#include "AST.h"
#include "CtType.h"
#include "code-call.h"
#include "code-util.h"
#include "decls.h"
#include "errors.h"
#include "lgMacro.h"


const string ExprNode::emitBinOp( CodeContext &context,
				  const char op[] )
{
  // Although we are only evaluating each operand once, the
  // temporaries are needed to guarantee evaluation order.
  const string operand0 = child(0)->emitExpression( context );
  const string operand1 = child(1)->emitExpression( context );

  return operand0 + ' ' + op + ' ' + operand1;
}


const string MultNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "*" );
}


const string DivNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "/" );
}


const string RemNode::emitExpression( CodeContext &context )
{
  const string operand0 = child(0)->emitExpression( context );
  const string operand1 = child(1)->emitExpression( context );

  if (child(0)->type()->isFloatType() || child(1)->type()->isFloatType())
    return "fmod(" + operand0 + ", " + operand1 + ")";
  else
    return operand0 + " % " + operand1;
}


const string PlusNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "+" );
}


const string MinusNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "-" );
}


const string LeftShiftLogNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "<<" );
}


const string RightShiftLogNode::emitExpression( CodeContext &context )
{
  TypeNode *exprType = child(0)->type();
  assert(exprType->isPrimitive());

  // CM: Actually, the formula below is not quite right. Consider what
  // happens if n == 0 or if sizeof(x) == 8. Instead, use the following:
  // x >>> n = (x >> n) & ((~((julong) 0)) >>
  //                       (n + (sizeof(julong) - sizeof(x)) * 8));
  // Note that this assumes that julong is the longest type.
  // CM

  // x >>> n = (x >> n) & ((1 << (sizeof(x) * 8 - n)) - 1)
  // The alternative is to cast to the unsigned version of x->type() by 
  // defining methods in code-primitives.cc that do the type conversion.
  // Too bad you can't stick "unsigned" on user types in C.
  const string operand0 = child(0)->emitExpression( context );
  const string operand1 = child(1)->emitExpression( context );
  const string shiftExpr = operand0 + " >> " + operand1;
  const string sizeofType = "sizeof(" + 
    string(((PrimitiveTypeNode *)exprType)->cPrimitiveTypeName()) + ")";
  return string("(") + shiftExpr + ") & " +
    "((~((julong) 0)) >> (" + operand1 + " + (sizeof(julong) - " +
    sizeofType + ") * 8))";
}


const string RightShiftArithNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, ">>" );
}


const string LTNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "<" );
}


const string GTNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, ">" );
}


const string LENode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "<=" );
}


const string GENode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, ">=" );
}


/* Returns whether t is "null" or a cast of "null." */
static bool isNull(TreeNode *t)
{
  return
    t->type()->isNullType() ||
    isCastNode(t) && isNull(t->opnd0());
}

// opnd0 is a titanium array.  Therefore, opnd1 must be null or we
// signal an error.
static const string TiArrayEQNode(TreeNode *opnd0, TreeNode *opnd1, CodeContext &context)
{
  if (!isNull(opnd1)) {
    opnd1->error() << "Grids may be compared to null but not to anything else" << endl;
    return "";
  }
  
  return callGridMethod(*opnd0->type(), "isnull",
			"(" + opnd0->emitExpression(context) + ")");
}

static const string commonEQNode(TreeNode *opnd0, TreeNode *opnd1, CodeContext &context)
{
  const TypeNode &type0 = *opnd0->type();
  const TypeNode &type1 = *opnd1->type();

  if (type0.isTitaniumArrayType()) 
    return TiArrayEQNode(opnd0, opnd1, context);
  else if (type1.isTitaniumArrayType()) 
    return TiArrayEQNode(opnd1, opnd0, context);

  const string operand0 = opnd0->emitExpression( context );
  const string operand1 = opnd1->emitExpression( context );

  
  if (type0.isPrimitive())
    return operand0 + " == " + operand1;
  else {
    const string method = type0.isImmutable()
      ? (MANGLE_CLASS_EQUALS(+, ((TypeNameNode &)type0).decl()->cType()))
      : lgMacro( "EQUAL", type0 );

    return method + '(' + operand0 + ", " + operand1 + ')';
  }
}


const string EQNode::emitExpression( CodeContext &context )
{
  return commonEQNode(opnd0(), opnd1(), context);
}

const string TitaniumArrayEQNode::emitExpression( CodeContext &context )
{
  const string operand0 = opnd0()->emitExpression( context );
  const string operand1 = opnd1()->emitExpression( context );
  return "(memcmp(&" + operand0 + ", &" + operand1 + ", "
    "sizeof(" + operand0 + ")) == 0)";
}


const string NENode::emitExpression( CodeContext &context )
{
  return "!(" + commonEQNode(opnd0(), opnd1(), context) + ")";
}


const string BitAndNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "&" );
}


const string BitOrNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "|" );
}


const string BitXorNode::emitExpression( CodeContext &context )
{
  return emitBinOp( context, "^" );
}