/******************************************************************************
 * Icinga 2                                                                   *
 * Copyright (C) 2012-2018 Icinga Development Team (https://www.icinga.com/)  *
 *                                                                            *
 * This program is free software; you can redistribute it and/or              *
 * modify it under the terms of the GNU General Public License                *
 * as published by the Free Software Foundation; either version 2             *
 * 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 General Public License for more details.                               *
 *                                                                            *
 * You should have received a copy of the GNU General Public License          *
 * along with this program; if not, write to the Free Software Foundation     *
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.             *
 ******************************************************************************/

#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN //else winsock will be included with windows.h and conflict with winsock2
#endif

#include "plugins/thresholds.hpp"
#include <boost/program_options.hpp>
#include <iostream>
#include <winsock2.h>
#include <iphlpapi.h>
#include <icmpapi.h>
#include <shlwapi.h>
#include <ws2ipdef.h>
#include <mstcpip.h>
#include <ws2tcpip.h>

#define VERSION 1.0

namespace po = boost::program_options;

struct response
{
	double avg;
	unsigned int pMin = 0;
	unsigned int pMax = 0;
	unsigned int dropped = 0;
};

struct printInfoStruct
{
	threshold warn;
	threshold crit;
	threshold wpl;
	threshold cpl;
	std::wstring host;
	std::wstring ip;
	bool ipv6 = false;
	int timeout = 1000;
	int num = 5;
};

static bool l_Debug;

static int parseArguments(int ac, WCHAR **av, po::variables_map& vm, printInfoStruct& printInfo)
{
	WCHAR namePath[MAX_PATH];
	GetModuleFileName(NULL, namePath, MAX_PATH);
	WCHAR *progName = PathFindFileName(namePath);

	po::options_description desc;

	desc.add_options()
		("help,h", "Print usage message and exit")
		("version,V", "Print version and exit")
		("debug,d", "Verbose/Debug output")
		("host,H", po::wvalue<std::wstring>()->required(), "Target hostname or IP. If an IPv6 address is given, the '-6' option must be set")
		(",4", "--Host is an IPv4 address or if it's a hostname: Resolve it to an IPv4 address (default)")
		(",6", "--Host is an IPv6 address or if it's a hostname: Resolve it to an IPv6 address")
		("timeout,t", po::value<int>(), "Specify timeout for requests in ms (default=1000)")
		("packets,p", po::value<int>(), "Declare ping count (default=5)")
		("warning,w", po::wvalue<std::wstring>(), "Warning values: rtt,package loss")
		("critical,c", po::wvalue<std::wstring>(), "Critical values: rtt,package loss")
		;

	po::wcommand_line_parser parser(ac, av);

	try {
		po::store(
			parser
			.options(desc)
			.style(
				po::command_line_style::unix_style |
				po::command_line_style::allow_long_disguise &
				~po::command_line_style::allow_guessing
			)
			.run(),
			vm);
		vm.notify();
	} catch (const std::exception& e) {
		std::cout << e.what() << '\n' << desc << '\n';
		return 3;
	}

	if (vm.count("help")) {
		std::wcout << progName << " Help\n\tVersion: " << VERSION << '\n';
		wprintf(
			L"%s is a simple program to ping an ip4 address.\n"
			L"You can use the following options to define its behaviour:\n\n", progName);
		std::cout << desc;
		wprintf(
			L"\nIt will take at least timeout times number of pings to run\n"
			L"Then it will output a string looking something like this:\n\n"
			L"\tPING WARNING RTA: 72ms Packet loss: 20%% | ping=72ms;40;80;71;77 pl=20%%;20;50;0;100\n\n"
			L"\"PING\" being the type of the check, \"WARNING\" the returned status\n"
			L"and \"RTA: 72ms Packet loss: 20%%\" the relevant information.\n"
			L"The performance data is found behind the \"|\", in order:\n"
			L"returned value, warning threshold, critical threshold, minimal value and,\n"
			L"if applicable, the maximal value. \n\n"
			L"%s' exit codes denote the following:\n"
			L" 0\tOK,\n\tNo Thresholds were broken or the programs check part was not executed\n"
			L" 1\tWARNING,\n\tThe warning, but not the critical threshold was broken\n"
			L" 2\tCRITICAL,\n\tThe critical threshold was broken\n"
			L" 3\tUNKNOWN, \n\tThe program experienced an internal or input error\n\n"
			L"Threshold syntax:\n\n"
			L"-w THRESHOLD\n"
			L"warn if threshold is broken, which means VALUE > THRESHOLD\n"
			L"(unless stated differently)\n\n"
			L"-w !THRESHOLD\n"
			L"inverts threshold check, VALUE < THRESHOLD (analogous to above)\n\n"
			L"-w [THR1-THR2]\n"
			L"warn is VALUE is inside the range spanned by THR1 and THR2\n\n"
			L"-w ![THR1-THR2]\n"
			L"warn if VALUE is outside the range spanned by THR1 and THR2\n\n"
			L"-w THRESHOLD%%\n"
			L"if the plugin accepts percentage based thresholds those will be used.\n"
			L"Does nothing if the plugin does not accept percentages, or only uses\n"
			L"percentage thresholds. Ranges can be used with \"%%\", but both range values need\n"
			L"to end with a percentage sign.\n\n"
			L"All of these options work with the critical threshold \"-c\" too.",
			progName);
		std::cout << '\n';
		return 0;
	}

