package com.c2kernel.persistency.outcome;
import java.io.StringReader;
import java.util.StringTokenizer;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.w3c.dom.bootstrap.DOMImplementationRegistry;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSSerializer;
import org.xml.sax.InputSource;

import com.c2kernel.common.ObjectNotFoundException;
import com.c2kernel.common.PersistencyException;
import com.c2kernel.entity.C2KLocalObject;
import com.c2kernel.persistency.ClusterStorage;
import com.c2kernel.utils.LocalObjectLoader;
import com.c2kernel.utils.Logger;

public class Outcome implements C2KLocalObject {
    int mID = -1;
    String mData;
    String mSchemaType;
    int mSchemaVersion;
    Document dom;
    static DocumentBuilder parser;
    static DOMImplementationLS impl;

    static {
    	// Set up parser
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        dbf.setValidating(false);
        dbf.setNamespaceAware(false);
        try {
            parser = dbf.newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            Logger.error(e);
            Logger.die("Cannot function without XML parser");
        }

        // Set up serialiser
        try {
			DOMImplementationRegistry registry = DOMImplementationRegistry.newInstance();
	    	impl = (DOMImplementationLS)registry.getDOMImplementation("LS");
		} catch (Exception e) {
            Logger.error(e);
            Logger.die("Cannot function without XML serialiser");
		}

    }

    //id is the eventID
    public Outcome(int id, String data, String schemaType, int schemaVersion) {
        mID = id;
        mData = data;
        mSchemaType = schemaType;
        mSchemaVersion = schemaVersion;
    }

    public Outcome(String path, String data) throws PersistencyException {
    // derive all the meta data from the path
        StringTokenizer tok = new StringTokenizer(path,"/");
        if (tok.countTokens() != 3 && !(tok.nextToken().equals("Outcome")))
            throw new PersistencyException("Outcome() - Outcome path must have three components: "+path, null);
        mSchemaType = tok.nextToken();
        String verstring = tok.nextToken();
        String objId = tok.nextToken();
        try {
            mSchemaVersion = Integer.parseInt(verstring);
        } catch (NumberFormatException ex) {
            throw new PersistencyException("Outcome() - Outcome version was an invalid number: "+verstring, null);
        }
        try {
            mID = Integer.parseInt(objId);
        } catch (NumberFormatException ex) {
            mID = -1;
        }
        mData = data;
    }

    public void setID(int ID) {
        mID = ID;
    }

    public int getID() {
        return mID;
    }

    @Override
	public void setName(String name) {
    	try {
    		mID = Integer.parseInt(name);
    	} catch (NumberFormatException e) {
    		Logger.error("Invalid id set on Outcome:"+name);
    	}
    }

    @Override
	public String getName() {
        return String.valueOf(mID);
    }

    public void setData(String data) {
        mData = data;
        dom = null;
    }

    public void setData(Document data) {
        mData = serialize(data, false);
        dom = data;
    }

    public String getData() {
        return mData;
    }

    public Schema getSchema() throws ObjectNotFoundException {
    	return LocalObjectLoader.getSchema(mSchemaType, mSchemaVersion);
    }
    
    public void setSchemaType(String schemaType) {
        mSchemaType = schemaType;
    }

    public String getSchemaType() {
        return mSchemaType;
    }

    public int getSchemaVersion() {
        return mSchemaVersion;
    }

    public void setSchemaVersion(int schVer) {
        mSchemaVersion = schVer;
    }

	@Override
	public String getClusterType() {
		return ClusterStorage.OUTCOME;
	}

    // special script API methods

    /**
     * Parses the outcome into a DOM tree
     * @return a DOM Document
     */
    public Document getDOM() {
    	if (dom == null)
        try {
            synchronized (parser) {
            	if (mData!=null)
            		dom = parser.parse(new InputSource(new StringReader(mData)));
            	else
            		dom = parser.newDocument();
            }
        } catch (Exception e) {
            Logger.error(e);
            return null;
        }
    	return dom;
    }
    
    public String getField(String name) {
    	if (getDOM() == null) return null;
    	if (getDOM().getDocumentElement() == null) return null;
    	 NodeList elements = getDOM().getDocumentElement().getElementsByTagName(name);
    	 if (elements.getLength() == 1 && elements.item(0).hasChildNodes() && elements.item(0).getFirstChild() instanceof Text)
    		 return ((Text)elements.item(0).getFirstChild()).getData();
    	 else
    		 return null;
    }

    static public String serialize(Document doc, boolean prettyPrint)
    {
    	LSSerializer writer = impl.createLSSerializer();
    	writer.getDomConfig().setParameter("format-pretty-print", prettyPrint);
    	writer.getDomConfig().setParameter("xml-declaration", false);
    	return writer.writeToString(doc);
    }
}