/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xerces" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package dom;

import java.lang.reflect.Method;

import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;

import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

/**
 * A sample DOM writer. This sample program illustrates how to
 * traverse a DOM tree in order to print a document that is parsed.
 *
 * @author Andy Clark, IBM
 *
 * @version $Id$
 */
public class Writer {

    //
    // Constants
    //

    // feature ids

    /** Namespaces feature id (http://xml.org/sax/features/namespaces). */
    protected static final String NAMESPACES_FEATURE_ID = "http://xml.org/sax/features/namespaces";

    /** Validation feature id (http://xml.org/sax/features/validation). */
    protected static final String VALIDATION_FEATURE_ID = "http://xml.org/sax/features/validation";

    /** Schema validation feature id (http://apache.org/xml/features/validation/schema). */
    protected static final String SCHEMA_VALIDATION_FEATURE_ID = "http://apache.org/xml/features/validation/schema";

    /** Schema full checking feature id (http://apache.org/xml/features/validation/schema-full-checking). */
    protected static final String SCHEMA_FULL_CHECKING_FEATURE_ID = "http://apache.org/xml/features/validation/schema-full-checking";

    // property ids

    /** Lexical handler property id (http://xml.org/sax/properties/lexical-handler). */
    protected static final String LEXICAL_HANDLER_PROPERTY_ID = "http://xml.org/sax/properties/lexical-handler";

    // default settings

    /** Default parser name. */
    protected static final String DEFAULT_PARSER_NAME = "dom.wrappers.Xerces";

    /** Default namespaces support (true). */
    protected static final boolean DEFAULT_NAMESPACES = true;

    /** Default validation support (false). */
    protected static final boolean DEFAULT_VALIDATION = false;

    /** Default Schema validation support (false). */
    protected static final boolean DEFAULT_SCHEMA_VALIDATION = false;

    /** Default Schema full checking support (false). */
    protected static final boolean DEFAULT_SCHEMA_FULL_CHECKING = false;

    /** Default canonical output (false). */
    protected static final boolean DEFAULT_CANONICAL = false;

    //
    // Data
    //

    /** Print writer. */
    protected PrintWriter fOut;

    /** Canonical output. */
    protected boolean fCanonical;
    
    /** Processing XML 1.1 document. */
    protected boolean fXML11;

    //
    // Constructors
    //

    /** Default constructor. */
    public Writer() {
    } // <init>()

    public Writer(boolean canonical) {
        fCanonical = canonical;
    } // <init>(boolean)

    //
    // Public methods
    //

    /** Sets whether output is canonical. */
    public void setCanonical(boolean canonical) {
        fCanonical = canonical;
    } // setCanonical(boolean)

    /** Sets the output stream for printing. */
    public void setOutput(OutputStream stream, String encoding)
        throws UnsupportedEncodingException {

        if (encoding == null) {
            encoding = "UTF8";
        }

        java.io.Writer writer = new OutputStreamWriter(stream, encoding);
        fOut = new PrintWriter(writer);

    } // setOutput(OutputStream,String)

    /** Sets the output writer. */
    public void setOutput(java.io.Writer writer) {

        fOut = writer instanceof PrintWriter
             ? (PrintWriter)writer : new PrintWriter(writer);

    } // setOutput(java.io.Writer)

    /** Writes the specified node, recursively. */
    public void write(Node node) {

        // is there anything to do?
        if (node == null) {
            return;
        }

        short type = node.getNodeType();
        switch (type) {
            case Node.DOCUMENT_NODE: {
                Document document = (Document)node;
                fXML11 = "1.1".equals(getVersion(document));
                if (!fCanonical) {
                    if (fXML11) {
                        fOut.println("<?xml version=\"1.1\" encoding=\"UTF-8\"?>");
                    }
                    else {
                        fOut.println("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
                    }
                    fOut.flush();
                    write(document.getDoctype());
                }
                write(document.getDocumentElement());
                break;
            }