	if (vm.count("version")) {
		std::cout << progName << " Version: " << VERSION << '\n';
		return 0;
	}

	if (vm.count("-4") && vm.count("-6")) {
		std::cout << "Conflicting options \"4\" and \"6\"" << '\n';
		return 3;
	}

	printInfo.ipv6 = vm.count("-6") > 0;

	if (vm.count("warning")) {
		std::vector<std::wstring> sVec = splitMultiOptions(vm["warning"].as<std::wstring>());
		if (sVec.size() != 2) {
			std::cout << "Wrong format for warning thresholds" << '\n';
			return 3;
		}
		try {
			printInfo.warn = threshold(*sVec.begin());
			printInfo.wpl = threshold(sVec.back());
			if (!printInfo.wpl.perc) {
				std::cout << "Packet loss must be percentage" << '\n';
				return 3;
			}
		} catch (const std::invalid_argument& e) {
			std::cout << e.what() << '\n';
			return 3;
		}
	}

	if (vm.count("critical")) {
		std::vector<std::wstring> sVec = splitMultiOptions(vm["critical"].as<std::wstring>());
		if (sVec.size() != 2) {
			std::cout << "Wrong format for critical thresholds" << '\n';
			return 3;
		}
		try {
			printInfo.crit = threshold(*sVec.begin());
			printInfo.cpl = threshold(sVec.back());
			if (!printInfo.wpl.perc) {
				std::cout << "Packet loss must be percentage" << '\n';
				return 3;
			}
		} catch (const std::invalid_argument& e) {
			std::cout << e.what() << '\n';
			return 3;
		}
	}

	if (vm.count("timeout"))
		printInfo.timeout = vm["timeout"].as<int>();

	if (vm.count("packets"))
		printInfo.num = vm["packets"].as<int>();

	printInfo.host = vm["host"].as<std::wstring>();

	l_Debug = vm.count("debug") > 0;

	return -1;
}

static int printOutput(printInfoStruct& printInfo, response& response)
{
	if (l_Debug)
		std::wcout << L"Constructing output string" << '\n';

	state state = OK;

	double plp = ((double)response.dropped / printInfo.num) * 100.0;

	if (printInfo.warn.rend(response.avg) || printInfo.wpl.rend(plp))
		state = WARNING;

	if (printInfo.crit.rend(response.avg) || printInfo.cpl.rend(plp))
		state = CRITICAL;

	std::wstringstream perf;
	perf << L"rta=" << response.avg << L"ms;" << printInfo.warn.pString() << L";"
		<< printInfo.crit.pString() << L";0;" << " pl=" << removeZero(plp) << "%;"
		<< printInfo.wpl.pString() << ";" << printInfo.cpl.pString() << ";0;100";

	if (response.dropped == printInfo.num) {
		std::wcout << L"PING CRITICAL ALL CONNECTIONS DROPPED | " << perf.str() << '\n';
		return 2;
	}

	std::wcout << L"PING ";

	switch (state) {
	case OK:
		std::wcout << L"OK";
		break;
	case WARNING:
		std::wcout << L"WARNING";
		break;
	case CRITICAL:
		std::wcout << L"CRITICAL";
		break;
	}

	std::wcout << L" RTA: " << response.avg << L"ms Packet loss: " << removeZero(plp) << "% | " << perf.str() << '\n';

	return state;
}

static bool resolveHostname(const std::wstring& hostname, bool ipv6, std::wstring& ipaddr)
{
	ADDRINFOW hints;
	ZeroMemory(&hints, sizeof(hints));

	if (ipv6)
		hints.ai_family = AF_INET6;
	else
		hints.ai_family = AF_INET;

	if (l_Debug)
		std::wcout << L"Resolving hostname \"" << hostname << L"\"\n";

