// Copyright 2018 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;

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

import com.google.common.collect.ImmutableMap;
import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
import com.google.devtools.build.lib.analysis.test.TestConfiguration.TestOptions;
import com.google.devtools.build.lib.analysis.util.BuildViewTestCase;
import com.google.devtools.build.lib.cmdline.Label;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for StarlarkRuleTransitionProvider. */
@RunWith(JUnit4.class)
public class StarlarkRuleTransitionProviderTest extends BuildViewTestCase {

  @Test
  public void testOutputOnlyTransition() throws Exception {
    setSkylarkSemanticsOptions("--experimental_starlark_config_transitions=true");
    scratch.file(
        "test/transitions.bzl",
        "def _impl(settings, attr):",
        "  return {'//command_line_option:test_arg': ['post-transition']}",
        "my_transition = transition(implementation = _impl, inputs = [],",
        "  outputs = ['//command_line_option:test_arg'])");
    scratch.file(
        "test/rules.bzl",
        "load('//test:transitions.bzl', 'my_transition')",
        "def _impl(ctx):",
        "  return []",
        "my_rule = rule(implementation = _impl, cfg = my_transition)");
    scratch.file("test/BUILD", "load('//test:rules.bzl', 'my_rule')", "my_rule(name = 'test')");

    useConfiguration("--test_arg=pre-transition");

    BuildConfiguration configuration = getConfiguration(getConfiguredTarget("//test"));
    assertThat(configuration.getOptions().get(TestOptions.class).testArguments)
        .containsExactly("post-transition");
  }

  @Test
  public void testInputAndOutputTransition() throws Exception {
    setSkylarkSemanticsOptions("--experimental_starlark_config_transitions=true");
    scratch.file(
        "test/transitions.bzl",
        "def _impl(settings, attr):",
        "  return {'//command_line_option:test_arg': ",
        "    [settings['//command_line_option:test_arg'][0]+'->post-transition']}",
        "my_transition = transition(",
        "  implementation = _impl,",
        "  inputs = ['//command_line_option:test_arg'],",
        "  outputs = ['//command_line_option:test_arg'],",
        ")");

    scratch.file(
        "test/rules.bzl",
        "load('//test:transitions.bzl', 'my_transition')",
        "def _impl(ctx):",
        "  return []",
        "my_rule = rule(implementation = _impl, cfg = my_transition)");

    scratch.file("test/BUILD", "load('//test:rules.bzl', 'my_rule')", "my_rule(name = 'test')");

    useConfiguration("--test_arg=pre-transition");

    BuildConfiguration configuration = getConfiguration(getConfiguredTarget("//test"));
    assertThat(configuration.getOptions().get(TestOptions.class).testArguments)
        .containsExactly("pre-transition->post-transition");
  }

  @Test
  public void testBuildSettingCannotTransition() throws Exception {
    setSkylarkSemanticsOptions(
        "--experimental_starlark_config_transitions=true", "--experimental_build_setting_api=true");
    scratch.file(
        "test/transitions.bzl",
        "def _impl(settings, attr):",
        "  return {'//command_line_option:test_arg': ['post-transition']}",
        "my_transition = transition(implementation = _impl, inputs = [],",
        "  outputs = ['//command_line_option:test_arg'])");
    scratch.file(
        "test/rules.bzl",
        "load('//test:transitions.bzl', 'my_transition')",
        "def _impl(ctx):",
        "  return []",
        "my_rule = rule(",
        "  implementation = _impl,",
        "  cfg = my_transition,",
        "  build_setting = config.string()",
        ")");
    scratch.file("test/BUILD", "load('//test:rules.bzl', 'my_rule')", "my_rule(name = 'test')");

    reporter.removeHandler(failFastHandler);
    getConfiguredTarget("//test");
    assertContainsEvent(
        "Build setting rules cannot use the `cfg` param to apply transitions to themselves");
  }

  @Test
  public void testBadCfgInput() throws Exception {
    setSkylarkSemanticsOptions("--experimental_starlark_config_transitions=true");
    scratch.file(
        "test/rules.bzl",
        "def _impl(ctx):",
        "  return []",
        "my_rule = rule(",
        "  implementation = _impl,",
        "  cfg = 'my_transition',",
        ")");
    scratch.file("test/BUILD", "load('//test:rules.bzl', 'my_rule')", "my_rule(name = 'test')");

    reporter.removeHandler(failFastHandler);
    getConfiguredTarget("//test");
    assertContainsEvent(
        "`cfg` must be set to a transition object initialized by the transition() function.");
  }

