/*
 * $Id$
 * Copyright (C) 2001-2003 The Apache Software Foundation. All rights reserved.
 * For details on use and redistribution please refer to the
 * LICENSE file included with these sources.
 */

package org.apache.fop.apps;

// FOP
import org.apache.fop.fo.ElementMapping;
import org.apache.fop.fo.FOTreeBuilder;
import org.apache.fop.fo.FOUserAgent;
import org.apache.fop.render.Renderer;
import org.apache.fop.tools.DocumentInputSource;
import org.apache.fop.tools.DocumentReader;


// Avalon
import org.apache.avalon.framework.logger.ConsoleLogger;
import org.apache.avalon.framework.logger.LogEnabled;
import org.apache.avalon.framework.logger.Logger;

// DOM
import org.w3c.dom.Document;

// SAX
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import javax.xml.parsers.ParserConfigurationException;

// Java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;

/**
 * Primary class that drives overall FOP process.
 * <P>
 * The simplest way to use this is to instantiate it with the
 * InputSource and OutputStream, then set the renderer desired, and
 * calling run();
 * <P>
 * Here is an example use of Driver which outputs PDF:
 *
 * <PRE>
 * Driver driver = new Driver(new InputSource (args[0]),
 * new FileOutputStream(args[1]));
 * driver.enableLogging(myLogger); //optional
 * driver.setRenderer(RENDER_PDF);
 * driver.run();
 * </PRE>
 * If neccessary, calling classes can call into the lower level
 * methods to setup and
 * render. Methods can be called to set the
 * Renderer to use, the (possibly multiple) ElementMapping(s) to
 * use and the OutputStream to use to output the results of the
 * rendering (where applicable). In the case of the Renderer and
 * ElementMapping(s), the Driver may be supplied either with the
 * object itself, or the name of the class, in which case Driver will
 * instantiate the class itself. The advantage of the latter is it
 * enables runtime determination of Renderer and ElementMapping(s).
 * <P>
 * Once the Driver is set up, the render method
 * is called. Depending on whether DOM or SAX is being used, the
 * invocation of the method is either render(Document) or
 * buildFOTree(Parser, InputSource) respectively.
 * <P>
 * A third possibility may be used to build the FO Tree, namely
 * calling getContentHandler() and firing the SAX events yourself.
 * <P>
 * Once the FO Tree is built, the format() and render() methods may be
 * called in that order.
 * <P>
 * Here is an example use of Driver which outputs to AWT:
 *
 * <PRE>
 * Driver driver = new Driver();
 * driver.enableLogging(myLogger); //optional
 * driver.setRenderer(new org.apache.fop.render.awt.AWTRenderer(translator));
 * driver.render(parser, fileInputSource(args[0]));
 * </PRE>
 */
public class Driver implements LogEnabled {

    /**
     * Render to PDF. OutputStream must be set
     */
    public static final int RENDER_PDF = 1;

    /**
     * Render to a GUI window. No OutputStream neccessary
     */
    public static final int RENDER_AWT = 2;

    /**
     * Render to MIF. OutputStream must be set
     */
    public static final int RENDER_MIF = 3;

    /**
     * Render to XML. OutputStream must be set
     */
    public static final int RENDER_XML = 4;

    /**
     * Render to PRINT. No OutputStream neccessary
     */
    public static final int RENDER_PRINT = 5;

    /**
     * Render to PCL. OutputStream must be set
     */
    public static final int RENDER_PCL = 6;

    /**
     * Render to Postscript. OutputStream must be set
     */
    public static final int RENDER_PS = 7;

    /**
     * Render to Text. OutputStream must be set
     */
    public static final int RENDER_TXT = 8;

    /**
     * Render to SVG. OutputStream must be set
     */
    public static final int RENDER_SVG = 9;

    /**
     * Render to RTF. OutputStream must be set
     */
    public static final int RENDER_RTF = 10;

    /**
     * the FO tree builder
     */
    private FOTreeBuilder treeBuilder;

    /**
     * the renderer type code given by setRenderer
     */
    private int rendererType;

    /**
     * the renderer to use to output the area tree
     */
    private Renderer renderer;

    /**
     * the structure handler
     */
    private StructureHandler structHandler;

    /**
     * the source of the FO file
     */
    private InputSource source;

    /**
     * the stream to use to output the results of the renderer
     */
    private OutputStream stream;

    /**
     * The XML parser to use when building the FO tree
     */
    private XMLReader reader;

