// 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 static com.android.tools.r8.utils.BiPredicateUtils.or;

import com.android.tools.r8.cf.CfPrinter;
import com.android.tools.r8.errors.Unreachable;
import com.android.tools.r8.graph.AppView;
import com.android.tools.r8.graph.CfCode;
import com.android.tools.r8.graph.CfCompareHelper;
import com.android.tools.r8.graph.DexField;
import com.android.tools.r8.graph.DexItemFactory;
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.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 com.android.tools.r8.utils.structural.CompareToVisitor;
import com.android.tools.r8.utils.structural.StructuralSpecification;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;

public abstract class CfFieldInstruction extends CfInstruction {

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

  private static void specify(StructuralSpecification<CfFieldInstruction, ?> spec) {
    spec.withInt(f -> f.opcode).withItem(f -> f.field).withItem(f -> f.declaringField);
  }

  public CfFieldInstruction(int opcode, DexField field) {
    this(opcode, field, field);
  }

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

  public static CfFieldInstruction create(int opcode, DexField field, DexField declaringField) {
    switch (opcode) {
      case Opcodes.GETSTATIC:
        return new CfStaticFieldRead(field, declaringField);
      case Opcodes.PUTSTATIC:
        return new CfStaticFieldWrite(field, declaringField);
      case Opcodes.GETFIELD:
        return new CfInstanceFieldRead(field, declaringField);
      case Opcodes.PUTFIELD:
        return new CfInstanceFieldWrite(field, declaringField);
      default:
        throw new Unreachable("Unexpected opcode " + opcode);
    }
  }

  public DexField getField() {
    return field;
  }

  public int getOpcode() {
    return opcode;
  }

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

  @Override
  public int internalAcceptCompareTo(
      CfInstruction other, CompareToVisitor visitor, CfCompareHelper helper) {
    return visitor.visit(this, other.asFieldInstruction(), CfFieldInstruction::specify);
  }

  public boolean isFieldGet() {
    return opcode == Opcodes.GETFIELD || opcode == Opcodes.GETSTATIC;
  }

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

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

  @Override
  public void write(
      AppView<?> appView,
      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
  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, CfCode code, ProgramMethod 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.popAndDiscardInitialized(field.holder).push(field.type);
        return;
      case Opcodes.GETSTATIC:
        // ..., →
        // ..., value
        frameBuilder.push(field.type);
        return;
      case Opcodes.PUTFIELD:
        // ..., objectref, value →
        // ...,
        frameBuilder
            .popAndDiscardInitialized(field.type)
            .pop(
                field.holder,
                or(
                    frameBuilder::isUninitializedThisAndTarget,
                    frameBuilder::isAssignableAndInitialized));
        return;
      case Opcodes.PUTSTATIC:
        // ..., value →
        // ...
        frameBuilder.popAndDiscardInitialized(field.type);
        return;
      default:
        throw new Unreachable("Unexpected opcode " + opcode);
    }
  }
}