/*
 * Copyright 2017 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.BugCheckerRefactoringTestHelper.TestMode;
import com.google.errorprone.CompilationTestHelper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Unit tests for {@link TypeParameterShadowing} */
@RunWith(JUnit4.class)
public class TypeParameterShadowingTest {

  private final CompilationTestHelper compilationHelper =
      CompilationTestHelper.newInstance(TypeParameterShadowing.class, getClass());
  private final BugCheckerRefactoringTestHelper refactoring =
      BugCheckerRefactoringTestHelper.newInstance(TypeParameterShadowing.class, getClass());

  @Test
  public void singleLevel() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            package foo.bar;

            class Test<T> {
              // BUG: Diagnostic contains: T declared in Test
              <T> void something() {}
            }
            """)
        .doTest();
  }

  @Test
  public void staticNotFlagged() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            package foo.bar;

            class Test<T> {
              static <T> void something() {}
            }
            """)
        .doTest();
  }

  @Test
  public void staticMethodInnerDoesntConflictWithOuter() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "package foo.bar;",
            "class Test<D> {",
            "  static <T> void something() {",
            "    class MethodInner<D> {}", // Doesn't clash with Test<D>
            "    class MethodInner2 {",
            "      // BUG: Diagnostic contains: T declared in something",
            "      <T> void clashingMethod() {}",
            "      <D> void nonClashingMethod() {}", // <D> not in scope
            "    }",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void nestedClassDeclarations() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            package foo.bar;

            class Test<D> {
              // BUG: Diagnostic contains: D declared in Test
              class Test2<D> {}
            }
            """)
        .doTest();
  }

  @Test
  public void twoLevels() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            package foo.bar;

            class Test<T> {
              class MyTest<J> {
                // BUG: Diagnostic matches: combo
                public <T, J> void something() {}
              }
            }
            """)
        .expectErrorMessage(
            "combo", s -> s.contains("J declared in MyTest") && s.contains("T declared in Test"))
        .doTest();
  }

  @Test
  public void renameTypeVar() {
    refactoring
        .addInputLines(
            "in/Test.java",
            """
            package foo.bar;

            class Test<T> {
              /**
               * @param <T> foo
               */
              <T> void something(T t) {
                T other = t;
              }
            }
            """)
        .addOutputLines(
            "out/Test.java",
            """
            package foo.bar;

            class Test<T> {
              /**
               * @param <T2> foo
               */
              <T2> void something(T2 t) {
                T2 other = t;
              }
            }
            """)
        .doTest(TestMode.TEXT_MATCH);
  }

  @Test
  public void renameRecursiveBound() {
    refactoring
        .addInputLines(
            "in/Test.java",
            """
            package foo.bar;

            class Test<T> {
              <T extends Comparable<T>> void something(T t) {
                T other = t;
              }
            }
            """)
        .addOutputLines(
            "out/Test.java",
            """
            package foo.bar;

            class Test<T> {
              <T2 extends Comparable<T2>> void something(T2 t) {
                T2 other = t;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void refactorUnderneathStuff() {
    refactoring
        .addInputLines(
            "in/Test.java",
            """
            package foo.bar;

            class Test<T> {
              <T> void something(T t) {
                T other = t;
              }

              <T> T identity(T t) {
                return t;
              }
            }
            """)
        .addOutputLines(
            "out/Test.java",
            """
            package foo.bar;

            class Test<T> {
              <T2> void something(T2 t) {
                T2 other = t;
              }

              <T2> T2 identity(T2 t) {
                return t;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void refactorMultipleVars() {
    refactoring
        .addInputLines(
            "in/Test.java",
            """
            package foo.bar;

            class Test<T, D> {
              <T, D> void something(T t) {
                T other = t;
                java.util.List<T> ts = new java.util.ArrayList<T>();
                D d = null;
              }
            }
            """)
        .addOutputLines(
            "out/Test.java",
            """
            package foo.bar;

            class Test<T, D> {
              <T2, D2> void something(T2 t) {
                T2 other = t;
                java.util.List<T2> ts = new java.util.ArrayList<T2>();
                D2 d = null;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void refactorWithNestedTypeParameterDeclaration() {
    // The nested @SuppressWarnings are because there will be multiple findings
    // (T is shadowed multiple times). We're trying to test all of the fixes suggested by the
    // finding generated from the outermost instance method, namely that it doesn't attempt to
    // rewrite symbols T that don't match the T we're rewriting.
    refactoring
        .addInputLines(
            "in/Test.java",
            """
            package foo.bar;

