#include <cstdlib>
#include <string>
#include <algorithm>
#include <cctype>
#include <functional>
#include <fstream>
#include <set>
#include <boost/asio.hpp>
#include <boost/filesystem.hpp>
#include <boost/filesystem/fstream.hpp>
#include <boost/foreach.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/program_options/detail/config_file.hpp>
#include <boost/program_options/parsers.hpp>
#include <boost/algorithm/string.hpp>
#include "util.h"
#include "Log.h"

#if defined(__linux__) || defined(__FreeBSD_kernel__) || defined(__APPLE__) || defined(__OpenBSD__)
#include <sys/types.h>
#include <ifaddrs.h>
#elif defined(WIN32)
#include <stdlib.h>
#include <string.h>
#include <stdio.h>    
#include <winsock2.h>
#include <ws2tcpip.h>
#include <iphlpapi.h>
#include <shlobj.h>

#ifdef _MSC_VER
#pragma comment(lib, "IPHLPAPI.lib")
#endif

#define MALLOC(x) HeapAlloc(GetProcessHeap(), 0, (x))
#define FREE(x) HeapFree(GetProcessHeap(), 0, (x))

int inet_pton(int af, const char *src, void *dst)
{ /* This function was written by Petar Korponai?. See
http://stackoverflow.com/questions/15660203/inet-pton-identifier-not-found */
	struct sockaddr_storage ss;
	int size = sizeof (ss);
	char src_copy[INET6_ADDRSTRLEN + 1];

	ZeroMemory (&ss, sizeof (ss));
	strncpy (src_copy, src, INET6_ADDRSTRLEN + 1);
	src_copy[INET6_ADDRSTRLEN] = 0;

	if (WSAStringToAddress (src_copy, af, NULL, (struct sockaddr *)&ss, &size) == 0)
	{
		switch (af)
		{
		case AF_INET:
			*(struct in_addr *)dst = ((struct sockaddr_in *)&ss)->sin_addr;
			return 1;
		case AF_INET6:
			*(struct in6_addr *)dst = ((struct sockaddr_in6 *)&ss)->sin6_addr;
			return 1;
		}
	}
	return 0;
}
#endif

namespace i2p
{
namespace util
{

namespace config
{
	std::map<std::string, std::string> mapArgs;
	std::map<std::string, std::vector<std::string> > mapMultiArgs;

	void OptionParser(int argc, const char* const argv[])
	{
		mapArgs.clear();
		mapMultiArgs.clear();
		for (int i = 1; i < argc; i++)
		{
			std::string strKey (argv[i]);
			std::string strValue;
			size_t has_data = strKey.find('=');
			if (has_data != std::string::npos)
			{
				strValue = strKey.substr(has_data+1);
				strKey = strKey.substr(0, has_data);
			}

#ifdef WIN32
			boost::to_lower(strKey);
			if (boost::algorithm::starts_with(strKey, "/"))
				strKey = "-" + strKey.substr(1);
#endif
			if (strKey[0] != '-')
				break;

			mapArgs[strKey] = strValue;
			mapMultiArgs[strKey].push_back(strValue);
		}

		BOOST_FOREACH(PAIRTYPE(const std::string,std::string)& entry, mapArgs)
		{
			std::string name = entry.first;

			//  interpret --foo as -foo (as long as both are not set)
			if (name.find("--") == 0)
			{
				std::string singleDash(name.begin()+1, name.end());
				if (mapArgs.count(singleDash) == 0)
					mapArgs[singleDash] = entry.second;
				name = singleDash;
			}
		}
	}

	std::string GetArg(const std::string& strArg, const std::string& strDefault)
	{
		if (mapArgs.count(strArg))
			return mapArgs[strArg];
		return strDefault;
	}

	int GetArg(const std::string& strArg, int nDefault)
	{
		if (mapArgs.count(strArg))
			return atoi(mapArgs[strArg].c_str());
		return nDefault;
	}
}

namespace filesystem
{
	std::string appName ("i2pd");	

	void SetAppName (const std::string& name)
	{
		appName = name;
	}

	std::string GetAppName ()
	{
		return appName;
	}

	const boost::filesystem::path &GetDataDir()
	{
		static boost::filesystem::path path;

