/*
 *                    BioJava development code
 *
 * This code may be freely distributed and modified under the
 * terms of the GNU Lesser General Public Licence.  This should
 * be distributed with the code.  If you do not have a copy,
 * see:
 *
 *      http://www.gnu.org/copyleft/lesser.html
 *
 * Copyright for this code is held jointly by the individual
 * authors.  These should be listed in @author doc comments.
 *
 * For more information on the BioJava project and its aims,
 * or to join the biojava-l mailing list, visit the home page
 * at:
 *
 *      http://www.biojava.org/
 *
 */

package org.biojava.bio.program.das;

import java.util.ArrayList;
import java.util.List;

import org.biojava.bio.BioError;
import org.biojava.bio.BioRuntimeException;
import org.biojava.bio.SmallAnnotation;
import org.biojava.bio.seq.ComponentFeature;
import org.biojava.bio.seq.Feature;
import org.biojava.bio.seq.StrandedFeature;
import org.biojava.bio.seq.io.SeqIOListener;
import org.biojava.bio.symbol.Location;
import org.biojava.bio.symbol.RangeLocation;
import org.biojava.utils.ChangeVetoException;
import org.biojava.utils.stax.DelegationManager;
import org.biojava.utils.stax.IntElementHandlerBase;
import org.biojava.utils.stax.StAXContentHandler;
import org.biojava.utils.stax.StAXContentHandlerBase;
import org.biojava.utils.stax.StringElementHandlerBase;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

/**
 * StAX handler for parsing a single DASGFF feature.
 *
 * @author Thomas Down
 * @since 1.2
 */

class DASGFFFeatureHandler extends StAXContentHandlerBase {
    private SeqIOListener featureListener;

    private String f_id = null;
    private String f_label = null;
    private String type = "unknown";
    private String method = "unknown";
    private int start = -1, end = -1;
    private String orientation="0";
    private Location loc = null;
    private boolean isReferenceFeature = false;
    private String category = null;
    private List groups = new ArrayList();
    private List targets = new ArrayList();
    private List links = new ArrayList();

    public DASGFFFeatureHandler(SeqIOListener siol) {
	this.featureListener = siol;
    }

    public void startElement(String nsURI,
			     String localName,
			     String qName,
			     Attributes attrs,
			     DelegationManager dm)
	 throws SAXException
    {
	if ("FEATURE".equals(localName)) {
	    f_id = attrs.getValue("id");
	    f_label = attrs.getValue("label");
	} else if ("TYPE".equals(localName)) {
	    String reference = attrs.getValue("reference");
	    if ("yes".equals(reference)) {
		isReferenceFeature = true;
	    }
	    category = attrs.getValue("category");
	    type = attrs.getValue("id");
	} else if ("METHOD".equals(localName)) {
	    dm.delegate(new StringElementHandlerBase() {
		    protected void setStringValue(String s) {
			method = s.trim();
		    }
		} );
	} else if ("START".equals(localName)) {
	    dm.delegate(new IntElementHandlerBase() {
		    protected void setIntValue(int i) {
			start = i;
		    }
		} );
	} else if ("END".equals(localName)) {
	    dm.delegate(new IntElementHandlerBase() {
		    protected void setIntValue(int i) {
			end = i;
		    }
		} );
	} else if ("ORIENTATION".equals(localName)) {
	    dm.delegate(new StringElementHandlerBase() {
		    protected void setStringValue(String s) {
			orientation = s.trim();
		    }
		} );
	} else if ("NOTE".equals(localName)) {
	} else if ("LINK".equals(localName)) {
	    dm.delegate(new LinkHandler());
	} else if ("TARGET".equals(localName)) {
	    Target targetHandler = new Target();
	    dm.delegate(targetHandler);
	} else if ("GROUP".equals(localName)) {
	    Group groupHandler = new Group();
	    dm.delegate(groupHandler);
	} else {
	    // Unknown element -- let's be flexible for now...

	    dm.delegate(new StAXContentHandlerBase());
	}
    }

    public void endElement(String nsURI,
			   String localName,
			   String qName,
			   StAXContentHandler handler)
	 throws SAXException
    {
    }

    public void endTree()
        throws SAXException
    {
	Feature.Template temp;
	if (isReferenceFeature && category.equals("component")) {
	    if (targets.size() != 1) {
		throw new SAXException("Expecting 1 TARGET element in a component feature [FIXME?]");
	    }
	    Target targetGroup = (Target) targets.get(0);
	    if (targetGroup.target_id == null) {
		throw new SAXException("Target must be specified for component features");
	    }

