#include "Server.h"

#include "config/ConfigParser.h"
#include "data-variant/FormUrlencoded.h"
#include "data-variant/MultipartFormData.h"
#include "data-variant/TextPlain.h"
#include "protocol/ServerHttp1.h"
#include "protocol/ServerHttp2.h"
#include "protocol/ServerHttp2Stream.h"

#include "ServerStructuresArguments.h"

#include "../socket/List.h"
#include "../socket/AdapterDefault.h"
#include "../socket/AdapterTls.h"
#include "../system/GlobalMutex.h"
#include "../system/SharedMemory.h"
#include "../system/System.h"
#include "../utils/Utils.h"

#include <cstring>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <thread>

namespace HttpServer
{
	static std::unique_ptr<ServerProtocol> getProtocolVariant(
		Socket::Adapter &sock,
		const ServerSettings &settings,
		ServerControls &controls,
		SocketsQueue &sockets,
		Http2::IncStream *stream
	)
	{
		std::unique_ptr<ServerProtocol> prot;

		// If request is HTTP/2 Stream
		if (stream)
		{
			prot.reset(new ServerHttp2Stream(sock, settings, controls, stream) );

			return prot;
		}

		if (sock.get_tls_session() )
		{
			::gnutls_datum_t datum;

			if (0 == ::gnutls_alpn_get_selected_protocol(sock.get_tls_session(), &datum) )
			{
				const std::string protocol(reinterpret_cast<char *>(datum.data), datum.size);

				if ("h2" == protocol)
				{
					prot.reset(new ServerHttp2(sock, settings, controls, sockets) );
				}
				else if ("http/1.1" == protocol)
				{
					prot.reset(new ServerHttp1(sock, settings, controls) );
				}
			}

			return prot;
		}

		prot.reset(new ServerHttp1(sock, settings, controls) );

		return prot;
	}

	/**
	 * Метод для обработки запроса
	 */
	void Server::threadRequestProc(Socket::Adapter &sock, SocketsQueue &sockets, Http2::IncStream *stream) const
	{
		std::unique_ptr<ServerProtocol> prot = getProtocolVariant(sock, this->settings, this->controls, sockets, stream);

		if (prot)
		{
			// Check if switching protocol
			for (ServerProtocol *ret = nullptr; ; )
			{
				ret = prot->process();

				if (prot.get() == ret)
				{
					break;
				}

				prot.reset(ret);
			}

			prot->close();
		}
	}

	/**
	 * Метод для обработки запросов (запускается в отдельном потоке)
	 *	извлекает сокет клиенты из очереди и передаёт его на обслуживание
	 */
	void Server::threadRequestCycle(SocketsQueue &sockets, Utils::Event &eventThreadCycle) const
	{
		while (true)
		{
			Socket::Socket sock;
			Http2::IncStream *stream = nullptr;

			eventThreadCycle.wait();

			if (false == this->controls.process_flag)
			{
				break;
			}

			sockets.lock();

			if (sockets.size() )
			{
				std::tie(sock, stream) = sockets.front();
/*
				sockaddr_in addr {};
				socklen_t addr_size = sizeof(sockaddr_in);
				::getpeername(sock.get_handle(), reinterpret_cast<sockaddr *>(&addr), &addr_size);
*/
				sockets.pop();
			}

			if (sockets.empty() )
			{
				eventThreadCycle.reset();

				this->controls.eventNotFullQueue->notify();
			}

			sockets.unlock();

			if (sock.is_open() )
			{
				++this->threads_working_count;

				::sockaddr_in sock_addr {};
				::socklen_t sock_addr_len = sizeof(sock_addr);

				::getsockname(sock.get_handle(), reinterpret_cast<sockaddr *>(&sock_addr), &sock_addr_len);

				const int port = ntohs(sock_addr.sin_port);

				auto const it = this->tls_data.find(port);

				if (this->tls_data.cend() != it) // if TLS connection
				{
					if (stream)
					{
						Socket::AdapterTls socket_adapter(reinterpret_cast<gnutls_session_t>(stream->reserved) );

						this->threadRequestProc(socket_adapter, sockets, stream);
					}
					else
					{
						const std::tuple<gnutls_certificate_credentials_t, gnutls_priority_t> &data = it->second;

