/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <memory>
#include <string>
#include "core/ClassLoader.h"

namespace org {
namespace apache {
namespace nifi {
namespace minifi {
namespace core {

ClassLoader::ClassLoader() = default;

ClassLoader &ClassLoader::getDefaultClassLoader() {
  static ClassLoader ret;
  // populate ret
  return ret;
}

uint16_t ClassLoader::registerResource(const std::string &resource, const std::string &resourceFunction) {
  void *resource_ptr = nullptr;
  if (resource.empty()) {
    dlclose(dlopen(0, RTLD_LAZY | RTLD_GLOBAL));
    resource_ptr = dlopen(0, RTLD_NOW | RTLD_GLOBAL);
  } else {
    dlclose(dlopen(resource.c_str(), RTLD_LAZY | RTLD_GLOBAL));
    resource_ptr = dlopen(resource.c_str(), RTLD_NOW | RTLD_GLOBAL);
  }
  if (!resource_ptr) {
    return RESOURCE_FAILURE;
  } else {
    std::lock_guard<std::mutex> lock(internal_mutex_);
    dl_handles_.push_back(resource_ptr);
  }

  // reset errors
  dlerror();

  // load the symbols
  createFactory* create_factory_func = reinterpret_cast<createFactory*>(dlsym(resource_ptr, resourceFunction.c_str()));
  const char* dlsym_error = dlerror();
  if ((dlsym_error != nullptr && strlen(dlsym_error) > 0) || create_factory_func == nullptr) {
    return RESOURCE_FAILURE;
  }

  ObjectFactory *factory = create_factory_func();

  std::lock_guard<std::mutex> lock(internal_mutex_);

  auto initializer = factory->getInitializer();
  if (initializer != nullptr) {
    if (!initializer->initialize()) {
      delete factory;
      return RESOURCE_FAILURE;
    }
    initializers_.emplace_back(std::move(initializer));
  }

  for (auto class_name : factory->getClassNames()) {
    loaded_factories_[class_name] = std::unique_ptr<ObjectFactory>(factory->assign(class_name));
  }

  delete factory;

  return RESOURCE_SUCCESS;
}

} /* namespace core */
} /* namespace minifi */
} /* namespace nifi */
} /* namespace apache */
} /* namespace org */