		// TODO: datadir parameter is useless because GetDataDir is called before OptionParser
		// and mapArgs is not initialized yet
		/*if (i2p::util::config::mapArgs.count("-datadir")) 
			path = boost::filesystem::system_complete(i2p::util::config::mapArgs["-datadir"]);
		else */
			path = GetDefaultDataDir();

		if (!boost::filesystem::exists( path ))
		{
			// Create data directory
			if (!boost::filesystem::create_directory( path ))
			{
				LogPrint(eLogError, "FS: Failed to create data directory!");
				path = "";
				return path;
			}
		}
		if (!boost::filesystem::is_directory(path)) 
			path = GetDefaultDataDir();
		return path;
	}

	std::string GetFullPath (const std::string& filename)
	{
		std::string fullPath = GetDataDir ().string ();
#ifndef _WIN32
		fullPath.append ("/");
#else
		fullPath.append ("\\");
#endif
		fullPath.append (filename);
		return fullPath;
	}		

	boost::filesystem::path GetConfigFile()
	{
		boost::filesystem::path pathConfigFile(i2p::util::config::GetArg("-conf", "i2p.conf"));
		if (!pathConfigFile.is_complete()) pathConfigFile = GetDataDir() / pathConfigFile;
		return pathConfigFile;
	}

	boost::filesystem::path GetTunnelsConfigFile()
	{
	  boost::filesystem::path pathTunnelsConfigFile(i2p::util::config::GetArg("-tunnelscfg", "tunnels.cfg"));
		if (!pathTunnelsConfigFile.is_complete())
		  pathTunnelsConfigFile = GetDataDir() / pathTunnelsConfigFile;
		return pathTunnelsConfigFile;
	}

	void ReadConfigFile(std::map<std::string, std::string>& mapSettingsRet,
						std::map<std::string, std::vector<std::string> >& mapMultiSettingsRet)
	{
		boost::filesystem::ifstream streamConfig(GetConfigFile());
		if (!streamConfig.good())
			return; // No i2pd.conf file is OK

		std::set<std::string> setOptions;
		setOptions.insert("*");

		for (boost::program_options::detail::config_file_iterator it(streamConfig, setOptions), end; it != end; ++it)
		{
			// Don't overwrite existing settings so command line settings override i2pd.conf
			std::string strKey = std::string("-") + it->string_key;
			if (mapSettingsRet.count(strKey) == 0)
			{
				mapSettingsRet[strKey] = it->value[0];
			}
			mapMultiSettingsRet[strKey].push_back(it->value[0]);
		}
	}

	boost::filesystem::path GetDefaultDataDir()
	{
		// Windows < Vista: C:\Documents and Settings\Username\Application Data\i2pd
		// Windows >= Vista: C:\Users\Username\AppData\Roaming\i2pd
		// Mac: ~/Library/Application Support/i2pd
		// Unix: ~/.i2pd or /var/lib/i2pd is system=1
#ifdef WIN32
		// Windows
		char localAppData[MAX_PATH];
		SHGetFolderPath(NULL, CSIDL_APPDATA, 0, NULL, localAppData);
		return boost::filesystem::path(std::string(localAppData) + "\\" + appName);
#else
		if (i2p::util::config::GetArg("-service", 0)) // use system folder
			return boost::filesystem::path(std::string ("/var/lib/") + appName);
		boost::filesystem::path pathRet;
		char* pszHome = getenv("HOME");
		if (pszHome == NULL || strlen(pszHome) == 0)
			pathRet = boost::filesystem::path("/");
		else
			pathRet = boost::filesystem::path(pszHome);
#ifdef MAC_OSX
		// Mac
		pathRet /= "Library/Application Support";
		boost::filesystem::create_directory(pathRet);
		return pathRet / appName;
#else
		// Unix
		return pathRet / (std::string (".") + appName);
#endif
#endif
	}

	boost::filesystem::path GetCertificatesDir()
	{
		return GetDataDir () / "certificates";
	}	
}

namespace http
{
	std::string GetHttpContent (std::istream& response)
	{
		std::string version, statusMessage;
		response >> version; // HTTP version
		int status;
		response >> status; // status
		std::getline (response, statusMessage);
		if (status == 200) // OK
		{
			bool isChunked = false;
			std::string header;
			while (!response.eof () && header != "\r")
			{
				std::getline(response, header);
				auto colon = header.find (':');
				if (colon != std::string::npos)
				{
					std::string field = header.substr (0, colon);
					if (field == i2p::util::http::TRANSFER_ENCODING)
						isChunked = (header.find ("chunked", colon + 1) != std::string::npos);
				}	
			}