    /**
     * the system resources that FOP will use
     */
    private Logger log = null;
    private FOUserAgent userAgent = null;

    public static final String getParserClassName() {
        try {
            return javax.xml.parsers.SAXParserFactory.newInstance()
                .newSAXParser().getXMLReader().getClass().getName();
        } catch (javax.xml.parsers.ParserConfigurationException e) {
            return null;
        } catch (org.xml.sax.SAXException e) {
            return null;
        }
    }

    /**
     * create a new Driver
     */
    public Driver() {
        stream = null;
    }

    public Driver(InputSource source, OutputStream stream) {
        this();
        this.source = source;
        this.stream = stream;
    }

    public void initialize() {
        stream = null;
        treeBuilder = new FOTreeBuilder();
        treeBuilder.setUserAgent(getUserAgent());
        setupDefaultMappings();
    }

    public void setUserAgent(FOUserAgent agent) {
        userAgent = agent;
    }

    private FOUserAgent getUserAgent() {
        if (userAgent == null) {
            userAgent = new FOUserAgent();
            userAgent.enableLogging(getLogger());
            userAgent.setBaseURL("");
        }
        return userAgent;
    }

    public void enableLogging(Logger log) {
        if (this.log == null) {
            this.log = log;
        } else {
            getLogger().warn("Logger is already set! Won't use the new logger.");
        }
    }


    protected Logger getLogger() {
        if (this.log == null) {
            this.log = new ConsoleLogger(ConsoleLogger.LEVEL_INFO);
            this.log.error("Logger not set. Using ConsoleLogger as default.");
        }

        return this.log;
    }

    /**
     * Resets the Driver so it can be reused. Property and element
     * mappings are reset to defaults.
     * The output stream is cleared. The renderer is cleared.
     */
    public synchronized void reset() {
        source = null;
        stream = null;
        reader = null;
        treeBuilder.reset();
    }

    public boolean hasData() {
        return (treeBuilder.hasData());
    }

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

    /**
     * Set the source for the FO document. This can be a normal SAX
     * InputSource, or an DocumentInputSource containing a DOM document.
     * @see DocumentInputSource
     */
    public void setInputSource(InputSource source) {
        this.source = source;
    }

    /**
     * Sets the reader used when reading in the source. If not set,
     * this defaults to a basic SAX parser.
     * @param reader the reader to use.
     */
    public void setXMLReader(XMLReader reader) {
        this.reader = reader;
    }

    /**
     * Sets all the element and property list mappings to their default values.
     *
     */
    public void setupDefaultMappings() {
        addElementMapping("org.apache.fop.fo.FOElementMapping");
        addElementMapping("org.apache.fop.svg.SVGElementMapping");
        addElementMapping("org.apache.fop.extensions.ExtensionElementMapping");

        // add mappings from available services
        Enumeration providers =
            Service.providers(org.apache.fop.fo.ElementMapping.class);
        if (providers != null) {
            while (providers.hasMoreElements()) {
                String str = (String)providers.nextElement();
                try {
                    addElementMapping(str);
                } catch (IllegalArgumentException e) {
                }

            }
        }
    }

    /**
     * Shortcut to set the rendering type to use. Must be one of
     * <ul>
     * <li>RENDER_PDF</li>
     * <li>RENDER_AWT</li>
     * <li>RENDER_MIF</li>
     * <li>RENDER_XML</li>
     * <li>RENDER_PCL</li>
     * <li>RENDER_PS</li>
     * <li>RENDER_TXT</li>
     * <li>RENDER_SVG</li>
     * <li>RENDER_RTF</li>
     * </ul>
     * @param renderer the type of renderer to use
     * @throws IllegalArgumentException if an unsupported renderer type was required.
     */
    public void setRenderer(int renderer) throws IllegalArgumentException {
        rendererType = renderer;
        switch (renderer) {
        case RENDER_PDF:
            setRenderer("org.apache.fop.render.pdf.PDFRenderer");
            break;
        case RENDER_AWT:
            throw new IllegalArgumentException("Use renderer form of setRenderer() for AWT");
        case RENDER_PRINT:
            throw new IllegalArgumentException("Use renderer form of setRenderer() for PRINT");
        case RENDER_PCL:
            setRenderer("org.apache.fop.render.pcl.PCLRenderer");
            break;
        case RENDER_PS:
            setRenderer("org.apache.fop.render.ps.PSRenderer");
            break;
        case RENDER_TXT:
            setRenderer("org.apache.fop.render.txt.TXTRenderer()");
            break;
        case RENDER_MIF:
            //structHandler will be set later
            break;
        case RENDER_XML:
            setRenderer("org.apache.fop.render.xml.XMLRenderer");
            break;
        case RENDER_SVG:
            setRenderer("org.apache.fop.render.svg.SVGRenderer");
            break;
        case RENDER_RTF:
            //structHandler will be set later
            break;
        default:
            throw new IllegalArgumentException("Unknown renderer type");
        }
    }

