package com.fsenablers.io;

import java.io.*;
import java.util.regex.*;

public class MultilineReader {
	
	private BufferedReader bufferedReader;
	private String preReadLine;
	private Pattern lineRegExPattern;
	
	public MultilineReader( BufferedReader reader, String lineRegExStr ) {
		bufferedReader = reader;
		lineRegExPattern = Pattern.compile( lineRegExStr );
	}
	
	public String readLine() throws IOException {
		
		String line = null;
		boolean done = false;
		StringBuffer lineOfText = new StringBuffer();
		
		// use any previously read line part
		if( preReadLine != null ) {
			lineOfText.append( preReadLine );
			preReadLine = null;
		}
		
		do {
			
			String currentLine = bufferedReader.readLine();
			if( currentLine == null ) {
				if( lineOfText.length() > 0 ) {
					line = lineOfText.toString();
				} 
				done = true;
			} else {
				
				if( lineRegExPattern.matcher( currentLine ).matches() ) {
					// matches the pattern for a new line
					if( lineOfText.length() > 0 ) {
						// current line ended
						preReadLine = currentLine;
						line = lineOfText.toString();
						done = true;
					} else {
						// start of new line
						lineOfText.append( currentLine );
					}
				} else { 
					// append to existing line
					if( lineOfText.length() > 0  ) {
						lineOfText.append( "\r\n" );
					}
					lineOfText.append( currentLine );
				}
				
			}
			
			
		} while( !done );
		
		return line;
			
	}
	
	public void close() throws IOException {
		bufferedReader.close();
	}
	
	
	public static void main( String[] args ) throws Exception{
		
		String filePath = "X:\\_devteam\\chris\\US_20140627131944.txt";
		// BufferedReader reader = new BufferedReader( new FileReader( "X:\\_devteam\\chris\\US_20140627131944.txt" ));
		
		if( 1 == 2 ) {
			String encoding = null;
			
			// In order to read files with non-default encoding, specify an encoding in the FileInputStream constructor.
			BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(new FileInputStream(filePath)));

			char buffer[] = new char[3];
			int length = bufferedReader.read(buffer);

			if (length >= 2) {
			if ((buffer[0] == (char) 0xff && buffer[1] == (char) 0xfe) /* UTF-16, little endian */ || 
			    (buffer[0] == (char) 0xfe && buffer[1] == (char) 0xff) /* UTF-16, big endian */) {
				encoding = "UTF16";
			}
			}
			if (length >= 3) {
				if (buffer[0] == (char) 0xef && buffer[1] == (char) 0xbb && buffer[2] == (char) 0xbf) /* UTF-8 */  {
				encoding = "UTF8";
				}
			}

			bufferedReader.close();
	

			System.out.println( "Encoding = " + encoding );
			
			BufferedReader reader = new BufferedReader( new InputStreamReader( new FileInputStream( filePath ), encoding ));

			
		}
	
		BufferedReader reader = new BufferedReader( new FileReader( "X:\\_devteam\\chris\\US_20140627131944.txt" ));

		char buffer[] = new char[3];
		int length = reader.read(buffer);

		String rx1 = "^CANADA.*|^US.*";
		String rx2 = ".*";
		MultilineReader mlr = new MultilineReader( reader, rx1 );
		
		String line = mlr.readLine();
		int lineCount = 0;
		while( line != null) {
			System.out.println( "START");
			System.out.println( line );
			System.out.println( "END" );
			System.out.println();
			line = mlr.readLine();
			lineCount++;
			
			if( lineCount == 3 ) {
				break;
			}
		}
		
		mlr.close();
	}
	
	
}