// XAAL toolkit
// Copyright (C) 2009 Ville Karavirta <vkaravir(a)cs.hut.fi>
//
// 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 3 of the License, or
// (at your option) 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, see <http://www.gnu.org/licenses/>.
package xaal.parser;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.ListIterator;
import java.util.Stack;

import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;


/**
 * Xaal parser: a general parser that allows specifying classes that handle
 * certain types of elements. For example, by specifying a start/endElement<tag-name>(...)
 * in a class that extend the class xaal.parser.ParserModule and
 * registering the class to the main "parser" the parser passes the SAX
 * events of such element to the registered class. 
 * 
 * The xaal.parser.ParserModule has methods for passing information between different
 * parser modules using the get/setProperty methods. It also contains a stack of the 
 * elements that can (and should) be used when parsing xml. 
 * 
 * @author vkaravir@cs.hut.fi
 * @see xaal.parser.ParserModule
 * 
 */
public class XmlParser implements ContentHandler {
    private HashMap startTagHandlers;
    private HashMap endTagHandlers;
    private Stack currHandlers;
    
    public XmlParser() {
        startTagHandlers = new HashMap();
        endTagHandlers = new HashMap();
        currHandlers = new Stack();
    }

    public void characters(char[] ch, int start, int length) throws SAXException {
        if (!currHandlers.isEmpty()) {
            List l = (List) currHandlers.peek();
            ListIterator i = l.listIterator();
            while (i.hasNext()) {
                ParserModuleWrapper p = (ParserModuleWrapper) i.next();
                p.getParserModule().characters(ch, start, length);
            }
        }
    }

    public void endDocument() throws SAXException {
        // TODO Auto-generated method stub

    }

    public void endElement(String nsUri, String localName,
            String qName)
            throws SAXException {
        String elemName = cleanString(localName).toLowerCase();
        if (endTagHandlers.containsKey(elemName)) {
            //System.out.println("end element: "+localName);
            List l = (List) endTagHandlers.get(elemName);
            ListIterator i = l.listIterator();
            while (i.hasNext()) {
                ParserModuleWrapper p = (ParserModuleWrapper) i.next();
                try {
                    p.getMethod().invoke(p.getParserModule(), new Object[] {nsUri, localName, qName});
                } catch (IllegalArgumentException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IllegalAccessException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (InvocationTargetException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
        currHandlers.pop();
        String currPath = (String) ParserModule.getProperty(ParserModule.CURRENT_PATH);
        if (currPath.lastIndexOf("/") != -1) {
            currPath = currPath.substring(0, currPath.lastIndexOf("/"));
        } else {
            currPath = "";
        }
        ParserModule.setProperty(ParserModule.CURRENT_PATH, currPath);
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#endPrefixMapping(java.lang.String)
     */
    public void endPrefixMapping(String arg0) throws SAXException {
        // TODO Auto-generated method stub

    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#ignorableWhitespace(char[], int, int)
     */
    public void ignorableWhitespace(char[] arg0, int arg1, int arg2)
            throws SAXException {
        // TODO Auto-generated method stub

    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#processingInstruction(java.lang.String, java.lang.String)
     */
    public void processingInstruction(String arg0, String arg1)
            throws SAXException {
        // TODO Auto-generated method stub

    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#setDocumentLocator(org.xml.sax.Locator)
     */
    public void setDocumentLocator(Locator arg0) {
        // TODO Auto-generated method stub

    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#skippedEntity(java.lang.String)
     */
    public void skippedEntity(String arg0) throws SAXException {
        // TODO Auto-generated method stub

