/**
 *  Copyright (c) 2018-present, Facebook, Inc.
 *  All rights reserved.
 *
 *  This source code is licensed under both the Apache 2.0 license (found in the
 *  LICENSE file in the root directory of this source tree) and the GPLv2 (found
 *  in the COPYING file in the root directory of this source tree).
 *  You may select, at your option, one of the above-listed licenses.
 */

#include <osquery/core.h>
#include <osquery/registry_factory.h>

#include <cstdlib>
#include <sstream>

#include <osquery/extensions.h>
#include <osquery/logger.h>
#include <osquery/registry.h>

#include "osquery/core/conversions.h"
#include "osquery/core/json.h"
#include "osquery/core/process.h"

namespace osquery {

HIDDEN_FLAG(bool, registry_exceptions, false, "Allow plugin exceptions");

RegistryFactory& RegistryFactory::get() {
  static RegistryFactory instance;
  return instance;
}

void RegistryFactory::add(const std::string& name, RegistryInterfaceRef reg) {
  if (exists(name)) {
    throw std::runtime_error("Cannot add duplicate registry: " + name);
  }
  registries_[name] = std::move(reg);
}

RegistryInterfaceRef RegistryFactory::registry(const std::string& t) const {
  if (!exists(t)) {
    throw std::runtime_error("Unknown registry requested: " + t);
  }
  return registries_.at(t);
}

std::map<std::string, RegistryInterfaceRef> RegistryFactory::all() const {
  return registries_;
}

std::map<std::string, PluginRef> RegistryFactory::plugins(
    const std::string& registry_name) const {
  return registry(registry_name)->plugins();
}

PluginRef RegistryFactory::plugin(const std::string& registry_name,
                                  const std::string& item_name) const {
  return registry(registry_name)->plugin(item_name);
}

RegistryBroadcast RegistryFactory::getBroadcast() {
  RegistryBroadcast broadcast;
  for (const auto& registry : registries_) {
    broadcast[registry.first] = registry.second->getRoutes();
  }
  return broadcast;
}

Status RegistryFactory::addBroadcast(const RouteUUID& uuid,
                                     const RegistryBroadcast& broadcast) {
  {
    ReadLock lock(mutex_);
    if (extensions_.count(uuid) > 0) {
      return Status(1, "Duplicate extension UUID: " + std::to_string(uuid));
    }
  }

  // Make sure the extension does not broadcast conflicting registry items.
  if (!allowDuplicates()) {
    for (const auto& registry : broadcast) {
      for (const auto& item : registry.second) {
        if (exists(registry.first, item.first)) {
          VLOG(1) << "Extension " << uuid
                  << " has duplicate plugin name: " << item.first
                  << " in registry: " << registry.first;
          return Status(1, "Duplicate registry item: " + item.first);
        }
      }
    }
  }

  // Once duplication is satisfied call each registry's addExternal.
  Status status;
  for (const auto& registry : broadcast) {
    if (!exists(registry.first)) {
      VLOG(1) << "Extension " << uuid
              << "contains unknown registry: " << registry.first;
      return Status(1, "Unknown registry: " + registry.first);
    }

    status = this->registry(registry.first)->addExternal(uuid, registry.second);
    if (!status.ok()) {
      // If any registry fails to add the set of external routes, stop.
      break;
    }

    for (const auto& plugin : registry.second) {
      VLOG(1) << "Extension " << uuid << " registered " << registry.first
              << " plugin " << plugin.first;
    }
  }

  // If any registry failed, remove each (assume a broadcast is atomic).
  {
    if (!status.ok()) {
      for (const auto& registry : broadcast) {
        this->registry(registry.first)->removeExternal(uuid);
      }
    }

    WriteLock lock(mutex_);
    extensions_.insert(uuid);
  }
  return status;
}

Status RegistryFactory::removeBroadcast(const RouteUUID& uuid) {
  {
    ReadLock lock(mutex_);
    if (extensions_.count(uuid) == 0) {
      return Status(1, "Unknown extension UUID: " + std::to_string(uuid));
    }
  }

  for (const auto& registry : registries_) {
    registry.second->removeExternal(uuid);
  }