						Socket::AdapterTls socket_adapter(
							sock,
							std::get<gnutls_priority_t>(data),
							std::get<gnutls_certificate_credentials_t>(data)
						);

						if (socket_adapter.handshake() )
						{
							this->threadRequestProc(socket_adapter, sockets, nullptr);
						}
					}
				}
				else
				{
					Socket::AdapterDefault socket_adapter(sock);

					this->threadRequestProc(socket_adapter, sockets, stream);
				}

				--this->threads_working_count;
			}
		}
	}

	/**
	 * Цикл управления количеством рабочих потоков
	 */
	int Server::cycleQueue(SocketsQueue &sockets)
	{
		auto const it_option = this->settings.global.find("threads_max_count");

		size_t threads_max_count = 0;

		if (this->settings.global.cend() != it_option)
		{
			const std::string &option = it_option->second;

			threads_max_count = std::strtoull(option.c_str(), nullptr, 10);
		}

		if (0 == threads_max_count)
		{
			threads_max_count = std::thread::hardware_concurrency();

			if (0 == threads_max_count)
			{
				threads_max_count = 1;
			}

			threads_max_count *= 2;
		}

		this->threads_working_count = 0;

		Utils::Event eventThreadCycle(false, true);

		std::function<void(Server *, SocketsQueue &, Utils::Event &)> serverThreadRequestCycle
			= std::mem_fn(&Server::threadRequestCycle);

		std::vector<std::thread> active_threads;
		active_threads.reserve(threads_max_count);

		// For update applications modules
		do
		{
			if (this->controls.eventUpdateModule->notifed() )
			{
				updateModules();
			}

			// Cycle creation threads applications requests
			do
			{
				while (this->threads_working_count == active_threads.size() && active_threads.size() < threads_max_count && sockets.empty() == false)
				{
					active_threads.emplace_back(serverThreadRequestCycle, this, std::ref(sockets), std::ref(eventThreadCycle) );
				}

				size_t notify_count = active_threads.size() - this->threads_working_count;

				if (notify_count > sockets.size() )
				{
					notify_count = sockets.size();
				}

				eventThreadCycle.notify(notify_count);

				this->controls.eventProcessQueue->wait();
			}
			while (this->controls.process_flag);

			// Data clear

			eventThreadCycle.notify();

			if (false == active_threads.empty() )
			{
				// Join threads (wait completion)
				for (auto &th : active_threads)
				{
					th.join();
				}

				active_threads.clear();
			}

			this->controls.eventNotFullQueue->notify();
		}
		while (this->controls.eventUpdateModule->notifed() );

		return 0;
	}

	bool Server::updateModule(System::Module &module, std::unordered_set<ServerApplicationSettings *> &applications, const size_t moduleIndex)
	{
		std::unordered_set<ServerApplicationSettings *> same;

		for (auto &app : applications)
		{
			if (app->module_index == moduleIndex)
			{
				same.emplace(app);

				try
				{
					if (app->application_final)
					{
						const std::string root = app->root_dir;
						app->application_final(root.data() );
					}
				}
				catch (std::exception &exc)
				{
					std::cout << "Warning: an exception was thrown when the application '" << app->server_module << "' was finishes: " << exc.what() << std::endl;
				}

				app->application_call = std::function<int(Transfer::app_request *, Transfer::app_response *)>();
				app->application_clear = std::function<void(void *, size_t)>();
				app->application_init = std::function<bool(const char *)>();
				app->application_final = std::function<void(const char *)>();
			}
		}

		module.close();

		auto const app = *(same.cbegin() );

		const std::string &module_name = app->server_module;

	#ifdef WIN32
		std::ifstream src(app->server_module_update, std::ifstream::binary);

		if ( ! src)
		{
			std::cout << "Error: file '" << app->server_module_update << "' cannot be open;" << std::endl;
			return false;
		}

		std::ofstream dst(module_name, std::ofstream::binary | std::ofstream::trunc);

		if ( ! dst)
		{
			std::cout << "Error: file '" << module_name << "' cannot be open;" << std::endl;
			return false;
		}

