/*
 * 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.apple.clang.HeaderMap;
import com.facebook.buck.io.ProjectFilesystem;
import com.facebook.buck.log.Logger;
import com.facebook.buck.step.ExecutionContext;
import com.facebook.buck.step.Step;
import com.facebook.buck.step.StepExecutionResult;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableMap;
import java.io.IOException;
import java.nio.file.Path;
import java.util.Map;

public class HeaderMapStep implements Step {

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

  private final ProjectFilesystem filesystem;
  private final Path output;
  private final ImmutableMap<Path, Path> entries;

  public HeaderMapStep(
      ProjectFilesystem filesystem, Path output, ImmutableMap<Path, Path> entries) {
    this.filesystem = filesystem;
    this.output = output;
    this.entries = entries;
  }

  @Override
  public String getDescription(ExecutionContext context) {
    return "header map @ " + output.toString();
  }

  @Override
  public String getShortName() {
    return "header_map";
  }

  @Override
  public StepExecutionResult execute(ExecutionContext context) throws IOException {
    LOG.debug("Writing header map with %d entries to %s", entries.size(), output);
    HeaderMap.Builder builder = HeaderMap.builder();
    for (Map.Entry<Path, Path> entry : entries.entrySet()) {
      builder.add(entry.getKey().toString(), entry.getValue());
    }
    HeaderMap headerMap = builder.build();
    filesystem.writeBytesToPath(headerMap.getBytes(), output);
    return StepExecutionResult.SUCCESS;
  }

  @Override
  public boolean equals(Object obj) {
    if (!(obj instanceof HeaderMapStep)) {
      return false;
    }
    HeaderMapStep that = (HeaderMapStep) obj;
    return Objects.equal(this.output, that.output) && Objects.equal(this.entries, that.entries);
  }

  @Override
  public int hashCode() {
    return Objects.hashCode(output, entries);
  }
}