	ADDRINFOW *result = NULL;
	DWORD ret = GetAddrInfoW(hostname.c_str(), NULL, &hints, &result);

	if (ret) {
		std::cout << "Failed to resolve hostname. Winsock Error Code: " << ret << '\n';
		return false;
	}

	wchar_t ipstringbuffer[46];

	if (ipv6) {
		struct sockaddr_in6 *address6 = (struct sockaddr_in6 *)result->ai_addr;
		InetNtop(AF_INET6, &address6->sin6_addr, ipstringbuffer, 46);
	}
	else {
		struct sockaddr_in *address4 = (struct sockaddr_in *)result->ai_addr;
		InetNtop(AF_INET, &address4->sin_addr, ipstringbuffer, 46);
	}

	if (l_Debug)
		std::wcout << L"Resolved to \"" << ipstringbuffer << L"\"\n";

	ipaddr = ipstringbuffer;
	return true;
}

static int check_ping4(const printInfoStruct& pi, response& response)
{
	if (l_Debug)
		std::wcout << L"Parsing ip address" << '\n';

	in_addr ipDest4;
	LPCWSTR term;
	if (RtlIpv4StringToAddress(pi.ip.c_str(), TRUE, &term, &ipDest4) == STATUS_INVALID_PARAMETER) {
		std::wcout << pi.ip << " is not a valid ip address\n";
		return 3;
	}

	if (*term != L'\0') {
		std::wcout << pi.ip << " is not a valid ip address\n";
		return 3;
	}

	if (l_Debug)
		std::wcout << L"Creating Icmp File\n";

	HANDLE hIcmp;
	if ((hIcmp = IcmpCreateFile()) == INVALID_HANDLE_VALUE)
		goto die;

	DWORD dwRepSize = sizeof(ICMP_ECHO_REPLY) + 8;
	void *repBuf = reinterpret_cast<VOID *>(new BYTE[dwRepSize]);

	if (repBuf == NULL)
		goto die;

	unsigned int rtt = 0;
	int num = pi.num;

	LARGE_INTEGER frequency;
	QueryPerformanceFrequency(&frequency);

	do {
		LARGE_INTEGER timer1;
		QueryPerformanceCounter(&timer1);

		if (l_Debug)
			std::wcout << L"Sending Icmp echo\n";

		if (!IcmpSendEcho2(hIcmp, NULL, NULL, NULL, ipDest4.S_un.S_addr,
			NULL, 0, NULL, repBuf, dwRepSize, pi.timeout)) {
			response.dropped++;
			if (l_Debug)
				std::wcout << L"Dropped: Response was 0" << '\n';
			continue;
		}

		if (l_Debug)
			std::wcout << "Ping recieved" << '\n';

		PICMP_ECHO_REPLY pEchoReply = static_cast<PICMP_ECHO_REPLY>(repBuf);

		if (pEchoReply->Status != IP_SUCCESS) {
			response.dropped++;
			if (l_Debug)
				std::wcout << L"Dropped: echo reply status " << pEchoReply->Status << '\n';
			continue;
		}

		if (l_Debug)
			std::wcout << L"Recorded rtt of " << pEchoReply->RoundTripTime << '\n';

		rtt += pEchoReply->RoundTripTime;
		if (response.pMin == 0 || pEchoReply->RoundTripTime < response.pMin)
			response.pMin = pEchoReply->RoundTripTime;
		else if (pEchoReply->RoundTripTime > response.pMax)
			response.pMax = pEchoReply->RoundTripTime;

		LARGE_INTEGER timer2;
		QueryPerformanceCounter(&timer2);

		if (((timer2.QuadPart - timer1.QuadPart) * 1000 / frequency.QuadPart) < pi.timeout)
			Sleep(pi.timeout - ((timer2.QuadPart - timer1.QuadPart) * 1000 / frequency.QuadPart));
	} while (--num);

	if (l_Debug)
		std::wcout << L"All pings sent. Cleaning up and returning" << '\n';

	if (hIcmp)
		IcmpCloseHandle(hIcmp);
	if (repBuf)
		delete reinterpret_cast<VOID *>(repBuf);

	response.avg = ((double)rtt / pi.num);

	return -1;

die:
	printErrorInfo();
	if (hIcmp)
		IcmpCloseHandle(hIcmp);
	if (repBuf)
		delete reinterpret_cast<VOID *>(repBuf);

