// Copyright 2022 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.analysis.config;

import static com.google.common.truth.Truth.assertThat;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.devtools.build.lib.analysis.ConfiguredTarget;
import com.google.devtools.build.lib.analysis.util.BuildViewTestCase;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.packages.Provider;
import com.google.devtools.build.lib.packages.StarlarkProvider;
import com.google.devtools.build.lib.packages.StructImpl;
import com.google.devtools.build.lib.skyframe.BuildConfigurationFunction;
import java.util.List;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for {@link BuildConfigurationFunction}'s special behaviors. */
@RunWith(JUnit4.class)
public final class BuildConfigurationFunctionTest extends BuildViewTestCase {

  @Before
  public void setupMyInfo() throws Exception {
    scratch.file("myinfo/myinfo.bzl", "MyInfo = provider()");

    scratch.file("myinfo/BUILD");
  }

  private static StructImpl getMyInfoFromTarget(ConfiguredTarget configuredTarget)
      throws Exception {
    Provider.Key key =
        new StarlarkProvider.Key(Label.parseCanonical("//myinfo:myinfo.bzl"), "MyInfo");
    return (StructImpl) configuredTarget.get(key);
  }

  private void writeAllowlistFile() throws Exception {
    scratch.overwriteFile(
        "tools/allowlists/function_transition_allowlist/BUILD",
        "package_group(",
        "    name = 'function_transition_allowlist',",
        "    packages = [",
        "        '//test/...',",
        "    ],",
        ")");
  }

  private void writeBuildSettingsBzl() throws Exception {
    scratch.file(
        "test/build_settings.bzl",
        "BuildSettingInfo = provider(fields = ['value'])",
        "def _impl(ctx):",
        "  return [BuildSettingInfo(value = ctx.build_setting_value)]",
        "string_flag = rule(implementation = _impl, build_setting = config.string(flag=True))");
  }

  private CoreOptions getCoreOptions(ConfiguredTarget target) {
    return getConfiguration(target).getOptions().get(CoreOptions.class);
  }

  private String getTransitionDirectoryNameFragment(ConfiguredTarget target) {
    return getConfiguration(target).getTransitionDirectoryNameFragment();
  }

  @Test
  public void testDiffAgainstBaselineOutputScheme_hasHash() throws Exception {
    writeAllowlistFile();
    writeBuildSettingsBzl();
    scratch.file(
        "test/transitions.bzl",
        "def _foo_impl(settings, attr):",
        "  return {'//test:foo': 'transitioned'}",
        "foo_transition = transition(implementation = _foo_impl, inputs = [],",
        "  outputs = ['//test:foo'])");
    scratch.file(
        "test/rules.bzl",
        "load('//myinfo:myinfo.bzl', 'MyInfo')",
        "load('//test:transitions.bzl', 'foo_transition')",
        "def _impl(ctx):",
        "  return MyInfo(dep = ctx.attr.dep)",
        "my_rule = rule(",
        "  implementation = _impl,",
        "  attrs = {",
        "    'dep': attr.label(cfg = foo_transition), ",
        "    '_allowlist_function_transition': attr.label(",
        "        default = '//tools/allowlists/function_transition_allowlist',",
        "    ),",
        "  })",
        "def _basic_impl(ctx):",
        "  return []",
        "simple = rule(_basic_impl)");
    scratch.file(
        "test/BUILD",
        "load('//test:rules.bzl', 'my_rule', 'simple')",
        "load('//test:build_settings.bzl', 'string_flag')",
        "string_flag(name = 'foo', build_setting_default='default')",
        "my_rule(name = 'test', dep = ':dep')",
        "simple(name = 'dep')");

    useConfiguration("--experimental_output_directory_naming_scheme=diff_against_baseline");
    ConfiguredTarget test = getConfiguredTarget("//test");

    assertThat(getTransitionDirectoryNameFragment(test)).isEmpty();
    assertThat(getCoreOptions(test).affectedByStarlarkTransition).isEmpty();

    @SuppressWarnings("unchecked")
    ConfiguredTarget dep =
        Iterables.getOnlyElement(
            (List<ConfiguredTarget>) getMyInfoFromTarget(test).getValue("dep"));

    assertThat(getTransitionDirectoryNameFragment(dep))
        .isEqualTo(
            BuildConfigurationFunction.transitionDirectoryNameFragment(
                ImmutableList.of("//test:foo=transitioned")));
    assertThat(getCoreOptions(dep).affectedByStarlarkTransition).isEmpty();
  }

