/*******************************************************************************
 * Copyright 2014 Federal Chancellery Austria
 * MOA-ID has been developed in a cooperation between BRZ, the Federal
 * Chancellery Austria - ICT staff unit, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.1 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:
 * http://www.osor.eu/eupl/
 *
 * 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.egovernment.moa.id.protocols.stork2.attributeproviders;

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

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import at.gv.egovernment.moa.id.auth.exception.MOAIDException;
import at.gv.egovernment.moa.id.config.auth.OAAuthParameter;
import at.gv.egovernment.moa.id.data.IAuthData;
import at.gv.egovernment.moa.id.protocols.stork2.ExternalAttributeRequestRequiredException;
import at.gv.egovernment.moa.id.protocols.stork2.MOASTORKRequest;
import at.gv.egovernment.moa.id.protocols.stork2.UnsupportedAttributeException;
import eu.stork.peps.auth.commons.IPersonalAttributeList;
import eu.stork.peps.auth.commons.PersonalAttribute;

/**
 * An {@link AttributeProvider} can fetch a set of stork attributes. It might complete the query within one method call,
 * but might also need to redirect to another webservice to accomplish its task.
 */
public abstract class AttributeProvider implements Comparable<AttributeProvider>{

	protected String attributes;
	
	public AttributeProvider(String attributes){
		this.attributes = attributes;
	}
	
	/**
	 * Acquire the specified attribute. Returns {@code null} when attribute retrieval is in progress, but requires for
	 * for redirecting the user to an external service. Use {@link AttributeProvider#parse(HttpServletRequest)} to parse
	 * the response.
	 *
	 * @param currentProviderConfiguredAttributes the list of attributes to be acquired
	 * @param moastorkRequest the sp county code
	 * @param authData the moasession
	 * @return the personal attribute
	 * @throws UnsupportedAttributeException the unsupported attribute exception
	 * @throws ExternalAttributeRequestRequiredException an attribute request to an external service has to be done
	 * @throws MOAIDException the mOAID exception
	 */
	protected abstract IPersonalAttributeList acquire(PersonalAttribute currentProviderConfiguredAttributes, MOASTORKRequest moastorkRequest, IAuthData authData) throws UnsupportedAttributeException, ExternalAttributeRequestRequiredException, MOAIDException;

    public IPersonalAttributeList acquire(List<PersonalAttribute> attributes, MOASTORKRequest moastorkRequest, IAuthData authData) throws UnsupportedAttributeException, ExternalAttributeRequestRequiredException, MOAIDException {
        if (attributes.size() == 1) {
            return acquire(attributes.get(0), moastorkRequest, authData);
        } else {
            throw new MOAIDException("stork.13", new Object[] {  });  // TODO message only one attribute supported by this provider

        }
    }

    /**
	 * Perform redirect.
	 *
	 * @param url the return URL ending with ?artifactId=...
	 * @param req the request we got from the S-PEPS and for which we have to ask our APs
	 * @param resp the response to the preceding request
	 * @param oaParam the oa param
	 * @throws MOAIDException the mOAID exception
	 */
	public abstract void performRedirect(String url, HttpServletRequest req, HttpServletResponse resp, OAAuthParameter oaParam) throws MOAIDException;
	
	/**
	 * Parses the response we got from the external attribute provider.
	 *
	 * @param httpReq the http req
	 * @return a list of attributes
	 * @throws UnsupportedAttributeException if the provider cannot find anything familiar in the provided httpReq
	 * @throws MOAIDException if something went wrong
	 */
	public abstract IPersonalAttributeList parse(HttpServletRequest httpReq) throws UnsupportedAttributeException, MOAIDException;

    /**
     * Returns the list of supported attributes
     *
     * @return a list of attributes
     * @throws MOAIDException if something went wrong
     */
    public List<String> getSupportedAttributeNames() throws MOAIDException {
        ArrayList<String> supportedAttributeNames = new ArrayList<String>();
        for (String attributeName : this.attributes.split(",")) {
            supportedAttributeNames.add(attributeName);
        }
        return supportedAttributeNames;
    }

    
    /**
     * Returns the sequence priority of this attribute provider.
     * Providers with small numbers are requested first. 
     * 
     * @return a sequence priority of this provider
     */
    public abstract int getPriority();
 
    /**
     * Compare the sequence priority of two attribute providers 
     * @param o attribute provider
     * @return 0 if priority is equal
     * @return -1 if priority if this is higher then from o
     * @return +1 if priority if o is higher then from this
     */
	@Override
	public int compareTo(AttributeProvider o) {
    	if (this.getPriority() == o.getPriority())
    		return 0;
    	
    	if (this.getPriority() < o.getPriority())
    		return -1;
    	
    	else
    		return +1;
	}
    
}