package org.simantics.xml.sax.base;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;

import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.exception.DatabaseException;

public abstract class XMLElementNamedChildWriterBase implements XMLElementNamedChildWriter{

	private Map<Resource,Class<? extends XMLElementWriter>> typeWriters = new HashMap<>();
	private Map<Resource,Class<? extends XMLElementWriter>> relationWriters = new HashMap<>();
	private Map<Resource,Map<Resource,Class<? extends XMLElementWriter>>> relationTypeWriters = new HashMap<>();
	private Set<Class<? extends XMLElementWriter>> writers = new HashSet<Class<? extends XMLElementWriter>>();
	
	
	public XMLElementNamedChildWriterBase() {
	
	}
	
	public XMLElementNamedChildWriterBase(ReadGraph graph) {
		
	}
	
	@Override
	public Resource getType(ReadGraph graph) throws DatabaseException {
		return null;
	}
	
	@Override
	public void start(ReadGraph graph, WriterElement instance, XMLStreamWriter writer) throws XMLStreamException {
		writer.writeStartElement(getElementId());
	}
	
	@Override
	public void characters(ReadGraph graph, WriterElement instance, XMLStreamWriter writer)
			throws XMLStreamException, DatabaseException {
		
	}
	
	@Override
	public void end(ReadGraph graph, WriterElement instance, XMLStreamWriter writer) throws XMLStreamException {
		writer.writeEndElement();
	}
	
	@Override
	public void children(ReadGraph graph, WriterElement instance, Set<Resource> sorted)
			throws XMLStreamException, DatabaseException {
	
	}
	
	@Override
	public Class<? extends XMLElementWriter> getWriter(ReadGraph graph, Map<Resource, XMLElementWriter> writers, WriterElement child) throws DatabaseException{
		Resource type = graph.getSingleType(child.instance);
		Class<? extends XMLElementWriter> writerClass =  typeWriters.get(type);
		if (writerClass != null)
			return writerClass;
		if (child.statement != null) {
			Map<Resource,Class<? extends XMLElementWriter>> typeWriters = relationTypeWriters.get(child.statement.getPredicate());
			if (typeWriters != null) {
				writerClass = typeWriters.get(type);
				if (writerClass != null)
					return writerClass;
			}
			writerClass = relationWriters.get(child.statement.getPredicate());
			if (writerClass != null)
				return writerClass;
		}
		XMLElementWriter writer = writers.get(type);
		if (writer == null)
			return null;
		writerClass = writer.getClass();
		if (this.writers.contains(writerClass))
			return writerClass;
		for (Class<?> c : this.writers)
			if (c.isAssignableFrom(writerClass))
				return writerClass;
		return null;
	}
	
	public void addTypeWriter(Resource type, Class<? extends XMLElementWriter> writer) {
		typeWriters.put(type, writer);
	}
	
	public void addRelationWriter(Resource relation, Class<? extends XMLElementWriter> writer) {
		relationWriters.put(relation, writer);
	}
	
	public void addRelationTypeWriter(Resource relation, Resource type, Class<? extends XMLElementWriter> writer) {
		Map<Resource,Class<? extends XMLElementWriter>> typeWriters = relationTypeWriters.get(relation);
		if (typeWriters == null) {
			typeWriters = new HashMap<>();
			relationTypeWriters.put(relation, typeWriters);
		}
		typeWriters.put(type, writer);
	}
	
	
	public void addWriter(Class<? extends XMLElementWriter> writer) {
		writers.add(writer);
	}
}