		// Copy (rewrite) file
		dst << src.rdbuf();

		src.close();
		dst.close();

		// Open updated module
		module.open(module_name);

	#elif POSIX
		// HACK: for posix system — load new version shared library

		const size_t dir_pos = module_name.rfind('/');
		const size_t ext_pos = module_name.rfind('.');

		std::string module_name_temp;

		if (std::string::npos != ext_pos && (std::string::npos == dir_pos || dir_pos < ext_pos) )
		{
			module_name_temp = module_name.substr(0, ext_pos) + '-' + Utils::getUniqueName() + module_name.substr(ext_pos);
		}
		else
		{
			module_name_temp = module_name + '-' + Utils::getUniqueName();
		}

		std::ifstream src(app->server_module_update, std::ifstream::binary);

		if ( ! src)
		{
			std::cout << "Error: file '" << app->server_module_update << "' cannot be open;" << std::endl;
			return false;
		}

		std::ofstream dst(module_name_temp, std::ofstream::binary | std::ofstream::trunc);

		if ( ! dst)
		{
			std::cout << "Error: file '" << module_name << "' cannot be open;" << std::endl;
			return false;
		}

		// Copy (rewrite) file
		dst << src.rdbuf();

		src.close();
		dst.close();

		// Open updated module
		module.open(module_name_temp);

		if (0 != std::remove(module_name.c_str() ) )
		{
			std::cout << "Error: file '" << module_name << "' could not be removed;" << std::endl;
			return false;
		}

		if (0 != std::rename(module_name_temp.c_str(), module_name.c_str() ) )
		{
			std::cout << "Error: file '" << module_name_temp << "' could not be renamed;" << std::endl;
			return false;
		}
	#else
		#error "Undefined platform"
	#endif

		if (false == module.is_open() )
		{
			std::cout << "Error: the application module '" << module_name << "' can not be opened;" << std::endl;
			return false;
		}

		void *(*addr)(void *) = nullptr;

		if (false == module.find("application_call", &addr) )
		{
			std::cout << "Error: function 'application_call' was not found in the module '" << module_name << "';" << std::endl;
			return false;
		}

		std::function<int(Transfer::app_request *, Transfer::app_response *)> app_call = reinterpret_cast<int(*)(Transfer::app_request *, Transfer::app_response *)>(addr);

		if ( ! app_call)
		{
			std::cout << "Error: invalid function 'application_call' is in the module '" << module_name << "';" << std::endl;
			return false;
		}

		if (false == module.find("application_clear", &addr) )
		{
			std::cout << "Error: function 'application_clear' was not found in the module '" << module_name << "';" << std::endl;
			return false;
		}

		std::function<void(void *, size_t)> app_clear = reinterpret_cast<void(*)(void *, size_t)>(addr);

		std::function<bool(const char *)> app_init = std::function<bool(const char *)>();

		if (module.find("application_init", &addr) )
		{
			app_init = reinterpret_cast<bool(*)(const char *)>(addr);
		}

		std::function<void(const char *)> app_final = std::function<void(const char *)>();

		if (module.find("application_final", &addr) )
		{
			app_final = reinterpret_cast<void(*)(const char *)>(addr);
		}

		for (auto &app : same)
		{
			app->application_call = app_call;
			app->application_clear = app_clear;
			app->application_init = app_init;
			app->application_final = app_final;

			try
			{
				if (app->application_init)
				{
					const std::string root = app->root_dir;
					app->application_init(root.data() );
				}
			}
			catch (std::exception &exc)
			{
				std::cout << "Warning: an exception was thrown when the application '" << module_name << "' was initialized: " << exc.what() << std::endl;
			}
		}

		return true;
	}

	void Server::updateModules()
	{
		// Applications settings list
		std::unordered_set<ServerApplicationSettings *> applications;
		// Get full applications settings list
		this->settings.apps_tree.collectApplicationSettings(applications);

		std::unordered_set<size_t> updated;

		for (auto const &app : applications)
		{
			const size_t module_index = app->module_index;

