/*
 * HL7ServerTest.java
 */

package ca.uhn.hl7v2.app;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PushbackReader;
import java.io.Reader;
import java.net.Socket;
import java.util.ArrayList;
import java.util.GregorianCalendar;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.CommandLineParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.apache.commons.cli.PosixParser;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Helper class used to send messages from a flat file to 
 * an ip and port. 
 * 
 * Messasges are sent using MLLP and ACK protocal
 * 
 * @author Laura Bright
 * @author Neal Acharya
 * 
 * @version $Revision: 1.2 $ updated on $Date: 2009-03-18 23:27:58 $ by $Author: jamesagnew $
 * @deprecated
 */
public class HL7ServerTestHelper {
    
    private static final Logger ourLog = LoggerFactory.getLogger(HL7ServerTestHelper.class);
    
    private static final String HL7_START_OF_MESSAGE = "\u000b";
    private static final String HL7_END_OF_MESSGAE = "\u001c";

    private String host = null;
    
    private int port = 0;

    private Socket socket = null;

    private OutputStream os = null;
    private InputStream is = null;
    
    public HL7ServerTestHelper(String host, int port) {
        this.host = host;
        this.port = port;
    }

    /*
     * 
     */
    public void openSocket() throws IOException{
        socket = new Socket(host, port);
        socket.setSoLinger(true, 1000);
        
        os = socket.getOutputStream();
        is = socket.getInputStream();
    }
    
    /**
     * 
     *
     */
    public void closeSocket() {
        try {
            Socket sckt = socket;
            socket = null;
            if (sckt != null)
                sckt.close();
        }
        catch (Exception e) {
            ourLog.error(e.getMessage(), e);
        }
    }
 
    
    public int process( InputStream theMsgInputStream ) throws FileNotFoundException, IOException
    {
     
        BufferedReader in = null;
        try {
                in = new BufferedReader( 
                        new CommentFilterReader( new InputStreamReader( theMsgInputStream ) )
                    );
                        
                StringBuffer rawMsgBuffer = new StringBuffer();
                
                //String line = in.readLine();
                int c = 0;
                        while( (c = in.read()) >= 0) {
                                rawMsgBuffer.append( (char) c);
                        }
                        
                        String[] messages = getHL7Messages(rawMsgBuffer.toString());
                int retVal = 0;
                
                //start time
                long startTime = new GregorianCalendar().getTimeInMillis(); 
                    
                    
                        for (int i = 0; i < messages.length; i++) {
                                sendMessage(messages[i]);       
                                readAck();      
                    retVal++;
                        }
                
                //end time
                long endTime =  new GregorianCalendar().getTimeInMillis();
                
                //elapsed time
                long elapsedTime = (endTime - startTime) / 1000;
                
                ourLog.info("{} messages sent.", retVal);
                ourLog.info("Elapsed Time in seconds: {} ", elapsedTime);
                return retVal;
        } finally {
                if (in != null) {
                        try {
                                        in.close();
                                } catch (IOException e) {
                                }
                }
        }
                        
        
    }
    
        private String readAck() throws IOException
        {
                StringBuffer stringbuffer = new StringBuffer();
                int i = 0;
                do {
                        i = is.read();
                        if (i == -1)
                                return null;
            
                        stringbuffer.append((char) i);
                }
                while (i != 28);        
                return stringbuffer.toString();
        }
    
    
    
        /** 
         * Given a string that contains HL7 messages, and possibly other junk, 
         * returns an array of the HL7 messages.  
         * An attempt is made to recognize segments even if there is other 
         * content between segments, for example if a log file logs segments 
         * individually with timestamps between them.  
         * 
         * @param theSource a string containing HL7 messages 
         * @return the HL7 messages contained in theSource
         */
        public static String[] getHL7Messages(String theSource) {
                List<String> messages = new ArrayList<String>(20); 
                Pattern startPattern = Pattern.compile("^MSH", Pattern.MULTILINE);
                Matcher startMatcher = startPattern.matcher(theSource);

                while (startMatcher.find()) {
                        String messageExtent = 
                                getMessageExtent(theSource.substring(startMatcher.start()), startPattern);
                        
                        char fieldDelim = messageExtent.charAt(3);
                        Pattern segmentPattern = Pattern.compile("^[A-Z\\d]{3}\\" + fieldDelim + ".*$", Pattern.MULTILINE);
                        Matcher segmentMatcher = segmentPattern.matcher(messageExtent);
                        StringBuffer msg = new StringBuffer();
                        while (segmentMatcher.find()) {
                                msg.append(segmentMatcher.group().trim());
                                msg.append('\r');
                        }
                        messages.add(msg.toString());
                }
                return messages.toArray(new String[0]);
        }
    
