/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* $Id: MultipleFO2PDF.java 1804125 2017-08-04 14:15:05Z ssteiner $ */

package embedding;

// Java
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.stream.StreamSource;

import org.apache.commons.io.IOUtils;

import org.apache.fop.apps.FOPException;
import org.apache.fop.apps.FOUserAgent;
import org.apache.fop.apps.Fop;
import org.apache.fop.apps.FopFactory;
import org.apache.fop.apps.FormattingResults;
import org.apache.fop.apps.MimeConstants;
import org.apache.fop.apps.PageSequenceResults;

/**
 * This class demonstrates the conversion of multiple FO files to PDF using FOP.
 * The FopFactory is reused. Its configuration is applied to each rendering run.
 * The FOUserAgent and Fop are newly created by the FopFactory for each run.
 * The FOUserAgent can be configured differently for each run.
 */
public class MultipleFO2PDF {

    // configure fopFactory as desired
    // JAXP TransformerFactory can be reused, too
    private TransformerFactory factory = TransformerFactory.newInstance();

    /**
     * Converts an FO file to a PDF file using FOP
     * @param fo the FO file
     * @param pdf the target PDF file
     * @throws TransformerException in case of a transformation problem
     * @throws IOException in case of an I/O problem
     * @throws FOPException in case of a FOP problem
     * @return the formatting results of the run
     */
    public FormattingResults convertFO2PDF(File fo, File pdf)
        throws TransformerException, IOException, FOPException {
        FopFactory fopFactory = FopFactory.newInstance(new File(".").toURI());

        OutputStream out = null;
        Fop fop;

        try {
            FOUserAgent foUserAgent = fopFactory.newFOUserAgent();
            // configure foUserAgent as desired

            // Setup output stream.  Note: Using BufferedOutputStream
            // for performance reasons (helpful with FileOutputStreams).
            out = new FileOutputStream(pdf);
            out = new BufferedOutputStream(out);

            // Construct fop with desired output format and output stream
            fop = fopFactory.newFop(MimeConstants.MIME_PDF, foUserAgent, out);

            // Setup JAXP using identity transformer
            Transformer transformer = factory.newTransformer(); // identity transformer

            // Setup input stream
            Source src = new StreamSource(fo);

            // Resulting SAX events (the generated FO) must be piped through to FOP
            Result res = new SAXResult(fop.getDefaultHandler());

            // Start XSLT transformation and FOP processing
            transformer.transform(src, res);
        } finally {
            IOUtils.closeQuietly(out);
        }

        return fop.getResults();
    }

    /**
     * Listens on standard in for names of fo files to be transformed to pdf.
     * 'quit' or the null string (for piped input) cause the listener to stop listening.
     */
    public void listen() {

        //Setup directories
        File baseDir = new File(".");
        File outDir = new File(baseDir, "out");
        outDir.mkdirs();
        BufferedReader in = new BufferedReader(new java.io.InputStreamReader(System.in));

        while (true) {
            try {
                // Listen for the input file name
                System.out.print("Input XSL-FO file ('quit' to stop): ");
                String foname = in.readLine();
                if (foname == null) {
                    System.out.println("Null input, quitting");
                    return;
                }
                foname.trim();
                if (foname.equals("quit")) {
                    System.out.println("Quitting");
                    return;
                }
                File fofile = new File(baseDir, foname);
                String pdfname = foname;
                int p = foname.lastIndexOf('.');
                pdfname = foname.substring(0, p) + ".pdf";
                File pdffile = new File(outDir, pdfname);

                // transform and render
                System.out.print("Transforming " + fofile + " to PDF file " + pdffile + "...");
                FormattingResults foResults = convertFO2PDF(fofile, pdffile);
                System.out.println("done!");

                // Result processing
                java.util.List pageSequences = foResults.getPageSequences();
                for (Object pageSequence : pageSequences) {
                    PageSequenceResults pageSequenceResults = (PageSequenceResults) pageSequence;
                    System.out.println("PageSequence "
                            + (String.valueOf(pageSequenceResults.getID()).length() > 0
                            ? pageSequenceResults.getID() : "<no id>")
                            + " generated " + pageSequenceResults.getPageCount() + " pages.");
                }
                System.out.println("Generated " + foResults.getPageCount() + " pages in total.");

            } catch (Exception e) {
                System.out.println("failure!");
                e.printStackTrace(System.out);
            } finally {
                System.out.println("");
            }
        }
    }

    /**
     * Main method. Set up the listener.
     * @param args command-line arguments
     */
    public static void main(String[] args) {
        System.out.println("FOP MultipleFO2PDF\n");
        System.out.println("Preparing...");
        MultipleFO2PDF m = new MultipleFO2PDF();
        m.listen();
    }

}
