/*
*  AbstractIndentingTransformer.java - Indents XML elements, by adding whitespace where appropriate.
*
*  Copyright (c) 2002, 2003 Robert McKinnon
*
*  This program is free software; you can redistribute it and/or
*  modify it under the terms of the GNU General Public License
*  as published by the Free Software Foundation; either version 2
*  of the License, or any later version.
*
*  This program is distributed in the hope that it will be useful,
*  but WITHOUT ANY WARRANTY; without even the implied warranty of
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*  GNU General Public License for more details.
*
*  You should have received a copy of the GNU General Public License
*  along with this program; if not, write to the Free Software
*  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*
*  email: robmckinnon@users.sourceforge.net
*/

package xml.indent;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.ext.DeclHandler;
import org.xml.sax.helpers.AttributesImpl;

import javax.xml.transform.sax.TransformerHandler;
import java.io.IOException;
import java.io.Writer;
import java.util.regex.*;

import org.gjt.sp.jedit.jEdit;


/**
 * Indents elements, by adding whitespace where appropriate.
 * Does not remove blank lines between nodes.
 * Does not remove new lines within text nodes.
 * Puts element tags immediately following mixed content text on the same line as the text.
 *
 * @author Robert McKinnon - robmckinnon@users.sourceforge.net
 */
public abstract class IndentingTransformer implements TransformerHandler, DeclHandler {

    private static final String ON_NEW_LINE = "onNewLine";

    /** buffer to hold character data */
    private Writer writer;

    private String xml;
    private char[] chars;
    private boolean okToContinue = true;
    private boolean isClosingTag = false;
    private boolean isEmptyElement = false;
    private boolean isDocType = false;

    public void characters( char ch[], int start, int length ) throws SAXException {
        try {
            if ( isDocType ) {
                isDocType = false;
            }
            else {
                writer.write( ch, start, length );
            }
        }
        catch ( IOException e ) {
            throw new SAXException( e );
        }
    }


    public void comment( char ch[], int start, int length ) throws SAXException {
        try {
            writer.write( "<!--" );
            writer.write( ch, start, length );
            writer.write( "-->" );
        }
        catch ( IOException e ) {
            throw new SAXException( e );
        }
    }


    public void processingInstruction( String target, String data ) throws SAXException {
        try {
            writer.write( "<?" );
            writer.write( target );
            writer.write( " " );
            writer.write( data );
            writer.write( "?>" );
        }
        catch ( IOException e ) {
            throw new SAXException( e );
        }
    }


    public void endElement( String namespaceURI, String localName, String qName ) throws SAXException {
        try {
            if ( isClosingTag ) {
                writer.write( "</" );
                writer.write( qName );
                writer.write( ">" );
                isClosingTag = false;
            }
        }
        catch ( IOException e ) {
            throw new SAXException( e );
        }
    }


    public void startElement( String namespaceURI, String localName, String qName, Attributes atts )
    throws SAXException {

        try {
            writer.write( "<" );

            boolean spaceAtEnd = qName.charAt( qName.length() - 1 ) == ' ';
            if ( spaceAtEnd ) {
                writer.write( qName.substring( 0, qName.length() - 1 ) );
            }
            else {
                writer.write( qName );
            }

            boolean onNewLine = jEdit.getBooleanProperty("xmlindenter.splitAttributes", false);
            for ( int i = 0; i < atts.getLength(); i++ ) {
                String attributeQName = atts.getQName( i );
                String attributeValue = atts.getValue( i );
                //boolean onNewLine = ( atts.getType( i ) == ON_NEW_LINE );

                boolean containsDoubleQuote = ( attributeValue.indexOf( '"' ) != -1 );
                char quote = containsDoubleQuote ? '\'' : '\"';

                if ( onNewLine ) {
                    indent( 1 );
                }
                else {
                    writer.write( ' ' );
                }

                writer.write( attributeQName );
                writer.write( '=' );
                writer.write( quote );
                writer.write( attributeValue );
                writer.write( quote );
            }

            if ( isEmptyElement ) {
                if ( spaceAtEnd ) {
                    writer.write( " />" ); // to cater for <br /> elements
                }
                else {
                    writer.write( "/>" );
                }
            }
            else {
                writer.write( ">" );
            }
        }
        catch ( IOException e ) {
            throw new SAXException( e );
        }

    }

    protected abstract void indent( int levelAdjustment ) throws SAXException;

    protected String indentXml( final String xmlString, final Writer outputWriter ) throws IOException, SAXException {
        this.okToContinue = true;
        this.isClosingTag = false;
        this.isEmptyElement = false;
        this.isDocType = false;
        this.writer = outputWriter;
        this.xml = xmlString;
        this.chars = xml.toCharArray();

        int start = 0;
        int end = 0;

        while ( okToContinue ) {
            end = xml.indexOf( '<', start );
            writeTextPrecedingLessThan( start, end );

            if ( okToContinue ) {
                start = end;

                if ( xml.startsWith( "<!--", start ) ) {
                    end = writeComment( start );

