/*
    * 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;
  
  
  import org.basepom.mojo.propertyhelper.definitions.FieldDefinition;
  
  import java.util.Optional;
  
  import com.google.common.collect.ImmutableMap;
  import org.apache.maven.plugin.MojoExecutionException;
  
  /**
   * Describe all the fields.
   */
  public abstract class Field<T, U extends FieldDefinition<T>> {
  
      protected final U fieldDefinition;
      private final InterpolatorFactory interpolatorFactory;
      private final TransformerRegistry transformerRegistry;
  
  
      protected Field(U fieldDefinition, FieldContext context) {
          this.fieldDefinition = fieldDefinition;
          this.interpolatorFactory = context.getInterpolatorFactory();
          this.transformerRegistry = context.getTransformerRegistry();
      }
  
      /**
       * The name of the field.
       */
      public abstract String getFieldName();
  
      /**
       * The value of the field. {@link Optional#empty()} can be returned if the value is not defined.
       */
      public abstract String getValue() throws MojoExecutionException;
  
      protected String formatResult(T value) {
  
          return Optional.ofNullable(value)
              .map(fieldDefinition.getPreFormat())
              .map(interpolatorFactory.interpolate(getFieldName(), fieldDefinition.getOnMissingProperty(), ImmutableMap.of()))
              .map(fieldDefinition.getPostFormat())
              .map(fieldDefinition.getRegexp())
              .map(transformerRegistry.applyTransformers(fieldDefinition.getTransformers()))
              .orElse("");
      }
  
      /**
       * True if the value of this element should be exposed as a maven property.
       */
      public boolean isExposeAsProperty() {
          return fieldDefinition.isExport();
      }
  }