nSessionFactory.close(mySession);
    } catch (Exception ex) {
    }
    // Close any other sessions within this JVM so that we can exit
    nSessionFactory.shutdown();
  }

  protected void processArgs(String[] args) {
    switch (args.length) {
      case 5:
        System.getProperties().put("SELECTOR", args[4]);
      case 4:
        System.getProperties().put("COUNT", args[3]);
      case 3:
        System.getProperties().put("DEBUG", args[2]);
      case 2:
        System.getProperties().put("TIMEOUT", args[1]);
      case 1:
        if (args[0].equals("-?")) {
          Usage();
          UsageEnv();
        }
        System.getProperties().put("QUEUENAME", args[0]);
        break;
    }
  }

  public static void main(String[] args) {

    // Create an instance for this class
    mySelf = new QSubscriber();

    // Process command line arguments
    mySelf.processArgs(args);

    // Process Environment Variables
    nSampleApp.processEnvironmentVariables();

    // Check the queue name specified
    String queueName = null;
    if (System.getProperty("QUEUENAME") != null) {
      queueName = System.getProperty("QUEUENAME");
    } else {
      Usage();
      System.exit(1);
    }

    int loglvl = 1; // Default value
    // Check to see if a DEBUG value has been specified.
    if (System.getProperty("DEBUG") != null) {
      try {
        loglvl = Integer.parseInt(System.getProperty("DEBUG"));
      } catch (Exception num) {
      } // Ignore and use the default
    }

    int reportCount = 1000; // Default value
    // Check to see if a value for report count has been specified. Every
    // time
    // N events get received where N = report count, a subscription rate
    // report will
    // be printed in System.out
    if (System.getProperty("COUNT") != null) {
      try {
        reportCount = Integer.parseInt(System.getProperty("COUNT"));
      } catch (Exception num) {
      } // Ignore and use the default
    }

    // Check to see if a value for the selector has been specified.
    if (System.getProperty("SELECTOR") != null) {
      try {
        selector = System.getProperty("SELECTOR");
      } catch (Exception num) {
      } // Ignore and use the default
    }

    // Check the local realm details
    String RNAME = null;
    if (System.getProperty("RNAME") != null) {
      RNAME = System.getProperty("RNAME");
    } else {
      Usage();
      System.exit(1);
    }

    // Process the local REALM RNAME details
    String[] rproperties = new String[4];
    rproperties = parseRealmProperties(RNAME);

    // Pop to the queue specified
    mySelf.doit(rproperties, queueName, loglvl, reportCount, selector);
  }

  /**
   * Each time the queue.pop operation this method will be called to output
   * the event details.
   *
   * @param evt An nConsumeEvent object containing the message received from
   * the queue
   */
  public void go(nConsumeEvent evt) {

    // If this is the first message we receive
    if (count == -1) {
      // Get a timestamp to be used for message rate calculations
      startTime = System.currentTimeMillis();
      count = 0;
    }

    // Increment he counter
    count++;
    totalMsgs++;

    // Have we reached the point where we need to report the rates?
    if (count == reportCount) {

      // Reset the counter
      count = 0;

      // Get a timestampt to calculate the rates
      long end = System.currentTimeMillis();

      // Does the specified log level permits us to print on the screen?
      if (logLevel >= 1) {

        // Dump the rates on the screen
        if (end != startTime) {
          System.out.println(
              "Received " + reportCount + " in " + (end - startTime) + " Evt/Sec = " + ((reportCount * 1000) / (end
                  - startTime)) + " Bytes/sec=" + ((byteCount * 1000) / (end - startTime)));
        } else {
          System.out.println("Received " + reportCount + " faster than the system millisecond counter");
        }
      }
      // Set the startTime for the next report equal to the end timestamp
      // for the previous one
      startTime = end;

      // Reset the byte counter
      byteCount = 0;
    }

    // If the last EID counter is not equal to the current event ID
    if (lastEID != evt.getEventID()) {
      lastEID = evt.getEventID() + 1;
    } else {

      // Increment the last eid counter
      lastEID++;
    }
    // Get the data of the message
    byte[] buffer = evt.getEventData();
    if (buffer != null) {
      // Add its length to the byte counter
      byteCount += buffer.length;
    }
    // If the loglevel permits printing on the screen
    if (logLevel >= 2) {
      // Print the eid
      System.out.println("Event id : " + evt.getEventID());
      // If the loglevel permits printing on the screen
      if (logLevel >= 3) {
        // Print the message tag
        System.out.println("Event tag : " + evt.getEventTag());
        // Print the message data
        System.out.println("Event data : " + new String(evt.getEventData()));
        if (evt.hasAttributes()) {
          displayEventAttributes(evt.getAttributes());
        }

        nEventProperties prop = evt.getProperties();
        if (prop != null) {
          displayEventProperties(prop);
        }
      }
    }
  }

  /**
   * Prints the usage message for this class
   */
  private static void Usage() {

    System.out.println("Usage ...\n");
    System.out.println("npopqasync <queue name> [debug] [count] [selector] \n");

    System.out.println("<Required Arguments> \n");
    System.out.println("<queue name> - Queue name parameter for the queue to pop from");
    System.out.println("\n[Optional Arguments] \n");
    System.out.println("[debug] - The level of output from each event, 0 - none, 1 - summary, 2 - EIDs, 3 - All");
    System.out.println("[count] - The number of events to wait before printing out summary information");
    System.out.println("[selector] - The event filter string to use");
    System.out.println("\n\nNote: -? provides help on environment variables \n");
  }

} // End of QSubscriber Class