			// If module is not updated (not checked)
			if (updated.cend() == updated.find(module_index) )
			{
				if (false == app->server_module_update.empty() && app->server_module_update != app->server_module)
				{
					size_t module_size_new = 0;
					time_t module_time_new = 0;

					if (System::getFileSizeAndTimeGmt(app->server_module_update, &module_size_new, &module_time_new) )
					{
						size_t module_size_cur = 0;
						time_t module_time_cur = 0;

						System::Module &module = this->modules[module_index];

						if (System::getFileSizeAndTimeGmt(app->server_module, &module_size_cur, &module_time_cur) )
						{
							if (module_size_cur != module_size_new || module_time_cur < module_time_new)
							{
								this->updateModule(module, applications, module_index);
							}
						}
					}
				}

				updated.emplace(module_index);
			}
		}

		std::cout << "Notice: application modules have been updated;" << std::endl;

		this->controls.setProcess();
		this->controls.eventUpdateModule->reset();
	}

	bool Server::init()
	{
		ConfigParser conf_parser;

		if (Socket::Socket::Startup() && conf_parser.loadConfig("main.conf", this->settings, this->modules) )
		{
			this->settings.addDataVariant(new DataVariant::FormUrlencoded() );
			this->settings.addDataVariant(new DataVariant::MultipartFormData() );
			this->settings.addDataVariant(new DataVariant::TextPlain() );

			::gnutls_global_init();

			return true;
		}

		return false;
	}

	void Server::clear()
	{
		this->controls.clear();

		if (false == this->tls_data.empty() )
		{
			for (auto &pair : this->tls_data)
			{
				std::tuple<gnutls_certificate_credentials_t, gnutls_priority_t> &data = pair.second;

				::gnutls_certificate_free_credentials(std::get<gnutls_certificate_credentials_t>(data) );
				::gnutls_priority_deinit(std::get<gnutls_priority_t>(data) );
			}
		}

		this->settings.clear();

		if (false == this->modules.empty() )
		{
			for (auto &module : this->modules)
			{
				module.close();
			}

			this->modules.empty();
		}

		::gnutls_global_deinit();

		Socket::Socket::Cleanup();
	}

	static bool tlsInit(const ServerApplicationSettings &app, std::tuple<gnutls_certificate_credentials_t, gnutls_priority_t> &data)
	{
		::gnutls_certificate_credentials_t x509_cred;

		int ret = ::gnutls_certificate_allocate_credentials(&x509_cred);

		if (ret < 0)
		{
			std::cout << "Error [tls]: certificate credentials has not been allocated;" << std::endl;

			return false;
		}

		if (false == app.chain_file.empty() )
		{
			ret = ::gnutls_certificate_set_x509_trust_file(x509_cred, app.chain_file.c_str(), GNUTLS_X509_FMT_PEM);

			if (ret < 0)
			{
				std::cout << "Warning [tls]: (CA) chain file has not been accepted;" << std::endl;
			}
		}

		if (false == app.crl_file.empty() )
		{
			ret = ::gnutls_certificate_set_x509_crl_file(x509_cred, app.crl_file.c_str(), GNUTLS_X509_FMT_PEM);

			if (ret < 0)
			{
				std::cout << "Warning [tls]: (CLR) clr file has not been accepted;" << std::endl;
			}
		}

		ret = ::gnutls_certificate_set_x509_key_file(x509_cred, app.cert_file.c_str(), app.key_file.c_str(), GNUTLS_X509_FMT_PEM);

		if (ret < 0)
		{
			std::cout << "Error [tls]: (CERT) cert file or/and (KEY) key file has not been accepted;" << std::endl;

			return false;
		}

		if (false == app.stapling_file.empty() )
		{
			ret = ::gnutls_certificate_set_ocsp_status_request_file(x509_cred, app.stapling_file.c_str(), 0);

			if (ret < 0)
			{
				std::cout << "Warning [tls]: (OCSP) stapling file has not been accepted;" << std::endl;
			}
		}

		::gnutls_dh_params_t dh_params;

