// Copyright (c) 2019, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
package com.android.tools.r8.ir.optimize.callsites.nullability;

import static com.android.tools.r8.utils.codeinspector.Matchers.isPresent;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.junit.Assert.assertTrue;

import com.android.tools.r8.NeverClassInline;
import com.android.tools.r8.NeverInline;
import com.android.tools.r8.NeverMerge;
import com.android.tools.r8.TestBase;
import com.android.tools.r8.TestParameters;
import com.android.tools.r8.TestParametersCollection;
import com.android.tools.r8.graph.DexEncodedMethod;
import com.android.tools.r8.ir.analysis.type.TypeLatticeElement;
import com.android.tools.r8.ir.optimize.info.CallSiteOptimizationInfo;
import com.android.tools.r8.utils.codeinspector.ClassSubject;
import com.android.tools.r8.utils.codeinspector.CodeInspector;
import com.android.tools.r8.utils.codeinspector.InstructionSubject;
import com.android.tools.r8.utils.codeinspector.MethodSubject;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

@RunWith(Parameterized.class)
public class InvokeInterfaceNegativeTest extends TestBase {
  private static final Class<?> MAIN = Main.class;

  @Parameterized.Parameters(name = "{0}")
  public static TestParametersCollection data() {
    return getTestParameters().withAllRuntimesAndApiLevels().build();
  }

  private final TestParameters parameters;

  public InvokeInterfaceNegativeTest(TestParameters parameters) {
    this.parameters = parameters;
  }

  @Test
  public void testR8() throws Exception {
    testForR8(parameters.getBackend())
        .addInnerClasses(InvokeInterfaceNegativeTest.class)
        .addKeepMainRule(MAIN)
        .enableMergeAnnotations()
        .enableNeverClassInliningAnnotations()
        .enableInliningAnnotations()
        .addOptionsModification(
            o -> {
              // To prevent invoke-interface from being rewritten to invoke-virtual w/ a single
              // target.
              o.enableDevirtualization = false;
              o.testing.callSiteOptimizationInfoInspector = this::callSiteOptimizationInfoInspect;
            })
        .setMinApi(parameters.getApiLevel())
        .run(parameters.getRuntime(), MAIN)
        .assertSuccessWithOutputLines("null", "A")
        .inspect(this::inspect);
  }

  private void callSiteOptimizationInfoInspect(DexEncodedMethod encodedMethod) {
    assert encodedMethod.method.name.toString().equals("m")
        : "Unexpected revisit: " + encodedMethod.toSourceString();
    CallSiteOptimizationInfo callSiteOptimizationInfo = encodedMethod.getCallSiteOptimizationInfo();
    TypeLatticeElement upperBoundType = callSiteOptimizationInfo.getDynamicUpperBoundType(1);
    assert upperBoundType.isNullable();
    assert upperBoundType.isClassType()
        && upperBoundType.asClassType().getClassType().toSourceString().endsWith("$A");
  }

  private void inspect(CodeInspector inspector) {
    ClassSubject i = inspector.clazz(I.class);
    assertThat(i, isPresent());

    ClassSubject a = inspector.clazz(A.class);
    assertThat(a, isPresent());

    MethodSubject a_m = a.uniqueMethodWithName("m");
    assertThat(a_m, isPresent());
    // Should not optimize branches since the nullability of `arg` is unsure.
    assertTrue(a_m.streamInstructions().anyMatch(InstructionSubject::isIf));
  }

  @NeverMerge
  interface I {
    void m(Object arg);
  }

  @NeverClassInline
  static class A implements I {
    @NeverInline
    @Override
    public void m(Object arg) {
      // Technically same as String#valueOf.
      if (arg != null) {
        System.out.println(arg.toString());
      } else {
        System.out.println("null");
      }
    }

    @NeverInline
    @Override
    public String toString() {
      return "A";
    }
  }

  static class Main {
    public static void main(String... args) {
      I i = new A();
      i.m(null);  // calls A.m() with null.
      i.m(i);     // calls A.m() with non-null instance.
    }
  }
}