  @Test
  public void testMultipleReturnConfigs() throws Exception {
    setSkylarkSemanticsOptions("--experimental_starlark_config_transitions=true");
    scratch.file(
        "test/transitions.bzl",
        "def _impl(settings, attr):",
        "  return {",
        "      't0': {'//command_line_option:test_arg': ['split_one']},",
        "      't1': {'//command_line_option:test_arg': ['split_two']},",
        "  }",
        "my_transition = transition(implementation = _impl, inputs = [],",
        "  outputs = ['//command_line_option:test_arg'])");
    scratch.file(
        "test/rules.bzl",
        "load('//test:transitions.bzl', 'my_transition')",
        "def _impl(ctx):",
        "  return []",
        "my_rule = rule(implementation = _impl, cfg = my_transition)");
    scratch.file("test/BUILD", "load('//test:rules.bzl', 'my_rule')", "my_rule(name = 'test')");

    reporter.removeHandler(failFastHandler);
    getConfiguredTarget("//test");
    assertContainsEvent(
        "Rule transition only allowed to return a single transitioned configuration.");
  }

  @Test
  public void testCanDoBadStuffWithParameterizedTransitionsAndSelects() throws Exception {
    setSkylarkSemanticsOptions("--experimental_starlark_config_transitions=true");
    scratch.file(
        "test/transitions.bzl",
        "def _impl(settings, attr):",
        "  if (attr.my_configurable_attr):",
        "    return {'//command_line_option:test_arg': ['true']}",
        "  else:",
        "    return {'//command_line_option:test_arg': ['false']}",
        "my_transition = transition(implementation = _impl, inputs = [],",
        "  outputs = ['//command_line_option:test_arg'])");
    scratch.file(
        "test/rules.bzl",
        "load('//test:transitions.bzl', 'my_transition')",
        "def _impl(ctx):",
        "  return []",
        "my_rule = rule(",
        "  implementation = _impl,",
        "  cfg = my_transition,",
        "  attrs = {'my_configurable_attr': attr.bool(default = False)},",
        ")");
    scratch.file(
        "test/BUILD",
        "load('//test:rules.bzl', 'my_rule')",
        "my_rule(",
        "  name = 'test',",
        "  my_configurable_attr = select({",
        "    '//conditions:default': False,",
        "    ':true-config': True,",
        "  })",
        ")",
        "config_setting(",
        "  name = 'true-config',",
        "  values = {'test_arg': 'true'},",
        ")");

    reporter.removeHandler(failFastHandler);
    getConfiguredTarget("//test");
    assertContainsEvent(
        "No attribute 'my_configurable_attr'. "
            + "Either this attribute does not exist for this rule or is set by a select. "
            + "Starlark rule transitions currently cannot read attributes behind selects.");
  }

  @Test
  public void testLabelTypedAttrReturnsLabelNotDep() throws Exception {
    setSkylarkSemanticsOptions("--experimental_starlark_config_transitions=true");
    scratch.file(
        "test/transitions.bzl",
        "def _impl(settings, attr):",
        "  if attr.dict_attr[Label('//test:key')] == 'value':",
        "    return {'//command_line_option:test_arg': ['post-transition']}",
        "  else:",
        "    return {'//command_line_option:test_arg': ['uh-oh']}",
        "my_transition = transition(implementation = _impl, inputs = [],",
        "  outputs = ['//command_line_option:test_arg'])");
    scratch.file(
        "test/rules.bzl",
        "load('//test:transitions.bzl', 'my_transition')",
        "def _impl(ctx):",
        "  return []",
        "my_rule = rule(",
        "  implementation = _impl,",
        "  cfg = my_transition,",
        "  attrs = {'dict_attr': attr.label_keyed_string_dict()},",
        ")",
        "simple_rule = rule(_impl)");
    scratch.file(
        "test/BUILD",
        "load('//test:rules.bzl', 'my_rule', 'simple_rule')",
        "my_rule(",
        "  name = 'test',",
        "  dict_attr = {':key': 'value'},",
        ")",
        "simple_rule(name = 'key')");

    useConfiguration("--test_arg=pre-transition");

    BuildConfiguration configuration = getConfiguration(getConfiguredTarget("//test"));
    assertThat(configuration.getOptions().get(TestOptions.class).testArguments)
        .containsExactly("post-transition");
  }

  @Test
  public void testCannotTransitionWithoutFlag() throws Exception {
    setSkylarkSemanticsOptions("--experimental_starlark_config_transitions=false");
    scratch.file(
        "test/transitions.bzl",
        "def _impl(settings, attr):",
        "  return {'//command_line_option:test_arg': ['post-transition']}",
        "my_transition = transition(implementation = _impl, inputs = [],",
        "  outputs = ['//command_line_option:test_arg'])");
    scratch.file(
        "test/rules.bzl",
        "load('//test:transitions.bzl', 'my_transition')",
        "def _impl(ctx):",
        "  return []",
        "my_rule = rule(implementation = _impl, cfg = my_transition)");
    scratch.file("test/BUILD", "load('//test:rules.bzl', 'my_rule')", "my_rule(name = 'test')");

    reporter.removeHandler(failFastHandler);
    getConfiguredTarget("//test");
    assertContainsEvent(
        "transition() is experimental and disabled by default. This API is in "
            + "development and subject to change at any time. Use "
            + "--experimental_starlark_config_transitions to use this experimental API.");
  }

