/*
 *
 * This file is part of the iText (R) project.
    Copyright (c) 1998-2017 iText Group NV
 * Authors: Bruno Lowagie, Kevin Day, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS
 *
 * This program 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 Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * a covered work must retain the producer line in every PDF that is created
 * or manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
 *
 * For more information, please contact iText Software Corp. at this
 * address: sales@itextpdf.com
 */
package com.itextpdf.text.pdf.parser;

import java.io.IOException;

import com.itextpdf.text.pdf.PdfDictionary;
import com.itextpdf.text.pdf.PdfName;
import com.itextpdf.text.pdf.PdfReader;

import java.util.HashMap;
import java.util.Map;

/**
 * A utility class that makes it cleaner to process content from pages of a PdfReader
 * through a specified RenderListener.
 * @since 5.0.2
 */
public class PdfReaderContentParser {
    /** the reader this parser will process */
    private final PdfReader reader;
    
    public PdfReaderContentParser(PdfReader reader) {
        this.reader = reader;
    }
    
    /**
     * Processes content from the specified page number using the specified listener.
     * Also allows registration of custom ContentOperators
     * @param <E> the type of the renderListener - this makes it easy to chain calls
     * @param pageNumber the page number to process
     * @param renderListener the listener that will receive render callbacks
     * @param additionalContentOperators an optional map of custom ContentOperators for rendering instructions
     * @return the provided renderListener
     * @throws IOException if operations on the reader fail
     */
    
    public <E extends RenderListener> E processContent(int pageNumber, E renderListener, Map<String, ContentOperator> additionalContentOperators) throws IOException{
        PdfDictionary pageDic = reader.getPageN(pageNumber);
        PdfDictionary resourcesDic = pageDic.getAsDict(PdfName.RESOURCES);
        
        PdfContentStreamProcessor processor = new PdfContentStreamProcessor(renderListener);
        for(Map.Entry<String, ContentOperator> entry : additionalContentOperators.entrySet()) {
            processor.registerContentOperator(entry.getKey(), entry.getValue());
        }
        processor.processContent(ContentByteUtils.getContentBytesForPage(reader, pageNumber), resourcesDic);        
        return renderListener;

    }
    
    /**
     * Processes content from the specified page number using the specified listener
     * @param <E> the type of the renderListener - this makes it easy to chain calls
     * @param pageNumber the page number to process
     * @param renderListener the listener that will receive render callbacks
     * @return the provided renderListener
     * @throws IOException if operations on the reader fail
     *
     * @link PdfReaderContentParser#processContent(int, E, Map)
     * {@code map} defaults to null.
     */
    public <E extends RenderListener> E processContent(int pageNumber, E renderListener) throws IOException{
        return processContent(pageNumber, renderListener, new HashMap<String, ContentOperator>());
    }
}
