/*
    * 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 static com.google.common.base.Preconditions.checkNotNull;
  import static com.google.common.base.Preconditions.checkState;
  import static java.lang.String.format;
  
  import org.basepom.mojo.propertyhelper.beans.MacroDefinition;
  import org.basepom.mojo.propertyhelper.macros.MacroType;
  
  import java.io.IOException;
  import java.util.List;
  import java.util.Optional;
  
  import com.google.common.collect.ImmutableList;
  import com.google.common.collect.ImmutableList.Builder;
  import org.apache.maven.plugin.MojoExecutionException;
  
  public class MacroField
          implements PropertyElement {
  
      private final MacroDefinition macroDefinition;
      private final ValueProvider valueProvider;
      private final AbstractPropertyHelperMojo mojo;
  
      public MacroField(final MacroDefinition macroDefinition,
              final ValueProvider valueProvider,
              final AbstractPropertyHelperMojo mojo) {
          this.macroDefinition = macroDefinition;
          this.valueProvider = valueProvider;
          this.mojo = mojo;
      }
  
      public static List<MacroField> createMacros(final ValueCache valueCache,
              final MacroDefinition[] macroDefinitions,
              final AbstractPropertyHelperMojo mojo)
              throws IOException {
          checkNotNull(valueCache, "valueCache is null");
          checkNotNull(macroDefinitions, "macroDefinitions is null");
          checkNotNull(mojo, "mojo is null");
  
          final Builder<MacroField> result = ImmutableList.builder();
  
          for (MacroDefinition macroDefinition : macroDefinitions) {
              macroDefinition.check();
              final ValueProvider macroValue = valueCache.getValueProvider(macroDefinition);
              final MacroField macroField = new MacroField(macroDefinition, macroValue, mojo);
              result.add(macroField);
          }
  
          return result.build();
      }
  
      @Override
      public String getPropertyName() {
          return macroDefinition.getId();
      }
  
      @Override
      public Optional<String> getPropertyValue() throws MojoExecutionException {
          final Optional<String> type = macroDefinition.getMacroType();
          final MacroType macroType;
  
          try {
              if (type.isPresent()) {
                  macroType = mojo.getMacros().get(type.get());
                  checkState(macroType != null, "Could not locate macro '%s'", type.get());
              } else {
                  final Optional<String> macroClassName = macroDefinition.getMacroClass();
                  checkState(macroClassName.isPresent(), "No definition for macro '%s' found!", macroDefinition.getId());
                  final Class<?> macroClass = Class.forName(macroClassName.get());
                  macroType = (MacroType) macroClass.getDeclaredConstructor().newInstance();
              }
  
              Optional<String> result = macroType.getValue(macroDefinition, valueProvider, mojo);
              if (result.isPresent()) {
                  return macroDefinition.formatResult(result.get());
              }
              return result;
          } catch (ReflectiveOperationException e) {
              throw new MojoExecutionException(format("Could not instantiate '%s'", macroDefinition), e);
          }
      }
  
      @Override
      public boolean isExport() {
         return macroDefinition.isExport();
     }
 
     @Override
     public String toString() {
         try {
             return getPropertyValue().orElse("");
         } catch (Exception e) {
             return "<unset>";
         }
     }
 }