/*
 * Copyright 2015 The Error Prone Authors.
 *
 * 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.errorprone.bugpatterns;

import com.google.errorprone.CompilationTestHelper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for {@link BadAnnotationImplementation}. */
@RunWith(JUnit4.class)
public class BadAnnotationImplementationTest {

  private final CompilationTestHelper compilationHelper =
      CompilationTestHelper.newInstance(BadAnnotationImplementation.class, getClass());

  @Test
  public void declaredClassImplementsAnnotation() {
    compilationHelper
        .addSourceLines(
            "TestAnnotation.java",
            """
            import java.lang.annotation.Annotation;

            // BUG: Diagnostic contains:
            public class TestAnnotation implements Annotation {
              @Override
              public Class<? extends Annotation> annotationType() {
                return TestAnnotation.class;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void anonymousClassImplementsAnnotation() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            import java.lang.annotation.Annotation;

            public class Test {
              public Annotation getAnnotation() {
                // BUG: Diagnostic contains:
                return new Annotation() {
                  @Override
                  public Class<? extends Annotation> annotationType() {
                    return Annotation.class;
                  }
                };
              }
            }
            """)
        .doTest();
  }

  @Test
  public void anonymousClassImplementsUserDefinedAnnotation() {
    compilationHelper
        .addSourceLines("MyAnnotation.java", "public @interface MyAnnotation {}")
        .addSourceLines(
            "AnonymousClass.java",
            """
            import java.lang.annotation.Annotation;

            public class AnonymousClass {
              public Annotation getAnnotation() {
                // BUG: Diagnostic contains:
                return new MyAnnotation() {
                  @Override
                  public Class<? extends Annotation> annotationType() {
                    return Annotation.class;
                  }
                };
              }
            }
            """)
        .doTest();
  }

  @Test
  public void overridesEqualsButNotHashCode() {
    compilationHelper
        .addSourceLines(
            "TestAnnotation.java",
            """
            import java.lang.annotation.Annotation;

            // BUG: Diagnostic contains:
            public class TestAnnotation implements Annotation {
              @Override
              public Class<? extends Annotation> annotationType() {
                return TestAnnotation.class;
              }

              @Override
              public boolean equals(Object other) {
                return false;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void overridesHashCodeButNotEquals() {
    compilationHelper
        .addSourceLines(
            "TestAnnotation.java",
            """
            import java.lang.annotation.Annotation;

            // BUG: Diagnostic contains:
            public class TestAnnotation implements Annotation {
              @Override
              public Class<? extends Annotation> annotationType() {
                return TestAnnotation.class;
              }

              @Override
              public int hashCode() {
                return 0;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void wrongEquals() {
    compilationHelper
        .addSourceLines(
            "TestAnnotation.java",
            """
            import java.lang.annotation.Annotation;

            // BUG: Diagnostic contains:
            public class TestAnnotation implements Annotation {
              @Override
              public Class<? extends Annotation> annotationType() {
                return TestAnnotation.class;
              }

              public boolean equals(TestAnnotation other) {
                return false;
              }

              @Override
              public int hashCode() {
                return 0;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void wrongHashCode() {
    compilationHelper
        .addSourceLines(
            "TestAnnotation.java",
            """
            import java.lang.annotation.Annotation;

            // BUG: Diagnostic contains:
            public class TestAnnotation implements Annotation {
              @Override
              public Class<? extends Annotation> annotationType() {
                return TestAnnotation.class;
              }

              @Override
              public boolean equals(Object other) {
                return false;
              }

              public int hashCode(Object obj) {
                return 0;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void overridesEqualsAndHashCode() {
    compilationHelper
        .addSourceLines(
            "TestAnnotation.java",
            """
            import java.lang.annotation.Annotation;

            public class TestAnnotation implements Annotation {
              @Override
              public Class<? extends Annotation> annotationType() {
                return TestAnnotation.class;
              }

              @Override
              public boolean equals(Object other) {
                return false;
              }

              @Override
              public int hashCode() {
                return 0;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void declareInterfaceThatExtendsAnnotation() {
    compilationHelper
        .addSourceLines(
            "TestAnnotation.java",
            """
            import java.lang.annotation.Annotation;

            public interface TestAnnotation extends Annotation {}
            """)
        .doTest();
  }

  @Test
  public void declareEnumThatImplementsAnnotation() {
    compilationHelper
        .addSourceLines(
            "TestEnum.java",
            """
            import java.lang.annotation.Annotation;

            // BUG: Diagnostic contains: Enums cannot correctly implement Annotation
            public enum TestEnum implements Annotation {
              VALUE_1,
              VALUE_2;

              @Override
              public Class<? extends Annotation> annotationType() {
                return TestEnum.class;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void extendsClassThatImplementsEqualsAndHashCode() {
    compilationHelper
        .addSourceLines(
            "BaseAnnotation.java",
            """
            import java.lang.annotation.Annotation;

            public class BaseAnnotation implements Annotation {
              @Override
              public Class<? extends Annotation> annotationType() {
                return Annotation.class;
              }

              @Override
              public boolean equals(Object other) {
                return false;
              }

              @Override
              public int hashCode() {
                return 0;
              }
            }
            """)
        .addSourceLines(
            "MyAnnotation.java",
            """
            import java.lang.annotation.Annotation;

            public class MyAnnotation extends BaseAnnotation {}
            """)
        .doTest();
  }
}
