// Copyright 2015 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.analysis;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.actions.Artifact;
import com.google.devtools.build.lib.actions.BaseSpawn;
import com.google.devtools.build.lib.actions.RunfilesSupplier;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.io.IOException;
import java.util.Map;
import javax.annotation.Nullable;

/** {@link RunfilesSupplier} implementation wrapping a single {@link Runfiles} directory mapping. */
// TODO(bazel-team): Consider renaming to SingleRunfilesSupplierImpl.
public class RunfilesSupplierImpl implements RunfilesSupplier {
  private final PathFragment runfilesDir;
  private final Runfiles runfiles;
  @Nullable
  private final Artifact manifest;

  /**
   * Create an instance for an executable.
   *
   * @param executable the executable the runfiles are for, used for determining the runfiles
   *    directory
   * @param runfiles the associated runfiles
   */
  public RunfilesSupplierImpl(Artifact executable, Runfiles runfiles) {
    this(BaseSpawn.runfilesForFragment(executable.getExecPath()), runfiles);
  }

  /**
   * Create an instance. When a manifest is available consider using
   * {@link #RunfilesSupplierImpl(PathFragment, Runfiles, Artifact)} instead.
   */
  public RunfilesSupplierImpl(PathFragment runfilesDir, Runfiles runfiles) {
    this(runfilesDir, runfiles, /*manifest=*/ null);
  }

  /**
   * Create an instance mapping {@code runfiles} to {@code runfilesDir}.
   *
   * @param runfilesDir the desired runfiles directory. Should be relative.
   * @param runfiles the runfiles for runilesDir.
   * @param manifest runfiles' associated runfiles manifest artifact, if present.
   */
  public RunfilesSupplierImpl(
      PathFragment runfilesDir,
      Runfiles runfiles,
      @Nullable Artifact manifest) {
    Preconditions.checkArgument(!runfilesDir.isAbsolute());
    this.runfilesDir = Preconditions.checkNotNull(runfilesDir);
    this.runfiles = Preconditions.checkNotNull(runfiles);
    this.manifest = manifest;
  }

  @Override
  public Iterable<Artifact> getArtifacts() {
    return Iterables.filter(runfiles.getAllArtifacts(), Artifact.MIDDLEMAN_FILTER);
  }

  @Override
  public ImmutableSet<PathFragment> getRunfilesDirs() {
    return ImmutableSet.of(runfilesDir);
  }

  @Override
  public ImmutableMap<PathFragment, Map<PathFragment, Artifact>> getMappings() throws IOException {
    return ImmutableMap.of(
        runfilesDir,
        runfiles.getRunfilesInputs(/*eventHandler=*/ null, /*location=*/ null));
  }

  @Override
  public ImmutableList<Artifact> getManifests() {
    return manifest != null ? ImmutableList.of(manifest) : ImmutableList.<Artifact>of();
  }
}