/*
 * 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.file;

import com.facebook.buck.model.BuildTargets;
import com.facebook.buck.rules.AbstractBuildRule;
import com.facebook.buck.rules.AddToRuleKey;
import com.facebook.buck.rules.BuildContext;
import com.facebook.buck.rules.BuildRuleParams;
import com.facebook.buck.rules.BuildableContext;
import com.facebook.buck.rules.ExplicitBuildTargetSourcePath;
import com.facebook.buck.rules.SourcePath;
import com.facebook.buck.step.Step;
import com.facebook.buck.step.fs.CopyStep;
import com.facebook.buck.step.fs.MakeCleanDirectoryStep;
import com.facebook.buck.step.fs.MakeExecutableStep;
import com.facebook.buck.zip.UnzipStep;
import com.google.common.collect.ImmutableList;
import com.google.common.hash.HashCode;
import java.net.URI;
import java.nio.file.Path;

/**
 * Represents a remote file that needs to be downloaded. Optionally, this class can be prevented
 * from running at build time, requiring a user to run {@code buck fetch} before executing the
 * build.
 */
public class RemoteFile extends AbstractBuildRule {
  @AddToRuleKey(stringify = true)
  private final URI uri;

  @AddToRuleKey(stringify = true)
  private final HashCode sha1;

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

  private final Downloader downloader;

  @AddToRuleKey(stringify = true)
  private final Type type;

  public RemoteFile(
      BuildRuleParams params,
      Downloader downloader,
      URI uri,
      HashCode sha1,
      String out,
      Type type) {
    super(params);

    this.uri = uri;
    this.sha1 = sha1;
    this.downloader = downloader;
    this.type = type;

    output = BuildTargets.getGenPath(getProjectFilesystem(), params.getBuildTarget(), "%s/" + out);
  }

  @Override
  public ImmutableList<Step> getBuildSteps(
      BuildContext context, BuildableContext buildableContext) {
    ImmutableList.Builder<Step> steps = ImmutableList.builder();

    Path tempFile =
        BuildTargets.getScratchPath(
            getProjectFilesystem(), getBuildTarget(), "%s/" + output.getFileName());

    steps.addAll(MakeCleanDirectoryStep.of(getProjectFilesystem(), tempFile.getParent()));
    steps.add(new DownloadStep(getProjectFilesystem(), downloader, uri, sha1, tempFile));

    steps.addAll(MakeCleanDirectoryStep.of(getProjectFilesystem(), output.getParent()));
    if (type == Type.EXPLODED_ZIP) {
      steps.addAll(MakeCleanDirectoryStep.of(getProjectFilesystem(), output));
      steps.add(new UnzipStep(getProjectFilesystem(), tempFile, output));
    } else {
      steps.add(CopyStep.forFile(getProjectFilesystem(), tempFile, output));
    }
    if (type == Type.EXECUTABLE) {
      steps.add(new MakeExecutableStep(getProjectFilesystem(), output));
    }

    buildableContext.recordArtifact(output);

    return steps.build();
  }

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

  enum Type {
    DATA,
    EXECUTABLE,
    EXPLODED_ZIP,
  }
}