/*
 * Copyright 2017 Graz University of Technology EAAF-Core Components has been developed in a
 * cooperation between EGIZ, A-SIT Plus, 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.core.impl.idp.builder.attributes;

import javax.annotation.Nonnull;

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.Assert;

import at.gv.egiz.eaaf.core.api.data.EaafConstants;
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.IPvpAttributeBuilder;
import at.gv.egiz.eaaf.core.api.idp.ISpConfiguration;
import at.gv.egiz.eaaf.core.exceptions.AttributeBuilderException;
import at.gv.egiz.eaaf.core.exceptions.UnavailableAttributeException;

@PvpMetadata
public class BpkAttributeBuilder implements IPvpAttributeBuilder {

  private static final Logger log = LoggerFactory.getLogger(BpkAttributeBuilder.class);
  public static final String DELIMITER_BPKTYPE_BPK = ":";

  @Override
  public String getName() {
    return BPK_NAME;
  }

  @Override
  public <ATT> ATT build(final ISpConfiguration oaParam, final IAuthData authData,
      final IAttributeGenerator<ATT> g) throws AttributeBuilderException {
    final String result = getBpkForSP(authData);
    log.trace("Authenticate user with bPK/wbPK: " + result);
    return g.buildStringAttribute(BPK_FRIENDLY_NAME, BPK_NAME, result);

  }

  @Override
  public <ATT> ATT buildEmpty(final IAttributeGenerator<ATT> g) {
    return g.buildEmptyAttribute(BPK_FRIENDLY_NAME, BPK_NAME);
  }

  protected String getBpkForSP(final IAuthData authData) throws UnavailableAttributeException {
    final String bpk = attrMaxSize(authData.getBpk());
    final String type = removeBpkTypePrefix(authData.getBpkType());

    if (StringUtils.isEmpty(bpk)) {
      throw new UnavailableAttributeException(BPK_NAME);
    }

    return type + DELIMITER_BPKTYPE_BPK + bpk;

  }

  protected String attrMaxSize(String attr) {
    if (attr != null && attr.length() > BPK_MAX_LENGTH) {
      attr = attr.substring(0, BPK_MAX_LENGTH);
    }
    return attr;

  }

  @Nonnull
  protected String removeBpkTypePrefix(@Nonnull final String type) {
    Assert.isTrue(type != null, "bPKType is 'NULL'");
    if (type.startsWith(EaafConstants.URN_PREFIX_WBPK)) {
      return type.substring(EaafConstants.URN_PREFIX_WBPK.length());
      
    } else if (type.startsWith(EaafConstants.URN_PREFIX_CDID)) {
      return type.substring(EaafConstants.URN_PREFIX_CDID.length());
      
    } else if (type.startsWith(EaafConstants.URN_PREFIX_EIDAS)) {
      return type.substring(EaafConstants.URN_PREFIX_EIDAS.length());
      
    } else {
      return type;
      
    }

  }
}