/*
 *
 *   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.foundation.utils.xmlHelper;
import com.pcbsys.nirvana.client.*;

import java.io.*;

/**
 * Subscribes to a nirvana channel that contains XML messages
 */
public class XMLSubscribe extends nSampleApp implements nEventListener {

  static long starteid;
  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 reportCount = 1000;

  private xmlHelper xh = null;
  private nChannel myChannel;

  private static XMLSubscribe mySelf = null;

  /**
   * This method demonstrates the Nirvana API calls necessary to subscribe to
   * a channel that contains XML messages. It is called after all command line
   * arguments have been received and validated
   *
   * @param realmDetails a String[] containing the possible RNAME values
   * @param achannelName the channel name to create
   * @param selector the subscription selector filter
   * @param startEid the eid to start subscribing from
   * @param loglvl the specified log level
   * @param repCount the specified report count
   */
  private void doit(String[] realmDetails, String achannelName, String selector, int startEid, int loglvl,
      int repCount) {
    logLevel = loglvl;
    reportCount = repCount;

    mySelf.constructSession(realmDetails);

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

      // Obtain the channel reference
      myChannel = mySession.findChannel(nca);

      // if the latest event has been implied (by specifying -1)
      if (startEid == -1) {
        // Get the last eid on the channel and reset the start eid with
        // that value
        starteid = myChannel.getLastEID();
      }

      // Add this object as a subscribe to the channel with the specified
      // message selector
      // and start eid
      myChannel.addSubscriber(this, selector, starteid);

      // Stay subscribed until the user presses any key
      System.out.println("Press any key to quit !");
      BufferedInputStream bis = new BufferedInputStream(System.in);
      try {
        bis.read();
      } catch (Exception read) {
      } // Ignore this

      // Remove this subscriber
      myChannel.removeSubscriber(this);
    }
    // Handle errors
    catch (nChannelNotFoundException cnfe) {
      System.out.println("The channel specified could not be found.");
      System.out.println("Please ensure that the channel 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 channel specified resided in a remote realm which could not be found.");
      System.out.println("Please ensure the channel 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 (nChannelAlreadySubscribedException chase) {
      System.out.println("You are already subscribed to this channel.");
      chase.printStackTrace();
      System.exit(1);
    } catch (nSelectorParserException spe) {
      System.out.println("An error occured while parsing the selector filter specified.");
      System.out.println("Please check the JMS documentation on how to write a valid selector.");
      spe.printStackTrace();
      System.exit(1);
    } catch (nBaseClientException nbce) {
      System.out.println("An error occured while creating the Channel Attributes object.");
      nbce.printStackTrace();
      System.exit(1);
    }
    // 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("START", args[1]);
      case 1:
        if (args[0].equals("-?")) {
          UsageEnv();
        }
        System.getProperties().put("CHANNAME", args[0]);
        break;
    }
  }

  public static void main(String[] args) {

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

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

    // Process Environment Variables
    nSampleApp.processEnvironmentVariables();

    // Check the channel name specified
    String channelName = null;
    if (System.getProperty("CHANNAME") != null) {
      channelName = System.getProperty("CHANNAME");
    } else {
      Usage();
      System.exit(1);
    }

    int startEid = -1; // Default value (points to last event in the channel
    // + 1)
    // Check to see if a start EID value has been specified
    if (System.getProperty("START") != null) {
      try {
        startEid = Integer.parseInt(System.getProperty("START"));
      } catch (Exception num) {
      } // Ignore and use the defaults
    }

    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 for a selector message filter value
    String selector = System.getProperty("SELECTOR");

    // 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);

    // Subscribe to the channel specified
    mySelf.doit(rproperties, channelName, selector, startEid, loglvl, reportCount);
  }

  /**
   * A callback is received by the API to this method each time an event is
   * received from the nirvana channel. Be carefull not to spend too much time
   * processing the message inside this method, as until it exits the next
   * message can not be pushed.
   *
   * @param evt An nConsumeEvent object containing the message received from
   * the channel
   */
  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++;

    // 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
        System.out.println(
            "Received " + reportCount + " in " + (end - startTime) + " Evt/Sec = " + ((reportCount * 1000) / (end
                - startTime)) + " Bytes/sec=" + ((byteCount * 1000) / (end - startTime)));
      }
      // 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()) {
      // If yes, maybe we have missed an event, so print a message on the
      // screen.
      // This message could be printed for a number of other reasons.
      // One of them would be someone purging a range creating an 'eid
      // gap'.
      // As eids are never reused within a channel you could have a
      // situation
      // where this gets printed but nothing is missed.
      System.out.println("Expired event range " + (lastEID) + " - " + (evt.getEventID() - 1));
      // Reset the last eid counter
      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
        try {
          System.out.print("Event data : ");
          if (xh == null) {
            xh = new xmlHelper(evt.getDocument());
          } else {
            xh.setDoc(evt.getDocument());
          }
          xh.dumpDoc();
        } catch (Exception xmlError) {
          System.out.println("\nAn error occured while parsing the XML data contained in the event");
        }
        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("nxmlsub <channel name> [start eid] [debug] [count] [selector] \n");

    System.out.println("<Required Arguments> \n");
    System.out.println("<channel name> - Channel name parameter for the channel to subscribe to");
    System.out.println("\n[Optional Arguments] \n");
    System.out.println("[start eid] - The Event ID to start subscribing from");
    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 XMLSubscribe Class