/* ===========================================================

 * JFreeChart : a free chart library for the Java(tm) platform

 * ===========================================================

 *

 * (C) Copyright 2000-2004, by Object Refinery Limited and Contributors.

 *

 * Project Info:  http://www.jfree.org/jfreechart/index.html

 *

 * This library is free software; you can redistribute it and/or modify it under the terms

 * of the GNU Lesser General Public License as published by the Free Software Foundation;

 * either version 2.1 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;

 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 * See the GNU Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License along with this

 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,

 * Boston, MA 02111-1307, USA.

 *

 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 

 * in the United States and other countries.]

 *

 * --------

 * CSV.java

 * --------

 * (C) Copyright 2003, 2004, by Object Refinery Limited.

 *

 * Original Author:  David Gilbert (for Object Refinery Limited);

 * Contributor(s):   -;

 *

 * $Id: CSV.java,v 1.2 2004/09/08 09:17:16 mungady Exp $

 *

 * Changes

 * -------

 * 24-Nov-2003 : Version 1 (DG);

 *

 */



package org.jfree.data.io;



import java.io.BufferedReader;

import java.io.IOException;

import java.io.Reader;

import java.util.List;



import org.jfree.data.category.CategoryDataset;

import org.jfree.data.category.DefaultCategoryDataset;



/**

 * A utility class for reading {@link CategoryDataset} data from a CSV file.  This initial version

 * is very basic, and won't handle errors in the data file very gracefully.

 */

public class CSV {



    /** The field delimiter. */

    private char fieldDelimiter;

    

    /** The text delimiter. */

    private char textDelimiter;

     

    /** 

     * Creates a new CSV reader where the field delimiter is a comma, and the text delimiter is 

     * a double-quote.

     */

    public CSV() {

        this(',', '"');    

    }

    

    /**

     * Creates a new reader with the specified field and text delimiters.

     * 

     * @param fieldDelimiter  the field delimiter (usually a comma, semi-colon, colon, tab or 

     *        space).

     * @param textDelimiter  the text delimiter (usually a single or double quote).

     */

    public CSV(char fieldDelimiter, char textDelimiter) {

        this.fieldDelimiter = fieldDelimiter;

        this.textDelimiter = textDelimiter;

    }

    

    /**

     * Reads a {@link CategoryDataset} from a CSV file or input source.

     * 

     * @param in  the input source.

     * 

     * @return a category dataset.

     * 

     * @throws IOException if there is an I/O problem.

     */

    public CategoryDataset readCategoryDataset(Reader in) throws IOException {

        

        DefaultCategoryDataset dataset = new DefaultCategoryDataset();

        BufferedReader reader = new BufferedReader(in);

        List columnKeys = null;

        int lineIndex = 0;

        String line = reader.readLine();

        while (line != null) {

            if (lineIndex == 0) {  // first line contains column keys

                columnKeys = extractColumnKeys(line);

            }

            else {  // remaining lines contain a row key and data values

                extractRowKeyAndData(line, dataset, columnKeys);

            }

            line = reader.readLine();

            lineIndex++;

        }

        return dataset;     

         

    }

    

    /**

     * Extracts the column keys from a string.

     * 

     * @param line  a line from the input file.

     * 

     * @return a list of column keys.

     */

    private List extractColumnKeys(String line) {

        List keys = new java.util.ArrayList();

        int fieldIndex = 0;

        int start = 0;

        for (int i = 0; i < line.length(); i++) {

            if (line.charAt(i) == this.fieldDelimiter) {

                if (fieldIndex > 0) {  // first field is ignored, since column 0 is for row keys

                    String key = line.substring(start, i);

                    keys.add(removeStringDelimiters(key));

                }

                start = i + 1;

                fieldIndex++;

            }

        }

        String key = line.substring(start, line.length());

        keys.add(removeStringDelimiters(key));

        return keys;        

    }

    

    /**

     * Extracts the row key and data for a single line from the input source.

     * 

     * @param line  the line from the input source.

     * @param dataset  the dataset to be populated.

     * @param columnKeys  the column keys.

     */

    private void extractRowKeyAndData(String line,

                                      DefaultCategoryDataset dataset,

                                      List columnKeys) {

        Comparable rowKey = null;

        int fieldIndex = 0;

        int start = 0;

        for (int i = 0; i < line.length(); i++) {

            if (line.charAt(i) == this.fieldDelimiter) {

                if (fieldIndex == 0) {  // first field contains the row key

                    String key = line.substring(start, i);

                    rowKey = removeStringDelimiters(key);

                }

                else {  // remaining fields contain values

                    Double value = Double.valueOf(

                        removeStringDelimiters(line.substring(start, i))

                    );

                    dataset.addValue(value, rowKey, (Comparable) columnKeys.get(fieldIndex - 1));

                }

                start = i + 1;

                fieldIndex++;

            }

        }

        Double value = Double.valueOf(

            removeStringDelimiters(line.substring(start, line.length()))

        );

        dataset.addValue(value, rowKey, (Comparable) columnKeys.get(fieldIndex - 1)); 

    }

    

    /**

     * Removes the string delimiters from a key (as well as any white space outside the delimiters).

     * 

     * @param key  the key (including delimiters).

     * 

     * @return the key without delimiters.

     */

    private String removeStringDelimiters(String key) {

        String k = key.trim();

        if (k.charAt(0) == this.textDelimiter) {

            k = k.substring(1);

        }

        if (k.charAt(k.length() - 1) == this.textDelimiter) {

            k = k.substring(0, k.length() - 1);

        }

        return k;

    }

    

}