            case Node.DOCUMENT_TYPE_NODE: {
                DocumentType doctype = (DocumentType)node;
                fOut.print("<!DOCTYPE ");
                fOut.print(doctype.getName());
                String publicId = doctype.getPublicId();
                String systemId = doctype.getSystemId();
                if (publicId != null) {
                    fOut.print(" PUBLIC '");
                    fOut.print(publicId);
                    fOut.print("' '");
                    fOut.print(systemId);
                    fOut.print('\'');
                }
                else if (systemId != null) {
                    fOut.print(" SYSTEM '");
                    fOut.print(systemId);
                    fOut.print('\'');
                }
                String internalSubset = doctype.getInternalSubset();
                if (internalSubset != null) {
                    fOut.println(" [");
                    fOut.print(internalSubset);
                    fOut.print(']');
                }
                fOut.println('>');
                break;
            }

            case Node.ELEMENT_NODE: {
                fOut.print('<');
                fOut.print(node.getNodeName());
                Attr attrs[] = sortAttributes(node.getAttributes());
                for (int i = 0; i < attrs.length; i++) {
                    Attr attr = attrs[i];
                    fOut.print(' ');
                    fOut.print(attr.getNodeName());
                    fOut.print("=\"");
                    normalizeAndPrint(attr.getNodeValue(), true);
                    fOut.print('"');
                }
                fOut.print('>');
                fOut.flush();

                Node child = node.getFirstChild();
                while (child != null) {
                    write(child);
                    child = child.getNextSibling();
                }
                break;
            }

            case Node.ENTITY_REFERENCE_NODE: {
                if (fCanonical) {
                    Node child = node.getFirstChild();
                    while (child != null) {
                        write(child);
                        child = child.getNextSibling();
                    }
                }
                else {
                    fOut.print('&');
                    fOut.print(node.getNodeName());
                    fOut.print(';');
                    fOut.flush();
                }
                break;
            }

            case Node.CDATA_SECTION_NODE: {
                if (fCanonical) {
                    normalizeAndPrint(node.getNodeValue(), false);
                }
                else {
                    fOut.print("<![CDATA[");
                    fOut.print(node.getNodeValue());
                    fOut.print("]]>");
                }
                fOut.flush();
                break;
            }

            case Node.TEXT_NODE: {
                normalizeAndPrint(node.getNodeValue(), false);
                fOut.flush();
                break;
            }

            case Node.PROCESSING_INSTRUCTION_NODE: {
                fOut.print("<?");
                fOut.print(node.getNodeName());
                String data = node.getNodeValue();
                if (data != null && data.length() > 0) {
                    fOut.print(' ');
                    fOut.print(data);
                }
                fOut.print("?>");
                fOut.flush();
                break;
            }
            
            case Node.COMMENT_NODE: {
                if (!fCanonical) {
                    fOut.print("<!--");
                    String comment = node.getNodeValue();
                    if (comment != null && comment.length() > 0) {
                        fOut.print(comment);
                    }
                    fOut.print("-->");
                    fOut.flush();
                }
            }
        }

        if (type == Node.ELEMENT_NODE) {
            fOut.print("</");
            fOut.print(node.getNodeName());
            fOut.print('>');
            fOut.flush();
        }

    } // write(Node)

    /** Returns a sorted list of attributes. */
    protected Attr[] sortAttributes(NamedNodeMap attrs) {

        int len = (attrs != null) ? attrs.getLength() : 0;
        Attr array[] = new Attr[len];
        for (int i = 0; i < len; i++) {
            array[i] = (Attr)attrs.item(i);
        }
        for (int i = 0; i < len - 1; i++) {
            String name = array[i].getNodeName();
            int index = i;
            for (int j = i + 1; j < len; j++) {
                String curName = array[j].getNodeName();
                if (curName.compareTo(name) < 0) {
                    name = curName;
                    index = j;
                }
            }
            if (index != i) {
                Attr temp = array[i];
                array[i] = array[index];
                array[index] = temp;
            }
        }

        return array;

    } // sortAttributes(NamedNodeMap):Attr[]

    //
    // Protected methods
    //

    /** Normalizes and prints the given string. */
    protected void normalizeAndPrint(String s, boolean isAttValue) {

        int len = (s != null) ? s.length() : 0;
        for (int i = 0; i < len; i++) {
            char c = s.charAt(i);
            normalizeAndPrint(c, isAttValue);
        }