        /** 
         * Given a string that contains at least one HL7 message, returns the 
         * smallest string that contains the first of these messages.  
         */
        private static String getMessageExtent(String theSource, Pattern theStartPattern) {
                Matcher startMatcher = theStartPattern.matcher(theSource);
                if (!startMatcher.find()) {
                        throw new IllegalArgumentException(theSource + "does not contain message start pattern" 
                                + theStartPattern.toString());
                }
        
                int start = startMatcher.start();
                int end = theSource.length();
                if (startMatcher.find()) {
                        end = startMatcher.start();
                }
        
                return theSource.substring(start, end).trim();
        }
    
    
    private void sendMessage(String theMessage) throws IOException
    {
        os.write( HL7_START_OF_MESSAGE.getBytes() );
        os.write( theMessage.getBytes() );
        os.write( HL7_END_OF_MESSGAE.getBytes() );
        os.write(13);
        os.flush();
        ourLog.info("Sent: " + theMessage);
    }
     
    
    
    /**
     * Main method for running the application
     * 
     * example command lines args:
     * 
     * -f UHN_PRO_DEV_PATIENTS.dat -h 142.224.178.152 -p 3999
     * 
     */
    public static void main( String[] theArgs ) {

        //parse command line arguments        

        //create the command line parser
        CommandLineParser parser = new PosixParser();

        //create the Options
        Options options = new Options();

        options.addOption("h", "host", true, "IP of host to send to");
        options.addOption("p", "port", true, "port to send to");
        options.addOption("f", "file", true, "file to read HL7 messages from");
        
        CommandLine cmdLine = null;
        try
        {
            // parse the command line arguments
            cmdLine = parser.parse(options, theArgs);
        }
        catch (ParseException e)
        {
            ourLog.error(e.getMessage(), e);
            return;
        }

        String portString = cmdLine.getOptionValue("p");
        int port = 0;
        String host = cmdLine.getOptionValue("h");        
        String file = cmdLine.getOptionValue("f");
        
        if (portString == null || host == null || file == null)
        {
            //automatically generate the help statement
            HelpFormatter formatter = new HelpFormatter();
            //assuming that a shell script named serverTest will be created
            formatter.printHelp( "serverTest", options );
            return;
        }
        else {
            //parse portAsString
            port = Integer.parseInt(portString);
        }
        
        HL7ServerTestHelper serverTest = new HL7ServerTestHelper( host, port );
        
        //InputStream msgInputStream = HL7ServerTestHelper.class.getResourceAsStream( file );
                InputStream msgInputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream(file);          
        try{            
            serverTest.openSocket();
            serverTest.process( msgInputStream );
        }
        catch(Exception e){
                e.printStackTrace();
            HelpFormatter formatter = new HelpFormatter();
            //assuming that a shell script named hl7mom will be created
            formatter.printHelp( "serverTest", options );
            System.exit(-1);
        }
        
        serverTest.closeSocket();
    }
    
        /**
         * TODO: this code is copied from HAPI ... should make it part of HAPI public API instead
         * Removes C and C++ style comments from a reader stream.  C style comments are
         * distinguished from URL protocol delimiters by the preceding colon in the
         * latter.
         */
        public static class CommentFilterReader extends PushbackReader {
        
                private final char[] startCPPComment = {'/', '*'};
                private final char[] endCPPComment = {'*', '/'};
                private final char[] startCComment = {'/', '/'};
                private final char[] endCComment = {'\n'};
                private final char[] protocolDelim = {':', '/', '/'};
        
                public CommentFilterReader(Reader in) {
                        super(in, 5);
                }
        
                /**
                 * Returns the next character, not including comments.
                 */
                public int read() throws IOException {
                        if (atSequence(protocolDelim)) {
                                //proceed normally
                        } else if (atSequence(startCPPComment)) {
                                //skip() doesn't seem to work for some reason
                                while (!atSequence(endCPPComment)) super.read();
                                for (int i = 0; i < endCPPComment.length; i++) super.read();
                        } else if (atSequence(startCComment)) {
                                while (!atSequence(endCComment)) super.read();
                                for (int i = 0; i < endCComment.length; i++) super.read();
                        }
                        int ret = super.read();
                        if (ret == 65535) ret = -1;
                        return ret;            
                }
                
                public int read(char[] cbuf, int off, int len) throws IOException {
                        int i = -1;
                        boolean done = false;
                        while (++i < len) {
                                int next = read();
                                if (next == 65535 || next == -1) { //Pushback causes -1 to convert to 65535
                                        done = true;
                                        break;  
                                }
                                cbuf[off + i] = (char) next;
                        }
                        if (i == 0 && done) i = -1; 
                        return i; 
                }            
        
                /**
                 * Tests incoming data for match with char sequence, resets reader when done.
                 */
                private boolean atSequence(char[] sequence) throws IOException {
                        boolean result = true;
                        int i = -1;
                        int[] data = new int[sequence.length];
                        while (++i < sequence.length && result == true) {
                                data[i] = super.read();
                                if ((char) data[i] != sequence[i]) result = false; //includes case where end of stream reached
                        }
                        for (int j = i-1; j >= 0; j--) {
                                this.unread(data[j]);
                        }
                        return result;
                }        
        }
    

}