	    ComponentFeature.Template ctemp = new ComponentFeature.Template();
	    ctemp.componentLocation = new RangeLocation(targetGroup.target_start, 
							targetGroup.target_stop);
	    ctemp.strand = orientation.equals("+") ? StrandedFeature.POSITIVE :
	                                             StrandedFeature.NEGATIVE;

	    ctemp.annotation = new SmallAnnotation();
	    try {
		ctemp.annotation.setProperty("sequence.id", targetGroup.target_id);
	    } catch (ChangeVetoException ex) {
		throw new BioError(ex);
	    }

	    temp = ctemp;
	} else if (orientation.equals("+") || orientation.equals("-")) {
	    StrandedFeature.Template stemp = new StrandedFeature.Template();
	    stemp.strand = orientation.equals("+") ? StrandedFeature.POSITIVE :
	                                             StrandedFeature.NEGATIVE;
	    temp = stemp;
	} else {
	    temp = new Feature.Template();
	}

	temp.type = type;
	temp.source = method;
	if (loc == null) {
	    temp.location = new RangeLocation(start, end);
	} else {
	    temp.location = loc;
	}

	
	if (temp.annotation == null) {
	    temp.annotation = new SmallAnnotation();
	}

	try {
	    if (f_id != null && f_id.length() > 0) {
		temp.annotation.setProperty(DASSequence.PROPERTY_FEATUREID, f_id);
	    }
	    if (f_label != null && f_label.length() > 0) {
		temp.annotation.setProperty(DASSequence.PROPERTY_FEATURELABEL, f_label);
	    }
	    if (links.size() > 0) {
		temp.annotation.setProperty(DASSequence.PROPERTY_LINKS, links);
	    }
	} catch (ChangeVetoException ex) {
	    throw new BioError(ex);
	}

	try {
	    featureListener.startFeature(temp);
	    featureListener.endFeature();
	} catch (Exception ex) {
	    throw new BioRuntimeException(ex);
	}
    }

    private class Target extends StAXContentHandlerBase {
	String target_id;
	int target_start;
	int target_stop;

	public void startElement(String nsURI,
				 String localName,
				 String qName,
				 Attributes attrs,
				 DelegationManager dm)
	    throws SAXException
	{
	    if ("TARGET".equals(localName)) {
		target_id = attrs.getValue("id");
		if (target_id == null) {
		    target_id = attrs.getValue("ref");
		}
		try {
		    target_start = Integer.parseInt(attrs.getValue("start"));
		    target_stop = Integer.parseInt(attrs.getValue("stop"));
		} catch (NumberFormatException ex) {
		    throw new SAXException("Bad start/stop parsing TARGET");
		}
	    } 
	}

	public void endTree() {
	    targets.add(this);
	}
    }

    private class Group extends StAXContentHandlerBase {
	String gid;
	String note;

	public void startElement(String nsURI,
				 String localName,
				 String qName,
				 Attributes attrs,
				 DelegationManager dm)
	    throws SAXException
	{
	    if ("GROUP".equals(localName)) {
		gid = attrs.getValue("id");
	    } else if ("NOTE".equals(localName)) {
		dm.delegate(new StringElementHandlerBase() {
		    protected void setStringValue(String s) {
		        note = s.trim();
		    }
		} );
	    } else if ("LINK".equals(localName)) {
		dm.delegate(new LinkHandler());
	    } else if ("TARGET".equals(localName)) {
		dm.delegate(new Target());
	    } 
	}

	public void endTree() {
	    groups.add(this);
	}
    }

    private class LinkHandler extends StAXContentHandlerBase {
	String link;
	String link_text;

	public void startElement(String nsURI,
				 String localName,
				 String qName,
				 Attributes attrs,
				 DelegationManager dm)
	    throws SAXException
	{
	    if ("LINK".equals(localName)) {
		link = attrs.getValue("href");
		dm.delegate(new StringElementHandlerBase() {
			protected void setStringValue(String s) {
			    link_text = s.trim();
			}
		    } );
	    }
	}

	public void endTree() {
	    links.add(new DASLink(link, link_text));
	}
    }
}