			std::stringstream ss;
			if (isChunked)
				MergeChunkedResponse (response, ss);
			else	
				ss << response.rdbuf();
			return ss.str();
		}
		else
		{
			LogPrint (eLogError, "HTTPClient: error, server responds ", status);
			return "";
		}
	}

	void MergeChunkedResponse (std::istream& response, std::ostream& merged)
	{
		while (!response.eof ())
		{	
			std::string hexLen;
			int len;
			std::getline (response, hexLen);
			std::istringstream iss (hexLen);
			iss >> std::hex >> len;
			if (!len) break;
			char * buf = new char[len];
			response.read (buf, len);
			merged.write (buf, len);
			delete[] buf;
			std::getline (response, hexLen); // read \r\n after chunk
		}
	}	
	
	url::url(const std::string& url_s)
	{
		portstr_ = "80";
		port_ = 80;
		user_ = "";
		pass_ = "";

		parse(url_s);
	}


	// code for parser tests
	//{
    //  i2p::util::http::url u_0("http://127.0.0.1:7070/asdasd?qqqqqqqqqqqq");
	//	i2p::util::http::url u_1("http://user:password@site.com:8080/asdasd?qqqqqqqqqqqqq");
	//	i2p::util::http::url u_2("http://user:password@site.com/asdasd?qqqqqqqqqqqqqq");
	//	i2p::util::http::url u_3("http://user:@site.com/asdasd?qqqqqqqqqqqqq");
	//	i2p::util::http::url u_4("http://user@site.com/asdasd?qqqqqqqqqqqq");
	//	i2p::util::http::url u_5("http://@site.com:800/asdasd?qqqqqqqqqqqq");
	//	i2p::util::http::url u_6("http://@site.com:err_port/asdasd?qqqqqqqqqqqq");
    //	i2p::util::http::url u_7("http://user:password@site.com:err_port/asdasd?qqqqqqqqqqqq");
	//}
	void url::parse(const std::string& url_s)
	{
		const std::string prot_end("://");
		std::string::const_iterator prot_i = search(url_s.begin(), url_s.end(),
										   prot_end.begin(), prot_end.end());
		protocol_.reserve(distance(url_s.begin(), prot_i));
		transform(url_s.begin(), prot_i,
			  back_inserter(protocol_),
			  std::ptr_fun<int,int>(tolower)); // protocol is icase
		if( prot_i == url_s.end() )
			return;
		advance(prot_i, prot_end.length());
		std::string::const_iterator path_i = find(prot_i, url_s.end(), '/');
		host_.reserve(distance(prot_i, path_i));
		transform(prot_i, path_i,
			  back_inserter(host_),
			  std::ptr_fun<int,int>(tolower)); // host is icase

		// parse user/password
		auto user_pass_i = find(host_.begin(), host_.end(), '@');
		if (user_pass_i != host_.end())
		{
			std::string user_pass = std::string(host_.begin(), user_pass_i);
			auto pass_i = find(user_pass.begin(), user_pass.end(), ':');
			if (pass_i != user_pass.end())
			{
				user_ = std::string(user_pass.begin(), pass_i);
				pass_ = std::string(pass_i + 1, user_pass.end());
			}
			else
				user_ = user_pass;

			host_.assign(user_pass_i + 1, host_.end());
		}

		// parse port
		auto port_i = find(host_.begin(), host_.end(), ':');
		if (port_i != host_.end())
		{
			portstr_ = std::string(port_i + 1, host_.end());
			host_.assign(host_.begin(), port_i);
			try{
				port_ = boost::lexical_cast<decltype(port_)>(portstr_);
			}
			catch (std::exception e) {
				port_ = 80;
			}
		}

		std::string::const_iterator query_i = find(path_i, url_s.end(), '?');
		path_.assign(path_i, query_i);
		if( query_i != url_s.end() )
			++query_i;
		query_.assign(query_i, url_s.end());
	}

	std::string urlDecode(const std::string& data)
	{
		std::string res(data);
		for (size_t pos = res.find('%'); pos != std::string::npos; pos = res.find('%',pos+1))
		{
			char c = strtol(res.substr(pos+1,2).c_str(), NULL, 16);
			res.replace(pos,3,1,c);
		}
		return res;
	}
} 

