/*
 * Copyright 2012-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.android;

import com.facebook.buck.shell.ShellStep;
import com.facebook.buck.step.ExecutionContext;
import com.facebook.buck.util.AndroidPlatformTarget;
import com.facebook.buck.util.ProjectFilesystem;
import com.facebook.buck.util.Verbosity;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.base.Supplier;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;

import java.nio.file.Path;
import java.util.EnumSet;
import java.util.Set;

import javax.annotation.CheckForNull;

public class DxStep extends ShellStep {

  /** Options to pass to {@code dx}. */
  public static enum Option {
    /** Specify the {@code --no-optimize} flag when running {@code dx}. */
    NO_OPTIMIZE,

    /** Specify the {@code --force-jumbo} flag when running {@code dx}. */
    FORCE_JUMBO,

    /**
     * See if the {@code buck.dx} property was specified, and if so, use the executable that that
     * points to instead of the {@code dx} in the user's Android SDK.
     */
    USE_CUSTOM_DX_IF_AVAILABLE,
    ;
  }

  private static final Supplier<String> DEFAULT_GET_CUSTOM_DX = new Supplier<String>() {
    @Override
    @CheckForNull
    public String get() {
      return Strings.emptyToNull(System.getProperty("buck.dx"));
    }
  };

  private final String outputDexFile;
  private final Set<Path> filesToDex;
  private final Set<Option> options;
  private final Supplier<String> getPathToCustomDx;

  /**
   * @param outputDexFile path to the file where the generated classes.dex should go.
   * @param filesToDex each element in this set is a path to a .class file, a zip file of .class
   *     files, or a directory of .class files.
   */
  public DxStep(String outputDexFile, Iterable<Path> filesToDex) {
    this(outputDexFile, filesToDex, EnumSet.noneOf(DxStep.Option.class));
  }

  /**
   * @param outputDexFile path to the file where the generated classes.dex should go.
   * @param filesToDex each element in this set is a path to a .class file, a zip file of .class
   *     files, or a directory of .class files.
   * @param options to pass to {@code dx}.
   */
  public DxStep(String outputDexFile, Iterable<Path> filesToDex, EnumSet<Option> options) {
    this(outputDexFile, filesToDex, options, DEFAULT_GET_CUSTOM_DX);
  }

  @VisibleForTesting
  DxStep(String outputDexFile, Iterable<Path> filesToDex, EnumSet<Option> options,
      Supplier<String> getPathToCustomDx) {
    this.outputDexFile = Preconditions.checkNotNull(outputDexFile);
    this.filesToDex = ImmutableSet.copyOf(filesToDex);
    this.options = Sets.immutableEnumSet(options);
    this.getPathToCustomDx = Preconditions.checkNotNull(getPathToCustomDx);
  }

  @Override
  protected ImmutableList<String> getShellCommandInternal(ExecutionContext context) {
    ImmutableList.Builder<String> builder = ImmutableList.builder();

    AndroidPlatformTarget androidPlatformTarget = context.getAndroidPlatformTarget();
    String dx = androidPlatformTarget.getDxExecutable().getAbsolutePath();

    if (options.contains(Option.USE_CUSTOM_DX_IF_AVAILABLE)) {
      String customDx = getPathToCustomDx.get();
      dx = customDx != null ? customDx : dx;
    }

    builder.add(dx);
    builder.add("--dex");

    // --statistics flag, if appropriate.
    if (context.getVerbosity().shouldPrintSelectCommandOutput()) {
      builder.add("--statistics");
    }

    if (options.contains(Option.NO_OPTIMIZE)) {
      builder.add("--no-optimize");
    }

    if (options.contains(Option.FORCE_JUMBO)) {
      builder.add("--force-jumbo");
    }

    // verbose flag, if appropriate.
    if (context.getVerbosity().shouldUseVerbosityFlagIfAvailable()) {
      builder.add("--verbose");
    }

    builder.add("--output", outputDexFile);
    ProjectFilesystem projectFilesystem = context.getProjectFilesystem();
    for (Path fileToDex : filesToDex) {
      builder.add(projectFilesystem.resolve(fileToDex).toString());
    }

    return builder.build();
  }

  @Override
  protected boolean shouldPrintStderr(Verbosity verbosity) {
    return verbosity.shouldPrintSelectCommandOutput();
  }

  @Override
  protected boolean shouldPrintStdout(Verbosity verbosity) {
    return verbosity.shouldPrintSelectCommandOutput();
  }

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

}