            class Test<T> {
              <T, T2> void something(T t) {
                T var = t;
                @SuppressWarnings("TypeParameterShadowing")
                class MethodInnerWithGeneric<T> {}
                MethodInnerWithGeneric<T> innerVar = null;
                class MethodInner {
                  @SuppressWarnings("TypeParameterShadowing")
                  <T> void doSomething() {}

                  void doSomethingElse(T t) {
                    this.<T>doSomething();
                  }
                }
                MethodInner myInner = null;
              }
            }
            """)
        .addOutputLines(
            "out/Test.java",
            """
            package foo.bar;

            class Test<T> {
              <T3, T2> void something(T3 t) {
                T3 var = t;
                @SuppressWarnings("TypeParameterShadowing")
                class MethodInnerWithGeneric<T> {}
                MethodInnerWithGeneric<T3> innerVar = null;
                class MethodInner {
                  @SuppressWarnings("TypeParameterShadowing")
                  <T> void doSomething() {}

                  void doSomethingElse(T3 t) {
                    this.<T3>doSomething();
                  }
                }
                MethodInner myInner = null;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void refactorCheckForExisting() {
    refactoring
        .addInputLines(
            "in/Test.java",
            """
            package foo.bar;

            class Test<T> {
              class A<T2, T3, T4> {
                <T> void something(T t) {
                  T var = t;
                }
              }
            }
            """)
        .addOutputLines(
            "out/Test.java",
            """
            package foo.bar;

            class Test<T> {
              class A<T2, T3, T4> {
                <T5> void something(T5 t) {
                  T5 var = t;
                }
              }
            }
            """)
        .doTest();
  }

  @Test
  public void refactorMethodInnerInner() {
    refactoring
        .addInputLines(
            "in/Test.java",
            """
            package foo.bar;

            class Test<T> {
              static <D> void something(D t) {
                class B {
                  class C<T, D> {}
                }
              }
            }
            """)
        .addOutputLines(
            "out/Test.java",
            "package foo.bar;",
            "class Test<T> {",
            "  static <D> void something(D t) {",
            "    class B {",
            // T isn't accessible to the inner since the method is static
            "      class C<T,D2> {}",
            "    }",
            "  }",
            "}")
        .doTest();
  }

  // don't try to read type parameters off the enclosing local variable declaration
  @Test
  public void symbolWithoutTypeParameters() {
    compilationHelper
        .addSourceLines(
            "Test.java",
"""
package foo.bar;

import java.util.Map;
import java.util.Comparator;

class Test {
  static Comparator<Map.Entry<Integer, String>> ENTRY_COMPARATOR =
      new Comparator<Map.Entry<Integer, String>>() {
        public int compare(Map.Entry<Integer, String> o1, Map.Entry<Integer, String> o2) {
          return 0;
        }

        private <T extends Comparable> int c(T o1, T o2) {
          return 0;
        }
      };
}
""")
        .doTest();
  }

  @Test
  public void lambdaParameterDesugaring() {
    refactoring
        .addInputLines(
            "in/A.java",
            """
            import java.util.function.Consumer;

            class A<T> {
              abstract class B<T> {
                void f() {
                  g(t -> {});
                }

                abstract void g(Consumer<T> c);
              }
            }
            """)
        .addOutputLines(
            "out/A.java",
            """
            import java.util.function.Consumer;

            class A<T> {
              abstract class B<T2> {
                void f() {
                  g(t -> {});
                }

                abstract void g(Consumer<T2> c);
              }
            }
            """)
        .doTest();
  }

  @Test
  public void typesWithBounds() {
    refactoring
        .addInputLines(
            "in/Test.java",
            """
            import java.util.function.Predicate;

            class Test<T> {
              <B extends Object & Comparable> void something(B b) {
                class Foo<B extends Object & Comparable> implements Predicate<B> {
                  public boolean test(B b) {
                    return false;
                  }
                }
                new Foo<>();
              }
            }
            """)
        .addOutputLines(
            "out/Test.java",
            """
            import java.util.function.Predicate;

            class Test<T> {
              <B extends Object & Comparable> void something(B b) {
                class Foo<B2 extends Object & Comparable> implements Predicate<B2> {
                  public boolean test(B2 b) {
                    return false;
                  }
                }
                new Foo<>();
              }
            }
            """)
        .doTest();
  }
}
