// 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.cf.code;

import com.android.tools.r8.cf.CfPrinter;
import com.android.tools.r8.errors.Unreachable;
import com.android.tools.r8.graph.CfCompareHelper;
import com.android.tools.r8.graph.DexClassAndMethod;
import com.android.tools.r8.graph.DexField;
import com.android.tools.r8.graph.DexItemFactory;
import com.android.tools.r8.graph.DexProgramClass;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.graph.GraphLens;
import com.android.tools.r8.graph.InitClassLens;
import com.android.tools.r8.graph.ProgramMethod;
import com.android.tools.r8.graph.UseRegistry;
import com.android.tools.r8.ir.conversion.CfSourceCode;
import com.android.tools.r8.ir.conversion.CfState;
import com.android.tools.r8.ir.conversion.CfState.Slot;
import com.android.tools.r8.ir.conversion.IRBuilder;
import com.android.tools.r8.ir.conversion.LensCodeRewriterUtils;
import com.android.tools.r8.ir.optimize.Inliner.ConstraintWithTarget;
import com.android.tools.r8.ir.optimize.InliningConstraints;
import com.android.tools.r8.naming.NamingLens;
import java.util.Comparator;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

public class CfFieldInstruction extends CfInstruction {

  private final int opcode;
  private final DexField field;
  private final DexField declaringField;

  public CfFieldInstruction(int opcode, DexField field, DexField declaringField) {
    this.opcode = opcode;
    this.field = field;
    this.declaringField = declaringField;
    assert field.type == declaringField.type;
  }

  public DexField getField() {
    return field;
  }

  public int getOpcode() {
    return opcode;
  }

  @Override
  public int getCompareToId() {
    return opcode;
  }

  @Override
  public int internalCompareTo(CfInstruction other, CfCompareHelper helper) {
    return Comparator.comparing(CfFieldInstruction::getField, DexField::slowCompareTo)
        .thenComparing(field -> field.declaringField, DexField::slowCompareTo)
        .compare(this, (CfFieldInstruction) other);
  }

  @Override
  public CfFieldInstruction asFieldInstruction() {
    return this;
  }

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

  @Override
  public void write(
      ProgramMethod context,
      DexItemFactory dexItemFactory,
      GraphLens graphLens,
      InitClassLens initClassLens,
      NamingLens namingLens,
      LensCodeRewriterUtils rewriter,
      MethodVisitor visitor) {
    DexField rewrittenField = graphLens.lookupField(field);
    DexField rewrittenDeclaringField = graphLens.lookupField(declaringField);
    String owner = namingLens.lookupInternalName(rewrittenField.holder);
    String name = namingLens.lookupName(rewrittenDeclaringField).toString();
    String desc = namingLens.lookupDescriptor(rewrittenField.type).toString();
    visitor.visitFieldInsn(opcode, owner, name, desc);
  }

  @Override
  public void print(CfPrinter printer) {
    printer.print(this);
  }

  @Override
  void internalRegisterUse(UseRegistry registry, DexClassAndMethod context) {
    switch (opcode) {
      case Opcodes.GETFIELD:
        registry.registerInstanceFieldRead(field);
        break;
      case Opcodes.PUTFIELD:
        registry.registerInstanceFieldWrite(field);
        break;
      case Opcodes.GETSTATIC:
        registry.registerStaticFieldRead(field);
        break;
      case Opcodes.PUTSTATIC:
        registry.registerStaticFieldWrite(field);
        break;
      default:
        throw new Unreachable("Unexpected opcode " + opcode);
    }
  }

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

  @Override
  public void buildIR(IRBuilder builder, CfState state, CfSourceCode code) {
    DexType type = field.type;
    switch (opcode) {
      case Opcodes.GETSTATIC:
        {
          builder.addStaticGet(state.push(type).register, field);
          break;
        }
      case Opcodes.PUTSTATIC:
        {
          Slot value = state.pop();
          builder.addStaticPut(value.register, field);
          break;
        }
      case Opcodes.GETFIELD:
        {
          Slot object = state.pop();
          builder.addInstanceGet(state.push(type).register, object.register, field);
          break;
        }
      case Opcodes.PUTFIELD:
        {
          Slot value = state.pop();
          Slot object = state.pop();
          builder.addInstancePut(value.register, object.register, field);
          break;
        }
      default:
        throw new Unreachable("Unexpected opcode " + opcode);
    }
  }

  @Override
  public ConstraintWithTarget inliningConstraint(
      InliningConstraints inliningConstraints, DexProgramClass context) {
    switch (opcode) {
      case Opcodes.GETSTATIC:
        return inliningConstraints.forStaticGet(field, context);
      case Opcodes.PUTSTATIC:
        return inliningConstraints.forStaticPut(field, context);
      case Opcodes.GETFIELD:
        return inliningConstraints.forInstanceGet(field, context);
      case Opcodes.PUTFIELD:
        return inliningConstraints.forInstancePut(field, context);
      default:
        throw new Unreachable("Unexpected opcode " + opcode);
    }
  }

  @Override
  public void evaluate(
      CfFrameVerificationHelper frameBuilder,
      DexType context,
      DexType returnType,
      DexItemFactory factory,
      InitClassLens initClassLens) {
    switch (opcode) {
      case Opcodes.GETFIELD:
        // ..., objectref →
        // ..., value
        frameBuilder.popAndDiscard(field.holder).push(field.type);
        return;
      case Opcodes.GETSTATIC:
        // ..., →
        // ..., value
        frameBuilder.push(field.type);
        return;
      case Opcodes.PUTFIELD:
        // ..., objectref, value →
        // ...,
        frameBuilder.popAndDiscard(field.holder, field.type);
        return;
      case Opcodes.PUTSTATIC:
        // ..., value →
        // ...
        frameBuilder.pop(field.type);
        return;
      default:
        throw new Unreachable("Unexpected opcode " + opcode);
    }
  }
}