content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * 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 androidx.test.espresso.remote;
  
  import static androidx.test.internal.util.Checks.checkNotNull;
  import static androidx.test.internal.util.Checks.checkState;
  
  import androidx.annotation.NonNull;
  import androidx.test.espresso.remote.annotation.RemoteMsgField;
  import java.lang.annotation.Annotation;
  import java.lang.reflect.Field;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Locale;
  import java.util.TreeMap;
  
  /**
   * Provides additional meta data about a {@link Field} declared in a class.
   *
   * <p>The data provided here is used at runtime to reflectively access fields that require proto
   * serialization.
   */
  public final class FieldDescriptor {
    public final Class<?> fieldType;
    public final String fieldName;
    public final int order;
  
    private FieldDescriptor(@NonNull Class<?> fieldType, @NonNull String fieldName, int order) {
      this.fieldType = checkNotNull(fieldType, "fieldType cannot be null!");
      this.fieldName = checkNotNull(fieldName, "fieldName cannot be null!");
      checkState(order >= 0, "Field order must be greater then or equal to 0!");
      this.order = order;
    }
  
    /**
     * Creates a {@link FieldDescriptor} instance.
     *
     * @param fieldType the type of the field
     * @param fieldName the name of the field as declared in the class
     * @param order the declared order of the field, order values need to start with 0
     */
    public static FieldDescriptor of(
        @NonNull Class<?> fieldType, @NonNull String fieldName, int order) {
      return new FieldDescriptor(fieldType, fieldName, order);
    }
  
    /**
     * Creates a {@link FieldDescriptor} instance from a {@link Field} and {@link Annotation}.
     *
     * @param field a {@link Field} object
     * @param remoteMsgFieldAnnotation an {@link Annotation} attached to {@code field}
     */
    static FieldDescriptor of(
        @NonNull Field field, @NonNull RemoteMsgField remoteMsgFieldAnnotation) {
      checkNotNull(field, "field cannot be null");
      checkNotNull(remoteMsgFieldAnnotation, "remoteMsgFieldAnnotation cannot be null");
      return of(field.getType(), field.getName(), remoteMsgFieldAnnotation.order());
    }
  
    static List<FieldDescriptor> getFieldDescriptorsFromAnnotation(
        Class<?> clazz, Class<RemoteMsgField> annotation) {
      TreeMap<Integer, FieldDescriptor> targetFields = new TreeMap<>();
      Field[] declaredFields = clazz.getDeclaredFields();
      for (Field field : declaredFields) {
        if (field.isAnnotationPresent(annotation)) {
          RemoteMsgField remoteMsgFieldAnnotation = field.getAnnotation(annotation);
          int order = remoteMsgFieldAnnotation.order();
          if (targetFields.containsKey(order)) {
            throw new IllegalStateException(
                String.format(
                    Locale.ROOT, "Duplicate field order %s for field %s", order, field.getName()));
          }
          targetFields.put(order, of(field, remoteMsgFieldAnnotation));
        }
      }
      return new ArrayList<>(targetFields.values());
    }
  
    @Override
    public boolean equals(Object o) {
      if (this == o) {
        return true;
      }
      if (o == null || getClass() != o.getClass()) {
        return false;
      }
  
      FieldDescriptor that = (FieldDescriptor) o;
  
      if (order != that.order) {
        return false;
      }
      if (fieldType != null ? !fieldType.equals(that.fieldType) : that.fieldType != null) {
        return false;
      }
      return fieldName != null ? fieldName.equals(that.fieldName) : that.fieldName == null;
    }
  
    @Override
    public int hashCode() {
      int result = fieldType != null ? fieldType.hashCode() : 0;
      result = 31 * result + (fieldName != null ? fieldName.hashCode() : 0);
      result = 31 * result + order;
      return result;
    }
  }
  