/*******************************************************************************
 * Copyright (c) 2012 Original authors and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Original authors and others - initial API and implementation
 ******************************************************************************/
package org.eclipse.nebula.widgets.nattable.dataset.pricing;

import java.io.FilterReader;
import java.io.IOException;
import java.io.PushbackReader;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;

public class DelimitedFileReader extends FilterReader {
    private char delimChar;
    private StringTokenizer tabbedLineRead;

    DelimitedFileReader(Reader reader, char delimeter) {
        super(reader);
        this.delimChar = delimeter;
    }

    /**
     * This method will read until it finds a return character.
     */
    @Override
    public int read() throws IOException {
        return readLine(new char[1], 0, 1);
    }

    @Override
    public int read(char[] cbuf, int off, int len) throws IOException {
        return readLine(cbuf, off, len);
    }

    /**
     * Return when a line is read. The line can then be processed by accessing
     * the tabbedLineRead tokenizer. The tokenzier is built using the delimChar
     * 
     * @param readBuffer
     * @param off
     * @param len
     * @return
     * @throws IOException
     */
    private int readLine(char[] readBuffer, int off, int len)
            throws IOException {
        int read = -1;
        boolean hasLineBeenRead = false;
        if (tabbedLineRead != null) {
            in.reset();
        }
        char prevChar = delimChar;
        List<Character> charBuffer = new ArrayList<Character>();
        PushbackReader pushBackReader = new PushbackReader(in, len);
        while ((read = pushBackReader.read(readBuffer, off, len)) >= 0) {
            // Read until new line is found. This allows users to handle line by
            // line.
            for (int charIndex = 0; charIndex < readBuffer.length; charIndex++) {
                char readChar = readBuffer[charIndex];
                if (readChar == '\n') {
                    in.mark(read);
                    pushBackReader.unread(readBuffer, 0, readBuffer.length
                            - (charIndex + 1));
                    hasLineBeenRead = true;
                    break;
                } else {
                    if (readChar == delimChar && delimChar == prevChar) {
                        charBuffer.add(Character.valueOf(' '));
                    }
                    prevChar = readChar;
                    charBuffer.add(Character.valueOf(readChar));
                }
            }
            // If line has been read, return control to caller
            if (hasLineBeenRead) {
                hasLineBeenRead = false;
                break;
            }
        }
        if (read >= 0) {
            tabbedLineRead = new StringTokenizer(
                    parseCharactersToString(charBuffer),
                    String.valueOf(delimChar));
        }
        return read;
    }

    public StringTokenizer getTabbedLineRead() {
        return tabbedLineRead;
    }

    private String parseCharactersToString(List<Character> chars) {
        char[] dataRead = new char[chars.size()];
        int charCounter = 0;
        for (char charRead : chars) {
            dataRead[charCounter++] = charRead;
        }

        return new String(dataRead);
    }
}