// Copyright (c) 2020, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
package com.android.tools.r8;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;

import com.android.tools.r8.desugar.desugaredlibrary.test.LibraryDesugaringSpecification;
import com.android.tools.r8.utils.AndroidApiLevel;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;
import org.junit.Assume;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

@RunWith(Parameterized.class)
public class BackportedMethodListTest {

  @Rule public TemporaryFolder temp = ToolHelper.getTemporaryFolderForTest();

  enum Mode {
    NO_LIBRARY,
    LIBRARY,
    LIBRARY_DESUGAR,
    LIBRARY_DESUGAR_11
  }

  @Parameterized.Parameters(name = "Mode: {0}")
  public static Object[] data() {
    return Mode.values();
  }

  private final Mode mode;

  public BackportedMethodListTest(Mode mode) {
    this.mode = mode;
  }

  private LibraryDesugaringSpecification getLibraryDesugaringSpecification() {
    if (mode == Mode.LIBRARY_DESUGAR) {
      return LibraryDesugaringSpecification.JDK8;
    }
    if (mode == Mode.LIBRARY_DESUGAR_11) {
      return LibraryDesugaringSpecification.JDK11;
    }
    return null;
  }

  private static class ListStringConsumer implements StringConsumer {
    List<String> strings = new ArrayList<>();
    boolean finished = false;

    @Override
    public void accept(String string, DiagnosticsHandler handler) {
      strings.add(string);
    }

    @Override
    public void finished(DiagnosticsHandler handler) {
      finished = true;
    }
  }

  private void checkContent(int apiLevel, List<String> backports) {
    // Java 8 methods added at various API levels.
    assertEquals(
        apiLevel < AndroidApiLevel.K.getLevel(), backports.contains("java/lang/Byte#compare(BB)I"));
    assertEquals(
        apiLevel < AndroidApiLevel.N.getLevel(),
        backports.contains("java/lang/Integer#hashCode(I)I"));
    assertEquals(
        apiLevel < AndroidApiLevel.O.getLevel(),
        backports.contains("java/lang/Short#toUnsignedLong(S)J"));

    // Java 9, 10 and 11 Optional methods which require Android N or library desugaring.
    // The methods are not backported in desugared library JDK 11 (already present).
    assertEquals(
        (mode == Mode.LIBRARY_DESUGAR) || apiLevel >= AndroidApiLevel.N.getLevel(),
        backports.contains(
            "java/util/Optional#or(Ljava/util/function/Supplier;)Ljava/util/Optional;"));
    assertEquals(
        (mode == Mode.LIBRARY_DESUGAR) || apiLevel >= AndroidApiLevel.N.getLevel(),
        backports.contains("java/util/OptionalInt#orElseThrow()I"));
    assertEquals(
        (mode == Mode.LIBRARY_DESUGAR) || apiLevel >= AndroidApiLevel.N.getLevel(),
        backports.contains("java/util/OptionalLong#isEmpty()Z"));

    // Java 9, 10 and 11 method added at API level S.
    assertEquals(
        apiLevel < AndroidApiLevel.S.getLevel(),
        backports.contains("java/lang/StrictMath#multiplyExact(JI)J"));
    // Java 9, 10 and 11 method added at API level S.
    // The method is not backported in desugared library JDK 11 (already present).
    // TODO(b/243679691): Should no use backport but retargeting in between 24 and 33,
    assertEquals(
        apiLevel < AndroidApiLevel.S.getLevel()
            && (mode != Mode.LIBRARY_DESUGAR_11 || apiLevel >= AndroidApiLevel.N.getLevel()),
        backports.contains("java/util/List#copyOf(Ljava/util/Collection;)Ljava/util/List;"));

    // Java 9, 10 and 11 methods not yet added.
    assertTrue(backports.contains("java/lang/Integer#parseInt(Ljava/lang/CharSequence;III)I"));
    assertTrue(backports.contains("java/lang/Character#toString(I)Ljava/lang/String;"));
    assertTrue(backports.contains("java/lang/String#repeat(I)Ljava/lang/String;"));
  }

  private void addLibraryDesugaring(BackportedMethodListCommand.Builder builder) {
    builder
        .addDesugaredLibraryConfiguration(
            StringResource.fromFile(getLibraryDesugaringSpecification().getSpecification()))
        .addLibraryFiles(getLibraryDesugaringSpecification().getLibraryFiles());
  }

  @Test
  public void testConsumer() throws Exception {
    for (int apiLevel = 1; apiLevel < AndroidApiLevel.LATEST.getLevel(); apiLevel++) {
      ListStringConsumer consumer = new ListStringConsumer();
      BackportedMethodListCommand.Builder builder =
          BackportedMethodListCommand.builder().setMinApiLevel(apiLevel).setConsumer(consumer);
      if (mode == Mode.LIBRARY) {
        builder.addLibraryFiles(ToolHelper.getAndroidJar(AndroidApiLevel.P.getLevel()));
      } else if (mode == Mode.LIBRARY_DESUGAR || mode == Mode.LIBRARY_DESUGAR_11) {
        addLibraryDesugaring(builder);
      }
      BackportedMethodList.run(builder.build());
      assertTrue(consumer.finished);
      checkContent(apiLevel, consumer.strings);
    }
  }

  @Test
  public void testFile() throws Exception {
    for (int apiLevel = 1; apiLevel < AndroidApiLevel.LATEST.getLevel(); apiLevel++) {
      Path output = temp.newFile().toPath();
      BackportedMethodListCommand.Builder builder =
          BackportedMethodListCommand.builder().setMinApiLevel(apiLevel).setOutputPath(output);
      if (mode == Mode.LIBRARY) {
        builder.addLibraryFiles(ToolHelper.getAndroidJar(AndroidApiLevel.P.getLevel()));
      } else if (mode == Mode.LIBRARY_DESUGAR || mode == Mode.LIBRARY_DESUGAR_11) {
        addLibraryDesugaring(builder);
      }
      BackportedMethodList.run(builder.build());
      checkContent(apiLevel, Files.readAllLines(output));
    }
  }

  @Test
  public void testFullList() throws Exception {
    Assume.assumeTrue(mode == Mode.NO_LIBRARY);
    ListStringConsumer consumer = new ListStringConsumer();
    // Not setting neither min API level not library should produce the full list.
    BackportedMethodList.run(BackportedMethodListCommand.builder().setConsumer(consumer).build());
    assertTrue(consumer.finished);
    checkContent(1, consumer.strings);
  }

  @Test
  public void requireLibraryForDesugar() {
    Assume.assumeTrue(mode == Mode.LIBRARY_DESUGAR || mode == Mode.LIBRARY_DESUGAR_11);
    // Require library when a desugar configuration is passed.
    try {
      BackportedMethodList.run(
          BackportedMethodListCommand.builder()
              .addDesugaredLibraryConfiguration(
                  StringResource.fromFile(getLibraryDesugaringSpecification().getSpecification()))
              .setConsumer(new ListStringConsumer())
              .build());
      fail("Expected failure");
    } catch (Throwable e) {
      // This should throw a CompilationFailedException but an assertion is failing first.
    }
  }
}