/*
 * ModuleManager.cpp
 *
 * Copyright (C) 2008 Matthias Schiffer <matthias@gamezock.de>
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation, either version 3 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */


#include <config.h>

#include "ModuleManager.h"
#include "Application.h"

#include <Core/ConfigEntry.h>
#include <Core/ConfigManager.h>

#include <modules/modules.h>

#include <boost/thread/locks.hpp>

#ifndef _WIN32
# include <dlfcn.h>
#endif

namespace Mad {
namespace Common {

const ModuleManager::ModuleHandle ModuleManager::STATIC_MODULE = 0;

ModuleManager::ModuleManager(Application *application0) : application(application0) {
  application->getConfigManager()->registerConfigurable(this);
}

ModuleManager::~ModuleManager() {
  application->getConfigManager()->unregisterConfigurable(this);

  boost::shared_lock<boost::shared_mutex> lock(mutex);
  while(!moduleOrder.empty()) {
    std::string mod = moduleOrder.top();

    lock.unlock();
    unloadModule(mod);
    lock.lock();

    moduleOrder.pop();
  }
}

void ModuleManager::configure() {
  std::vector<const Core::ConfigEntry*> entries = application->getConfigManager()->getEntries("LoadModule");
  for(std::vector<const Core::ConfigEntry*>::iterator entry = entries.begin(); entry != entries.end(); ++entry) {
    if(!loadModule((*entry)->getValue().toLocale()))
      application->log(Core::Logger::LOG_ERROR, Core::Format("Can't load module '%1%'.") % (*entry)->getValue());
  }
}

bool ModuleManager::loadModule(const std::string &name) {
  {
    boost::shared_lock<boost::shared_mutex> lock(mutex);

    if(modules.find(name) != modules.end())
      return true;
  }

  ModuleHandle handle = STATIC_MODULE;
  Module *mod = Modules::loadStaticModule(application, name);
  
  std::string libname = name + MODULE_SUFFIX;

  if(!mod) {
#ifdef WIN32
    handle = LoadLibrary(libname.c_str());
#else
    handle = dlopen(libname.c_str(), RTLD_NOW | RTLD_GLOBAL);
#endif

    if(!handle) {
#ifdef WIN32
      application->log(Core::Logger::LOG_VERBOSE, Core::Format("loadModule: Can't open module: Error %1%") % GetLastError());
#else
      application->log(Core::Logger::LOG_VERBOSE, Core::Format("loadModule: Can't open module: %1%") % dlerror());
#endif
      return false;
    }

    ModuleLoadFunc loader;
    std::string loadername = name + "_create";

#ifdef WIN32
    loader = (ModuleLoadFunc)GetProcAddress(handle, loadername.c_str());
#else
    *(void**)&loader = dlsym(handle, loadername.c_str());
#endif

    if(!loader) {
      application->log(Core::Logger::LOG_VERBOSE, "loadModule: Can't open module: Invalid module");
      return false;
    }

    Module *mod = loader(application);

    if(!mod) {
      application->log(Core::Logger::LOG_VERBOSE, "loadModule: Can't open module: Internal module error");
      return false;
    }
  }

  modules.insert(std::make_pair(name, std::make_pair(handle, mod))).first;
  moduleOrder.push(name);

  return true;
}

void ModuleManager::unloadModule(const std::string &name) {
  boost::upgrade_lock<boost::shared_mutex> lock(mutex);

  std::map<std::string, std::pair<ModuleHandle, Module*> >::iterator mod = modules.find(name);
  if(mod == modules.end())
    return;

  boost::upgrade_to_unique_lock<boost::shared_mutex> upgradeLock(lock);

  delete mod->second.second;

  if(mod->second.first != STATIC_MODULE) {
#ifdef WIN32
    FreeLibrary(mod->second.first);
#else
    dlclose(mod->second.first);
#endif
  }

  modules.erase(mod);
}

}
}