/*

   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.

*/

package org.apache.batik.transcoder.svg2svg;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;

import org.apache.batik.dom.util.DOMUtilities;
import org.apache.batik.transcoder.AbstractTranscoder;
import org.apache.batik.transcoder.ErrorHandler;
import org.apache.batik.transcoder.TranscoderException;
import org.apache.batik.transcoder.TranscoderInput;
import org.apache.batik.transcoder.TranscoderOutput;
import org.apache.batik.transcoder.TranscodingHints;
import org.apache.batik.transcoder.keys.BooleanKey;
import org.apache.batik.transcoder.keys.IntegerKey;
import org.apache.batik.transcoder.keys.StringKey;
import org.w3c.dom.Document;

/**
 * This class is a trancoder from SVG to SVG.
 *
 * @author <a href="mailto:stephane@hillion.org">Stephane Hillion</a>
 * @version $Id$
 */
public class SVGTranscoder extends AbstractTranscoder {

    /**
     * The default error handler.
     */
    public static final ErrorHandler DEFAULT_ERROR_HANDLER = new ErrorHandler() {
        public void error(TranscoderException ex) throws TranscoderException {
            throw ex;
        }
        public void fatalError(TranscoderException ex) throws TranscoderException {
            throw ex;
        }
        public void warning(TranscoderException ex) throws TranscoderException {
            // Do nothing
        }
    };

    /**
     * The key to specify the newline character sequence.
     */
    public static final TranscodingHints.Key KEY_NEWLINE = new NewlineKey();

    /**
     * The "\r" newline value.
     */
    public static final NewlineValue VALUE_NEWLINE_CR = new NewlineValue("\r");

    /**
     * The "\r\n" newline value.
     */
    public static final NewlineValue VALUE_NEWLINE_CR_LF = new NewlineValue("\r\n");

    /**
     * The "\n" newline value.
     */
    public static final NewlineValue VALUE_NEWLINE_LF = new NewlineValue("\n");

    /**
     * The key to specify whether to format the input.
     */
    public static final TranscodingHints.Key KEY_FORMAT = new BooleanKey();

    /**
     * The value to turn on formatting.
     */
    public static final Boolean VALUE_FORMAT_ON = Boolean.TRUE;

    /**
     * The value to turn off formatting.
     */
    public static final Boolean VALUE_FORMAT_OFF = Boolean.FALSE;

    /**
     * The key to specify the tabulation width.
     */
    public static final TranscodingHints.Key KEY_TABULATION_WIDTH
        = new IntegerKey();

    /**
     * The key to specify the document width.
     */
    public static final TranscodingHints.Key KEY_DOCUMENT_WIDTH
        = new IntegerKey();

    /**
     * The key to specify the doctype option.
     */
    public static final TranscodingHints.Key KEY_DOCTYPE
        = new DoctypeKey();

    /**
     * The doctype value to change the declaration.
     */
    public static final DoctypeValue VALUE_DOCTYPE_CHANGE =
        new DoctypeValue(PrettyPrinter.DOCTYPE_CHANGE);

    /**
     * The doctype value to remove the declaration.
     */
    public static final DoctypeValue VALUE_DOCTYPE_REMOVE =
        new DoctypeValue(PrettyPrinter.DOCTYPE_REMOVE);

    /**
     * The doctype value to keep unchanged the declaration.
     */
    public static final DoctypeValue VALUE_DOCTYPE_KEEP_UNCHANGED =
        new DoctypeValue(PrettyPrinter.DOCTYPE_KEEP_UNCHANGED);

    /**
     * The key to specify the public id.
     */
    public static final TranscodingHints.Key KEY_PUBLIC_ID
        = new StringKey();

    /**
     * The key to specify the system id.
     */
    public static final TranscodingHints.Key KEY_SYSTEM_ID
        = new StringKey();

    /**
     * The key to specify the XML declaration option.
     */
    public static final TranscodingHints.Key KEY_XML_DECLARATION
        = new StringKey();

    /**
     * Creates a new SVGTranscoder.
     */
    public SVGTranscoder() {
        setErrorHandler(DEFAULT_ERROR_HANDLER);
    }

    /**
     * Transcodes the specified input in the specified output.
     * @param input the input to transcode
     * @param output the ouput where to transcode
     * @exception TranscoderException if an error occured while transcoding
     */
    public void transcode(TranscoderInput input, TranscoderOutput output)
        throws TranscoderException {
        Reader r = input.getReader();
        Writer w = output.getWriter();

        if (r == null) {
            Document d = input.getDocument();
            if (d == null) {
                throw new Error("Reader or Document expected");
            }
            StringWriter sw = new StringWriter( 1024 );
            try {
                DOMUtilities.writeDocument(d, sw);
            } catch ( IOException ioEx ) {
                throw new Error("IO:" + ioEx.getMessage() );
            }
            r = new StringReader(sw.toString());
        }
        if (w == null) {
            throw new Error("Writer expected");
        }
        prettyPrint(r, w);
    }


    /**
     * Pretty print the given reader.
     */
    protected void prettyPrint(Reader in, Writer out) throws TranscoderException {
        try {
            PrettyPrinter pp = new PrettyPrinter();
            NewlineValue nlv = (NewlineValue)hints.get(KEY_NEWLINE);
            if (nlv != null) {
                pp.setNewline(nlv.getValue());
            }
            Boolean b = (Boolean)hints.get(KEY_FORMAT);
            if (b != null) {
                pp.setFormat(b.booleanValue());
            }
            Integer i = (Integer)hints.get(KEY_TABULATION_WIDTH);
            if (i != null) {
                pp.setTabulationWidth(i.intValue());
            }
            i = (Integer)hints.get(KEY_DOCUMENT_WIDTH);
            if (i != null) {
                pp.setDocumentWidth(i.intValue());
            }
            DoctypeValue dtv = (DoctypeValue)hints.get(KEY_DOCTYPE);
            if (dtv != null) {
                pp.setDoctypeOption(dtv.getValue());
            }
            String s = (String)hints.get(KEY_PUBLIC_ID);
            if (s != null) {
                pp.setPublicId(s);
            }
            s = (String)hints.get(KEY_SYSTEM_ID);
            if (s != null) {
                pp.setSystemId(s);
            }

            s = (String)hints.get(KEY_XML_DECLARATION);
            if (s != null) {
                pp.setXMLDeclaration(s);
            }

            pp.print(in, out);
            out.flush();
        } catch (IOException e) {
            getErrorHandler().fatalError(new TranscoderException(e.getMessage()));
        }
    }

    /**
     * To represent a newline key.
     */
    protected static class NewlineKey extends TranscodingHints.Key {
        public boolean isCompatibleValue(Object v) {
            return v instanceof NewlineValue;
        }
    }

    /**
     * To represent a newline value.
     */
    protected static class NewlineValue {
        protected final String value;
        protected NewlineValue(String val) {
            value = val;
        }
        public String getValue() {
            return value;
        }
    }

    /**
     * To represent a doctype key.
     */
    protected static class DoctypeKey extends TranscodingHints.Key {
        public boolean isCompatibleValue(Object v) {
            return v instanceof DoctypeValue;
        }
    }

    /**
     * To represent a doctype value.
     */
    protected static class DoctypeValue {
        final int value;
        protected DoctypeValue(int value) {
            this.value = value;
        }
        public int getValue() {
            return value;
        }
    }
}