/*
 * Copyright 2023 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.BugCheckerRefactoringTestHelper;
import com.google.errorprone.CompilationTestHelper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public final class NonFinalStaticFieldTest {
  private final CompilationTestHelper compilationTestHelper =
      CompilationTestHelper.newInstance(NonFinalStaticField.class, getClass());

  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
      BugCheckerRefactoringTestHelper.newInstance(NonFinalStaticField.class, getClass());

  @Test
  public void positiveFixable() {
    refactoringTestHelper
        .addInputLines(
            "Test.java",
            """
            public class Test {
              private static String FOO = "";
            }
            """)
        .addOutputLines(
            "Test.java",
            """
            public class Test {
              private static final String FOO = "";
            }
            """)
        .doTest();
  }

  @Test
  public void positiveButNotFixable_noRefactoring() {
    refactoringTestHelper
        .addInputLines(
            "Test.java",
            """
            public class Test {
              public static String FOO = "";
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void positiveNotFixable_finding() {
    refactoringTestHelper
        .addInputLines(
            "Test.java",
            """
            public class Test {
              // BUG: Diagnostic contains:
              public static String FOO = "";
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void negative() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            public class Test {
              private static final String FOO = "";
            }
            """)
        .doTest();
  }

  @Test
  public void reassigned_noFix() {
    refactoringTestHelper
        .addInputLines(
            "Test.java",
            """
            public class Test {
              // BUG: Diagnostic contains:
              private static String foo = "";

              public void set(String s) {
                foo = s;
              }
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void reassigned_finding() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            public class Test {
              // BUG: Diagnostic contains:
              private static String foo = "";

              public void set(String s) {
                foo = s;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void incremented_noFix() {
    refactoringTestHelper
        .addInputLines(
            "Test.java",
            """
            public class Test {
              private static int foo = 0;

              public void increment() {
                foo++;
              }
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void incrementedAnotherWay_noFix() {
    refactoringTestHelper
        .addInputLines(
            "Test.java",
            """
            public class Test {
              private static int foo = 0;

              public void increment() {
                foo += 1;
              }
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  // NOTE: this _is_ safe to suggest a fix for, just harder to detect.
  public void initialisedExactlyOnceInStaticInitializer_noFix() {
    refactoringTestHelper
        .addInputLines(
            "Test.java",
            """
            public class Test {
              private static int foo;

              {
                foo = 1;
              }
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void neverAssigned_getsDefaultInitializer() {
    refactoringTestHelper
        .addInputLines(
            "Test.java",
            """
            public class Test {
              private static int foo;
            }
            """)
        .addOutputLines(
            "Test.java",
            """
            public class Test {
              private static final int foo = 0;
            }
            """)
        .doTest();
  }

  @Test
  public void negativeInterface() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            public interface Test {
              String FOO = "";
            }
            """)
        .doTest();
  }

  @Test
  public void exemptedAnnotation_noFinding() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            import org.mockito.Mock;

            public class Test {
              @Mock private static String foo;
            }
            """)
        .doTest();
  }

  @Test
  public void volatileRemoved() {
    refactoringTestHelper
        .addInputLines(
            "Test.java",
            """
            public class Test {
              private static volatile String FOO = "";
            }
            """)
        .addOutputLines(
            "Test.java",
            """
            public class Test {
              private static final String FOO = "";
            }
            """)
        .doTest();
  }

  @Test
  public void beforeClass() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            import org.junit.BeforeClass;

            public class Test {
              private static String foo;

              @BeforeClass
              public static void setup() {
                foo = "";
              }
            }
            """)
        .doTest();
  }

  @Test
  public void beforeAll() {
    compilationTestHelper
        .addSourceLines(
            "org/junit/jupiter/api/BeforeAll.java",
            """
            package org.junit.jupiter.api;

            import java.lang.annotation.Documented;
            import java.lang.annotation.ElementType;
            import java.lang.annotation.Retention;
            import java.lang.annotation.RetentionPolicy;
            import java.lang.annotation.Target;

            @Target({ElementType.ANNOTATION_TYPE, ElementType.METHOD})
            @Retention(RetentionPolicy.RUNTIME)
            @Documented
            public @interface BeforeAll {}
            """)
        .addSourceLines(
            "Test.java",
            """
            import org.junit.jupiter.api.BeforeAll;

            public class Test {
              private static String foo;

              @BeforeAll
              public static void setup() {
                foo = "";
              }
            }
            """)
        .doTest();
  }
}