                }
                else if ( xml.startsWith( "<?", start ) ) {
                    end = writeXmlDeclarationOrProcessingInstruction( start );

                }
                else if ( xml.startsWith( "<!", start ) ) {
                    if ( xml.startsWith( "<![CDATA[", start ) ) {
                        end = writeCData( start );
                    }
                    else {
                        end = writeDocType( start );
                    }
                }
                else if ( xml.startsWith( "</", start ) ) {
                    end = writeClosingTag( start );

                }
                else if ( Character.isWhitespace( chars[ start + 1 ] ) ) {
                    throw new SAXException( "The content of elements must consist of well-formed character data or markup." );

                }
                else {
                    end = writeElement( start );
                }

                start = end;
            }
        }

        return outputWriter.toString();
    }


    private int writeCData( int start ) throws IOException, SAXException {
        int end = xml.indexOf( "]]>", start );
        writeRemaining( start, end );
        if ( okToContinue ) {
            startCDATA();
            end = end + 3;
            writer.write( xml, start, end - start );
            endCDATA();
        }

        return end;
    }


    private int writeElement( int start ) throws IOException, SAXException {
        int end = getStartTagEnd( start );
        writeRemaining( start, end );

        if ( okToContinue ) {
            int offset = 1;
            while ( Character.isWhitespace( chars[ end - offset ] ) ) {
                offset++;
            }
            isEmptyElement = ( chars[ end - offset ] == '/' );

            if ( isEmptyElement ) {
                end = end - offset;
            }

            AttributesImpl attributes = new AttributesImpl();
            String elementName = getElementNameAndPopulateAttributes( start, end, attributes );

            if ( isEmptyElement && chars[ end - 1 ] == ' ' ) {
                elementName += ' '; // to cater for <br /> elements
            }

            startElement( "", "", elementName, attributes );

            if ( isEmptyElement ) {
                endElement( "", "", elementName );
                end = end + offset + 1;
                isEmptyElement = false;
            }
            else {
                end = end + 1;
            }
        }

        return end;
    }


    /**
     * Ignores '>' characters that are inside of attribute values.
     */
    private int getStartTagEnd( int start ) {
        int end = -1;
        int index = start;

        while ( index < chars.length && end == -1 ) {
            char aChar = chars[ index ];
            index++;

            if ( aChar == '\"' ) {
                while ( chars[ index ] != '\"' ) {
                    index++;
                }
                index++;
            }
            else if ( aChar == '\'' ) {
                while ( chars[ index ] != '\'' ) {
                    index++;
                }
                index++;
                //      } else if(aChar == '/') {
                //        while(chars[index] != '>') {
                //          index++;
                //        }
            }
            else if ( aChar == '>' ) {
                end = index - 1;
                //        end = index;
            }
        }
        return end;
    }


    Pattern p = Pattern.compile( "([<].*?)\\s", Pattern.DOTALL );
    private String getElementNameAndPopulateAttributes( int start, int end, AttributesImpl attributes ) throws SAXException {
        // element name ends at _first_ white space char
        int nameEnd = -1;
        Matcher m = p.matcher(xml.substring(start, end));
        boolean found = m.find();
        if (found) {
            nameEnd = start + m.end();
        }
        else {
            nameEnd = xml.indexOf( ' ', start );

            if ( nameEnd == -1 || nameEnd > end ) {
                nameEnd = xml.indexOf( '\n', start );
            }

            if ( nameEnd == -1 || nameEnd > end ) {
                nameEnd = xml.indexOf( '\r', start );
            }
        }
        if ( nameEnd == -1 || nameEnd > end ) {
            nameEnd = end;
        }
        else if ( nameEnd + 1 != end ) {
            while ( Character.isWhitespace( chars[ nameEnd - 1 ] ) ) {
                nameEnd--; // want to check if char at nameEnd is a new line char
            }
            char[] elementChars = xml.substring( nameEnd, end ).toCharArray();
            populateAttributes( elementChars, attributes );
        }

