/**
 * @file MiNiFiMain.cpp
 * MiNiFiMain implementation
 *
 * 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.
 */


#ifdef WIN32
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif

#include <WinSock2.h>
#include <WS2tcpip.h>
#include <Windows.h>
#include "MiNiFiWindowsService.h"
#pragma comment(lib, "Ws2_32.lib")
#pragma comment(lib, "legacy_stdio_definitions.lib")
#ifdef ENABLE_JNI
  #pragma comment(lib, "jvm.lib")
#endif
#include <direct.h>

#endif

#include <fcntl.h>
#include <stdio.h>
#include <cstdlib>
#include <semaphore.h>
#include <signal.h>
#include <vector>
#include <queue>
#include <map>
#include <iostream>
#include <utils/file/FileUtils.h>
#include "ResourceClaim.h"
#include "core/Core.h"

#include "core/FlowConfiguration.h"
#include "core/ConfigurationFactory.h"
#include "core/RepositoryFactory.h"
#include "DiskSpaceWatchdog.h"
#include "utils/file/PathUtils.h"
#include "utils/file/FileUtils.h"
#include "utils/Environment.h"
#include "FlowController.h"
#include "AgentDocs.h"
#include "MainHelper.h"

 // Variables that allow us to avoid a timed wait.
sem_t *running;
//! Flow Controller

/**
 * Removed the stop command from the signal handler so that we could trigger
 * unload after we exit the semaphore controlled critical section in main.
 *
 * Semaphores are a portable choice when using signal handlers. Threads,
 * mutexes, and condition variables are not guaranteed to work within
 * a signal handler. Consequently we will use the semaphore to avoid thread
 * safety issues.
 */

#ifdef WIN32
BOOL WINAPI consoleSignalHandler(DWORD signal) {
  if (signal == CTRL_C_EVENT || signal == CTRL_BREAK_EVENT) {
    
    sem_post(running);
    if (sem_wait(running) == -1)
      perror("sem_wait");
  }

  return TRUE;
}

void SignalExitProcess() {
  sem_post(running);
}
#endif

void sigHandler(int signal) {
  if (signal == SIGINT || signal == SIGTERM) {
    // avoid stopping the controller here.
    sem_post(running);
  }
}

void dumpDocs(const std::shared_ptr<minifi::Configure> &configuration, const std::string &dir, std::ostream &out) {
  auto pythoncreator = core::ClassLoader::getDefaultClassLoader().instantiate("PythonCreator", "PythonCreator");
  if (nullptr != pythoncreator) {
    pythoncreator->configure(configuration);
  }

  minifi::docs::AgentDocs docsCreator;

  docsCreator.generate(dir, out);
}

int main(int argc, char **argv) {
#ifdef WIN32
  RunAsServiceIfNeeded();

  bool isStartedByService = false;
  HANDLE terminationEventHandler = GetTerminationEventHandle(&isStartedByService);
  if (terminationEventHandler == nullptr) {
    return -1;
  }

  utils::Environment::setRunningAsService(isStartedByService);
#endif

  if (utils::Environment::isRunningAsService()) {
    setSyslogLogger();
  }
  std::shared_ptr<logging::Logger> logger = logging::LoggerConfiguration::getConfiguration().getLogger("main");

#ifdef WIN32
  if (isStartedByService) {
    if (!CreateServiceTerminationThread(logger, terminationEventHandler)) {
      return -1;
    }
  } else {
    CloseHandle(terminationEventHandler);
  }
#endif

  uint16_t stop_wait_time = STOP_WAIT_TIME_MS;

  // initialize static functions that were defined apriori
  core::FlowConfiguration::initialize_static_functions();

  std::string graceful_shutdown_seconds;
  std::string prov_repo_class = "provenancerepository";
  std::string flow_repo_class = "flowfilerepository";
  std::string nifi_configuration_class_name = "yamlconfiguration";
  std::string content_repo_class = "filesystemrepository";

  running = sem_open("/MiNiFiMain", O_CREAT, 0644, 0);
  if (running == SEM_FAILED || running == 0) {

    logger->log_error("could not initialize semaphore");
    perror("initialization failure");
  }

#ifdef WIN32
  if (!SetConsoleCtrlHandler(consoleSignalHandler, TRUE)) {
    logger->log_error("Cannot install signal handler");
    return -1;
  }

  if (signal(SIGINT, sigHandler) == SIG_ERR || signal(SIGTERM, sigHandler) == SIG_ERR) {
    logger->log_error("Cannot install signal handler");
    return -1;
  }
#ifdef SIGBREAK
  if (signal(SIGBREAK, sigHandler) == SIG_ERR) {
    logger->log_error("Cannot install signal handler");
    return -1;
  }
#endif
#else
  if (signal(SIGINT, sigHandler) == SIG_ERR || signal(SIGTERM, sigHandler) == SIG_ERR || signal(SIGPIPE, SIG_IGN) == SIG_ERR) {
    logger->log_error("Cannot install signal handler");
    return -1;
  }
#endif

