/*
    * Copyright 2015 the original author or authors.
    * 
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *     
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.openehealth.ipf.commons.ihe.xds.core.validate;
  
  import org.openehealth.ipf.commons.core.URN;
  
  import java.net.URI;
  import java.util.Optional;
  import java.util.UUID;
  import java.util.regex.Pattern;
  
  import static org.apache.commons.lang3.Validate.notNull;
  import static org.openehealth.ipf.commons.ihe.xds.core.validate.ValidationMessage.INVALID_UUID;
  import static org.openehealth.ipf.commons.ihe.xds.core.validate.ValidatorAssertions.metaDataAssert;
  
  /**
   * Validator for UUIDs
   * @author Boris Stanojevic
   */
  public class UUIDValidator implements ValueValidator {
  
      private static final Pattern UUID_PATTERN =
              Pattern.compile(".*[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}");
  
      @Override
      public void validate(String uuid) throws XDSMetaDataException {
          notNull(uuid, "uuid cannot be null");
          metaDataAssert(UUID_PATTERN.matcher(uuid).matches(), INVALID_UUID, uuid);
      }
  
      /**
       * @param id identifier
       * @return identifier if the id is not an UUID, Optional.empty otherwise
       */
      public Optional<String> getSymbolicId(String id) {
          return !isUUID(id) ? Optional.of(id) : Optional.empty();
      }
  
      /**
       * @param id identifier
       * @return true if identifier is a valid UUID
       */
      public boolean isUUID(String id) {
          return getAsUUID(id).isPresent();
      }
  
      /**
       * @param urn urn
       * @return UUID if uri is a valid UUID, Optional.empty otherwise
       */
      public Optional<UUID> getAsUUID(String urn) {
          try {
              return Optional.of(UUID.fromString(urn.substring("urn:uuid:".length())));
          } catch (RuntimeException e) {
              return Optional.empty();
          }
      }
  
      /**
       * @param uri uri
       * @return UUID if uri is a valid UUID, Optional.empty otherwise
       */
      public Optional<UUID> getAsUUID(URI uri) {
          return getAsUUID(uri.toString());
      }
  
      /**
       * @param urn urn
       * @return UUID if uri is a valid UUID, Optional.empty otherwise
       */
      public Optional<UUID> getAsUUID(URN urn) {
          return getAsUUID(urn.toString());
      }
  }