        StringBuffer elementName = new StringBuffer();
        int index = start + 1;

        while ( !Character.isWhitespace( chars[ index ] ) && chars[ index ] != '>' && chars[ index ] != '/' ) {
            elementName.append( chars[ index++ ] );
        }

        return elementName.toString();
    }


    private void populateAttributes( char[] chars, AttributesImpl attributes ) throws SAXException {
        StringBuffer qName = new StringBuffer();
        StringBuffer value = new StringBuffer();
        boolean isLastSpace = false;
        char quote = '\"';
        int i = 0;
        boolean attributeOnNewLine;

        while ( i < chars.length ) {
            attributeOnNewLine = false;
            qName.setLength( 0 );
            value.setLength( 0 );

            while ( i < chars.length && Character.isWhitespace( chars[ i ] ) ) {
                if ( chars[ i ] == '\r' || chars[ i ] == '\n' ) {
                    attributeOnNewLine = true;
                }
                i++;
            }

            if ( i < chars.length ) {
                while ( i < chars.length && chars[ i ] != '=' ) {
                    qName.append( chars[ i ] );
                    i++;
                }
                i++; // get past equals

                while ( i < chars.length && Character.isWhitespace( chars[ i ] ) ) {
                    i++; // get past whitespace before first quote
                }

                if ( i < chars.length ) {
                    if ( chars[ i ] != '\"' && chars[ i ] != '\'' ) {
                        throw new SAXException( "value for attribute " + qName.toString().trim() + " must be in quotes" );
                    }
                    else {
                        quote = chars[ i ];
                        i++; // get past first quote
                    }
                }

                while ( i < chars.length && chars[ i ] != quote ) {
                    if ( Character.isWhitespace( chars[ i ] ) ) {
                        if ( !isLastSpace ) {
                            if ( chars[ i ] == '\f' || chars[ i ] == '\n' || chars[ i ] == '\r' || chars[ i ] == '\t' || chars[ i ] == ' ' ) {
                                value.append( ' ' );
                            }
                            isLastSpace = true;
                        }
                        else {
                            // don't add consecutive space
                        }
                    }
                    else {
                        value.append( chars[ i ] );
                        isLastSpace = false;
                    }

                    i++;
                }

                i++; // get past quote

                String type = attributeOnNewLine ? ON_NEW_LINE : "";
                attributes.addAttribute( "", "", qName.toString().trim(), type, value.toString() );
            }
        }
    }


    private int writeClosingTag( int start ) throws IOException, SAXException {
        int end = xml.indexOf( '>', start );
        writeRemaining( start, end );

        if ( okToContinue ) {
            isClosingTag = true;
            endElement( "", "", xml.substring( start + 2, end ).trim() );
            end = end + 1;
        }
        return end;
    }


    private int writeDocType( int start ) throws IOException {
        int end = xml.indexOf( '>', start );
        int bracketStart = xml.indexOf( '[', start );

        if ( bracketStart != -1 && bracketStart < end ) {
            int bracketEnd = xml.indexOf( ']', bracketStart );
            end = xml.indexOf( '>', bracketEnd );
        }

        writeRemaining( start, end );

        if ( okToContinue ) {
            end = end + 1;
            writer.write( "\n" );
            int length = end - start;
            writer.write( xml, start, length );
            isDocType = true;
        }

        return end;
    }


    private int writeXmlDeclarationOrProcessingInstruction( int start ) throws IOException, SAXException {
        int end;

        if ( xml.startsWith( "<?xml ", start ) ) {
            end = writeXmlDeclaration( start );
        }
        else {
            end = writeProcessingInstruction( start );
        }

        return end;
    }


    private int writeProcessingInstruction( int start ) throws IOException, SAXException {
        int end = xml.indexOf( "?>", start );
        writeRemaining( start, end );

        if ( okToContinue ) {
            int targetEnd = xml.indexOf( " ", start );
            String target = xml.substring( start + "<?".length(), targetEnd );
            String data = xml.substring( targetEnd + 1, end );
            processingInstruction( target, data );
            end = end + "?>".length();
        }

        return end;
    }


    private int writeXmlDeclaration( int start ) throws IOException {
        int end = xml.indexOf( "?>", start );
        writeRemaining( start, end );

        if ( okToContinue ) {
            end = end + "?>".length();
            int length = end - start;
            writer.write( xml, start, length );
        }

        return end;
    }


    private int writeComment( int start ) throws IOException, SAXException {
        int end = xml.indexOf( "-->", start );
        writeRemaining( start, end );

        if ( okToContinue ) {
            int commentTextStart = start + "<!--".length();
            int commentTextLength = end - commentTextStart;
            comment( chars, commentTextStart, commentTextLength );
            end = end + "-->".length();
        }

        return end;
    }


    private void writeTextPrecedingLessThan( int start, int end ) throws IOException, SAXException {
        writeRemaining( start, end );

        if ( okToContinue && end > start ) {
            int length = end - start;
            characters( chars, start, length );
        }
    }


    private void writeRemaining( int start, int end ) throws IOException {
        if ( end == -1 ) {
            int length = xml.length() - start;
            writer.write( xml, start, length );
            okToContinue = false;
        }
    }


}