namespace net
{
#if defined(__linux__) || defined(__FreeBSD_kernel__) || defined(__APPLE__) || defined(__OpenBSD__)
    
	int GetMTUUnix(const boost::asio::ip::address& localAddress, int fallback)
    {
        ifaddrs* ifaddr, *ifa = nullptr;
        if(getifaddrs(&ifaddr) == -1) 
		{
            LogPrint(eLogError, "NetIface: Can't call getifaddrs(): ", strerror(errno));
            return fallback;
        }

        int family = 0;
        // look for interface matching local address   
        for(ifa = ifaddr; ifa != nullptr; ifa = ifa->ifa_next) 
		{
            if(!ifa->ifa_addr)
                continue;

            family = ifa->ifa_addr->sa_family;
            if(family == AF_INET && localAddress.is_v4()) 
			{
                sockaddr_in* sa = (sockaddr_in*) ifa->ifa_addr;
                if(!memcmp(&sa->sin_addr, localAddress.to_v4().to_bytes().data(), 4))
                    break; // address matches
            } 
			else if(family == AF_INET6 && localAddress.is_v6()) 
			{
                sockaddr_in6* sa = (sockaddr_in6*) ifa->ifa_addr;
                if(!memcmp(&sa->sin6_addr, localAddress.to_v6().to_bytes().data(), 16))
                    break; // address matches
            }
        }
        int mtu = fallback;
        if(ifa && family) 
		{ // interface found?
            int fd = socket(family, SOCK_DGRAM, 0);
            if(fd > 0) 
			{
                ifreq ifr;
                strncpy(ifr.ifr_name, ifa->ifa_name, IFNAMSIZ); // set interface for query
                if(ioctl(fd, SIOCGIFMTU, &ifr) >= 0)  
                    mtu = ifr.ifr_mtu; // MTU
                else
                    LogPrint (eLogError, "NetIface: Failed to run ioctl: ", strerror(errno));
                close(fd);
            } 
			else
                LogPrint(eLogError, "NetIface: Failed to create datagram socket");
        } 
		else 
            LogPrint(eLogWarning, "NetIface: interface for local address", localAddress.to_string(), " not found");
       freeifaddrs(ifaddr);

       return mtu;
    }

#elif defined(_WIN32)
    int GetMTUWindowsIpv4(sockaddr_in inputAddress, int fallback)
    {
        ULONG outBufLen = 0;
        PIP_ADAPTER_ADDRESSES pAddresses = nullptr;
        PIP_ADAPTER_ADDRESSES pCurrAddresses = nullptr;
        PIP_ADAPTER_UNICAST_ADDRESS pUnicast = nullptr;


        if(GetAdaptersAddresses(AF_INET, GAA_FLAG_INCLUDE_PREFIX, nullptr, pAddresses, &outBufLen)
          == ERROR_BUFFER_OVERFLOW) {
            FREE(pAddresses);
            pAddresses = (IP_ADAPTER_ADDRESSES*) MALLOC(outBufLen);
        }

        DWORD dwRetVal = GetAdaptersAddresses(
            AF_INET, GAA_FLAG_INCLUDE_PREFIX, nullptr, pAddresses, &outBufLen
        );

        if(dwRetVal != NO_ERROR) {
            LogPrint(eLogError, "NetIface: GetMTU(): enclosed GetAdaptersAddresses() call has failed");
            FREE(pAddresses);
            return fallback;
        }

        pCurrAddresses = pAddresses;
        while(pCurrAddresses) {
            PIP_ADAPTER_UNICAST_ADDRESS firstUnicastAddress = pCurrAddresses->FirstUnicastAddress;

            pUnicast = pCurrAddresses->FirstUnicastAddress;
            if(pUnicast == nullptr) {
                LogPrint(eLogError, "NetIface: GetMTU(): not a unicast ipv4 address, this is not supported");
            }
            for(int i = 0; pUnicast != nullptr; ++i) {
                LPSOCKADDR lpAddr = pUnicast->Address.lpSockaddr;
                sockaddr_in* localInterfaceAddress = (sockaddr_in*) lpAddr;
                if(localInterfaceAddress->sin_addr.S_un.S_addr == inputAddress.sin_addr.S_un.S_addr) {
                    auto result = pAddresses->Mtu;
                    FREE(pAddresses);
                    return result;
                }
                pUnicast = pUnicast->Next;
            }
            pCurrAddresses = pCurrAddresses->Next;
        }