  WriteLock lock(mutex_);
  extensions_.erase(uuid);
  return Status(0, "OK");
}

/// Adds an alias for an internal registry item. This registry will only
/// broadcast the alias name.
Status RegistryFactory::addAlias(const std::string& registry_name,
                                 const std::string& item_name,
                                 const std::string& alias) {
  if (!exists(registry_name)) {
    return Status(1, "Unknown registry: " + registry_name);
  }
  return registries_.at(registry_name)->addAlias(item_name, alias);
}

/// Returns the item_name or the item alias if an alias exists.
std::string RegistryFactory::getAlias(const std::string& registry_name,
                                      const std::string& alias) const {
  if (!exists(registry_name)) {
    return alias;
  }
  return registries_.at(registry_name)->getAlias(alias);
}

Status RegistryFactory::call(const std::string& registry_name,
                             const std::string& item_name,
                             const PluginRequest& request,
                             PluginResponse& response) {
  // Forward factory call to the registry.
  try {
    if (item_name.find(',') != std::string::npos) {
      // Call is multiplexing plugins (usually for multiple loggers).
      for (const auto& item : osquery::split(item_name, ",")) {
        get().registry(registry_name)->call(item, request, response);
      }
      // All multiplexed items are called without regard for statuses.
      return Status(0);
    }
    return get().registry(registry_name)->call(item_name, request, response);
  } catch (const std::exception& e) {
    LOG(ERROR) << registry_name << " registry " << item_name
               << " plugin caused exception: " << e.what();
    if (FLAGS_registry_exceptions) {
      throw;
    }
    return Status(1, e.what());
  } catch (...) {
    LOG(ERROR) << registry_name << " registry " << item_name
               << " plugin caused unknown exception";
    if (FLAGS_registry_exceptions) {
      throw std::runtime_error(registry_name + ": " + item_name + " failed");
    }
    return Status(2, "Unknown exception");
  }
}

Status RegistryFactory::call(const std::string& registry_name,
                             const std::string& item_name,
                             const PluginRequest& request) {
  PluginResponse response;
  // Wrapper around a call expecting a response.
  return call(registry_name, item_name, request, response);
}

Status RegistryFactory::call(const std::string& registry_name,
                             const PluginRequest& request,
                             PluginResponse& response) {
  auto plugin = get().registry(registry_name)->getActive();
  return call(registry_name, plugin, request, response);
}

Status RegistryFactory::call(const std::string& registry_name,
                             const PluginRequest& request) {
  PluginResponse response;
  return call(registry_name, request, response);
}

Status RegistryFactory::setActive(const std::string& registry_name,
                                  const std::string& item_name) {
  WriteLock lock(mutex_);
  return registry(registry_name)->setActive(item_name);
}

std::string RegistryFactory::getActive(const std::string& registry_name) const {
  return registry(registry_name)->getActive();
}

void RegistryFactory::setUp() {
  for (const auto& registry : get().all()) {
    registry.second->setUp();
  }
}

bool RegistryFactory::exists(const std::string& registry_name,
                             const std::string& item_name,
                             bool local) const {
  if (!exists(registry_name)) {
    return false;
  }

  // Check the registry.
  return registry(registry_name)->exists(item_name, local);
}

std::vector<std::string> RegistryFactory::names() const {
  std::vector<std::string> names;
  for (const auto& registry : all()) {
    names.push_back(registry.second->getName());
  }
  return names;
}

std::vector<std::string> RegistryFactory::names(
    const std::string& registry_name) const {
  if (registries_.at(registry_name) == nullptr) {
    std::vector<std::string> names;
    return names;
  }
  return registry(registry_name)->names();
}

std::vector<RouteUUID> RegistryFactory::routeUUIDs() const {
  ReadLock lock(mutex_);
  std::vector<RouteUUID> uuids;
  for (const auto& extension : extensions_) {
    uuids.push_back(extension);
  }
  return uuids;
}

size_t RegistryFactory::count(const std::string& registry_name) const {
  if (!exists(registry_name)) {
    return 0;
  }
  return registry(registry_name)->count();
}

} // namespace osquery