  // Determine MINIFI_HOME
  const std::string minifiHome = determineMinifiHome(logger);
  if (minifiHome.empty()) {
    // determineMinifiHome already logged everything we need
    return -1;
  }

  // chdir to MINIFI_HOME
  if (!utils::Environment::setCurrentWorkingDirectory(minifiHome.c_str())) {
    logger->log_error("Failed to change working directory to MINIFI_HOME (%s)", minifiHome);
    return -1;
  }

  std::shared_ptr<logging::LoggerProperties> log_properties = std::make_shared<logging::LoggerProperties>();
  log_properties->setHome(minifiHome);
  log_properties->loadConfigureFile(DEFAULT_LOG_PROPERTIES_FILE);
  logging::LoggerConfiguration::getConfiguration().initialize(log_properties);

  std::shared_ptr<minifi::Properties> uid_properties = std::make_shared<minifi::Properties>("UID properties");
  uid_properties->setHome(minifiHome);
  uid_properties->loadConfigureFile(DEFAULT_UID_PROPERTIES_FILE);
  utils::IdGenerator::getIdGenerator()->initialize(uid_properties);

  // Make a record of minifi home in the configured log file.
  logger->log_info("MINIFI_HOME=%s", minifiHome);

  const std::shared_ptr<minifi::Configure> configure = std::make_shared<minifi::Configure>();
  configure->setHome(minifiHome);
  configure->loadConfigureFile(DEFAULT_NIFI_PROPERTIES_FILE);

  if (argc >= 3 && std::string("docs") == argv[1]) {
    if (utils::file::FileUtils::create_dir(argv[2]) != 0) {
      std::cerr << "Working directory doesn't exist and cannot be created: " << argv[2] << std::endl;
      exit(1);
    }

    std::cerr << "Dumping docs to " << argv[2] << std::endl;
    if (argc == 4) {
      std::string filepath, filename;
      utils::file::PathUtils::getFileNameAndPath(argv[3], filepath, filename);
      if (filepath == argv[2]) {
        std::cerr << "Target file should be out of the working directory: " << filepath << std::endl;
        exit(1);
      }
      std::ofstream outref(argv[3]);
      dumpDocs(configure, argv[2], outref);
    } else{
      dumpDocs(configure, argv[2], std::cout);
    }
    exit(0);
  }


  if (configure->get(minifi::Configure::nifi_graceful_shutdown_seconds, graceful_shutdown_seconds)) {
    try {
      stop_wait_time = std::stoi(graceful_shutdown_seconds);
    }
    catch (const std::out_of_range &e) {
      logger->log_error("%s is out of range. %s", minifi::Configure::nifi_graceful_shutdown_seconds, e.what());
    }
    catch (const std::invalid_argument &e) {
      logger->log_error("%s contains an invalid argument set. %s", minifi::Configure::nifi_graceful_shutdown_seconds, e.what());
    }
  }
  else {
    logger->log_debug("%s not set, defaulting to %d", minifi::Configure::nifi_graceful_shutdown_seconds,
      STOP_WAIT_TIME_MS);
  }

  configure->get(minifi::Configure::nifi_provenance_repository_class_name, prov_repo_class);
  // Create repos for flow record and provenance
  std::shared_ptr<core::Repository> prov_repo = core::createRepository(prov_repo_class, true, "provenance");

  if (!prov_repo->initialize(configure)) {
    logger->log_error("Provenance repository failed to initialize, exiting..");
    exit(1);
  }

  configure->get(minifi::Configure::nifi_flow_repository_class_name, flow_repo_class);

  std::shared_ptr<core::Repository> flow_repo = core::createRepository(flow_repo_class, true, "flowfile");

  if (!flow_repo->initialize(configure)) {
    logger->log_error("Flow file repository failed to initialize, exiting..");
    exit(1);
  }

  configure->get(minifi::Configure::nifi_content_repository_class_name, content_repo_class);

  std::shared_ptr<core::ContentRepository> content_repo = core::createContentRepository(content_repo_class, true, "content");

  if (!content_repo->initialize(configure)) {
    logger->log_error("Content repository failed to initialize, exiting..");
    exit(1);
  }

  std::string content_repo_path;
  if (configure->get(minifi::Configure::nifi_dbcontent_repository_directory_default, content_repo_path)) {
    logging::LOG_INFO(logger) << "setting default dir to " << content_repo_path;
    minifi::setDefaultDirectory(content_repo_path);
  }

  configure->get(minifi::Configure::nifi_configuration_class_name, nifi_configuration_class_name);

