// 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.constants;

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.NoVerticalClassMerging;
import com.android.tools.r8.TestBase;
import com.android.tools.r8.TestParameters;
import com.android.tools.r8.TestParametersCollection;
import com.android.tools.r8.graph.ProgramMethod;
import com.android.tools.r8.ir.analysis.value.AbstractValue;
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;
import org.junit.runners.Parameterized.Parameter;
import org.junit.runners.Parameterized.Parameters;

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

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

  @Parameter(0)
  public TestParameters parameters;

  @Test
  public void testR8() throws Exception {
    testForR8(parameters.getBackend())
        .addInnerClasses(InvokeVirtualPositiveTest.class)
        .addKeepMainRule(MAIN)
        .addOptionsModification(
            o ->
                o.testing.callSiteOptimizationInfoInspector = this::callSiteOptimizationInfoInspect)
        .enableNoVerticalClassMergingAnnotations()
        .enableNeverClassInliningAnnotations()
        .enableInliningAnnotations()
        .setMinApi(parameters.getApiLevel())
        .run(parameters.getRuntime(), MAIN)
        .assertSuccessWithOutputLines("non-null", "null")
        .inspect(this::inspect);
  }

  private void callSiteOptimizationInfoInspect(ProgramMethod method) {
    assert method.getReference().name.toString().equals("m")
        : "Unexpected revisit: " + method.toSourceString();
    CallSiteOptimizationInfo callSiteOptimizationInfo =
        method.getOptimizationInfo().getArgumentInfos();
    assert callSiteOptimizationInfo.getDynamicType(1).getNullability().isDefinitelyNotNull();
    AbstractValue abstractValue = callSiteOptimizationInfo.getAbstractArgumentValue(1);
    if (method.getHolderType().toSourceString().endsWith("$A")) {
      assert abstractValue.isSingleStringValue()
          && abstractValue.asSingleStringValue().getDexString().toString().equals("nul");
    } else {
      assert abstractValue.isUnknown();
    }
  }

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

    MethodSubject a_m = a.uniqueMethodWithName("m");
    assertThat(a_m, isPresent());
    // Can optimize branches since `arg` is definitely "nul", i.e., not containing "null".
    assertTrue(a_m.streamInstructions().noneMatch(InstructionSubject::isIf));

    ClassSubject b = inspector.clazz(B.class);
    assertThat(b, isPresent());

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

  @NoVerticalClassMerging
  @NeverClassInline
  static class A {
    @NeverInline
    void m(String arg) {
      if (arg.contains("null")) {
        System.out.println("null");
      } else {
        System.out.println("non-null");
      }
    }
  }

  @NeverClassInline
  static class B extends A {
    @NeverInline
    @Override
    void m(String arg) {
      // Same as A#m.
      if (arg.contains("null")) {
        System.out.println("null");
      } else {
        System.out.println("non-null");
      }
    }
  }

  static class Main {
    public static void main(String... args) {
      A a = System.currentTimeMillis() > 0 ? new A() : new B();
      a.m("nul");  // calls A.m() with "nul".

      A b = new B();  // with the exact type:
      b.m("null");    // calls B.m() with "null".
    }
  }
}