// 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.actions;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.analysis.platform.PlatformInfo;
import com.google.devtools.build.lib.vfs.PathFragment;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;

/** Base implementation of a Spawn. */
@Immutable
public class BaseSpawn implements Spawn {
  private final ImmutableList<String> arguments;
  private final ImmutableMap<String, String> environment;
  private final ImmutableMap<String, String> executionInfo;
  private final RunfilesSupplier runfilesSupplier;
  private final ActionExecutionMetadata action;
  private final ResourceSet localResources;

  public BaseSpawn(
      List<String> arguments,
      Map<String, String> environment,
      Map<String, String> executionInfo,
      RunfilesSupplier runfilesSupplier,
      ActionExecutionMetadata action,
      ResourceSet localResources) {
    this.arguments = ImmutableList.copyOf(arguments);
    this.environment = ImmutableMap.copyOf(environment);
    this.executionInfo = ImmutableMap.copyOf(executionInfo);
    this.runfilesSupplier = runfilesSupplier;
    this.action = action;
    this.localResources = localResources;
  }

  public BaseSpawn(
      List<String> arguments,
      Map<String, String> environment,
      Map<String, String> executionInfo,
      ActionExecutionMetadata action,
      ResourceSet localResources) {
    this(
        arguments,
        environment,
        executionInfo,
        EmptyRunfilesSupplier.INSTANCE,
        action,
        localResources);
  }

  public static PathFragment runfilesForFragment(PathFragment pathFragment) {
    return pathFragment.getParentDirectory().getChild(pathFragment.getBaseName() + ".runfiles");
  }

  @Override
  public final ImmutableMap<String, String> getExecutionInfo() {
    return executionInfo;
  }

  @Override
  public RunfilesSupplier getRunfilesSupplier() {
    return runfilesSupplier;
  }

  @Override
  public ImmutableList<String> getArguments() {
    // TODO(bazel-team): this method should be final, as the correct value of the args can be
    // injected in the ctor.
    return arguments;
  }

  @Override
  public ImmutableMap<PathFragment, ImmutableList<FilesetOutputSymlink>> getFilesetMappings() {
    return ImmutableMap.of();
  }

  @Override
  public ImmutableMap<String, String> getEnvironment() {
    PathFragment runfilesRoot = getRunfilesRoot();
    if (runfilesRoot == null
        || (environment.containsKey("JAVA_RUNFILES")
            && environment.containsKey("PYTHON_RUNFILES"))) {
      return environment;
    } else {
      ImmutableMap.Builder<String, String> env = ImmutableMap.builder();
      env.putAll(environment);
      // TODO(bazel-team): Unify these into a single env variable.
      String runfilesRootString = runfilesRoot.getPathString();
      env.put("JAVA_RUNFILES", runfilesRootString);
      env.put("PYTHON_RUNFILES", runfilesRootString);
      return env.build();
    }
  }

  /** @return the runfiles directory if there is only one, otherwise null */
  private PathFragment getRunfilesRoot() {
    Set<PathFragment> runfilesSupplierRoots = runfilesSupplier.getRunfilesDirs();
    if (runfilesSupplierRoots.size() == 1) {
      return Iterables.getOnlyElement(runfilesSupplierRoots);
    } else {
      return null;
    }
  }

  @Override
  public Iterable<? extends ActionInput> getToolFiles() {
    return action.getTools();
  }

  @Override
  public Iterable<? extends ActionInput> getInputFiles() {
    return action.getInputs();
  }

  @Override
  public Collection<? extends ActionInput> getOutputFiles() {
    return action.getOutputs();
  }

  @Override
  public ActionExecutionMetadata getResourceOwner() {
    return action;
  }

  @Override
  public ResourceSet getLocalResources() {
    return localResources;
  }

  @Override
  public String getMnemonic() {
    return action.getMnemonic();
  }

  @Override
  @Nullable
  public PlatformInfo getExecutionPlatform() {
    return action.getExecutionPlatform();
  }
}