/*
 * Copyright 1999-2005 The Apache Software Foundation.
 *
 * Licensed 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.
 */

/* $Id$ */

package org.apache.fop.apps;

// Java
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileFilter;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;

// XML
import org.xml.sax.helpers.DefaultHandler;

// FOP
import org.apache.fop.fo.Constants;
import org.apache.fop.fo.FOTreeBuilder;

/**
 * Primary class that activates the FOP process for both command line
 * and embedded usage.
 * <P>
 * JAXP is the standard method of embedding FOP in Java programs.
 * Please check our embedding page (http://xml.apache.org/fop/embedding.html)
 * for samples (these are also available within the distribution in 
 * FOP_DIR\examples\embedding)
 * <P>
 * Methods within FOUserAgent are available to customize portions of the
 * process.  For example, a specific Renderer object can be specified, 
 * also ElementMappings which determine elements in the FO that can be
 * processed) can be added.
 */
public class Fop implements Constants {

    // desired output type: RENDER_PDF, RENDER_PS, etc.
    private int renderType = NOT_SET;

    // output stream to send results to
    private OutputStream stream = null;

    // FOUserAgent object to set processing options
    private FOUserAgent foUserAgent = null;

    /**
     * Constructor for use with already-created FOUserAgents
     * @param renderType the type of renderer to use.  Must be one of
     * <ul>
     * <li>Fop.RENDER_PDF</li>
     * <li>Fop.RENDER_AWT</li>
     * <li>Fop.RENDER_PRINT</li>
     * <li>Fop.RENDER_MIF</li>
     * <li>Fop.RENDER_XML</li>
     * <li>Fop.RENDER_PCL</li>
     * <li>Fop.RENDER_PS</li>
     * <li>Fop.RENDER_TXT</li>
     * <li>Fop.RENDER_SVG</li>
     * <li>Fop.RENDER_RTF</li>
     * <li>Fop.RENDER_TIFF</li>
     * <li>Fop.RENDER_PNG</li>
     * </ul>
     * @param ua FOUserAgent object
     * @throws IllegalArgumentException if an unsupported renderer type was requested.
     */
    public Fop(int renderType, FOUserAgent ua) {
        if (renderType < Constants.RENDER_MIN_CONST 
            || renderType > Constants.RENDER_MAX_CONST) {
            throw new IllegalArgumentException(
                "Invalid render type #" + renderType);
        }

        this.renderType = renderType;

        foUserAgent = ua;
        if (foUserAgent == null) {
            foUserAgent = new FOUserAgent();
        }
    }

    /**
     * Constructor that creates a default FOUserAgent
     * @see org.apache.fop.apps.Fop#(int, FOUserAgent)
     */
    public Fop(int renderType) {
        this(renderType, new FOUserAgent());
    }

    /**
     * Get the FOUserAgent instance for this process
     * @return the user agent
     */
    public FOUserAgent getUserAgent() {
        return foUserAgent;
    }

    /**
     * Set the OutputStream to use to output the result of the Render
     * (if applicable)
     * @param stream the stream to output the result of rendering to
     */
    public void setOutputStream(OutputStream stream) {
        this.stream = stream;
    }

    /**
     * Returns a DefaultHandler object used to generate the document.
     * Note this object implements the ContentHandler interface.
     * For processing with a Transformer object, this DefaultHandler object
     * can be used in the SAXResult constructor.
     * Alternatively, for processing with a SAXParser, this object can be
     * used as the DefaultHandler argument to its parse() methods.
     *
     * @return a SAX DefaultHandler for handling the SAX events.
     * @throws FOPException if setting up the DefaultHandler fails
     */
    public DefaultHandler getDefaultHandler() throws FOPException {
        return new FOTreeBuilder(renderType, foUserAgent, stream);
    }

