///
/// Created by Anonymous275 on 7/31/2020
///
#include "Security/Enc.h"
#include "Curl/Http.h"
#include "Settings.h"
#include "Network.h"
#include "Logger.h"
#include <sstream>
#include <thread>
#include <cstring>
#include <algorithm>
#include <string>
#include "UnixCompat.h"


struct Hold{
    SOCKET TCPSock{};
    bool Done = false;
};
bool Send(SOCKET TCPSock,std::string Data){
#ifdef WIN32
    int BytesSent;
    int len = static_cast<int>(Data.size());
#else
    int64_t BytesSent;
    size_t len = Data.size();
#endif // WIN32
    BytesSent = send(TCPSock, Data.c_str(), len, 0);
    Data.clear();
    if (BytesSent <= 0) {
#ifndef WIN32
        error(__func__ + std::string(" ") + strerror(errno));
#else
        error(__func__ + std::string(" ") + std::to_string(WSAGetLastError()));
#endif // WIN32
        return false;
    }
    return true;
}
std::string Rcv(SOCKET TCPSock){
    uint32_t RealSize;
    #ifdef WIN32
        int64_t BytesRcv = recv(TCPSock, reinterpret_cast<char*>(&RealSize), sizeof(RealSize), 0);
    #else
        int64_t BytesRcv = recv(TCPSock, reinterpret_cast<void*>(&RealSize), sizeof(RealSize), 0);
    #endif
    if (BytesRcv != sizeof(RealSize)) {
        error(std::string(Sec("invalid packet: expected 4, got ")) + std::to_string(BytesRcv));
        return "";
    }
    // RealSize is big-endian, so we convert it to host endianness
    RealSize = ntohl(RealSize);
    debug(std::string("got ") + std::to_string(RealSize) + " as size");
    if (RealSize > 7000) {
        error(Sec("Larger than allowed TCP packet received"));
        return "";
    }
    char buf[7000];
    std::fill_n(buf, 7000, 0);
    BytesRcv = recv(TCPSock, buf, RealSize, 0);
    if (BytesRcv != RealSize) {
        debug("expected " + std::to_string(RealSize) + " bytes, got " + std::to_string(BytesRcv) + " instead");
    }
    if (BytesRcv <= 0)
        return "";
    return std::string(buf);
}
std::string GetRole(const std::string &DID){
    if(!DID.empty()){
        std::string a = HttpRequest(Sec("https://beammp.com/entitlement?did=")+DID,443);
        std::string b = HttpRequest(Sec("https://backup1.beammp.com/entitlement?did=")+DID,443);
        if(!a.empty() || !b.empty()){
            if(a != b)a = b;
            auto pos = a.find('"');
            if(pos != std::string::npos){
                return a.substr(pos+1,a.find('"',pos+1)-2);
            }else if(a == "[]")return Sec("Member");
        }
    }
    return "";
}
void Check(Hold* S){
    std::this_thread::sleep_for(std::chrono::seconds(5));
    if(S != nullptr){
        if(!S->Done)closesocket(S->TCPSock);
    }
}
int Max(){
    int M = MaxPlayers;
    for(auto& c : CI->Clients){
        if(c != nullptr){
            if(c->GetRole() == Sec("MDEV"))M++;
        }
    }
    return M;
}
void CreateClient(SOCKET TCPSock,const std::string &Name, const std::string &DID,const std::string &Role) {
    auto *c = new Client;
    c->SetTCPSock(TCPSock);
    c->SetName(Name);
    c->SetRole(Role);
    c->SetDID(DID);
    Client& Client = *c;
    CI->AddClient(std::move(c));
    InitClient(&Client);
}
std::pair<int,int> Parse(const std::string& msg){
    std::stringstream ss(msg);
    std::string t;
    std::pair<int,int> a = {0,0}; //N then E
    while (std::getline(ss, t, 'g')) {
        if(t.find_first_not_of(Sec("0123456789abcdef")) != std::string::npos)return a;
        if(a.first == 0){
            a.first = std::stoi(t, nullptr, 16);
        }else if(a.second == 0){
            a.second = std::stoi(t, nullptr, 16);
        }else return a;
    }
    return {0,0};
}
std::string GenerateM(RSA*key){
    std::stringstream stream;
    stream << std::hex << key->n << "g" << key->e << "g" << RSA_E(Sec("IDC"),key);
    return stream.str();
}

