#include "tidentifiable.h"

#include <set></set>

namespace {

class IdentifierTable {  // singleton

  unsigned long m_lastId;

  std::map<unsigned *="" long,="" tidentifiable=""> m_table;</unsigned>

  std::set<tidentifiable *=""> m_objects;</tidentifiable>

  IdentifierTable() : m_lastId(0) {}

public:

  static IdentifierTable *instance() {

    // NON DEVE MORIRE

    // static IdentifierTable _instance;

    // return &_instance;

    static IdentifierTable *_instance = 0;

    if (!_instance) _instance         = new IdentifierTable;

    return _instance;

  }

  unsigned long getNextId() { return ++m_lastId; }

  void insert(TIdentifiable *o) {

    unsigned long id = o->getIdentifier();

    std::map<unsigned *="" long,="" tidentifiable="">::iterator it = m_table.find(id);</unsigned>

    if (it != m_table.end()) {

      if (it->second == o) return;

      m_objects.erase(it->second);

      it->second = o;

    } else {

      m_table[id] = o;

    }

    m_objects.insert(o);

  }

  void erase(TIdentifiable *o) {

    unsigned long id = o->getIdentifier();

    m_table.erase(id);

    m_objects.erase(o);

  }

  TIdentifiable *fetch(unsigned long id) {

    std::map<unsigned *="" long,="" tidentifiable="">::iterator it = m_table.find(id);</unsigned>

    return it == m_table.end() ? 0 : it->second;

  }

};

}  // namespace

TIdentifiable::TIdentifiable() : m_id(0) {}

TIdentifiable::~TIdentifiable() {

  if (m_id != 0) IdentifierTable::instance()->erase(this);

}

TIdentifiable::TIdentifiable(const TIdentifiable &src) : m_id(src.m_id) {}

const TIdentifiable &TIdentifiable::operator=(const TIdentifiable &src) {

  if (src.m_id != m_id && m_id != 0) IdentifierTable::instance()->erase(this);

  m_id = src.m_id;

  return *this;

}

void TIdentifiable::setIdentifier(unsigned long id) {

  bool wasStored = m_id > 0 && IdentifierTable::instance()->fetch(m_id) == this;

  if (m_id != id && m_id != 0) IdentifierTable::instance()->erase(this);

  m_id = id;

  if (wasStored) IdentifierTable::instance()->insert(this);

}

void TIdentifiable::setNewIdentifier() {

  setIdentifier(IdentifierTable::instance()->getNextId());

}

void TIdentifiable::storeByIdentifier() {

  assert(getIdentifier() >= 1);

  IdentifierTable::instance()->insert(this);

}

TIdentifiable *TIdentifiable::fetchByIdentifier(unsigned long id) {

  return IdentifierTable::instance()->fetch(id);

}