    /**
     * Set the Renderer to use.
     * @param renderer the renderer instance to use (Note: Logger must be set at this point)
     */
    public void setRenderer(Renderer renderer) {
        renderer.setUserAgent(getUserAgent());
        this.renderer = renderer;
    }

    public Renderer getRenderer() {
        return renderer;
    }

    /**
     * @deprecated use renderer.setProducer(version) + setRenderer(renderer) or just setRenderer(rendererType) which will use the default producer string.
     * @see #setRenderer(int)
     * @see #setRenderer(Renderer)
     */
    public void setRenderer(String rendererClassName, String version) {
        setRenderer(rendererClassName);
    }

    /**
     * Set the class name of the Renderer to use as well as the
     * producer string for those renderers that can make use of it.
     * @param rendererClassName classname of the renderer to use such as
     * "org.apache.fop.render.pdf.PDFRenderer"
     * @exception IllegalArgumentException if the classname was invalid.
     * @see #setRenderer(int)
     */
    public void setRenderer(String rendererClassName)
    throws IllegalArgumentException {
        try {
            renderer =
                (Renderer)Class.forName(rendererClassName).newInstance();
            if (renderer instanceof LogEnabled) {
                ((LogEnabled)renderer).enableLogging(getLogger());
            }
            renderer.setProducer(Version.getVersion());
            renderer.setUserAgent(getUserAgent());
        } catch (ClassNotFoundException e) {
            throw new IllegalArgumentException("Could not find "
                                               + rendererClassName);
        } catch (InstantiationException e) {
            throw new IllegalArgumentException("Could not instantiate "
                                               + rendererClassName);
        } catch (IllegalAccessException e) {
            throw new IllegalArgumentException("Could not access "
                                               + rendererClassName);
        } catch (ClassCastException e) {
            throw new IllegalArgumentException(rendererClassName
                                               + " is not a renderer");
        }
    }

    /**
     * Add the given element mapping.
     * An element mapping maps element names to Java classes.
     *
     * @param mapping the element mappingto add
     */
    public void addElementMapping(ElementMapping mapping) {
        mapping.addToBuilder(treeBuilder);
    }

    /**
     * Add the element mapping with the given class name.
     * @param the class name representing the element mapping.
     * @throws IllegalArgumentException if there was not such element mapping.
     */
    public void addElementMapping(String mappingClassName)
        throws IllegalArgumentException {
        try {
            ElementMapping mapping =
                (ElementMapping)Class.forName(mappingClassName).newInstance();
            addElementMapping(mapping);
        } catch (ClassNotFoundException e) {
            throw new IllegalArgumentException("Could not find "
                                               + mappingClassName);
        } catch (InstantiationException e) {
            throw new IllegalArgumentException("Could not instantiate "
                                               + mappingClassName);
        } catch (IllegalAccessException e) {
            throw new IllegalArgumentException("Could not access "
                                               + mappingClassName);
        } catch (ClassCastException e) {
            throw new IllegalArgumentException(mappingClassName
                                               + " is not an ElementMapping");
        }
    }

    /**
     * Returns the tree builder (a SAX ContentHandler).
     *
     * Used in situations where SAX is used but not via a FOP-invoked
     * SAX parser. A good example is an XSLT engine that fires SAX
     * events but isn't a SAX Parser itself.
     * @return a content handler for handling the SAX events.
     */
    public ContentHandler getContentHandler() {
        // TODO - do this stuff in a better way
        // PIJ: I guess the structure handler should be created by the renderer.
        if (rendererType == RENDER_MIF) {
            structHandler = new org.apache.fop.mif.MIFHandler(stream);
        } else if (rendererType == RENDER_RTF) {
            structHandler = new org.apache.fop.rtf.renderer.RTFHandler(stream);
        } else {
            if (renderer == null) {
                throw new Error("Renderer not set when using standard structHandler");
            }
            structHandler = new LayoutHandler(stream, renderer, true);
        }

        structHandler.enableLogging(getLogger());

        treeBuilder.setUserAgent(getUserAgent());
        treeBuilder.setStructHandler(structHandler);

