/*
 * Copyright 2014-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.step.fs;

import com.facebook.buck.io.FileAttributesScrubber;
import com.facebook.buck.io.FileContentsScrubber;
import com.facebook.buck.io.FileScrubber;
import com.facebook.buck.io.ProjectFilesystem;
import com.facebook.buck.step.ExecutionContext;
import com.facebook.buck.step.Step;
import com.facebook.buck.step.StepExecutionResult;
import com.google.common.collect.ImmutableList;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;

/** Scrub any non-deterministic meta-data from the given file (e.g. timestamp, UID, GID). */
public class FileScrubberStep implements Step {

  private final ProjectFilesystem filesystem;
  private final Path input;
  private final ImmutableList<FileScrubber> scrubbers;

  public FileScrubberStep(
      ProjectFilesystem filesystem, Path input, ImmutableList<FileScrubber> scrubbers) {
    this.filesystem = filesystem;
    this.input = input;
    this.scrubbers = scrubbers;
  }

  private FileChannel readWriteChannel(Path path) throws IOException {
    return FileChannel.open(path, StandardOpenOption.READ, StandardOpenOption.WRITE);
  }

  @Override
  public StepExecutionResult execute(ExecutionContext context) throws InterruptedException {
    Path filePath = filesystem.resolve(input);
    try {
      for (FileScrubber scrubber : scrubbers) {
        try (FileChannel channel = readWriteChannel(filePath)) {
          if (scrubber instanceof FileContentsScrubber) {
            ((FileContentsScrubber) scrubber).scrubFile(channel);
          } else if (scrubber instanceof FileAttributesScrubber) {
            ((FileAttributesScrubber) scrubber).scrubFileWithPath(filePath);
          }
        }
      }
    } catch (IOException | FileContentsScrubber.ScrubException e) {
      context.logError(e, "Error scrubbing non-deterministic metadata from %s", filePath);
      return StepExecutionResult.ERROR;
    }
    return StepExecutionResult.SUCCESS;
  }

  @Override
  public String getShortName() {
    return "file-scrub";
  }

  @Override
  public String getDescription(ExecutionContext context) {
    return "file-scrub";
  }
}