    } // normalizeAndPrint(String,boolean)

    /** Normalizes and print the given character. */
    protected void normalizeAndPrint(char c, boolean isAttValue) {

        switch (c) {
            case '<': {
                fOut.print("&lt;");
                break;
            }
            case '>': {
                fOut.print("&gt;");
                break;
            }
            case '&': {
                fOut.print("&amp;");
                break;
            }
            case '"': {
                // A '"' that appears in character data 
                // does not need to be escaped.
                if (isAttValue) {
                    fOut.print("&quot;");
                }
                else {
                    fOut.print("\"");
                }
                break;
            }
            case '\r': {
            	// If CR is part of the document's content, it
            	// must not be printed as a literal otherwise
            	// it would be normalized to LF when the document
            	// is reparsed.
            	fOut.print("&#xD;");
            	break;
            }
            case '\n': {
                if (fCanonical) {
                    fOut.print("&#xA;");
                    break;
                }
                // else, default print char
            }
            default: {
            	// In XML 1.1, control chars in the ranges [#x1-#x1F, #x7F-#x9F] must be escaped.
            	//
            	// Escape space characters that would be normalized to #x20 in attribute values
            	// when the document is reparsed.
            	//
            	// Escape NEL (0x85) and LSEP (0x2028) that appear in content 
            	// if the document is XML 1.1, since they would be normalized to LF 
            	// when the document is reparsed.
            	if (fXML11 && ((c >= 0x01 && c <= 0x1F && c != 0x09 && c != 0x0A) 
            	    || (c >= 0x7F && c <= 0x9F) || c == 0x2028)
            	    || isAttValue && (c == 0x09 || c == 0x0A)) {
            	    fOut.print("&#x");
            	    fOut.print(Integer.toHexString(c).toUpperCase());
            	    fOut.print(";");
                }
                else {
                    fOut.print(c);
                }        
            }
        }
    } // normalizeAndPrint(char,boolean)

    /** Extracts the XML version from the Document. */
    protected String getVersion(Document document) {
    	if (document == null) {
    	    return null;
    	}
        String version = null;
        Method getXMLVersion = null;
        try {
            getXMLVersion = document.getClass().getMethod("getXmlVersion", new Class[]{});
            // If Document class implements DOM L3, this method will exist.
            if (getXMLVersion != null) {
                version = (String) getXMLVersion.invoke(document, null);
            }
        } 
        catch (Exception e) { 
            // Either this locator object doesn't have 
            // this method, or we're on an old JDK.
        }
        return version;
    } // getVersion(Document)

    //
    // Main
    //

    /** Main program entry point. */
    public static void main(String argv[]) {

        // is there anything to do?
        if (argv.length == 0) {
            printUsage();
            System.exit(1);
        }

        // variables
        Writer writer = null;
        ParserWrapper parser = null;
        boolean namespaces = DEFAULT_NAMESPACES;
        boolean validation = DEFAULT_VALIDATION;
        boolean schemaValidation = DEFAULT_SCHEMA_VALIDATION;
        boolean schemaFullChecking = DEFAULT_SCHEMA_FULL_CHECKING;
        boolean canonical = DEFAULT_CANONICAL;

        // process arguments
        for (int i = 0; i < argv.length; i++) {
            String arg = argv[i];
            if (arg.startsWith("-")) {
                String option = arg.substring(1);
                if (option.equals("p")) {
                    // get parser name
                    if (++i == argv.length) {
                        System.err.println("error: Missing argument to -p option.");
                    }
                    String parserName = argv[i];

                    // create parser
                    try {
                        parser = (ParserWrapper)Class.forName(parserName).newInstance();
                    }
                    catch (Exception e) {
                        parser = null;
                        System.err.println("error: Unable to instantiate parser ("+parserName+")");
                    }
                    continue;
                }
                if (option.equalsIgnoreCase("n")) {
                    namespaces = option.equals("n");
                    continue;
                }
                if (option.equalsIgnoreCase("v")) {
                    validation = option.equals("v");
                    continue;
                }
                if (option.equalsIgnoreCase("s")) {
                    schemaValidation = option.equals("s");
                    continue;
                }
                if (option.equalsIgnoreCase("f")) {
                    schemaFullChecking = option.equals("f");
                    continue;
                }
                if (option.equalsIgnoreCase("c")) {
                    canonical = option.equals("c");
                    continue;
                }
                if (option.equals("h")) {
                    printUsage();
                    continue;
                }
            }