  @Test
  public void testDiffAgainstBaselineOutputScheme_avoidHashForInExplicitOutputPath()
      throws Exception {
    writeAllowlistFile();
    scratch.file(
        "test/transitions.bzl",
        "def _opt_impl(settings, attr):",
        "  return {'//command_line_option:compilation_mode': 'opt'}",
        "opt_transition = transition(implementation = _opt_impl, inputs = [],",
        "  outputs = ['//command_line_option:compilation_mode'])");
    scratch.file(
        "test/rules.bzl",
        "load('//myinfo:myinfo.bzl', 'MyInfo')",
        "load('//test:transitions.bzl', 'opt_transition')",
        "def _impl(ctx):",
        "  return MyInfo(dep = ctx.attr.dep)",
        "my_rule = rule(",
        "  implementation = _impl,",
        "  attrs = {",
        "    'dep': attr.label(cfg = opt_transition), ",
        "    '_allowlist_function_transition': attr.label(",
        "        default = '//tools/allowlists/function_transition_allowlist',",
        "    ),",
        "  })",
        "def _basic_impl(ctx):",
        "  return []",
        "simple = rule(_basic_impl)");
    scratch.file(
        "test/BUILD",
        "load('//test:rules.bzl', 'my_rule', 'simple')",
        "my_rule(name = 'test', dep = ':dep')",
        "simple(name = 'dep')");

    useConfiguration(
        "--compilation_mode=fastbuild",
        "--experimental_output_directory_naming_scheme=diff_against_baseline");
    ConfiguredTarget test = getConfiguredTarget("//test");

    assertThat(getConfiguration(test).getMnemonic()).contains("fastbuild");
    assertThat(getTransitionDirectoryNameFragment(test)).isEmpty();
    assertThat(getCoreOptions(test).affectedByStarlarkTransition).isEmpty();

    @SuppressWarnings("unchecked")
    ConfiguredTarget dep =
        Iterables.getOnlyElement(
            (List<ConfiguredTarget>) getMyInfoFromTarget(test).getValue("dep"));

    assertThat(getConfiguration(dep).getMnemonic()).contains("opt");
    assertThat(getTransitionDirectoryNameFragment(dep)).isEmpty();
    assertThat(getCoreOptions(dep).affectedByStarlarkTransition).isEmpty();
  }

  @Test
  public void testDiffAgainstBaselineOutputScheme_abaAvoidsHash() throws Exception {
    writeAllowlistFile();
    writeBuildSettingsBzl();
    scratch.file(
        "test/transitions.bzl",
        "def _toggle_impl(settings, attr):",
        "  if (settings['//test:foo'] != 'default'):",
        "    return {'//test:foo': 'default'}",
        "  else:",
        "    return {'//test:foo': 'transitioned'}",
        "toggle_foo_transition = transition(implementation = _toggle_impl,",
        "  inputs = ['//test:foo'], outputs = ['//test:foo'])");
    scratch.file(
        "test/rules.bzl",
        "load('//myinfo:myinfo.bzl', 'MyInfo')",
        "load('//test:transitions.bzl', 'toggle_foo_transition')",
        "def _impl(ctx):",
        "  return MyInfo(dep = ctx.attr.dep)",
        "my_rule = rule(",
        "  implementation = _impl,",
        "  attrs = {",
        "    'dep': attr.label(cfg = toggle_foo_transition), ",
        "    '_allowlist_function_transition': attr.label(",
        "        default = '//tools/allowlists/function_transition_allowlist',",
        "    ),",
        "  })",
        "def _basic_impl(ctx):",
        "  return []",
        "simple = rule(_basic_impl)");
    scratch.file(
        "test/BUILD",
        "load('//test:rules.bzl', 'my_rule', 'simple')",
        "load('//test:build_settings.bzl', 'string_flag')",
        "string_flag(name = 'foo', build_setting_default='default')",
        "my_rule(name = 'test', dep = ':middle')",
        "my_rule(name = 'middle', dep = ':root')",
        "simple(name = 'root')");

    useConfiguration("--experimental_output_directory_naming_scheme=diff_against_baseline");
    ConfiguredTarget test = getConfiguredTarget("//test");

    assertThat(getTransitionDirectoryNameFragment(test)).isEmpty();
    assertThat(getCoreOptions(test).affectedByStarlarkTransition).isEmpty();

    @SuppressWarnings("unchecked")
    ConfiguredTarget middle =
        Iterables.getOnlyElement(
            (List<ConfiguredTarget>) getMyInfoFromTarget(test).getValue("dep"));

    assertThat(getTransitionDirectoryNameFragment(middle))
        .isEqualTo(
            BuildConfigurationFunction.transitionDirectoryNameFragment(
                ImmutableList.of("//test:foo=transitioned")));
    assertThat(getCoreOptions(middle).affectedByStarlarkTransition).isEmpty();

    @SuppressWarnings("unchecked")
    ConfiguredTarget root =
        Iterables.getOnlyElement(
            (List<ConfiguredTarget>) getMyInfoFromTarget(middle).getValue("dep"));

    assertThat(getTransitionDirectoryNameFragment(test)).isEmpty();
    assertThat(getCoreOptions(test).affectedByStarlarkTransition).isEmpty();

    assertThat(getConfiguration(test)).isEqualTo(getConfiguration(root));
    assertThat(getConfiguration(test)).isNotEqualTo(getConfiguration(middle));

    // This should be implied by everything else but as a final check....
    assertThat(getConfiguration(test).getMnemonic())
        .isEqualTo(getConfiguration(root).getMnemonic());
  }
}