        return treeBuilder;
    }

    /**
     * Render the FO document read by a SAX Parser from an InputSource.
     * @param parser the SAX parser.
     * @param source the input source the parser reads from.
     * @throws FOPException if anything goes wrong.
     */
    public synchronized void render(XMLReader parser, InputSource source)
        throws FOPException {
        parser.setContentHandler(getContentHandler());
        try {
            parser.parse(source);
        } catch (SAXException e) {
            if (e.getException() instanceof FOPException) {
                // Undo exception tunneling.
                throw (FOPException)e.getException();
            } else {
                throw new FOPException(e);
            }
        } catch (IOException e) {
            throw new FOPException(e);
        }
    }

    /**
     * Render the FO ducument represented by a DOM Document.
     * @param document the DOM document to read from
     * @throws FOPException if anything goes wrong.
     */
    public synchronized void render(Document document)
        throws FOPException {
        try {
            DocumentInputSource source = new DocumentInputSource(document);
            DocumentReader reader = new DocumentReader();
            reader.setContentHandler(getContentHandler());
            reader.parse(source);
        } catch (SAXException e) {
            if (e.getException() instanceof FOPException) {
                // Undo exception tunneling.
                throw (FOPException)e.getException();
            } else {
                throw new FOPException(e);
            }
        } catch (IOException e) {
            throw new FOPException(e);
        }

    }

    /**
     * Runs the formatting and renderering process using the previously set
     * parser, input source, renderer and output stream.
     * If the renderer was not set, default to PDF.
     * If no parser was set, and the input source is not a dom document,
     * get a default SAX parser.
     * @throws IOException in case of IO errors.
     * @throws FOPException if anything else goes wrong.
     */
    public synchronized void run()
        throws IOException, FOPException {
        if (renderer == null) {
            setRenderer(RENDER_PDF);
        }

        if (source == null) {
            throw new FOPException("InputSource is not set.");
        }

        if (reader == null) {
            if (!(source instanceof DocumentInputSource)) {
                try {
                    reader = javax.xml.parsers.SAXParserFactory.newInstance()
                        .newSAXParser().getXMLReader();
                } catch (SAXException e) {
                    throw new FOPException(e);
                } catch (ParserConfigurationException e) {
                    throw new FOPException(e);
                }
            }
        }

        if (source instanceof DocumentInputSource) {
            render(((DocumentInputSource)source).getDocument());
        } else {
            render(reader, source);
        }
    }

}

// code stolen from org.apache.batik.util and modified slightly
// does what sun.misc.Service probably does, but it cannot be relied on.
// hopefully will be part of standard jdk sometime.

/**
 * This class loads services present in the class path.
 */
class Service {

    static private Hashtable providerMap = new Hashtable();

    public static synchronized Enumeration providers(Class cls) {
        ClassLoader cl = cls.getClassLoader();
        // null if loaded by bootstrap class loader
        if (cl == null) {
            cl = ClassLoader.getSystemClassLoader();
        }
        String serviceFile = "META-INF/services/" + cls.getName();

        // getLogger().debug("File: " + serviceFile);

        Vector v = (Vector)providerMap.get(serviceFile);
        if (v != null) {
            return v.elements();
        }

        v = new Vector();
        providerMap.put(serviceFile, v);

        Enumeration e;
        try {
            e = cl.getResources(serviceFile);
        } catch (IOException ioe) {
            return v.elements();
        }

        while (e.hasMoreElements()) {
            try {
                java.net.URL u = (java.net.URL)e.nextElement();
                //getLogger().debug("URL: " + u);

                InputStream is = u.openStream();
                Reader r = new InputStreamReader(is, "UTF-8");
                BufferedReader br = new BufferedReader(r);

                String line = br.readLine();
                while (line != null) {
                    try {
                        // First strip any comment...
                        int idx = line.indexOf('#');
                        if (idx != -1) {
                            line = line.substring(0, idx);
                        }

                        // Trim whitespace.
                        line = line.trim();

                        // If nothing left then loop around...
                        if (line.length() == 0) {
                            line = br.readLine();
                            continue;
                        }
                        // getLogger().debug("Line: " + line);

                        // Try and load the class
                        // Object obj = cl.loadClass(line).newInstance();
                        // stick it into our vector...
                        v.add(line);
                    } catch (Exception ex) {
                        // Just try the next line
                    }

                    line = br.readLine();
                }
            } catch (Exception ex) {
                // Just try the next file...
            }

        }
        return v.elements();
    }

}