/*
    * 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.basepom.mojo.propertyhelper.fields;
  
  import static com.google.common.base.Preconditions.checkNotNull;
  
  import org.basepom.mojo.propertyhelper.Field;
  import org.basepom.mojo.propertyhelper.FieldContext;
  import org.basepom.mojo.propertyhelper.ValueProvider;
  import org.basepom.mojo.propertyhelper.definitions.UuidDefinition;
  
  import java.util.Optional;
  import java.util.Random;
  import java.util.StringJoiner;
  import java.util.UUID;
  
  import com.google.common.annotations.VisibleForTesting;
  
  public final class UuidField extends Field<String, UuidDefinition> {
  
      private final ValueProvider valueProvider;
      private final Random secureRandom;
  
      @VisibleForTesting
      public static UuidField forTesting(UuidDefinition uuidDefinition, ValueProvider valueProvider) {
          return new UuidField(uuidDefinition, valueProvider, FieldContext.forTesting());
      }
  
      public UuidField(final UuidDefinition uuidDefinition, final ValueProvider valueProvider,
          FieldContext fieldContext) {
          super(uuidDefinition, fieldContext);
  
          this.valueProvider = checkNotNull(valueProvider, "valueProvider is null");
  
          this.secureRandom = fieldContext.getRandom();
      }
  
      @Override
      public String getFieldName() {
          return fieldDefinition.getId();
      }
  
      @Override
      public String getValue() {
          final Optional<String> propValue = valueProvider.getValue();
  
          // Only add the value from the provider if it is not null.
          UUID result = propValue.map(UUID::fromString)
              .orElse(fieldDefinition.getValue()
                  .orElseGet(this::createRandomUUID));
  
          valueProvider.setValue(result.toString());
          return formatResult(result.toString());
      }
  
      private UUID createRandomUUID() {
          long upperValue = secureRandom.nextLong();
          long lowerValue = secureRandom.nextLong();
  
          // UUID v4 (random) - see https://datatracker.ietf.org/doc/html/rfc4122#section-4.4
          lowerValue &= 0xff0fffffffffffffL; // clear top four bits of time_hi_and_version
          lowerValue |= 0x0040000000000000L; // set to 0100 (UUID v4)
          upperValue &= 0xffffffffffffff3fL; // clear top two bits of clock_seq_hi_and_reserved
          upperValue |= 0x0000000000000080L; // set to 1 and 0
  
          return new UUID(upperValue, lowerValue);
      }
  
  
      @Override
      public String toString() {
          return new StringJoiner(", ", UuidField.class.getSimpleName() + "[", "]")
              .add("uuidDefinition=" + fieldDefinition)
              .add("valueProvider=" + valueProvider)
              .toString();
      }
  }