// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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 com.google.devtools.build.lib.skyframe;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.FileArtifactValue;
import com.google.devtools.build.lib.util.BigIntegerFingerprint;
import com.google.devtools.build.lib.util.Pair;
import com.google.devtools.build.skyframe.SkyValue;
import java.math.BigInteger;
import java.util.Collection;
import javax.annotation.Nullable;

/** Value for aggregating artifacts, which must be expanded to a set of other artifacts. */
class AggregatingArtifactValue implements SkyValue {
  private final FileArtifactValue selfData;
  private final ImmutableList<Pair<Artifact, FileArtifactValue>> fileInputs;
  private final ImmutableList<Pair<Artifact, TreeArtifactValue>> directoryInputs;

  AggregatingArtifactValue(
      ImmutableList<Pair<Artifact, FileArtifactValue>> fileInputs,
      ImmutableList<Pair<Artifact, TreeArtifactValue>> directoryInputs,
      FileArtifactValue selfData) {
    this.fileInputs = Preconditions.checkNotNull(fileInputs);
    this.directoryInputs = Preconditions.checkNotNull(directoryInputs);
    this.selfData = Preconditions.checkNotNull(selfData);
  }

  /** Returns the none tree artifacts that this artifact expands to, together with their data. */
  Collection<Pair<Artifact, FileArtifactValue>> getFileArtifacts() {
    return fileInputs;
  }

  /**
   * Returns the tree artifacts that this artifact expands to, together with the information
   * to which artifacts the tree artifacts expand to.
   */
  Collection<Pair<Artifact, TreeArtifactValue>> getTreeArtifacts() {
    return directoryInputs;
  }

  /** Returns the data of the artifact for this value, as computed by the action cache checker. */
  FileArtifactValue getSelfData() {
    return selfData;
  }

  protected final BigIntegerFingerprint getFingerprintBuilder() {
    BigIntegerFingerprint fp = new BigIntegerFingerprint();
    fp.addNullableBigIntegerOrdered(selfData.getValueFingerprint());
    addFingerprint(fileInputs, fp);
    addFingerprint(directoryInputs, fp);
    return fp;
  }

  private static void addFingerprint(
      ImmutableList<? extends Pair<Artifact, ? extends SkyValue>> list,
      BigIntegerFingerprint fingerprint) {
    list.forEach(
        pair -> {
          fingerprint.addPath(pair.first.getExecPath());
          fingerprint.addBigIntegerOrdered(pair.second.getValueFingerprint());
        });
  }

  @Nullable
  @Override
  public BigInteger getValueFingerprint() {
    return getFingerprintBuilder().getFingerprint();
  }

  @SuppressWarnings("EqualsGetClass") // RunfilesArtifactValue not equal to Aggregating.
  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    AggregatingArtifactValue that = (AggregatingArtifactValue) o;
    return selfData.equals(that.selfData)
        && fileInputs.equals(that.fileInputs)
        && directoryInputs.equals(that.directoryInputs);
  }

  @Override
  public int hashCode() {
    return 31 * 31 * directoryInputs.hashCode() + 31 * fileInputs.hashCode() + selfData.hashCode();
  }
}