/* $Id$ */

/*
 * Copyright (C) 2006 Richard Braun
 * 
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <cstdlib>
#include <cstring>
#include <vector>

#include "mtx.h"
#include "mtxvalue.h"
#include "mtxsymbol.h"
#include "mtxexception.h"

#include <sys/types.h>
#include <signal.h>
#include <unistd.h>

using namespace std;

struct mtx_special_name MtxSymbol::special_names[] =
{
  {"about", about},
  {"list", list},
  {"quit", quit},
  {"exit", quit},
  {NULL, NULL}
};

string
about(const MtxSymbol *symbol)
{
  return MTX_NOTICE;
}

string
list(const MtxSymbol *symbol)
{
  vector<MtxSymbol>::const_iterator iterator;
  vector<MtxSymbol> symbols;
  string list;

  symbols = symbol->getLanguage()->getSymbols();

  if (symbols.empty())
    return "No registered variable";

  list = "List of registered variables :\n";

  for (iterator = symbols.begin();
       iterator != symbols.end();
       iterator++)
    list += (*iterator).getName()
            + " = "
            + (*iterator).toString()
            + "\n";

  list.erase(list.length() - 1);
  return list;
}

string
quit(const MtxSymbol *symbol)
{
  std::exit(0);
}

MtxSymbol::MtxSymbol()
{
  value = NULL;
  language = NULL;
  setSpecial();
}

MtxSymbol::MtxSymbol(MtxLanguage *language, const string &name)
{
  this->name = name;
  value = NULL;
  this->language = language;
  setSpecial();
}

MtxSymbol::MtxSymbol(MtxLanguage *language, const MtxValue &value)
{
  this->value = value.clone();
  this->language = language;
  setSpecial();
}

MtxSymbol::MtxSymbol(MtxLanguage *language, const string &name,
                     const MtxValue &value)
{
  this->name = name;
  this->value = value.clone();
  this->language = language;
  setSpecial();
}

MtxSymbol::MtxSymbol(const MtxSymbol &symbol)
{
  name = symbol.name;

  if (symbol.value == NULL)
    value = NULL;

  else
    value = symbol.value->clone();

  language = symbol.language;
  special = symbol.special;
}

MtxSymbol::~MtxSymbol()
{
  if (value != NULL)
    delete value;
}

MtxSymbol &
MtxSymbol::operator=(const MtxSymbol &symbol)
{
  if (this != &symbol)
    {
      name = symbol.name;

      if (value != NULL)
        delete value;

      if (symbol.value == NULL)
        value = NULL;

      else
        value = symbol.value->clone();

      language = symbol.language;
      special = symbol.special;
    }

  return *this;
}

void
MtxSymbol::setSpecial()
{
  if (name.length() == 0)
    special = false;

  else
    {
      size_t i;

      i = 0;

      do
        {
          if (special_names[i].name == NULL)
            {
              special = false;
              break;
            }

          else if (name == special_names[i].name)
            {
              special = true;
              break;
            }

          i++;
        }
      while (true);
    }
}

size_t
MtxSymbol::getSpecial() const
{
  size_t i;

  if (special == false)
    throw MtxException("MtxSymbol::getSpecial() called whereas this->special "
                       "is false");

  i = 0;

  do
    {
      if (name == special_names[i].name)
        return i;

      i++;
    }
  while(true);
}

MtxSymbol
MtxSymbol::getSymbol(bool create, bool fail_if_special) const
                     
{
  if (special)
    {
      if (fail_if_special)
        throw MtxException("invalid use of special name in expression");

      else
        return *this;
    }

  if (name.length() == 0 && create)
    throw MtxException("invalid lvalue");

  if (!create)
    {
      if (name.length() == 0)
        return *this;

      else
        return language->getSymbol(name);
    }

  else
    {
      language->setSymbol(*this);
      return *this;
    }
}

string
MtxSymbol::getName() const
{
  return name;
}

void
MtxSymbol::setName(const string &name)
{
  this->name = name;
}

MtxValue *
MtxSymbol::getValue() const
{
  return value;
}

string
MtxSymbol::toString() const
{
  if (name.length() == 0)
    {
      if (value == NULL)
        throw MtxException("null value");

      return value->toString();
    }

  else
    {
      if (special)
        return special_names[getSpecial()].function(this);

      else
        return language->getSymbol(name).value->toString();
    }
}

bool
MtxSymbol::isSilent() const
{
  throw MtxException("MtxSymbol->isSilent() should never be called");
}

bool
MtxSymbol::isSpecial() const
{
  return special;
}

MtxLanguage *
MtxSymbol::getLanguage() const
{
  return language;
}