	return 3;
}

static int check_ping6(const printInfoStruct& pi, response& response)
{
	DWORD dwRepSize = sizeof(ICMPV6_ECHO_REPLY) + 8;
	void *repBuf = reinterpret_cast<void *>(new BYTE[dwRepSize]);

	int num = pi.num;
	unsigned int rtt = 0;

	if (l_Debug)
		std::wcout << L"Parsing ip address" << '\n';

	sockaddr_in6 ipDest6;
	if (RtlIpv6StringToAddressEx(pi.ip.c_str(), &ipDest6.sin6_addr, &ipDest6.sin6_scope_id, &ipDest6.sin6_port)) {
		std::wcout << pi.ip << " is not a valid ipv6 address" << '\n';
		return 3;
	}

	ipDest6.sin6_family = AF_INET6;

	sockaddr_in6 ipSource6;
	ipSource6.sin6_addr = in6addr_any;
	ipSource6.sin6_family = AF_INET6;
	ipSource6.sin6_flowinfo = 0;
	ipSource6.sin6_port = 0;

	if (l_Debug)
		std::wcout << L"Creating Icmp File" << '\n';

	HANDLE hIcmp = Icmp6CreateFile();
	if (hIcmp == INVALID_HANDLE_VALUE) {
		goto die;
	}

	IP_OPTION_INFORMATION ipInfo = { 30, 0, 0, 0, NULL };

	LARGE_INTEGER frequency;
	QueryPerformanceFrequency(&frequency);

	do {
		LARGE_INTEGER timer1;
		QueryPerformanceCounter(&timer1);

		if (l_Debug)
			std::wcout << L"Sending Icmp echo" << '\n';

		if (!Icmp6SendEcho2(hIcmp, NULL, NULL, NULL, &ipSource6, &ipDest6,
			NULL, 0, &ipInfo, repBuf, dwRepSize, pi.timeout)) {
			response.dropped++;
			if (l_Debug)
				std::wcout << L"Dropped: Response was 0" << '\n';
			continue;
		}

		if (l_Debug)
			std::wcout << "Ping recieved" << '\n';

		Icmp6ParseReplies(repBuf, dwRepSize);

		ICMPV6_ECHO_REPLY *pEchoReply = static_cast<ICMPV6_ECHO_REPLY *>(repBuf);

		if (pEchoReply->Status != IP_SUCCESS) {
			response.dropped++;
			if (l_Debug)
				std::wcout << L"Dropped: echo reply status " << pEchoReply->Status << '\n';
			continue;
		}

		rtt += pEchoReply->RoundTripTime;

		if (l_Debug)
			std::wcout << L"Recorded rtt of " << pEchoReply->RoundTripTime << '\n';

		if (response.pMin == 0 || pEchoReply->RoundTripTime < response.pMin)
			response.pMin = pEchoReply->RoundTripTime;
		else if (pEchoReply->RoundTripTime > response.pMax)
			response.pMax = pEchoReply->RoundTripTime;

		LARGE_INTEGER timer2;
		QueryPerformanceCounter(&timer2);

		if (((timer2.QuadPart - timer1.QuadPart) * 1000 / frequency.QuadPart) < pi.timeout)
			Sleep(pi.timeout - ((timer2.QuadPart - timer1.QuadPart) * 1000 / frequency.QuadPart));
	} while (--num);

	if (l_Debug)
		std::wcout << L"All pings sent. Cleaning up and returning" << '\n';

	if (hIcmp)
		IcmpCloseHandle(hIcmp);

	if (repBuf)
		delete reinterpret_cast<BYTE *>(repBuf);

	response.avg = ((double)rtt / pi.num);

	return -1;
die:
	printErrorInfo(GetLastError());

	if (hIcmp)
		IcmpCloseHandle(hIcmp);

	if (repBuf)
		delete reinterpret_cast<BYTE *>(repBuf);

	return 3;
}

int wmain(int argc, WCHAR **argv)
{
	WSADATA dat;
	if (WSAStartup(MAKEWORD(2, 2), &dat)) {
		std::cout << "WSAStartup failed\n";
		return 3;
	}

	po::variables_map vm;
	printInfoStruct printInfo;
	if (parseArguments(argc, argv, vm, printInfo) != -1)
		return 3;

	if (!resolveHostname(printInfo.host, printInfo.ipv6, printInfo.ip))
		return 3;

	response response;

	if (printInfo.ipv6) {
		if (check_ping6(printInfo, response) != -1)
			return 3;
	} else {
		if (check_ping4(printInfo, response) != -1)
			return 3;
	}

	WSACleanup();

	return printOutput(printInfo, response);
}