  std::shared_ptr<minifi::io::StreamFactory> stream_factory = minifi::io::StreamFactory::getInstance(configure);

  std::unique_ptr<core::FlowConfiguration> flow_configuration = core::createFlowConfiguration(prov_repo, flow_repo, content_repo, configure, stream_factory, nifi_configuration_class_name);

  const auto controller = std::make_shared<minifi::FlowController>(prov_repo, flow_repo, configure, std::move(flow_configuration), content_repo);

  const bool disk_space_watchdog_enable = (configure->get(minifi::Configure::minifi_disk_space_watchdog_enable) | utils::map([](const std::string& v){ return v == "true"; })).value_or(true);
  std::unique_ptr<utils::CallBackTimer> disk_space_watchdog;
  if (disk_space_watchdog_enable) {
    try {
      const auto repo_paths = [&] {
        std::vector<std::string> repo_paths;
        repo_paths.reserve(3);
        // REPOSITORY_DIRECTORY is a dummy path used by noop repositories
        const auto path_valid = [](const std::string& p) { return !p.empty() && p != REPOSITORY_DIRECTORY; };
        auto prov_repo_path = prov_repo->getDirectory();
        auto flow_repo_path = flow_repo->getDirectory();
        auto content_repo_storage_path = content_repo->getStoragePath();
        if (!prov_repo->isNoop() && path_valid(prov_repo_path)) { repo_paths.push_back(std::move(prov_repo_path)); }
        if (!flow_repo->isNoop() && path_valid(flow_repo_path)) { repo_paths.push_back(std::move(flow_repo_path)); }
        if (path_valid(content_repo_storage_path)) { repo_paths.push_back(std::move(content_repo_storage_path)); }
        return repo_paths;
      }();
      const auto available_spaces = minifi::disk_space_watchdog::check_available_space(repo_paths, logger.get());
      const auto config = minifi::disk_space_watchdog::read_config(*configure);
      const auto min_space = [](const std::vector<std::uintmax_t>& spaces) {
        const auto it = std::min_element(std::begin(spaces), std::end(spaces));
        return it != spaces.end() ? *it : (std::numeric_limits<std::uintmax_t>::max)();
      };
      if (min_space(available_spaces) <= config.stop_threshold_bytes) {
        logger->log_error("Cannot start MiNiFi due to insufficient available disk space");
        return -1;
      }
      auto interval_switch = minifi::disk_space_watchdog::disk_space_interval_switch(config);
      disk_space_watchdog = utils::make_unique<utils::CallBackTimer>(config.interval, [interval_switch, min_space, repo_paths, logger, &controller]() mutable {
        const auto stop = [&]{ controller->stop(); controller->unload(); };
        const auto restart = [&]{ controller->load(); controller->start(); };
        const auto switch_state = interval_switch(min_space(minifi::disk_space_watchdog::check_available_space(repo_paths, logger.get())));
        if (switch_state.state == utils::IntervalSwitchState::LOWER && switch_state.switched) {
          logger->log_warn("Stopping flow controller due to insufficient disk space");
          stop();
        } else if (switch_state.state == utils::IntervalSwitchState::UPPER && switch_state.switched) {
          logger->log_info("Restarting flow controller");
          restart();
        }
      });
    } catch (const std::runtime_error& error) {
      logger->log_error(error.what());
      return -1;
    }
  }

  logger->log_info("Loading FlowController");

  // Load flow from specified configuration file
  try {
    controller->load();
  }
  catch (std::exception &e) {
    logger->log_error("Failed to load configuration due to exception: %s", e.what());
    return -1;
  }
  catch (...) {
    logger->log_error("Failed to load configuration due to unknown exception");
    return -1;
  }

  // Start Processing the flow
  controller->start();

  if (disk_space_watchdog) { disk_space_watchdog->start(); }

  logger->log_info("MiNiFi started");

  /**
   * Sem wait provides us the ability to have a controlled
   * yield without the need for a more complex construct and
   * a spin lock
   */
  int ret_val;
  while ((ret_val = sem_wait(running)) == -1 && errno == EINTR);
  if(ret_val == -1) perror("sem_wait");

  while ((ret_val = sem_close(running)) == -1 && errno == EINTR);
  if(ret_val == -1) perror("sem_close");

  while ((ret_val = sem_unlink("/MiNiFiMain")) == -1 && errno == EINTR);
  if(ret_val == -1) perror("sem_unlink");

  disk_space_watchdog = nullptr;

  /**
   * Trigger unload -- wait stop_wait_time
   */
  controller->waitUnload(stop_wait_time);

  controller->stopC2();

  flow_repo = nullptr;

  prov_repo = nullptr;

  logger->log_info("MiNiFi exit");

#ifdef WIN32
  sem_post(running);
#endif

  return 0;
}