// Copyright 2019 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.lib.skyframe;

import static com.google.common.truth.Truth.assertThat;
import static com.google.devtools.build.lib.testutil.MoreAsserts.assertThrows;

import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.devtools.build.lib.actions.MissingInputFileException;
import com.google.devtools.build.lib.analysis.PlatformConfiguration;
import com.google.devtools.build.lib.analysis.PlatformOptions;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
import com.google.devtools.build.lib.analysis.config.BuildOptions;
import com.google.devtools.build.lib.analysis.config.FragmentOptions;
import com.google.devtools.build.lib.analysis.util.BuildViewTestCase;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.rules.repository.RepositoryDelegatorFunction;
import com.google.devtools.build.lib.skyframe.util.SkyframeExecutorTestUtils;
import com.google.devtools.build.lib.vfs.PathFragment;
import com.google.devtools.build.skyframe.EvaluationResult;
import com.google.devtools.common.options.OptionsParsingException;
import java.util.Set;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/**
 * Unit tests for {@link PlatformMappingFunction}.
 *
 * <p>Note that all parsing tests are located in {@link PlatformMappingFunctionParserTest}.
 */
@RunWith(JUnit4.class)
public class PlatformMappingFunctionTest extends BuildViewTestCase {

  // We don't actually care about the contents of this set other than that it is passed intact
  // through the mapping logic. The platform fragment in it is purely an example, it could be any
  // set of fragments.
  private static final Set<Class<? extends BuildConfiguration.Fragment>> PLATFORM_FRAGMENT_CLASS =
      ImmutableSet.of(PlatformConfiguration.class);

  private static final ImmutableList<Class<? extends FragmentOptions>>
      BUILD_CONFIG_PLATFORM_OPTIONS =
          ImmutableList.of(BuildConfiguration.Options.class, PlatformOptions.class);

  private static final Label PLATFORM1 = Label.parseAbsoluteUnchecked("//platforms:one");

  private static final BuildOptions DEFAULT_BUILD_CONFIG_PLATFORM_OPTIONS =
      getDefaultBuildConfigPlatformOptions();
  private static final BuildOptions.OptionsDiffForReconstruction EMPTY_DIFF =
      BuildOptions.diffForReconstruction(
          DEFAULT_BUILD_CONFIG_PLATFORM_OPTIONS, DEFAULT_BUILD_CONFIG_PLATFORM_OPTIONS);
  private static final Label DEFAULT_TARGET_PLATFORM =
      Label.parseAbsoluteUnchecked("@bazel_tools//platforms:target_platform");

  @Test
  public void testMappingFileDoesNotExist() throws Exception {
    MissingInputFileException exception =
        assertThrows(
            MissingInputFileException.class,
            () ->
                executeFunction(
                    PlatformMappingValue.Key.create(PathFragment.create("random_location"))));
    assertThat(exception).hasMessageThat().contains("random_location");
  }

  @Test
  public void testMappingFileDoesNotExistDefaultLocation() throws Exception {
    PlatformMappingValue platformMappingValue =
        executeFunction(PlatformMappingValue.Key.create(null));

    BuildConfigurationValue.Key key =
        BuildConfigurationValue.key(PLATFORM_FRAGMENT_CLASS, EMPTY_DIFF);

    BuildConfigurationValue.Key mapped =
        platformMappingValue.map(key, DEFAULT_BUILD_CONFIG_PLATFORM_OPTIONS);

    assertThat(toMappedOptions(mapped).get(PlatformOptions.class).platforms)
        .containsExactly(DEFAULT_TARGET_PLATFORM);
  }

  @Test
  public void testMappingFileIsDirectory() throws Exception {
    scratch.dir("somedir");

    MissingInputFileException exception =
        assertThrows(
            MissingInputFileException.class,
            () -> executeFunction(PlatformMappingValue.Key.create(PathFragment.create("somedir"))));
    assertThat(exception).hasMessageThat().contains("somedir");
  }

  @Test
  public void testMappingFileIsRead() throws Exception {
    scratch.file(
        "my_mapping_file",
        "platforms:", // Force line break
        "  //platforms:one", // Force line break
        "    --cpu=one");

    PlatformMappingValue platformMappingValue =
        executeFunction(PlatformMappingValue.Key.create(PathFragment.create("my_mapping_file")));

    BuildOptions modifiedOptions = DEFAULT_BUILD_CONFIG_PLATFORM_OPTIONS.clone();
    modifiedOptions.get(PlatformOptions.class).platforms = ImmutableList.of(PLATFORM1);

    BuildConfigurationValue.Key mapped =
        platformMappingValue.map(
            keyForOptions(modifiedOptions), DEFAULT_BUILD_CONFIG_PLATFORM_OPTIONS);

    assertThat(toMappedOptions(mapped).get(BuildConfiguration.Options.class).cpu).isEqualTo("one");
  }

  private PlatformMappingValue executeFunction(PlatformMappingValue.Key key) throws Exception {
    SkyframeExecutor skyframeExecutor = getSkyframeExecutor();
    skyframeExecutor.injectExtraPrecomputedValues(
        ImmutableList.of(
            PrecomputedValue.injected(
                RepositoryDelegatorFunction.RESOLVED_FILE_INSTEAD_OF_WORKSPACE,
                Optional.absent())));
    EvaluationResult<PlatformMappingValue> result =
        SkyframeExecutorTestUtils.evaluate(skyframeExecutor, key, /*keepGoing=*/ false, reporter);
    if (result.hasError()) {
      throw result.getError(key).getException();
    }
    return result.get(key);
  }

  private BuildOptions toMappedOptions(BuildConfigurationValue.Key mapped) {
    return DEFAULT_BUILD_CONFIG_PLATFORM_OPTIONS.applyDiff(mapped.getOptionsDiff());
  }

  private static BuildOptions getDefaultBuildConfigPlatformOptions() {
    try {
      return BuildOptions.of(BUILD_CONFIG_PLATFORM_OPTIONS);
    } catch (OptionsParsingException e) {
      throw new RuntimeException(e);
    }
  }

  private BuildConfigurationValue.Key keyForOptions(BuildOptions modifiedOptions) {
    BuildOptions.OptionsDiffForReconstruction diff =
        BuildOptions.diffForReconstruction(DEFAULT_BUILD_CONFIG_PLATFORM_OPTIONS, modifiedOptions);

    return BuildConfigurationValue.key(PLATFORM_FRAGMENT_CLASS, diff);
  }
}