/*
 * Copyright (C) 2015 Google, Inc.
 *
 * 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 dagger.internal.codegen;

import com.google.auto.common.BasicAnnotationProcessor.ProcessingStep;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.SetMultimap;
import dagger.producers.ProductionComponent;
import java.lang.annotation.Annotation;
import java.util.Set;
import javax.annotation.processing.Messager;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;

import static javax.lang.model.util.ElementFilter.typesIn;

/**
 * A processing step that is responsible for generating a special module for a
 * {@link ProductionComponent}.
 */
final class MonitoringModuleProcessingStep implements ProcessingStep {
  private final Messager messager;
  private final MonitoringModuleGenerator monitoringModuleGenerator;

  MonitoringModuleProcessingStep(
      Messager messager, MonitoringModuleGenerator monitoringModuleGenerator) {
    this.messager = messager;
    this.monitoringModuleGenerator = monitoringModuleGenerator;
  }

  @Override
  public Set<? extends Class<? extends Annotation>> annotations() {
    return ImmutableSet.of(ProductionComponent.class);
  }

  @Override
  public Set<Element> process(
      SetMultimap<Class<? extends Annotation>, Element> elementsByAnnotation) {
    for (TypeElement element : typesIn(elementsByAnnotation.get(ProductionComponent.class))) {
      try {
        monitoringModuleGenerator.generate(element);
      } catch (SourceFileGenerationException e) {
        e.printMessageTo(messager);
      }
    }
    return ImmutableSet.of();
  }
}