    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#startDocument()
     */
    public void startDocument() throws SAXException {
        ParserModule.setProperty(ParserModule.CURRENT_PATH, "");
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
     */
    public void startElement(String nsUri, String localName, String qName,
            Attributes atts) throws SAXException {
        String elemName = cleanString(localName).toLowerCase();
        String currPath = ParserModule.getProperty(ParserModule.CURRENT_PATH).toString();
        ParserModule.setProperty(ParserModule.CURRENT_PATH, currPath + "/" + localName);
        if (startTagHandlers.containsKey(elemName)) {
            //System.out.println("start element: "+localName);
            List l = (List) startTagHandlers.get(elemName);
            currHandlers.push(l);
            ListIterator i = l.listIterator();
            while (i.hasNext()) {
                ParserModuleWrapper p = (ParserModuleWrapper) i.next();
                try {
                    p.getMethod().invoke(p.getParserModule(), new Object[] {nsUri, localName, qName, atts});
                } catch (IllegalArgumentException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IllegalAccessException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (InvocationTargetException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        } else {
            //System.out.println("unsupported element: " + localName);
            currHandlers.push(new ArrayList(1));
        }
    }

    private String cleanString(String localName) {
        // TODO Correctly handle CombiningChar and Extender
        // see http://www.w3.org/TR/2006/REC-xml-20060816/#NT-CombiningChar
        // and http://www.w3.org/TR/2006/REC-xml-20060816/#NT-Extender
        String[] chars = new String[] { "\\.","\\-","\\_", "\\:"};
        for (int i = 0; i < chars.length; i++) {
            localName = localName.replaceAll(chars[i], "");
        }
        return localName;
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#startPrefixMapping(java.lang.String, java.lang.String)
     */
    public void startPrefixMapping(String arg0, String arg1)
            throws SAXException {
        // TODO Auto-generated method stub

    }
    
    public void registerParserModule(ParserModule pm) {
        Method[] methods = pm.getClass().getDeclaredMethods();
        for (int i = 0; i < methods.length; i++) {
            Method method = methods[i];
            if (method.getName().startsWith("startElement")) {                
                String tagName = method.getName().substring(12).toLowerCase();
                ParserModuleWrapper pmw = new ParserModuleWrapper(pm, method);
                List l = (List) startTagHandlers.get(tagName);
                if (l == null) {
                    l = new ArrayList();
                }
                l.add(pmw);
                startTagHandlers.put(tagName, l);
            } else if (method.getName().startsWith("endElement")) {
                String tagName = method.getName().substring(10).toLowerCase();
                ParserModuleWrapper pmw = new ParserModuleWrapper(pm, method);
                List l = (List) endTagHandlers.get(tagName);
                if (l == null) {
                    l = new ArrayList();
                }
                l.add(pmw);
                endTagHandlers.put(tagName, l);                
            }
        }
    }
    
    public void registerParserModule(String className) throws ParserModuleException {
        Class c;
        try {
            c = Class.forName(className);
            Object o = c.newInstance();
            if (o instanceof ParserModule)
                registerParserModule((ParserModule) o);
            else
                throw new ParserModuleException("Failed to register ParserModule " + className +
                        ": class not instance of fi.tkk.cs.svg.xmlparser.ParserModule.");
            return;
        } catch (Exception e) {
            throw new ParserModuleException("Failed to register ParserModule " + className, e);
        }
    }
    
    public void parse(String fileName) throws SAXException, IOException {
        XMLReader parser = XMLReaderFactory.createXMLReader();
        ErrorHandler errh = new XaalErrorHandler();
        parser.setContentHandler(this);
        parser.setErrorHandler(errh);
        //parser.parse("/home/vkaravir/projects/dippa/schema/out.xaal");
        parser.parse(fileName);
    }
    
    public void parse(InputSource in) throws IOException, SAXException {
        XMLReader parser = XMLReaderFactory.createXMLReader();
        ErrorHandler errh = new XaalErrorHandler();
        parser.setContentHandler(this);
        parser.setErrorHandler(errh);
        parser.parse(in);        
    }
    
    public void parse(InputStream in) throws IOException, SAXException {
        parse(new InputSource(in));
    }
    
    public void parse(Reader in) throws IOException, SAXException {
        parse(new InputSource(in));
    }    
}