  private void writeRulesBuildSettingsAndBUILDforBuildSettingTransitionTests() throws Exception {
    scratch.file(
        "test/rules.bzl",
        "load('//test:transitions.bzl', 'my_transition')",
        "def _rule_impl(ctx):",
        "  return []",
        "my_rule = rule(",
        "  implementation = _rule_impl,",
        "  cfg = my_transition,",
        ")");

    scratch.file(
        "test/build_settings.bzl",
        "def _impl(ctx):",
        "  return []",
        "string_flag = rule(implementation = _impl, build_setting = config.string(flag=True))");

    scratch.file(
        "test/BUILD",
        "load('//test:rules.bzl', 'my_rule')",
        "load('//test:build_settings.bzl', 'string_flag')",
        "my_rule(name = 'test')",
        "string_flag(",
        "  name = 'cute-animal-fact',",
        "  build_setting_default = 'cows produce more milk when they listen to soothing music',",
        ")");
  }

  @Test
  public void testTransitionOnBuildSetting() throws Exception {
    setSkylarkSemanticsOptions(
        "--experimental_starlark_config_transitions=true", "--experimental_build_setting_api");
    scratch.file(
        "test/transitions.bzl",
        "def _transition_impl(settings, attr):",
        "  return {'//test:cute-animal-fact': 'puffins mate for life'}",
        "my_transition = transition(",
        "  implementation = _transition_impl,",
        "  inputs = [],",
        "  outputs = ['//test:cute-animal-fact']",
        ")");
    writeRulesBuildSettingsAndBUILDforBuildSettingTransitionTests();

    useConfiguration(ImmutableMap.of("//test:cute-animal-fact", "cats can't taste sugar"));
    BuildConfiguration configuration = getConfiguration(getConfiguredTarget("//test"));
    assertThat(
            configuration
                .getOptions()
                .getStarlarkOptions()
                .get(Label.parseAbsoluteUnchecked("//test:cute-animal-fact")))
        .isEqualTo("puffins mate for life");
  }

  // TODO(juliexxia): flip this test when post-transition validation is implemented to prevent
  // transitions from setting (for example) string-typed build settings to ints.
  @Test
  public void testCanSetBuildSettingToBadValue() throws Exception {
    setSkylarkSemanticsOptions(
        "--experimental_starlark_config_transitions=true", "--experimental_build_setting_api");
    scratch.file(
        "test/transitions.bzl",
        "def _transition_impl(settings, attr):",
        "  return {'//test:cute-animal-fact': 24}",
        "my_transition = transition(",
        "  implementation = _transition_impl,",
        "  inputs = [],",
        "  outputs = ['//test:cute-animal-fact']",
        ")");
    writeRulesBuildSettingsAndBUILDforBuildSettingTransitionTests();

    useConfiguration(ImmutableMap.of("//test:cute-animal-fact", "cats can't taste sugar"));
    BuildConfiguration configuration = getConfiguration(getConfiguredTarget("//test"));
    assertThat(
            configuration
                .getOptions()
                .getStarlarkOptions()
                .get(Label.parseAbsoluteUnchecked("//test:cute-animal-fact")))
        .isEqualTo(24);
  }

  // TODO(juliexxia): flip this test when post-transition validation is implemented to prevent
  // transitions from setting non-existent build settings (note - we'll need to verify we can't
  // set non-build setting targets either).
  @Test
  public void testCanSetNonexistantBuildSetting() throws Exception {
    setSkylarkSemanticsOptions(
        "--experimental_starlark_config_transitions=true", "--experimental_build_setting_api");
    scratch.file(
        "test/transitions.bzl",
        "def _transition_impl(settings, attr):",
        "  return {'//test:i-am-not-real': 'imaginary-friend'}",
        "my_transition = transition(",
        "  implementation = _transition_impl,",
        "  inputs = [],",
        "  outputs = ['//test:i-am-not-real']",
        ")");
    writeRulesBuildSettingsAndBUILDforBuildSettingTransitionTests();

    BuildConfiguration configuration = getConfiguration(getConfiguredTarget("//test"));
    assertThat(
            configuration
                .getOptions()
                .getStarlarkOptions()
                .get(Label.parseAbsoluteUnchecked("//test:i-am-not-real")))
        .isEqualTo("imaginary-friend");
  }

  // TODO(juliexxia): flip this test when we can read build settings.
  @Test
  public void testCantReadNonNativeBuildSetting() throws Exception {
    setSkylarkSemanticsOptions(
        "--experimental_starlark_config_transitions=true", "--experimental_build_setting_api");
    scratch.file(
        "test/transitions.bzl",
        "def _transition_impl(settings, attr):",
        "  return {'//test:cute-animal-fact': settings['//test:cute-animal-fact']+' ADDED'}",
        "my_transition = transition(",
        "  implementation = _transition_impl,",
        "  inputs = ['//test:cute-animal-fact'],",
        "  outputs = ['//test:i-am-not-real']",
        ")");
    writeRulesBuildSettingsAndBUILDforBuildSettingTransitionTests();

    reporter.removeHandler(failFastHandler);
    getConfiguredTarget("//test");
    assertContainsEvent(
        "transition inputs [//test:cute-animal-fact] do not correspond to valid settings");
    }
}