/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-present, by David Gilbert 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
 * Other names may be trademarks of their respective owners.]
 *
 * ----------------------------
 * StandardPieURLGenerator.java
 * ----------------------------
 * (C) Copyright 2002-present, by Richard Atkinson and Contributors.
 *
 * Original Author:  Richard Atkinson;
 * Contributors:     David Gilbert;
 *
 */

package org.jfree.chart.urls;

import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Objects;

import org.jfree.chart.util.Args;
import org.jfree.data.general.PieDataset;

/**
 * A URL generator for pie charts.  Instances of this class are immutable.
 */
public class StandardPieURLGenerator implements PieURLGenerator, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = 1626966402065883419L;

    /** The prefix. */
    private String prefix = "index.html";

    /** The category parameter name. */
    private String categoryParamName = "category";

    /** The pie index parameter name. */
    private String indexParamName = "pieIndex";

    /**
     * Default constructor.
     */
    public StandardPieURLGenerator() {
        this("index.html");
    }

    /**
     * Creates a new generator.
     *
     * @param prefix  the prefix ({@code null} not permitted).
     */
    public StandardPieURLGenerator(String prefix) {
        this(prefix, "category");
    }

    /**
     * Creates a new generator.
     *
     * @param prefix  the prefix ({@code null} not permitted).
     * @param categoryParamName  the category parameter name ({@code null} not 
     *         permitted).
     */
    public StandardPieURLGenerator(String prefix, String categoryParamName) {
        this(prefix, categoryParamName, "pieIndex");
    }

    /**
     * Creates a new generator.
     *
     * @param prefix  the prefix ({@code null} not permitted).
     * @param categoryParamName  the category parameter name ({@code null} not 
     *         permitted).
     * @param indexParamName  the index parameter name ({@code null} permitted).
     */
    public StandardPieURLGenerator(String prefix, String categoryParamName,
            String indexParamName) {
        Args.nullNotPermitted(prefix, "prefix");
        Args.nullNotPermitted(categoryParamName, "categoryParamName");
        this.prefix = prefix;
        this.categoryParamName = categoryParamName;
        this.indexParamName = indexParamName;
    }

    /**
     * Generates a URL.
     *
     * @param dataset  the dataset (ignored).
     * @param key  the item key ({@code null} not permitted).
     * @param pieIndex  the pie index.
     *
     * @return A string containing the generated URL.
     */
    @Override
    public String generateURL(PieDataset dataset, Comparable key,
            int pieIndex) {
        String url = this.prefix;
        try {
            if (url.contains("?")) {
                url += "&amp;" + this.categoryParamName + "="
                        + URLEncoder.encode(key.toString(), "UTF-8");
            } else {
                url += "?" + this.categoryParamName + "="
                        + URLEncoder.encode(key.toString(), "UTF-8");
            }
            if (this.indexParamName != null) {
                url += "&amp;" + this.indexParamName + "=" + pieIndex;
            }
        } catch (UnsupportedEncodingException e) {  // this won't happen :)
            throw new RuntimeException(e);
        }
        return url;
    }

    /**
     * Tests if this object is equal to another.
     *
     * @param obj  the object ({@code null} permitted).
     *
     * @return A boolean.
     */
    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof StandardPieURLGenerator)) {
            return false;
        }
        StandardPieURLGenerator that = (StandardPieURLGenerator) obj;
        if (!this.prefix.equals(that.prefix)) {
            return false;
        }
        if (!this.categoryParamName.equals(that.categoryParamName)) {
            return false;
        }
        if (!Objects.equals(this.indexParamName, that.indexParamName)) {
            return false;
        }
        return true;
    }
}
