/* Swinder - Portable library for spreadsheet 
   Copyright (C) 2003 Ariya Hidayat <ariya@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
   
   This library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA
*/

#include "value.h"
#include "ustring.h"

#include <iostream>

namespace Swinder
{

// helper class for Value
class ValueData
{
  public:

    Value::Type type;

    // someday move to use union to reduce memory consumption
    bool b;
    int i;
    double f;
    UString s;

    // create empty data
    ValueData(){
      count = 0;
      b = false;
      i = 0;
      f = 0.0;
      s = UString::null;
      type = Value::Empty;
      ref();
      };

    // destroys data
    ~ValueData(){ 
       if( this == s_null ) s_null = 0;  
       }
       
    void ref(){ count++; }

    // static empty data to be shared
    static ValueData* null()
      { if( !s_null) s_null = new ValueData; else s_null->ref(); return s_null; }

    // decrease reference count
    void unref()
      {  --count; if( !count ) delete this; }

    // true if it's null (which is shared)
    bool isNull(){ return this == s_null; }

    unsigned count; // reference count
    
  private:

    static ValueData* s_null;
    
};

}

using namespace Swinder;

// to be shared between all empty value
ValueData* ValueData::s_null = 0;

// static things
Value ks_value_empty;
Value ks_error_div0;
Value ks_error_na;
Value ks_error_name;
Value ks_error_null;
Value ks_error_num;
Value ks_error_ref;
Value ks_error_value;

// create an empty value
Value::Value()
{
  d = ValueData::null();
}

// destructor
Value::~Value()
{
  d->unref();
}

// create value of certain type
Value::Value( Value::Type _type )
{
  d = new ValueData;
  d->type = _type;
}

// copy constructor
Value::Value( const Value& _value )
{
  d = ValueData::null();
  assign( _value );
}

// assignment operator
Value& Value::operator=( const Value& _value )
{
  return assign( _value );
}

// create a boolean value
Value::Value( bool b )
{
  d = ValueData::null();
  setValue( b );
}

// create an integer value
Value::Value( int i )
{
  d = ValueData::null();
  setValue ( i );
}

// create a floating-point value
Value::Value( double f )
{
  d = ValueData::null();
  setValue( f );
}

// create a string value
Value::Value( const UString& s )
{
  d = ValueData::null();
  setValue( s );
}

// assign value from other
// shallow copy: only copy the data pointer
Value& Value::assign( const Value& _value )
{
  d->unref();
  d = _value.d;
  d->ref();
  return *this;
}

// return type of the value
Value::Type Value::type() const
{
  return d ? d->type : Empty;
}

// set the value to boolean
void Value::setValue( bool b )
{
  detach();
  d->type = Boolean;
  d->b = b;
}

// get the value as boolean
bool Value::asBoolean() const
{
  bool result = false;

  if( type() == Value::Boolean )
    result = d->b;

  return result;
}

// set the value to integer
void Value::setValue( int i )
{
  detach();
  d->type = Integer;
  d->i = i;
}

// get the value as integer
int Value::asInteger() const
{
  int result = 0;

  if( type() == Value::Integer )
    result = d->i;

  if( type() == Value::Float )
    result = static_cast<int>(d->f);

  return result;
}

void Value::setValue( const Value& v )
{
  assign( v );
}

// set the value as floating-point
void Value::setValue( double f )
{
  detach();
  d->type = Float;
  d->f = f;
}

// get the value as floating-point
double Value::asFloat() const
{
  double result = 0.0;

  if( type() == Value::Float )
    result = d->f;

  if( type() == Value::Integer )
    result = static_cast<double>(d->i);

  return result;
}

// set the value as string
void Value::setValue( const UString& s )
{
  detach();
  d->type = String;
  d->s = s;
}

// get the value as string
UString Value::asString() const
{
  UString result;

  if( type() == Value::String )
    result = d->s;

  return result;
}

// set error message
void Value::setError( const UString& msg )
{
  detach();
  d->type = Error;
  d->s = msg;
}

// get error message
UString Value::errorMessage() const
{
  UString result;

  if( type() == Value::Error )
    result = d->s;

  return result;
}

// reference to empty value
const Value& Value::empty()
{
  return ks_value_empty;
}

// reference to #DIV/0! error
const Value& Value::errorDIV0()
{
  if( !ks_error_div0.isError() )
    ks_error_div0.setError( UString("#DIV/0!") );
  return ks_error_div0;
}

// reference to #N/A error
const Value& Value::errorNA()
{
  if( !ks_error_na.isError() )
    ks_error_na.setError( UString("#N/A") );
  return ks_error_na;
}

// reference to #NAME? error
const Value& Value::errorNAME()
{
  if( !ks_error_name.isError() )
    ks_error_name.setError( UString("#NAME?") );
  return ks_error_name;
}

// reference to #NUM! error
const Value& Value::errorNUM()
{
  if( !ks_error_num.isError() )
    ks_error_num.setError( UString("#NUM!") );
  return ks_error_num;
}

// reference to #NULL! error
const Value& Value::errorNULL()
{
  if( !ks_error_null.isError() )
    ks_error_null.setError( UString("#NULL!") );
  return ks_error_null;
}

// reference to #REF! error
const Value& Value::errorREF()
{
  if( !ks_error_ref.isError() )
    ks_error_ref.setError( UString("#REF!") );
  return ks_error_ref;
}

// reference to #VALUE! error
const Value& Value::errorVALUE()
{
  if( !ks_error_value.isError() )
    ks_error_value.setError( UString("#VALUE!") );
  return ks_error_value;
}

// detach, create deep copy of ValueData
void Value::detach()
{
  if( d->isNull() || ( d->count > 1 ) )
  {
    ValueData* n;
    n = new ValueData;

    n->type = d->type;
    switch( n->type )
    {
    case Empty: break;
    case Boolean: n->b = d->b; break;
    case Integer: n->i = d->i; break;
    case Float:   n->f = d->f; break;
    case String:  n->s = d->s; break;
    case Error:   n->s = d->s; break;
    default: break;
    }

    d->unref();
    d = n;
  }
}

std::ostream& Swinder::operator<<( std::ostream& s, Swinder::Value value )
{
  switch( value.type() )
  {
    case Value::Empty:
      s << "Empty";
      break;
    case Value::Boolean:
      s << "Boolean: " << (value.asBoolean()?"True":"False");
      break;
    case Value::Integer:
      s << "Integer: " << value.asInteger();
      break;
    case Value::Float:
      s << "Float: " << value.asFloat();
      break;
    case Value::String:
      s << "String: " << value.asString().ascii(); 
      break;
    case Value::Error:
      s << "Error: " << value.errorMessage().ascii();  
      break;
    default:
      break;
  };
  
  return s;
}
