/*
 * 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.fatptr;

import org.renjin.gcc.codegen.MethodGenerator;
import org.renjin.gcc.codegen.expr.GExpr;
import org.renjin.gcc.codegen.expr.JLValue;
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.Type;

import java.util.Arrays;
import java.util.List;
import java.util.Optional;

/**
 * Strategy for passing fat pointer expressions as two arguments
 */
public class FatPtrParamStrategy implements ParamStrategy {
  
  private ValueFunction valueFunction;

  public FatPtrParamStrategy(ValueFunction valueFunction) {
    this.valueFunction = valueFunction;
  }

  @Override
  public List<Type> getParameterTypes() {
    Type arrayType = Type.getType("[" + valueFunction.getValueType().getDescriptor());
    Type offsetType = Type.INT_TYPE;
    
    return Arrays.asList(arrayType, offsetType);
  }

  @Override
  public List<String> getParameterNames(String name) {
    return Arrays.asList(name, name + "_offset");
  }

  @Override
  public GExpr emitInitialization(MethodGenerator methodVisitor, GimpleParameter parameter, List<JLValue> paramVars, VarAllocator localVars) {
    if(parameter.isAddressable()) {
      throw new UnsupportedOperationException("TODO: Addressable parameters");
    }
    
    return new FatPtrPair(valueFunction, paramVars.get(0), paramVars.get(1));
  }

  @Override
  public void loadParameter(MethodGenerator mv, Optional<GExpr> argument) {
    if(argument.isPresent()) {
      FatPtrPair expr = (FatPtrPair) argument.get();
      expr.getArray().load(mv);
      expr.getOffset().load(mv);
    } else {
      mv.aconst(null);
      mv.iconst(0);
    }
  }
}
