/*
 * Copyright (C) 2019 The Dagger Authors.
 *
 * 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.hilt.processor.internal;

import com.google.auto.value.AutoValue;
import com.google.common.collect.ImmutableSet;
import com.squareup.javapoet.ClassName;
import java.util.Optional;

// TODO(bcorso): Reduce the visibility of this class and return ClassNames instead.
// TODO(erichang): Rename this class so it doesn't conflict with
// dagger.internal.codegen.ComponentDescriptor
/** Represents a single component in the hierarchy. */
@AutoValue
public abstract class ComponentDescriptor {
  public static Builder builder() {
    return new AutoValue_ComponentDescriptor.Builder()
        .scopes(ImmutableSet.of());
  }

  /** Returns the {@link ClassName} for this component descriptor. */
  public abstract ClassName component();

  /** Returns the {@link ClassName}s for the scopes of this component descriptor. */
  public abstract ImmutableSet<ClassName> scopes();

  /** Returns the {@link ClassName} for the creator interface. if it exists. */
  public abstract Optional<ClassName> creator();

  /** Returns the {@link ClassName} for the parent, if it exists. */
  public abstract Optional<ComponentDescriptor> parent();

  /** Returns {@code true} if the descriptor represents a root component. */
  public boolean isRoot() {
    return !parent().isPresent();
  }

  /**
   * Returns {@code true} if the given {@link ComponentDescriptor} represents the same {@link
   * #component()}.
   */
  // TODO(b/144939893): Remove equals and hashcode once we have unique ComponentDescriptor instances
  @Override
  public final boolean equals(Object obj) {
    if (obj == this) {
      return true;
    }
    if (!(obj instanceof ComponentDescriptor)) {
      return false;
    }
    ComponentDescriptor that = (ComponentDescriptor) obj;

    // Only check the component name, which should map 1:1 to each component descriptor created
    // by DefineComponents#componentDescriptor(Element). However, if users are building their own
    // ComponentDescriptors manually, then this might not be true. We should lock down the builder
    // method to avoid that.
    return component().equals(that.component());
  }

  @Override
  public final int hashCode() {
    return component().hashCode();
  }

  /** Builder for ComponentDescriptor. */
  @AutoValue.Builder
  public interface Builder {
    Builder component(ClassName component);

    Builder scopes(ImmutableSet<ClassName> scopes);

    Builder scopes(ClassName... scopes);

    Builder creator(ClassName creator);

    Builder parent(ComponentDescriptor parent);


    ComponentDescriptor build();
  }
}