/*
 * 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;

/** {@link UnusedAnonymousClass}Test */
@RunWith(JUnit4.class)
public class UnusedAnonymousClassTest {
  private final CompilationTestHelper compilationHelper =
      CompilationTestHelper.newInstance(UnusedAnonymousClass.class, getClass());

  @Test
  public void deadObject() {
    compilationHelper
        .addSourceLines(
            "a/One.java",
            """
            package a;

            public class One {
              public static void main(String[] args) {
                new Object();
              }
            }
            """)
        .doTest();
  }

  // Thread has a known side-effect free constructor
  @Test
  public void deadThread() {
    compilationHelper
        .addSourceLines(
            "a/One.java",
            """
            package a;

            public class One {
              public static void main(String[] args) {
                // BUG: Diagnostic contains:
                new Thread() {
                  public void run() {}
                };
              }
            }
            """)
        .doTest();
  }

  @Test
  public void liveObject() {
    compilationHelper
        .addSourceLines(
            "a/One.java",
            """
            package a;

            public class One {
              public static void main(String[] args) {
                new Object().toString();
              }
            }
            """)
        .doTest();
  }

  @Test
  public void deadCallable() {
    compilationHelper
        .addSourceLines(
            "a/One.java",
            """
            package a;

            import java.util.concurrent.Callable;

            public class One {
              public static void main(String[] args) throws Exception {
                // BUG: Diagnostic contains:
                new Callable<Void>() {
                  public Void call() throws Exception {
                    return null;
                  }
                };
              }
            }
            """)
        .doTest();
  }

  @Test
  public void liveCallable() {
    compilationHelper
        .addSourceLines(
            "a/One.java",
            """
            package a;

            import java.util.concurrent.Callable;

            public class One {
              public static void main(String[] args) throws Exception {
                new Callable<Void>() {
                  public Void call() throws Exception {
                    return null;
                  }
                }.call();
              }
            }
            """)
        .doTest();
  }

  @Test
  public void liveCallableViaCinit() {
    compilationHelper
        .addSourceLines(
            "a/One.java",
            """
            package a;

            import java.util.concurrent.Callable;
            import java.util.ArrayList;

            public class One {
              static ArrayList<Callable<Void>> callables = new ArrayList<>();

              public static void main(String[] args) throws Exception {
                new Callable<Void>() {
                  {
                    callables.add(this);
                  }

                  public Void call() throws Exception {
                    return null;
                  }
                };
              }
            }
            """)
        .doTest();
  }

  @Test
  public void deadCallableWithField() {
    compilationHelper
        .addSourceLines(
            "a/One.java",
            """
            package a;

            import java.util.concurrent.Callable;
            import java.util.ArrayList;

            public class One {
              public static void main(String[] args) throws Exception {
                // BUG: Diagnostic contains:
                new Callable<Void>() {
                  Void register;

                  public Void call() throws Exception {
                    return null;
                  }
                };
              }
            }
            """)
        .doTest();
  }

  @Test
  public void liveCallableViaField() {
    compilationHelper
        .addSourceLines(
            "a/One.java",
            """
            package a;

            import java.util.concurrent.Callable;
            import java.util.ArrayList;

            public class One {
              static ArrayList<Callable<Void>> callables = new ArrayList<>();

              static Void register(Callable<Void> callable) {
                callables.add(callable);
                return null;
              }

              public static void main(String[] args) throws Exception {
                new Callable<Void>() {
                  Void register = register(this);

                  public Void call() throws Exception {
                    return null;
                  }
                };
              }
            }
            """)
        .doTest();
  }
}