		::gnutls_dh_params_init(&dh_params);

		if (app.dh_file.empty() )
		{
			const unsigned int bits = ::gnutls_sec_param_to_pk_bits(GNUTLS_PK_DH, GNUTLS_SEC_PARAM_HIGH);

			ret = ::gnutls_dh_params_generate2(dh_params, bits);
		}
		else
		{
			std::ifstream dh_file(app.dh_file);

			if (dh_file)
			{
				const size_t max_file_size = 1024 * 1024;

				std::vector<char> buf(max_file_size);

				dh_file.read(buf.data(), buf.size() );

				gnutls_datum_t datum {
					reinterpret_cast<unsigned char *>(buf.data() ),
					static_cast<unsigned int>(dh_file.gcount() )
				};

				ret = ::gnutls_dh_params_import_pkcs3(dh_params, &datum, GNUTLS_X509_FMT_PEM);
			}
			else
			{
				ret = -1;

				std::cout << "Error [tls]: DH params file has not been opened;" << std::endl;;
			}

			dh_file.close();
		}

		if (ret < 0)
		{
			::gnutls_certificate_free_credentials(x509_cred);

			std::cout << "Error [tls]: DH params were not loaded;" << std::endl;

			return false;
		}

		::gnutls_certificate_set_dh_params(x509_cred, dh_params);

		::gnutls_priority_t priority_cache;

		ret = ::gnutls_priority_init(&priority_cache, "NORMAL", nullptr);

		if (ret < 0)
		{
			::gnutls_certificate_free_credentials(x509_cred);

			std::cout << "Error [tls]: priority cache cannot be init;" << std::endl;

			return false;
		}

		data = std::tuple<gnutls_certificate_credentials_t, gnutls_priority_t> { x509_cred, priority_cache };

		return true;
	}

	bool Server::tryBindPort(const int port, std::unordered_set<int> &ports)
	{
		// Only unique ports
		if (ports.cend() != ports.find(port) )
		{
			return false;
		}

		Socket::Socket sock;

		if (false == sock.open() )
		{
			std::cout << "Error: socket cannot be open; errno " << Socket::Socket::getLastError() << ";" << std::endl;
			return false;
		}

		if (false == sock.bind(port) )
		{
			std::cout << "Error: port " << port << " cannot be bind; errno " << Socket::Socket::getLastError() << ";" << std::endl;
			return false;
		}

		if (false == sock.listen() )
		{
			std::cout << "Error: socket " << port << " cannot be listen; errno " << Socket::Socket::getLastError() << ";" << std::endl;
			return false;
		}

		sock.nonblock(true);

		this->liseners.emplace_back(std::move(sock) );

		ports.emplace(port);

		return true;
	}

	void Server::initAppsPorts()
	{
		// Applications settings list
		std::unordered_set<ServerApplicationSettings *> applications;
		// Get full applications settings list
		this->settings.apps_tree.collectApplicationSettings(applications);

		// Bind ports set
		std::unordered_set<int> ports;

		// Open applications sockets
		for (auto const &app : applications)
		{
			const std::unordered_set<int> &tls = app->tls_ports;

			if (false == tls.empty() )
			{
				std::tuple<gnutls_certificate_credentials_t, gnutls_priority_t> data;

				if (tlsInit(*app, data) )
				{
					for (const int port : tls)
					{
						if (this->tryBindPort(port, ports) )
						{
							this->tls_data.emplace(port, data);
						}
					}
				}
			}

			const std::unordered_set<int> &list = app->ports;

			for (const int port : list)
			{
				this->tryBindPort(port, ports);
			}
		}
	}

	int Server::run()
	{
		if (false == this->init() )
		{
			return 0x10;
		}

		this->initAppsPorts();

		if (this->liseners.empty() )
		{
			std::cout << "Error: any socket was not open;" << std::endl;
			this->clear();
			return 0x20;
		}

		Socket::List sockets_list;

		sockets_list.create(this->liseners.size() );

		for (auto const &sock : this->liseners)
		{
			sockets_list.addSocket(sock);
		}

		std::cout << "Log: server started work;" << std::endl << std::endl;

		constexpr size_t queue_max_length = 1024;
		this->controls.eventNotFullQueue = new Utils::Event(true, true);
		this->controls.eventProcessQueue = new Utils::Event();
		this->controls.eventUpdateModule = new Utils::Event(false, true);