            // use default parser?
            if (parser == null) {

                // create parser
                try {
                    parser = (ParserWrapper)Class.forName(DEFAULT_PARSER_NAME).newInstance();
                }
                catch (Exception e) {
                    System.err.println("error: Unable to instantiate parser ("+DEFAULT_PARSER_NAME+")");
                    continue;
                }
            }

            // set parser features
            try {
                parser.setFeature(NAMESPACES_FEATURE_ID, namespaces);
            }
            catch (SAXException e) {
                System.err.println("warning: Parser does not support feature ("+NAMESPACES_FEATURE_ID+")");
            }
            try {
                parser.setFeature(VALIDATION_FEATURE_ID, validation);
            }
            catch (SAXException e) {
                System.err.println("warning: Parser does not support feature ("+VALIDATION_FEATURE_ID+")");
            }
            try {
                parser.setFeature(SCHEMA_VALIDATION_FEATURE_ID, schemaValidation);
            }
            catch (SAXException e) {
                System.err.println("warning: Parser does not support feature ("+SCHEMA_VALIDATION_FEATURE_ID+")");
            }
            try {
                parser.setFeature(SCHEMA_FULL_CHECKING_FEATURE_ID, schemaFullChecking);
            }
            catch (SAXException e) {
                System.err.println("warning: Parser does not support feature ("+SCHEMA_FULL_CHECKING_FEATURE_ID+")");
            }

            // setup writer
            if (writer == null) {
                writer = new Writer();
                try {
                    writer.setOutput(System.out, "UTF8");
                }
                catch (UnsupportedEncodingException e) {
                    System.err.println("error: Unable to set output. Exiting.");
                    System.exit(1);
                }
            }

            // parse file
            writer.setCanonical(canonical);
            try {
                Document document = parser.parse(arg);
                writer.write(document);
            }
            catch (SAXParseException e) {
                // ignore
            }
            catch (Exception e) {
                System.err.println("error: Parse error occurred - "+e.getMessage());
                if (e instanceof SAXException) {
                    Exception nested = ((SAXException)e).getException();
                    if (nested != null) {
                        e = nested;
                    }
                }
                e.printStackTrace(System.err);
            }
        }

    } // main(String[])

    //
    // Private static methods
    //

    /** Prints the usage. */
    private static void printUsage() {

        System.err.println("usage: java dom.Writer (options) uri ...");
        System.err.println();

        System.err.println("options:");
        System.err.println("  -p name  Select parser by name.");
        System.err.println("  -n | -N  Turn on/off namespace processing.");
        System.err.println("  -v | -V  Turn on/off validation.");
        System.err.println("  -s | -S  Turn on/off Schema validation support.");
        System.err.println("           NOTE: Not supported by all parsers.");
        System.err.println("  -f  | -F Turn on/off Schema full checking.");
        System.err.println("           NOTE: Requires use of -s and not supported by all parsers.");
        System.err.println("  -c | -C  Turn on/off Canonical XML output.");
        System.err.println("           NOTE: This is not W3C canonical output.");
        System.err.println("  -h       This help screen.");
        System.err.println();

        System.err.println("defaults:");
        System.err.println("  Parser:     "+DEFAULT_PARSER_NAME);
        System.err.print("  Namespaces: ");
        System.err.println(DEFAULT_NAMESPACES ? "on" : "off");
        System.err.print("  Validation: ");
        System.err.println(DEFAULT_VALIDATION ? "on" : "off");
        System.err.print("  Schema:     ");
        System.err.println(DEFAULT_SCHEMA_VALIDATION ? "on" : "off");
        System.err.print("  Schema full checking:     ");
        System.err.println(DEFAULT_SCHEMA_FULL_CHECKING ? "on" : "off");
        System.err.print("  Canonical:  ");
        System.err.println(DEFAULT_CANONICAL ? "on" : "off");

    } // printUsage()

}  // class Writer