/*
 * Renjin : JVM-based interpreter for the R language for the statistical analysis
 * Copyright Â© 2010-2019 BeDataDriven Groep B.V. and contributors
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, a copy is available at
 * https://www.gnu.org/licenses/gpl-2.0.txt
 */
package org.renjin.gcc.codegen.type.record;

import org.renjin.gcc.codegen.MethodGenerator;
import org.renjin.gcc.codegen.expr.Expressions;
import org.renjin.gcc.codegen.expr.GExpr;
import org.renjin.gcc.codegen.expr.JExpr;
import org.renjin.gcc.codegen.expr.JLValue;
import org.renjin.gcc.codegen.fatptr.FatPtrPair;
import org.renjin.gcc.codegen.type.ParamStrategy;
import org.renjin.gcc.codegen.var.VarAllocator;
import org.renjin.gcc.gimple.GimpleParameter;
import org.renjin.repackaged.asm.Opcodes;
import org.renjin.repackaged.asm.Type;

import java.util.Collections;
import java.util.List;
import java.util.Optional;


class ProvidedPtrParamStrategy implements ParamStrategy {

  private ProvidedPtrStrategy strategy;

  public ProvidedPtrParamStrategy(ProvidedPtrStrategy strategy) {
    this.strategy = strategy;
  }

  @Override
  public List<Type> getParameterTypes() {
    return Collections.singletonList(strategy.getJvmType());
  }

  @Override
  public List<String> getParameterNames(String name) {
    return Collections.singletonList(name);
  }

  @Override
  public GExpr emitInitialization(MethodGenerator methodVisitor, GimpleParameter parameter, List<JLValue> paramVars, VarAllocator localVars) {
    JLValue unitPtr = paramVars.get(0);
    if(parameter.isAddressable()) {
      // Allocate a unit array for this parameter
      JLValue unitArray = localVars.reserveUnitArray(parameter.getName() + "$address",
          unitPtr.getType(), Optional.of(unitPtr));
      FatPtrPair address = new FatPtrPair(strategy.getValueFunction(), unitArray);

      JExpr value = Expressions.elementAt(address.getArray(), 0);

      return new ProvidedPtrExpr(value, address);
    }
    return new ProvidedPtrExpr(unitPtr);
  }

  @Override
  public void loadParameter(MethodGenerator mv, Optional<GExpr> argument) {

    if(!argument.isPresent()) {
      mv.visitInsn(Opcodes.ACONST_NULL);
      return;
    }

    ProvidedPtrExpr unitPtrExpr = argument.get().toProvidedPtrExpr(strategy.getJvmType());

    unitPtrExpr.jexpr().load(mv);
  }
}
