// Copyright (c) 2020, 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.analysis.value;

import static com.android.tools.r8.ir.analysis.type.Nullability.definitelyNotNull;
import static com.android.tools.r8.ir.analysis.type.TypeLatticeElement.classClassType;
import static com.android.tools.r8.optimize.MemberRebindingAnalysis.isClassTypeVisibleFromContext;

import com.android.tools.r8.graph.AppInfoWithSubtyping;
import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.DebugLocalInfo;
import com.android.tools.r8.graph.DexClass;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.ir.analysis.type.TypeLatticeElement;
import com.android.tools.r8.ir.code.ConstClass;
import com.android.tools.r8.ir.code.IRCode;
import com.android.tools.r8.ir.code.Instruction;
import com.android.tools.r8.ir.code.TypeAndLocalInfoSupplier;
import com.android.tools.r8.ir.code.Value;

public class SingleConstClassValue extends SingleValue {

  private final DexType type;

  /** Intentionally package private, use {@link AbstractValueFactory} instead. */
  SingleConstClassValue(DexType type) {
    this.type = type;
  }

  @Override
  public boolean isSingleConstClassValue() {
    return true;
  }

  @Override
  public SingleConstClassValue asSingleConstClassValue() {
    return this;
  }

  public DexType getType() {
    return type;
  }

  @Override
  public boolean equals(Object o) {
    return this == o;
  }

  @Override
  public int hashCode() {
    return type.hashCode();
  }

  @Override
  public String toString() {
    return "SingleConstClassValue(" + type.toSourceString() + ")";
  }

  @Override
  public Instruction createMaterializingInstruction(
      AppView<? extends AppInfoWithSubtyping> appView, IRCode code, TypeAndLocalInfoSupplier info) {
    TypeLatticeElement typeLattice = info.getTypeLattice();
    DebugLocalInfo debugLocalInfo = info.getLocalInfo();
    assert typeLattice.isClassType();
    assert appView
        .isSubtype(
            appView.dexItemFactory().classType,
            typeLattice.asClassTypeLatticeElement().getClassType())
        .isTrue();
    Value returnedValue =
        code.createValue(classClassType(appView, definitelyNotNull()), debugLocalInfo);
    ConstClass instruction = new ConstClass(returnedValue, type);
    assert !instruction.instructionMayHaveSideEffects(appView, code.method.method.holder);
    return instruction;
  }

  @Override
  public boolean isMaterializableInContext(AppView<?> appView, DexType context) {
    DexType baseType = type.toBaseType(appView.dexItemFactory());
    if (baseType.isClassType()) {
      DexClass clazz = appView.definitionFor(type);
      return clazz != null
          && clazz.isResolvable(appView)
          && isClassTypeVisibleFromContext(appView, context, clazz);
    }
    assert baseType.isPrimitiveType();
    return true;
  }
}