package org.gcube.common.clients.stubs.jaxws;

import java.util.Iterator;
import java.util.Set;

import javax.xml.namespace.QName;
import javax.xml.soap.SOAPHeader;
import javax.xml.soap.SOAPHeaderElement;
import javax.xml.ws.handler.MessageContext;
import javax.xml.ws.handler.soap.SOAPHandler;
import javax.xml.ws.handler.soap.SOAPMessageContext;

import org.gcube.common.scope.api.ScopeProvider;

/**
 * A {@link SOAPHandler} that adds gCube headers to outgoing calls.
 * 
 * @author Fabio Simeoni
 *
 */
public class GCoreJAXWSHandler implements SOAPHandler<SOAPMessageContext> {
	
	/** Namespace of scope-related headers */
	public static final String SCOPE_NS = "http://gcube-system.org/namespaces/scope";

	/** Name of the scope call header. */
	public static final String SCOPE_HEADER_NAME = "scope";
	public static final QName SCOPE_QNAME = new QName(SCOPE_NS,SCOPE_HEADER_NAME);
	
	/** Name of the service class call header. */
	public static final String SERVICECLASS_HEADER_NAME = "serviceClass";
	public static final QName SERVICECLASS_QNAME = new QName(SCOPE_NS,SERVICECLASS_HEADER_NAME);
	
	/** Name of the service name call header. */
	public static final String SERVICENAME_HEADER_NAME = "serviceName";
	public static final QName SERVICENAME_QNAME = new QName(SCOPE_NS,SERVICENAME_HEADER_NAME);
	
	
	/** Name of the scope call header. */
	public static final String CALLER_HEADER_NAME = "caller";
	/** Namespace of scope-related headers */
	public static final String CALLER_NS = "http://gcube-system.org/namespaces/caller";

	public static final QName CALLER_QNAME = new QName(CALLER_NS,CALLER_HEADER_NAME);
	
	private final GCoreService<?> target;
	
	GCoreJAXWSHandler(GCoreService<?> target) {
		this.target=target;
	}

	public boolean handleMessage(SOAPMessageContext context) {

		Boolean outbound = (Boolean) context.get(MessageContext.MESSAGE_OUTBOUND_PROPERTY);

		if (outbound)
			try {
				
				SOAPHeader header = context.getMessage().getSOAPPart().getEnvelope().getHeader();
				
				if (header == null)
					header = context.getMessage().getSOAPPart().getEnvelope().addHeader();
				
				
				addCurrentScope(header);
				addTargetServiceCoordinates(header);
				addClientIdentity(header);
				
				correctWSAddressingHeader(header);

			} catch (Exception e) {
				throw new RuntimeException("cannot configure outgoing message", e);
			}
		
		return true;
	};

	public Set<QName> getHeaders() {
		return null;
	}

	public boolean handleFault(SOAPMessageContext context) {
		return true;
	}

	public void close(MessageContext context) {}

	
	//helper
	private void addClientIdentity(SOAPHeader header) throws Exception {
		addHeader(header,CALLER_QNAME, target.clientId());
	}
	
	//helper
	private void addTargetServiceCoordinates(SOAPHeader header) throws Exception {
		addHeader(header,SERVICECLASS_QNAME, target.gcubeClass());
		addHeader(header,SERVICENAME_QNAME, target.gcubeName());
	}

	//helper
	private void addCurrentScope(SOAPHeader header) throws Exception {
		String scope = ScopeProvider.instance.get();
		if (scope==null)
			throw new IllegalStateException("no scope is defined for this call");
		addHeader(header,SCOPE_QNAME, scope);
	}

	//helper: adapts ws-addressing headers to member submission's. brutal but there is no support for member submission in
	//jdk 1.6
	private void correctWSAddressingHeader(SOAPHeader header) throws Exception {
		
		Iterator<?> it = header.examineAllHeaderElements();
		while (it.hasNext()) {
			SOAPHeaderElement e = (SOAPHeaderElement) it.next();
			if (e.getElementQName().getNamespaceURI().equals("http://www.w3.org/2005/08/addressing")) {
				e.detachNode();
				addHeader(header,new QName("http://schemas.xmlsoap.org/ws/2004/03/addressing",e.getElementQName().getLocalPart()), e.getTextContent());
			}
				
		}
	}
	
	// helper
	private void addHeader(SOAPHeader header,QName name, String value) throws Exception {
		header.addHeaderElement(name).addTextNode(value);
	}
}