/*
 * Copyright 2015-present Facebook, Inc.
 *
 * 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.facebook.buck.cxx;

import com.facebook.buck.io.ProjectFilesystem;
import com.facebook.buck.log.Logger;
import com.facebook.buck.model.BuildTarget;
import com.facebook.buck.model.BuildTargets;
import com.facebook.buck.rules.AddToRuleKey;
import com.facebook.buck.rules.BuildContext;
import com.facebook.buck.rules.BuildableContext;
import com.facebook.buck.rules.ExplicitBuildTargetSourcePath;
import com.facebook.buck.rules.SourcePath;
import com.facebook.buck.rules.SourcePathRuleFinder;
import com.facebook.buck.step.Step;
import com.facebook.buck.step.fs.MkdirStep;
import com.facebook.buck.step.fs.RmStep;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import java.nio.file.Path;
import java.util.Optional;

public class DirectHeaderMap extends HeaderSymlinkTree {

  private static final Logger LOG = Logger.get(DirectHeaderMap.class);

  @AddToRuleKey(stringify = true)
  private final Path headerMapPath;

  public DirectHeaderMap(
      BuildTarget target,
      ProjectFilesystem filesystem,
      Path root,
      ImmutableMap<Path, SourcePath> links,
      SourcePathRuleFinder ruleFinder) {
    super(target, filesystem, root, links, ruleFinder);
    this.headerMapPath = BuildTargets.getGenPath(filesystem, target, "%s.hmap");
  }

  @Override
  public SourcePath getSourcePathToOutput() {
    return new ExplicitBuildTargetSourcePath(getBuildTarget(), headerMapPath);
  }

  @Override
  public ImmutableList<Step> getBuildSteps(
      BuildContext context, BuildableContext buildableContext) {
    LOG.debug("Generating post-build steps to write header map to %s", headerMapPath);
    ImmutableMap.Builder<Path, Path> headerMapEntries = ImmutableMap.builder();
    Path buckOut =
        getProjectFilesystem().resolve(getProjectFilesystem().getBuckPaths().getBuckOut());
    for (Path key : getLinks().keySet()) {
      Path path =
          buckOut.relativize(context.getSourcePathResolver().getAbsolutePath(getLinks().get(key)));
      LOG.debug("header map %s -> %s", key, path);
      headerMapEntries.put(key, path);
    }
    return ImmutableList.<Step>builder()
        .add(getVerifyStep())
        .add(MkdirStep.of(getProjectFilesystem(), headerMapPath.getParent()))
        .add(RmStep.of(getProjectFilesystem(), headerMapPath))
        .add(new HeaderMapStep(getProjectFilesystem(), headerMapPath, headerMapEntries.build()))
        .build();
  }

  @Override
  public Path getIncludePath() {
    return getProjectFilesystem().resolve(getProjectFilesystem().getBuckPaths().getBuckOut());
  }

  @Override
  public Optional<Path> getHeaderMap() {
    return Optional.of(getProjectFilesystem().resolve(headerMapPath));
  }
}