/*
 * This file is part of the Cforall project
 *
 * $Id: CastCost.cc,v 1.11 2005/08/29 20:14:15 rcbilson Exp $
 *
 */

#include "typeops.h"
#include "Cost.h"
#include "ConversionCost.h"
#include "SynTree/Type.h"
#include "SynTree/Visitor.h"
#include "SymTab/Indexer.h"


namespace ResolvExpr {

class CastCost : public ConversionCost
{
public:
  CastCost( Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env );
  
  virtual void visit(BasicType *basicType);
  virtual void visit(PointerType *pointerType);
};

Cost
castCost( Type *src, Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env )
{
//  std::cout << "casting" << std::endl;
//  src->print( std::cout, 8 );
//  std::cout << std::endl << "to" << std::endl;
//  dest->print( std::cout, 8 );
  if( TypeInstType *destAsTypeInst = dynamic_cast< TypeInstType* >( dest ) ) {
    EqvClass eqvClass;
    NamedTypeDecl *namedType;
    if( env.lookup( destAsTypeInst->get_name(), eqvClass ) ) {
      return castCost( src, eqvClass.type, indexer, env );
    } else if( ( namedType = indexer.lookupType( destAsTypeInst->get_name() ) ) ) {
      TypeDecl *type = dynamic_cast< TypeDecl* >( namedType );
      // all typedefs should be gone by this point
      assert( type );
      if( type->get_base() ) {
        return castCost( src, type->get_base(), indexer, env ) + Cost( 0, 0, 1 );
      }
    }
  }
  if( typesCompatibleIgnoreQualifiers( src, dest, indexer, env ) ) {
//    std::cout << "types are compatible" << std::endl;
    return Cost( 0, 0, 0 );
  } else if( dynamic_cast< VoidType* >( dest ) ) {
//    std::cout << "destination is void" << std::endl;
    return Cost( 0, 0, 1 );
  } else {
    CastCost converter( dest, indexer, env );
    src->accept( converter );
//    std::cout << "cost is " << converter.get_cost() << std::endl;
    if( converter.get_cost() == Cost::infinity ) {
      return Cost::infinity;
    } else {
      return converter.get_cost() + Cost( 0, 0, 0 );
    }
  }
}

CastCost::CastCost( Type *dest, const SymTab::Indexer &indexer, const TypeEnvironment &env )
  : ConversionCost( dest, indexer, env )
{
}

void 
CastCost::visit(BasicType *basicType)
{
  if( dynamic_cast< PointerType* >( dest ) ) {
    cost = Cost( 1, 0, 0 );
  } else {
    ConversionCost::visit( basicType );
  }
}

void 
CastCost::visit(PointerType *pointerType)
{
  if( PointerType *destAsPtr = dynamic_cast< PointerType* >( dest ) ) {
    if( pointerType->get_qualifiers() <= destAsPtr->get_qualifiers() && typesCompatibleIgnoreQualifiers( pointerType->get_base(), destAsPtr->get_base(), indexer, env ) ) {
      cost = Cost( 0, 0, 1 );
    } else if( BasicType *destAsBasic = dynamic_cast< BasicType* >( dest ) ) {
      if( destAsBasic->isInteger() ) {
        cost = Cost( 1, 0, 0 );
      }
    } else {
      TypeEnvironment newEnv( env );
      newEnv.add( pointerType->get_forall() );
      newEnv.add( pointerType->get_base()->get_forall() );
      int assignResult = ptrsCastable( pointerType->get_base(), destAsPtr->get_base(), newEnv, indexer );
      if( assignResult > 0 ) {
        cost = Cost( 0, 0, 1 );
      } else if( assignResult < 0 ) {
        cost = Cost( 1, 0, 0 );
      }
    }
  }
}

} // namespace ResolvExpr