/*
 * Copyright 2014 Google LLC
 *
 * 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.auto.common;

import static com.google.common.truth.Truth.assertAbout;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;
import static com.google.testing.compile.JavaSourceSubjectFactory.javaSource;

import com.google.common.collect.ImmutableSet;
import com.google.testing.compile.JavaFileObjects;
import java.util.Set;
import java.util.function.Consumer;
import javax.annotation.processing.AbstractProcessor;
import javax.annotation.processing.ProcessingEnvironment;
import javax.annotation.processing.RoundEnvironment;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.TypeElement;
import javax.tools.JavaFileObject;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public class SuperficialValidationTest {
  @Test
  public void missingReturnType() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass",
            "package test;",
            "",
            "abstract class TestClass {",
            "  abstract MissingType blah();",
            "}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  assertThat(SuperficialValidation.validateElement(testClassElement)).isFalse();
                }))
        .failsToCompile();
  }

  @Test
  public void missingGenericReturnType() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass",
            "package test;",
            "",
            "abstract class TestClass {",
            "  abstract MissingType<?> blah();",
            "}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  assertThat(SuperficialValidation.validateElement(testClassElement)).isFalse();
                }))
        .failsToCompile();
  }

  @Test
  public void missingReturnTypeTypeParameter() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass",
            "package test;",
            "",
            "import java.util.Map;",
            "import java.util.Set;",
            "",
            "abstract class TestClass {",
            "  abstract Map<Set<?>, MissingType<?>> blah();",
            "}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  assertThat(SuperficialValidation.validateElement(testClassElement)).isFalse();
                }))
        .failsToCompile();
  }

  @Test
  public void missingTypeParameter() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass", //
            "package test;",
            "",
            "class TestClass<T extends MissingType> {}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  assertThat(SuperficialValidation.validateElement(testClassElement)).isFalse();
                }))
        .failsToCompile();
  }

  @Test
  public void missingParameterType() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass",
            "package test;",
            "",
            "abstract class TestClass {",
            "  abstract void foo(MissingType x);",
            "}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  assertThat(SuperficialValidation.validateElement(testClassElement)).isFalse();
                }))
        .failsToCompile();
  }

  @Test
  public void missingAnnotation() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass", //
            "package test;",
            "",
            "@MissingAnnotation",
            "class TestClass {}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  // It appears that in some JDK versions, getAnnotationMirrors() doesn't return
                  // erroneous annotations such as we have here.
                  if (!testClassElement.getAnnotationMirrors().isEmpty()) {
                    assertThat(SuperficialValidation.validateElement(testClassElement)).isFalse();
                  }
                }))
        .failsToCompile();
  }

  @Test
  public void handlesRecursiveTypeParams() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass", //
            "package test;",
            "",
            "class TestClass<T extends Comparable<T>> {}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  assertThat(SuperficialValidation.validateElement(testClassElement)).isTrue();
                }))
        .compilesWithoutError();
  }

  @Test
  public void handlesRecursiveType() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass",
            "package test;",
            "",
            "abstract class TestClass {",
            "  abstract TestClass foo(TestClass x);",
            "}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  assertThat(SuperficialValidation.validateElement(testClassElement)).isTrue();
                }))
        .compilesWithoutError();
  }

  @Test
  public void missingWildcardBound() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass",
            "package test;",
            "",
            "import java.util.Set;",
            "",
            "class TestClass {",
            "  Set<? extends MissingType> extendsTest() {",
            "    return null;",
            "  }",
            "",
            "  Set<? super MissingType> superTest() {",
            "    return null;",
            "  }",
            "}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  assertThat(SuperficialValidation.validateElement(testClassElement)).isFalse();
                }))
        .failsToCompile();
  }

  @Test
  public void missingIntersection() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.TestClass",
            "package test;",
            "",
            "class TestClass<T extends Number & Missing> {}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.TestClass");
                  assertThat(SuperficialValidation.validateElement(testClassElement)).isFalse();
                }))
        .failsToCompile();
  }

  @Test
  public void invalidAnnotationValue() {
    JavaFileObject javaFileObject =
        JavaFileObjects.forSourceLines(
            "test.Outer",
            "package test;",
            "",
            "final class Outer {",
            "  @interface TestAnnotation {",
            "    Class[] classes();",
            "  }",
            "",
            "  @TestAnnotation(classes = Foo)",
            "  static class TestClass {}",
            "}");
    assertAbout(javaSource())
        .that(javaFileObject)
        .processedWith(
            new AssertingProcessor(
                processingEnv -> {
                  TypeElement testClassElement =
                      processingEnv.getElementUtils().getTypeElement("test.Outer.TestClass");
                  assertWithMessage("testClassElement is valid")
                      .that(SuperficialValidation.validateElement(testClassElement))
                      .isFalse();
                }))
        .failsToCompile();
  }

  private static class AssertingProcessor extends AbstractProcessor {

    @Override
    public SourceVersion getSupportedSourceVersion() {
      return SourceVersion.latestSupported();
    }

    private final Consumer<ProcessingEnvironment> assertions;

    AssertingProcessor(Consumer<ProcessingEnvironment> assertions) {
      this.assertions = assertions;
    }

    @Override
    public Set<String> getSupportedAnnotationTypes() {
      return ImmutableSet.of("*");
    }

    @Override
    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
      assertions.accept(processingEnv);
      return false;
    }
  }
}