/*

  * Created on 21-Apr-2004

  */

 package ca.uhn.hl7v2.protocol.impl;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.List;

 import java.util.StringTokenizer;

 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 import ca.uhn.hl7v2.HL7Exception;

 import ca.uhn.hl7v2.model.Message;

 import ca.uhn.hl7v2.parser.Parser;

 /**

  * A debugging utility that logs raw messages and parsed/encoded versions, and warnings about 

  * apparent discrepancies between them.  This information is all logged to HapiLog under 

  * the name of this class, at the "info" level.  

  * 

  * @author <a href="mailto:bryan.tripp@uhn.on.ca">Bryan Tripp</a>

  * @version $Revision: 1.1 $ updated on $Date: 2007-02-19 02:24:26 $ by $Author: jamesagnew $

  */

 public class ParseChecker {

     private static final Logger log = LoggerFactory.getLogger(ParseChecker.class);

     /**

      * Encodes the given message and compares it to the given string.  Any differences

      * are noted in the file [hapi.home]/parse_check.txt.  Ignores extra field delimiters.

      */

     public static void checkParse(String originalMessageText, Message parsedMessage, Parser parser)

             throws HL7Exception, IOException {

         log.info("ParseChecker is checking parse integrity (turn this off if you are not testing)");

         String newMessageText = parser.encode(parsedMessage);

         log.info("******************* Comparing Messages ****************\r\n");

         log.info("Original:           {}", originalMessageText);

         log.info("Parsed and Encoded: {}", newMessageText);

         if (!originalMessageText.equals(newMessageText)) {

             //check each segment

             StringTokenizer tok = new StringTokenizer(originalMessageText, "\r");

             List<String> one = new ArrayList<String>();

             while (tok.hasMoreTokens()) {

                 String seg = tok.nextToken();

                 if (seg.length() > 4)

                     one.add(seg);

             }

             tok = new StringTokenizer(newMessageText, "\r");

             List<String> two = new ArrayList<String>();

             while (tok.hasMoreTokens()) {

                 String seg = tok.nextToken();

                 if (seg.length() > 4)

                     two.add(stripExtraDelimiters(seg, seg.charAt(3)));

             }

             if (one.size() != two.size()) {

                 log.info("Warning: inbound and parsed messages have different numbers of segments: \r\n");

                 log.info("Original: {}", originalMessageText);

                 log.info("Parsed:   {}", newMessageText);

             }

             else {

                 //check each segment

                 for (int i = 0; i < one.size(); i++) {

                     String origSeg = one.get(i);

                     String newSeg = two.get(i);

                     if (!origSeg.equals(newSeg)) {

                         log.info("Warning: inbound and parsed message segment differs: \r\n");

                         log.info("Original: {}", origSeg);

                         log.info("Parsed:   {}", newSeg);

                     }

                 }

             }

         }

         else {

             log.info("No differences found");

         }

         log.info("********************  End Comparison  ******************\r\n");

     }

     /**

      * Removes unecessary delimiters from the end of a field or segment.

      * This is cut-and-pasted from PipeParser (just making it public in

      * PipeParser would kind of cloud the purpose of PipeParser).

      */

     private static String stripExtraDelimiters(String in, char delim) {

         char[] chars = in.toCharArray();

         //search from back end for first occurance of non-delimiter ...

         int c = chars.length - 1;

         boolean found = false;

         while (c >= 0 && !found) {

             if (chars[c--] != delim)

                 found = true;

         }

         String ret = "";

         if (found)

             ret = String.valueOf(chars, 0, c + 2);

         return ret;

     }

 }