#include <map>
#include <mutex>

#include "GeneratorInterface/Herwig7Interface/interface/Proxy.h"

using namespace ThePEG;

static std::mutex mutex;

typedef std::map<ProxyBase::ProxyID, std::weak_ptr<ProxyBase> > ProxyMap;

static ProxyMap *getProxyMapInstance() {
  static struct Sentinel {
    Sentinel() : instance(new ProxyMap) {}
    ~Sentinel() {
      delete instance;
      instance = nullptr;
    }

    ProxyMap *instance;
  } sentinel;

  return sentinel.instance;
}

ProxyBase::ProxyBase(ProxyID id) : id(id) {}

ProxyBase::~ProxyBase() {
  std::scoped_lock scoped_lock(mutex);

  ProxyMap *map = getProxyMapInstance();
  if (map)
    map->erase(id);
}

std::shared_ptr<ProxyBase> ProxyBase::create(ctor_t ctor) {
  static ProxyBase::ProxyID nextProxyID = 0;

  std::scoped_lock scoped_lock(mutex);

  std::shared_ptr<ProxyBase> proxy(ctor(++nextProxyID));

  ProxyMap *map = getProxyMapInstance();
  if (map)
    map->insert(ProxyMap::value_type(proxy->getID(), proxy));

  return proxy;
}

std::shared_ptr<ProxyBase> ProxyBase::find(ProxyID id) {
  std::scoped_lock scoped_lock(mutex);

  ProxyMap *map = getProxyMapInstance();
  if (!map)
    return std::shared_ptr<ProxyBase>();

  ProxyMap::const_iterator pos = map->find(id);
  if (pos == map->end())
    return std::shared_ptr<ProxyBase>();

  return std::shared_ptr<ProxyBase>(pos->second);
}