// Copyright 2016 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.android;

import com.google.common.base.Preconditions;
import com.google.common.base.Stopwatch;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;
import com.google.devtools.build.android.Converters.DependencySymbolFileProviderListConverter;
import com.google.devtools.build.android.Converters.PathConverter;
import com.google.devtools.common.options.Option;
import com.google.devtools.common.options.OptionsBase;
import com.google.devtools.common.options.OptionsParser;

import com.android.builder.core.VariantConfiguration;
import com.android.builder.dependency.SymbolFileProvider;
import com.android.builder.internal.SymbolLoader;
import com.android.utils.StdLogger;

import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.logging.Logger;


/**
 * Provides an entry point for the compiling resource classes using a custom compiler (simply parse
 * R.txt and make a jar, which is simpler than parsing R.java and running errorprone, etc.).
 *
 * For now, we assume this is only worthwhile for android_binary and not libraries.
 *
 * <pre>
 * Example Usage:
 *   java/com/google/build/android/RClassGeneratorAction\
 *      --primaryRTxt path/to/R.txt\
 *      --primaryManifest path/to/AndroidManifest.xml\
 *      --libraries p/t/1/AndroidManifest.txt:p/t/1/R.txt,\
 *                  p/t/2/AndroidManifest.txt:p/t/2/R.txt\
 *      --classJarOutput path/to/write/archive_resources.jar
 * </pre>
 */
public class RClassGeneratorAction {

  private static final StdLogger STD_LOGGER =
      new StdLogger(StdLogger.Level.WARNING);

  private static final Logger LOGGER = Logger.getLogger(RClassGeneratorAction.class.getName());

  /**
   * Flag specifications for this action.
   */
  public static final class Options extends OptionsBase {

    @Option(name = "primaryRTxt",
        defaultValue = "null",
        converter = PathConverter.class,
        category = "input",
        help = "The path to the binary's R.txt file")
    public Path primaryRTxt;

    @Option(name = "primaryManifest",
        defaultValue = "null",
        converter = PathConverter.class,
        category = "input",
        help = "The path to the binary's AndroidManifest.xml file. This helps provide the package.")
    public Path primaryManifest;

    @Option(name = "packageForR",
        defaultValue = "null",
        category = "config",
        help = "Custom java package to generate the R class files.")
    public String packageForR;

    @Option(name = "libraries",
        defaultValue = "",
        converter = DependencySymbolFileProviderListConverter.class,
        category = "input",
        help = "R.txt and manifests for the libraries in this binary's deps. We will write "
            + "class files for the libraries as well. Expected format: lib1/R.txt[:lib2/R.txt]")
    public List<DependencySymbolFileProvider> libraries;

    @Option(name = "classJarOutput",
        defaultValue = "null",
        converter = PathConverter.class,
        category = "output",
        help = "Path for the generated jar of R.class files.")
    public Path classJarOutput;

  }

  public static void main(String[] args) throws Exception {
    final Stopwatch timer = Stopwatch.createStarted();
    OptionsParser optionsParser = OptionsParser.newOptionsParser(Options.class);
    if (args.length == 1 && args[0].startsWith("@")) {
      args = Files.readAllLines(Paths.get(args[0].substring(1)), StandardCharsets.UTF_8)
          .toArray(new String[0]);
    }

    optionsParser.parseAndExitUponError(args);
    Options options = optionsParser.getOptions(Options.class);
    Preconditions.checkNotNull(options.classJarOutput);
    final AndroidResourceProcessor resourceProcessor = new AndroidResourceProcessor(STD_LOGGER);
    try (ScopedTemporaryDirectory scopedTmp =
        new ScopedTemporaryDirectory("android_res_compile_tmp")) {
      Path tmp = scopedTmp.getPath();
      Path classOutPath = tmp.resolve("compiled_classes");

      LOGGER.fine(String.format("Setup finished at %sms", timer.elapsed(TimeUnit.MILLISECONDS)));
      List<SymbolFileProvider> libraries = new ArrayList<>();
      for (DependencySymbolFileProvider library : options.libraries) {
        libraries.add(library);
      }
      // Note that we need to write the R class for the main binary (so proceed even if there
      // are no libraries).
      if (options.primaryRTxt != null) {
        String appPackageName = options.packageForR;
        if (appPackageName == null) {
          appPackageName = VariantConfiguration
              .getManifestPackage(options.primaryManifest.toFile());
        }
        Multimap<String, SymbolLoader> libSymbolMap = ArrayListMultimap.create();
        SymbolLoader fullSymbolValues = resourceProcessor.loadResourceSymbolTable(
            libraries, appPackageName, options.primaryRTxt, libSymbolMap);
        LOGGER.fine(
            String.format("Load symbols finished at %sms", timer.elapsed(TimeUnit.MILLISECONDS)));
        // For now, assuming not used for libraries and setting final access for fields.
        if (fullSymbolValues != null) {
          resourceProcessor.writePackageRClasses(libSymbolMap, fullSymbolValues, appPackageName,
              classOutPath, true /* finalFields */);
          LOGGER.fine(
              String.format("Finished R.class at %sms", timer.elapsed(TimeUnit.MILLISECONDS)));
        }
      } else {
        Files.createDirectories(classOutPath);
      }
      // We write .class files to temp, then jar them up after (we create a dummy jar, even if
      // there are no class files).
      resourceProcessor.createClassJar(classOutPath, options.classJarOutput);
      LOGGER.fine(
          String.format("createClassJar finished at %sms", timer.elapsed(TimeUnit.MILLISECONDS)));
    } finally {
      resourceProcessor.shutdown();
    }
    LOGGER.fine(String.format("Compile action done in %sms", timer.elapsed(TimeUnit.MILLISECONDS)));
  }
}
