/*******************************************************************************
 * Copyright 2017 Graz University of Technology
 * EAAF-Core Components has been developed in a cooperation between EGIZ,  
 * A-SIT+, A-SIT, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.2 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * https://joinup.ec.europa.eu/news/understanding-eupl-v12
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 *******************************************************************************/
/*******************************************************************************
 *******************************************************************************/
/*******************************************************************************
 *******************************************************************************/
package at.gv.egiz.eaaf.modules.pvp2.impl.validation.metadata;

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

import org.opensaml.common.xml.SAMLConstants;
import org.opensaml.saml2.common.Extensions;
import org.opensaml.saml2.core.Attribute;
import org.opensaml.saml2.metadata.AttributeConsumingService;
import org.opensaml.saml2.metadata.EntitiesDescriptor;
import org.opensaml.saml2.metadata.EntityDescriptor;
import org.opensaml.saml2.metadata.LocalizedString;
import org.opensaml.saml2.metadata.RequestedAttribute;
import org.opensaml.saml2.metadata.SPSSODescriptor;
import org.opensaml.saml2.metadata.ServiceName;
import org.opensaml.saml2.metadata.provider.FilterException;
import org.opensaml.saml2.metadata.provider.MetadataFilter;
import org.opensaml.samlext.saml2mdattr.EntityAttributes;
import org.opensaml.xml.XMLObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import at.gv.egiz.eaaf.core.impl.data.Trible;
import at.gv.egiz.eaaf.modules.pvp2.PVPConstants;
import at.gv.egiz.eaaf.modules.pvp2.exception.PVP2MetadataException;
import at.gv.egiz.eaaf.modules.pvp2.impl.builder.PVPAttributeBuilder;
import at.gv.egiz.eaaf.modules.pvp2.impl.utils.SAML2Utils;

/**
 * @author tlenz
 *
 */
public class PVPEntityCategoryFilter implements MetadataFilter {
	private static final Logger log = LoggerFactory.getLogger(PVPEntityCategoryFilter.class);
	
	private boolean isUsed = false;
	
	/**
	 * Filter to map PVP EntityCategories into a set of single PVP attributes 
	 * 
	 * @param isUsed if true PVP EntityCategories are mapped, otherwise they are ignored
	 * 
	 */
	public PVPEntityCategoryFilter(boolean isUsed) {
		this.isUsed = isUsed;
	}
	
	
	/* (non-Javadoc)
	 * @see org.opensaml.saml2.metadata.provider.MetadataFilter#doFilter(org.opensaml.xml.XMLObject)
	 */
	@Override
	public void doFilter(XMLObject metadata) throws FilterException {
		
		if (isUsed) {
			 log.trace("Map PVP EntityCategory to single PVP Attributes ... ");
			String entityId = null;
			try {
				if (metadata instanceof EntitiesDescriptor) {
					 log.trace("Find EnitiesDescriptor ... ");
					EntitiesDescriptor entitiesDesc = (EntitiesDescriptor) metadata;
					if (entitiesDesc.getEntityDescriptors() != null) {
						for (EntityDescriptor el : entitiesDesc.getEntityDescriptors()) 
							resolveEntityCategoriesToAttributes(el);
						
					}
									
				} else if (metadata instanceof EntityDescriptor) {
					 log.trace("Find EntityDescriptor");
					resolveEntityCategoriesToAttributes((EntityDescriptor)metadata);
					
					
				} else
					throw new PVP2MetadataException("Invalid Metadata file Root element is no Entities- or EntityDescriptor", null);
				
				
				
			} catch (Exception e) {
				 log.warn("SAML2 Metadata processing FAILED: Can not resolve EntityCategories for metadata: " + entityId, e);
				
			}
			
		} else
			 log.trace("Filter to map PVP EntityCategory to single PVP Attributes is deactivated");
		
