/*******************************************************************************
 * 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.builder;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.ServiceLoader;

import org.opensaml.saml2.core.Attribute;
import org.opensaml.saml2.metadata.RequestedAttribute;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import at.gv.egiz.eaaf.core.api.idp.IAttributeBuilder;
import at.gv.egiz.eaaf.core.api.idp.IAttributeGenerator;
import at.gv.egiz.eaaf.core.api.idp.IAuthData;
import at.gv.egiz.eaaf.core.api.idp.ISPConfiguration;
import at.gv.egiz.eaaf.core.exceptions.AttributeBuilderException;
import at.gv.egiz.eaaf.core.exceptions.InvalidDateFormatAttributeException;
import at.gv.egiz.eaaf.core.exceptions.UnavailableAttributeException;
import at.gv.egiz.eaaf.core.impl.idp.builder.attributes.PVPMETADATA;
import at.gv.egiz.eaaf.modules.pvp2.exception.InvalidDateFormatException;
import at.gv.egiz.eaaf.modules.pvp2.exception.PVP2Exception;
import at.gv.egiz.eaaf.modules.pvp2.impl.utils.SAML2Utils;

public class PVPAttributeBuilder {
	
	private static final Logger log = LoggerFactory.getLogger(PVPAttributeBuilder.class);
	
	private static IAttributeGenerator<Attribute> generator = new SamlAttributeGenerator();	
	private static HashMap<String, IAttributeBuilder> builders;
	
	private static ServiceLoader<IAttributeBuilder> attributBuilderLoader = 
			ServiceLoader.load(IAttributeBuilder.class);
	
	private static void addBuilder(IAttributeBuilder builder) {
		builders.put(builder.getName(), builder);
	}
	 
	static {
		builders = new HashMap<String, IAttributeBuilder>();
		
		log.info("Loading protocol attribut-builder modules:");
		if (attributBuilderLoader != null ) {		
			Iterator<IAttributeBuilder> moduleLoaderInterator = attributBuilderLoader.iterator();
			while (moduleLoaderInterator.hasNext()) {
				try {
					IAttributeBuilder modul = moduleLoaderInterator.next();
					log.info("Loading attribut-builder Modul Information: " + modul.getName());
					addBuilder(modul);
					
				} catch(Throwable e) {
					log.error("Check configuration! " + "Some attribute-builder modul" + 
							" is not a valid IAttributeBuilder", e);
				}	
			}
		}
		
		log.info("Loading attribute-builder modules done");
				
	}
	
	
	/**
	 * Get a specific attribute builder
	 * 
	 * @param name Attribute-builder friendly name
	 * 
	 * @return Attribute-builder with this name or null if builder does not exists
	 */
	public static IAttributeBuilder getAttributeBuilder(String name) {
		return builders.get(name);
		
	}
	
	public static Attribute buildAttribute(String name, ISPConfiguration  oaParam,
			IAuthData authData) throws PVP2Exception, AttributeBuilderException {
		if (builders.containsKey(name)) {
			try {
				return builders.get(name).build(oaParam, authData, generator);
			}
			catch (AttributeBuilderException e) {
				if (e instanceof UnavailableAttributeException) {
					throw e;
					
				} else if (e instanceof InvalidDateFormatAttributeException) {
					throw new InvalidDateFormatException();
										 
				} else {
					throw new UnavailableAttributeException(name);
					
				}
			}
		}
		return null;
	}
	
	public static Attribute buildEmptyAttribute(String name) {
		if (builders.containsKey(name)) {
			return builders.get(name).buildEmpty(generator);
		}
		return null;
	}

	public static Attribute buildAttribute(String name, String value) {
		if (builders.containsKey(name)) {
			return builders.get(name).buildEmpty(generator);
		}
		return null;
	}
	
	
	/**
	 * Return all attributes that has a {@link PVPMETADATA} annotation
	 * 
	 * @return
	 */
	public static List<Attribute> buildSupportedEmptyAttributes() {
		List<Attribute> attributes = new ArrayList<Attribute>();
		Iterator<IAttributeBuilder> builderIt = builders.values().iterator();
		while (builderIt.hasNext()) {
			IAttributeBuilder builder = builderIt.next();
			if (builder.getClass().isAnnotationPresent(PVPMETADATA.class)) {
				Attribute emptyAttribute = builder.buildEmpty(generator);
				if (emptyAttribute != null) {
					attributes.add(emptyAttribute);
				}
				
			} else {
				log.trace(builder.getName() + "is no PVP Metadata attribute");
				
			}
		}
		return attributes;
	}
	
	public static RequestedAttribute buildReqAttribute(String name, String friendlyName, boolean required) {
		RequestedAttribute attribute = SAML2Utils.createSAMLObject(RequestedAttribute.class);
		attribute.setIsRequired(required);
		attribute.setName(name);
		attribute.setFriendlyName(friendlyName);
		attribute.setNameFormat(Attribute.URI_REFERENCE);
		return attribute;
	}
	
	/**
	 * Build a set of PVP Response-Attributes
	 * <br><br>
	 * <b>INFO:</b> If a specific attribute can not be build, a info is logged, but no execpetion is thrown.
	 * Therefore, the return List must not include all requested attributes.    
	 * 
	 * @param authData AuthenticationData <code>IAuthData</code> which is used to build the attribute values, but never <code>null</code>
	 * @param reqAttributenName List of PVP attribute names which are requested, but never <code>null</code>
	 * @return List of PVP attributes, but never <code>null</code>
	 */
	public static List<Attribute> buildSetOfResponseAttributes(IAuthData authData, 
			Collection<String> reqAttributenName) {
		List<Attribute> attrList = new ArrayList<Attribute>();
		if (reqAttributenName != null) {		
			Iterator<String> it = reqAttributenName.iterator();
			while (it.hasNext()) {
				String reqAttributName = it.next();
				try {
					Attribute attr = PVPAttributeBuilder.buildAttribute(
							reqAttributName, null, authData);
					if (attr == null) {
						log.info(
								"Attribute generation failed! for "
										+ reqAttributName);
					
					} else {
						attrList.add(attr);
					
					}
									
				} catch (PVP2Exception e) {
					log.info(
							"Attribute generation failed! for "
									+ reqAttributName);
				
				} catch (Exception e) {
					log.warn(
							"General Attribute generation failed! for "
									+ reqAttributName, e);
				
				}
			}
		}
		
		return attrList;
	}
	
	
}