        LogPrint(eLogError, "NetIface: GetMTU(): no usable unicast ipv4 addresses found");
        FREE(pAddresses);
        return fallback;
    }

    int GetMTUWindowsIpv6(sockaddr_in6 inputAddress, int fallback)
    {
        ULONG outBufLen = 0;
        PIP_ADAPTER_ADDRESSES pAddresses = nullptr;
        PIP_ADAPTER_ADDRESSES pCurrAddresses = nullptr;
        PIP_ADAPTER_UNICAST_ADDRESS pUnicast = nullptr;

        if(GetAdaptersAddresses(AF_INET6, GAA_FLAG_INCLUDE_PREFIX, nullptr, pAddresses, &outBufLen)
          == ERROR_BUFFER_OVERFLOW) {
            FREE(pAddresses);
            pAddresses = (IP_ADAPTER_ADDRESSES*) MALLOC(outBufLen);
        }

        DWORD dwRetVal = GetAdaptersAddresses(
            AF_INET6, GAA_FLAG_INCLUDE_PREFIX, nullptr, pAddresses, &outBufLen
        );

        if(dwRetVal != NO_ERROR) {
            LogPrint(eLogError, "NetIface: GetMTU(): enclosed GetAdaptersAddresses() call has failed");
            FREE(pAddresses);
            return fallback;
        }

        bool found_address = false;
        pCurrAddresses = pAddresses;
        while(pCurrAddresses) {
            PIP_ADAPTER_UNICAST_ADDRESS firstUnicastAddress = pCurrAddresses->FirstUnicastAddress;
            pUnicast = pCurrAddresses->FirstUnicastAddress;
            if(pUnicast == nullptr) {
                LogPrint(eLogError, "NetIface: GetMTU(): not a unicast ipv6 address, this is not supported");
            }
            for(int i = 0; pUnicast != nullptr; ++i) {
                LPSOCKADDR lpAddr = pUnicast->Address.lpSockaddr;
                sockaddr_in6 *localInterfaceAddress = (sockaddr_in6*) lpAddr;

                for (int j = 0; j != 8; ++j) {
                    if (localInterfaceAddress->sin6_addr.u.Word[j] != inputAddress.sin6_addr.u.Word[j]) {
                        break;
                    } else {
                        found_address = true;
                    }
                } if (found_address) {
                    auto result = pAddresses->Mtu;
                    FREE(pAddresses);
                    pAddresses = nullptr;
                    return result;
                }
                pUnicast = pUnicast->Next;
            }

            pCurrAddresses = pCurrAddresses->Next;
        }

        LogPrint(eLogError, "NetIface: GetMTU(): no usable unicast ipv6 addresses found");
        FREE(pAddresses);
        return fallback;
    }

    int GetMTUWindows(const boost::asio::ip::address& localAddress, int fallback)
    { 
#ifdef UNICODE
        string localAddress_temporary = localAddress.to_string();
        wstring localAddressUniversal(localAddress_temporary.begin(), localAddress_temporary.end());
#else
        std::string localAddressUniversal = localAddress.to_string();
#endif

        if(localAddress.is_v4()) {
            sockaddr_in inputAddress;
            inet_pton(AF_INET, localAddressUniversal.c_str(), &(inputAddress.sin_addr));
            return GetMTUWindowsIpv4(inputAddress, fallback);
        } else if(localAddress.is_v6()) {
            sockaddr_in6 inputAddress;
            inet_pton(AF_INET6, localAddressUniversal.c_str(), &(inputAddress.sin6_addr)); 
            return GetMTUWindowsIpv6(inputAddress, fallback);
        } else {
            LogPrint(eLogError, "NetIface: GetMTU(): address family is not supported");
            return fallback;
        }

    }
#endif // WIN32

    int GetMTU(const boost::asio::ip::address& localAddress)
    {
        const int fallback = 576; // fallback MTU

#ifdef WIN32
        return GetMTUWindows(localAddress, fallback);
#else
        return GetMTUUnix(localAddress, fallback);
#endif
        return fallback;
    }	
} 

} // util
} // i2p