		SocketsQueue sockets;

		this->controls.setProcess();

		std::function<int(Server *, SocketsQueue &)> serverCycleQueue = std::mem_fn(&Server::cycleQueue);
		std::thread threadQueue(serverCycleQueue, this, std::ref(sockets) );

		std::vector<Socket::Socket> accept_sockets;

		// Cycle for receiving new connections
		do
		{
			if (sockets_list.accept(accept_sockets) )
			{
				sockets.lock();

				for (size_t i = 0; i < accept_sockets.size(); ++i)
				{
					const Socket::Socket &sock = accept_sockets[i];

					if (sock.is_open() )
					{
						sock.nonblock(true);
						sock.tcp_nodelay(true);

						sockets.emplace(
							std::tuple<Socket::Socket, Http2::IncStream *> {
								sock,
								nullptr
							}
						);
					}
				}

				sockets.unlock();

				this->controls.eventProcessQueue->notify();

				if (sockets.size() >= queue_max_length)
				{
					this->controls.eventNotFullQueue->reset();
				}

				accept_sockets.clear();

				this->controls.eventNotFullQueue->wait();
			}
		}
		while (this->controls.process_flag || this->controls.eventUpdateModule->notifed() );

		this->controls.eventProcessQueue->notify();

		threadQueue.join();

		sockets_list.destroy();

		if (false == this->liseners.empty() )
		{
			for (Socket::Socket &sock : this->liseners)
			{
				sock.close();
			}

			this->liseners.clear();
		}

		this->clear();

		std::cout << "Log: server work completed;" << std::endl;

		return EXIT_SUCCESS;
	}

	bool Server::get_start_args(const int argc, const char *argv[], struct server_start_args *st)
	{
		for (int i = 1; i < argc; ++i)
		{
			if (0 == ::strcmp(argv[i], "--start") )
			{

			}
			else if (0 == ::strcmp(argv[i], "--force") )
			{
				st->force = true;
			}
			else if (argv[i] == ::strstr(argv[i], "--config-path=") )
			{
				st->config_path = std::string(argv[i] + sizeof("--config-path=") - 1);
			}
			else if (argv[i] == ::strstr(argv[i], "--server-name=") )
			{
				st->server_name = std::string(argv[i] + sizeof("--server-name=") - 1);
			}
			else
			{
				std::cout << "Argument '" << argv[i] << "' can't be applied with --start;" << std::endl;

				return false;
			}
		}

		if (st->server_name.empty() )
		{
			st->server_name = argv[0];
		}

		System::filterSharedMemoryName(st->server_name);

		return true;
	}

	int Server::command_start(const int argc, const char *argv[])
	{
		struct server_start_args st = {};

		if (false == Server::get_start_args(argc, argv, &st) )
		{
			return 0x1;
		}

		if (false == st.config_path.empty() )
		{
			if (false == System::changeCurrentDirectory(st.config_path) )
			{
				std::cout << "Configuration path '" << st.config_path << "' has not been found;" << std::endl;

				return 0x2;
			}
		}

		if (st.force)
		{
			System::SharedMemory::destroy(st.server_name);
			System::GlobalMutex::destory(st.server_name);
		}

		System::GlobalMutex glob_mtx;
		System::SharedMemory glob_mem;

		bool is_exists = false;

		if (glob_mtx.open(st.server_name) )
		{
			glob_mtx.lock();

			if (glob_mem.open(st.server_name) )
			{
				System::native_processid_type pid = 0;

				if (glob_mem.read(&pid, sizeof(pid) ) )
				{
					is_exists = System::isProcessExists(pid);
				}
			}

			glob_mtx.unlock();
		}

		if (is_exists)
		{
			std::cout << "Server instance with the name '" << st.server_name << "' is already running;" << std::endl;

			return 0x3;
		}

		if (false == glob_mtx.open(st.server_name) )
		{
			if (false == glob_mtx.create(st.server_name) )
			{
				std::cout << "Global mutex could not been created;" << std::endl;

				return 0x4;
			}
		}

		glob_mtx.lock();