	}

	private void resolveEntityCategoriesToAttributes(EntityDescriptor metadata) {
		 log.debug("Resolving EntityCategorie for Entity: " + metadata.getEntityID() + " ...");
		Extensions extensions = metadata.getExtensions();
		if (extensions != null) {
			List<XMLObject> listOfExt = extensions.getUnknownXMLObjects();
			if (listOfExt != null && !listOfExt.isEmpty()) {
				 log.trace("Find #" + listOfExt.size() + " 'Extension' elements ");
				for (XMLObject el : listOfExt) {
					 log.trace("Find ExtensionElement: " + el.getElementQName().toString());
					if (el instanceof EntityAttributes) {
						EntityAttributes entityAttrElem = (EntityAttributes)el;
						if (entityAttrElem.getAttributes() != null) {
							 log.trace("Find EntityAttributes. Start attribute processing ...");
							for (Attribute entityAttr : entityAttrElem.getAttributes()) {
								if (entityAttr.getName().equals(PVPConstants.ENTITY_CATEGORY_ATTRIBITE)) {
									if (!entityAttr.getAttributeValues().isEmpty()) {
										String entityAttrValue = entityAttr.getAttributeValues().get(0).getDOM().getTextContent();
										if (PVPConstants.EGOVTOKEN.equals(entityAttrValue)) {
											 log.debug("Find 'EGOVTOKEN' EntityAttribute. Adding single pvp attributes ... ");
											addAttributesToEntityDescriptor(metadata, 
													buildAttributeList(PVPConstants.EGOVTOKEN_PVP_ATTRIBUTES), 
													entityAttrValue);
											
																													
										} else if (PVPConstants.CITIZENTOKEN.equals(entityAttrValue)) {
											 log.debug("Find 'CITIZENTOKEN' EntityAttribute. Adding single pvp attributes ... ");
											addAttributesToEntityDescriptor(metadata, 
													buildAttributeList(PVPConstants.CITIZENTOKEN_PVP_ATTRIBUTES), 
													entityAttrValue);
											
										} else
											 log.info("EntityAttributeValue: " + entityAttrValue + " is UNKNOWN!");
																			
									} else
										 log.info("EntityAttribute: No attribute value");
																		
								} else 
									 log.info("EntityAttribute: " + entityAttr.getName() + " is NOT supported");
								
							}
										
						} else
							 log.info("Can NOT resolve EntityAttributes! Reason: Only EntityAttributes are supported!");
						
					}					
				}
				
			} else
				 log.trace("'Extension' element is 'null' or empty");
			
		} else
			 log.trace("No 'Extension' element found");
				
	}
	
	/**
	 * @param metadata
	 * @param attrList
	 */
	private void addAttributesToEntityDescriptor(EntityDescriptor metadata, List<RequestedAttribute> attrList, String entityAttr) {
		SPSSODescriptor spSSODesc = metadata.getSPSSODescriptor(SAMLConstants.SAML20P_NS);
		if (spSSODesc != null) {
			if (spSSODesc.getAttributeConsumingServices() == null || 
					spSSODesc.getAttributeConsumingServices().isEmpty()) {
				 log.trace("No 'AttributeConsumingServices' found. Added it ...");
				
				AttributeConsumingService attributeService = SAML2Utils.createSAMLObject(AttributeConsumingService.class);						
				attributeService.setIndex(0);
				attributeService.setIsDefault(true);
				ServiceName serviceName = SAML2Utils.createSAMLObject(ServiceName.class);
				serviceName.setName(new LocalizedString("Default Service", "en"));
				attributeService.getNames().add(serviceName);
				
				if (attrList != null && !attrList.isEmpty()) {
					attributeService.getRequestAttributes().addAll(attrList);
					 log.info("Add  " + attrList.size() + " attributes for 'EntityAttribute': " + entityAttr);
					
				}
				
				spSSODesc.getAttributeConsumingServices().add(attributeService);
				
			} else {
				 log.debug("Find 'AttributeConsumingServices'. Starting updating process ... ");
				for (AttributeConsumingService el : spSSODesc.getAttributeConsumingServices()) {
					 log.debug("Update 'AttributeConsumingService' with Index: " + el.getIndex());
					
					//load currently requested attributes
					List<String> currentlyReqAttr = new ArrayList<String>();
					for (RequestedAttribute reqAttr : el.getRequestAttributes())
						currentlyReqAttr.add(reqAttr.getName());
						

					//check against EntityAttribute List
					for (RequestedAttribute entityAttrListEl : attrList) {
						if (!currentlyReqAttr.contains(entityAttrListEl.getName())) {
							el.getRequestAttributes().add(entityAttrListEl);
							
						} else
							 log.debug("'AttributeConsumingService' already contains attr: " + entityAttrListEl.getName());
						
					}
					
				}
				
			}
			
		} else
			 log.info("Can ONLY add 'EntityAttributes' to 'SPSSODescriptor'");
		
	}

	private List<RequestedAttribute> buildAttributeList(List<Trible<String, String, Boolean>> attrSet) {
		List<RequestedAttribute> requestedAttributes = new ArrayList<RequestedAttribute>();
		for (Trible<String, String, Boolean> el : attrSet)
			requestedAttributes.add(PVPAttributeBuilder.buildReqAttribute(el.getFirst(), el.getSecond(), el.getThird()));	
					
		return requestedAttributes;
		
		
	}
	 	
}