    /**
     * @return the list of URLs to all libraries.
     * @throws MalformedURLException In case there is a problem converting java.io.File
     * instances to URLs.
     */
    public static URL[] getJARList() throws MalformedURLException {
        File baseDir = new File(".").getAbsoluteFile().getParentFile();
        File buildDir;
        if ("build".equals(baseDir.getName())) {
            buildDir = baseDir;
            baseDir = baseDir.getParentFile();
        } else {
            buildDir = new File(baseDir, "build");
        }
        File fopJar = new File(buildDir, "fop.jar");
        if (!fopJar.exists()) {
            fopJar = new File(baseDir, "fop.jar");
        }
        if (!fopJar.exists()) {
            throw new RuntimeException("fop.jar not found in directory: " 
                    + baseDir.getAbsolutePath() + " (or below)");
        }
        List jars = new java.util.ArrayList();
        jars.add(fopJar.toURL());
        File[] files;
        FileFilter filter = new FileFilter() {
            public boolean accept(File pathname) {
                return pathname.getName().endsWith(".jar");
            }
        };
        File libDir = new File(baseDir, "lib");
        if (!libDir.exists()) {
            libDir = baseDir;
        }
        files = libDir.listFiles(filter);
        if (files != null) {
            for (int i = 0, size = files.length; i < size; i++) {
                jars.add(files[i].toURL());
            }
        }
        String optionalLib = System.getProperty("fop.optional.lib");
        if (optionalLib != null) {
            files = new File(optionalLib).listFiles(filter);
            if (files != null) {
                for (int i = 0, size = files.length; i < size; i++) {
                    jars.add(files[i].toURL());
                }
            }
        }
        URL[] urls = (URL[])jars.toArray(new URL[jars.size()]);
        /*
        for (int i = 0, c = urls.length; i < c; i++) {
            System.out.println(urls[i]);
        }*/
        return urls;
    }
    
    /**
     * @return true if FOP's dependecies are available in the current ClassLoader setup.
     */
    public static boolean checkDependencies() {
        try {
            //System.out.println(Thread.currentThread().getContextClassLoader());
            Class clazz = Class.forName("org.apache.batik.Version");
            if (clazz != null) {
                clazz = Class.forName("org.apache.avalon.framework.configuration.Configuration");
            }
            return (clazz != null);
        } catch (Exception e) {
            return false;
        }
    }
    
    /**
     * Dynamically builds a ClassLoader and executes FOP.
     * @param args command-line arguments
     */
    public static void startFOPWithDynamicClasspath(String[] args) {
        try {
            URL[] urls = getJARList();
            //System.out.println("CCL: " 
            //    + Thread.currentThread().getContextClassLoader().toString());
            ClassLoader loader = new java.net.URLClassLoader(urls, null);
            Thread.currentThread().setContextClassLoader(loader);
            Class clazz = Class.forName("org.apache.fop.apps.Fop", true, loader);
            //System.out.println("CL: " + clazz.getClassLoader().toString());
            Method mainMethod = clazz.getMethod("startFOP", new Class[] {String[].class});
            mainMethod.invoke(null, new Object[] {args});
        } catch (Exception e) {
            System.err.println("Unable to start FOP:");
            e.printStackTrace();
            System.exit(-1);
        }
    }
    
    /**
     * Executes FOP with the given ClassLoader setup.
     * @param args command-line arguments
     */
    public static void startFOP(String[] args) {
        //System.out.println("static CCL: " 
        //    + Thread.currentThread().getContextClassLoader().toString());
        //System.out.println("static CL: " + Fop.class.getClassLoader().toString());
        CommandLineOptions options = null;
        FOUserAgent foUserAgent = null;
        BufferedOutputStream bos = null;

        try {
            options = new CommandLineOptions();
            options.parse(args);
            foUserAgent = options.getFOUserAgent();
            
            Fop fop = new Fop(options.getRenderer(), foUserAgent);

            try {
                if (options.getOutputFile() != null) {
                    bos = new BufferedOutputStream(new FileOutputStream(
                        options.getOutputFile()));
                    fop.setOutputStream(bos);
                    foUserAgent.setOutputFile(options.getOutputFile());
                }
                foUserAgent.getInputHandler().render(fop);
             } finally {
                 if (bos != null) {
                     bos.close();
                 }
             }

            // System.exit(0) called to close AWT/SVG-created threads, if any.
            // AWTRenderer closes with window shutdown, so exit() should not
            // be called here
            if (options.getOutputMode() != CommandLineOptions.RENDER_AWT) {
                System.exit(0);
            }
        } catch (Exception e) {
            if (options != null) {
                options.getLogger().error("Exception", e);
            }
            System.exit(1);
        }
    }
    
    /**
     * The main routine for the command line interface
     * @param args the command line parameters
     */
    public static void main(String[] args) {
        if (checkDependencies()) {
            startFOP(args);
        } else {
            startFOPWithDynamicClasspath(args);
        }
    }


    /**
     * Get the version of FOP
     * @return the version string
     */
    public static String getVersion() {
        return "1.0dev";
    }
}