		if (false == glob_mem.open(st.server_name) )
		{
			if (false == glob_mem.create(st.server_name, sizeof(System::native_processid_type) ) )
			{
				glob_mtx.unlock();

				std::cout << "Shared memory could not been allocated;" << std::endl;

				return 0x5;
			}
		}

		System::native_processid_type pid = System::getProcessId();

		if (false == glob_mem.write(&pid, sizeof(pid) ) )
		{
			glob_mem.destroy();
			glob_mtx.unlock();

			std::cout << "Writing data to shared memory has failed;" << std::endl;

			return 0x6;
		}

		glob_mtx.unlock();

		int code = EXIT_FAILURE;

		do
		{
			this->controls.setProcess(false);
			this->controls.setRestart(false);

			code = this->run();
		}
		while (this->controls.process_flag || this->controls.restart_flag);

		glob_mem.destroy();
		glob_mtx.destory();

		return code;
	}

	System::native_processid_type Server::getServerProcessId(const std::string &serverName)
	{
		System::native_processid_type pid = 0;

		System::GlobalMutex glob_mtx;

		if (glob_mtx.open(serverName) )
		{
			System::SharedMemory glob_mem;

			glob_mtx.lock();

			if (glob_mem.open(serverName) )
			{
				glob_mem.read(&pid, sizeof(pid) );
			}

			glob_mtx.unlock();
		}

		return pid;
	}

	int Server::command_help(const int argc, const char *argv[]) const
	{
		std::cout << std::left << "Available arguments:" << std::endl
			<< std::setw(4) << ' ' << std::setw(26) << "--start" << "Start http server" << std::endl
			<< std::setw(8) << ' ' << std::setw(22) << "[options]" << std::endl
			<< std::setw(8) << ' ' << std::setw(22) << "--force" << "Forcibly start http server (ignore existing instance)" << std::endl
			<< std::setw(8) << ' ' << std::setw(22) << "--config-path=<path>" << "Path to directory with configuration files" << std::endl
			<< std::endl
			<< std::setw(4) << ' ' << std::setw(26) << "--restart" << "Restart http server" << std::endl
			<< std::setw(4) << ' ' << std::setw(26) << "--update-module" << "Update applications modules" << std::endl
			<< std::setw(4) << ' ' << std::setw(26) << "--kill" << "Shutdown http server" << std::endl
			<< std::setw(4) << ' ' << std::setw(26) << "--help" << "This help" << std::endl
			<< std::endl<< "Optional arguments:" << std::endl
			<< std::setw(4) << ' ' << std::setw(26) << "--server-name=<name>" << "Name of server instance" << std::endl;

		return EXIT_SUCCESS;
	}

	static std::string get_server_name(const int argc, const char *argv[])
	{
		std::string server_name;

		for (int i = 1; i < argc; ++i)
		{
			if (argv[i] == ::strstr(argv[i], "--server-name=") )
			{
				server_name = std::string(argv[i] + sizeof("--server-name=") - 1);
				break;
			}
		}

		if (server_name.empty() )
		{
			server_name = argv[0];
		}

		System::filterSharedMemoryName(server_name);

		return server_name;
	}

	int Server::command_restart(const int argc, const char *argv[]) const
	{
		const System::native_processid_type pid = Server::getServerProcessId(get_server_name(argc, argv) );

		if (1 < pid && System::sendSignal(pid, SIGUSR1) )
		{
			return EXIT_SUCCESS;
		}

		return EXIT_FAILURE;
	}

	int Server::command_terminate(const int argc, const char *argv[]) const
	{
		const System::native_processid_type pid = Server::getServerProcessId(get_server_name(argc, argv) );

		if (1 < pid && System::sendSignal(pid, SIGTERM) )
		{
			return EXIT_SUCCESS;
		}

		return EXIT_FAILURE;
	}

	int Server::command_update_module(const int argc, const char *argv[]) const
	{
		const System::native_processid_type pid = Server::getServerProcessId(get_server_name(argc, argv) );

		if (1 < pid && System::sendSignal(pid, SIGUSR2) )
		{
			return EXIT_SUCCESS;
		}

		return EXIT_FAILURE;
	}
};