// Copyright (c) 2018, 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;

import static org.junit.Assert.assertEquals;

import com.android.tools.r8.TestBase;
import com.android.tools.r8.ir.optimize.nonnull.FieldAccessTest;
import com.android.tools.r8.ir.optimize.nonnull.NonNullAfterArrayAccess;
import com.android.tools.r8.ir.optimize.nonnull.NonNullAfterFieldAccess;
import com.android.tools.r8.ir.optimize.nonnull.NonNullAfterInvoke;
import com.android.tools.r8.naming.MemberNaming.MethodSignature;
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 com.google.common.collect.ImmutableList;
import com.google.common.collect.Streams;
import java.util.List;
import org.junit.Test;

public class SimplifyIfNotNullTest extends TestBase {

  private void verifyAbsenceOfIf(
      CodeInspector codeInspector, Class<?> testClass, List<MethodSignature> signatures) {
    for (MethodSignature signature : signatures) {
      MethodSubject method =
          codeInspector.clazz(testClass).method(signature);
      long count = Streams.stream(method.iterateInstructions(InstructionSubject::isIf)).count();
      assertEquals(0, count);
    }
  }

  private void testD8(Class<?> testClass, List<MethodSignature> signatures) throws Exception {
    CodeInspector codeInspector =
        testForD8()
            .addProgramClasses(testClass)
            .addOptionsModification(options -> options.enableNonNullTracking = true)
            .compile()
            .inspector();
    verifyAbsenceOfIf(codeInspector, testClass, signatures);
  }

  private void testR8(Class<?> testClass, List<MethodSignature> signatures) throws Exception {
    CodeInspector codeInspector =
        testForR8(Backend.DEX)
            .addProgramClasses(testClass)
            .addKeepRules("-keep class " + testClass.getCanonicalName() + " { *; }")
            .compile()
            .inspector();
    verifyAbsenceOfIf(codeInspector, testClass, signatures);
  }

  @Test
  public void nonNullAfterSafeInvokes() throws Exception {
    MethodSignature foo =
        new MethodSignature("foo", "int", new String[]{"java.lang.String"});
    MethodSignature bar =
        new MethodSignature("bar", "int", new String[]{"java.lang.String"});
    testD8(NonNullAfterInvoke.class, ImmutableList.of(foo, bar));
    testR8(NonNullAfterInvoke.class, ImmutableList.of(foo, bar));
  }

  @Test
  public void nonNullAfterSafeArrayAccess() throws Exception {
    MethodSignature foo =
        new MethodSignature("foo", "int", new String[]{"java.lang.String[]"});
    MethodSignature bar =
        new MethodSignature("bar", "int", new String[]{"java.lang.String[]"});
    testD8(NonNullAfterArrayAccess.class, ImmutableList.of(foo, bar));
    testR8(NonNullAfterArrayAccess.class, ImmutableList.of(foo, bar));
  }

  @Test
  public void nonNullAfterSafeFieldAccess() throws Exception {
    MethodSignature foo = new MethodSignature("foo", "int",
        new String[]{FieldAccessTest.class.getCanonicalName()});
    MethodSignature bar = new MethodSignature("bar", "int",
        new String[]{FieldAccessTest.class.getCanonicalName()});
    MethodSignature foo2 = new MethodSignature("foo2", "int",
        new String[]{FieldAccessTest.class.getCanonicalName()});
    testD8(NonNullAfterFieldAccess.class, ImmutableList.of(foo, bar, foo2));
    testR8(NonNullAfterFieldAccess.class, ImmutableList.of(foo, bar, foo2));
  }
}