void Identification(SOCKET TCPSock,Hold*S,RSA*Skey){
    DebugPrintTID();
    Assert(S);
    Assert(Skey);
    S->TCPSock = TCPSock;
    //std::thread Timeout(Check,S);
    //Timeout.detach();
    std::string Name,DID,Role;
    if(!Send(TCPSock,GenerateM(Skey))) {
        error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
        closesocket(TCPSock);
        return;
    }
    std::string msg = Rcv(TCPSock);
    auto Keys = Parse(msg);
    if(!Send(TCPSock,RSA_E("HC",Keys.second,Keys.first))){
        error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
        closesocket(TCPSock);
        return;
    }

    std::string Res = Rcv(TCPSock);
    std::string Ver = Rcv(TCPSock);
    S->Done = true;
    Ver = RSA_D(Ver,Skey);
    if(Ver.size() > 3 && Ver.substr(0,2) == Sec("VC")){
        Ver = Ver.substr(2);
        if(Ver.length() > 4 || Ver != GetCVer()){
            error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
            closesocket(TCPSock);
            return;
        }
    }else{
        error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
        closesocket(TCPSock);
        return;
    }
    Res = RSA_D(Res,Skey);
    if(Res.size() < 3 || Res.substr(0,2) != Sec("NR")) {
        error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
        closesocket(TCPSock);
        return;
    }
    if(Res.find(':') == std::string::npos){
        error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
        closesocket(TCPSock);
        return;
    }
    Name = Res.substr(2,Res.find(':')-2);
    DID = Res.substr(Res.find(':')+1);
    Role = GetRole(DID);
    if(Role.empty() || Role.find(Sec("Error")) != std::string::npos){
        error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
        closesocket(TCPSock);
        return;
    }
    // DebugPrintTIDInternal(std::string("Client(") + Name + ")");
    debug(Sec("Name -> ") + Name + Sec(", Role -> ") + Role +  Sec(", ID -> ") + DID);
    for(auto& c : CI->Clients){
        if(c != nullptr){
            if(c->GetDID() == DID){
                error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
                closesocket(c->GetTCPSock());
                c->SetStatus(-2);
                break;
            }
        }
    }
    if(Role == Sec("MDEV") || CI->Size() < Max()){
        debug("Identification success");
        CreateClient(TCPSock,Name,DID,Role);
    } else {
        error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
        closesocket(TCPSock);
    }
}
void Identify(SOCKET TCPSock){
    auto* S = new Hold;
    RSA*Skey = GenKey();
    // this disgusting ifdef stuff is needed because for some
    // reason MSVC defines __try and __except and libg++ defines
    // __try and __catch so its all a big mess if we leave this in or undefine
    // the macros
/*#ifdef WIN32
    __try{
#endif // WIN32*/
        Identification(TCPSock,S,Skey);
/*#ifdef WIN32
    }__except(1){
        if(TCPSock != -1){
            error("died on " + std::string(__func__) + ":" + std::to_string(__LINE__));
            closesocket(TCPSock);
        }
    }
#endif // WIN32*/

    delete Skey;
    delete S;
}

void TCPServerMain(){
    DebugPrintTID();
#ifdef WIN32
    WSADATA wsaData;
    if (WSAStartup(514, &wsaData)){
        error(Sec("Can't start Winsock!"));
        return;
    }
    SOCKET client, Listener = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    sockaddr_in addr{};
    addr.sin_addr.S_un.S_addr = ADDR_ANY;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(Port);
    if (bind(Listener, (sockaddr*)&addr, sizeof(addr)) == SOCKET_ERROR){
        error(Sec("Can't bind socket! ") + std::to_string(WSAGetLastError()));
        std::this_thread::sleep_for(std::chrono::seconds(5));
        _Exit(-1);
    }
    if(Listener == -1){
        error(Sec("Invalid listening socket"));
        return;
    }
    if(listen(Listener,SOMAXCONN)){
        error(Sec("listener failed ")+ std::to_string(GetLastError()));
        return;
    }
    info(Sec("Vehicle event network online"));
    do{
        try {
        client = accept(Listener, nullptr, nullptr);
        if(client == -1){
            warn(Sec("Got an invalid client socket on connect! Skipping..."));
            continue;
        }
        std::thread ID(Identify,client);
        ID.detach();
        } catch (const std::exception& e) {
            error(Sec("fatal: ") + std::string(e.what()));
        }
    }while(client);

    closesocket(client);
    WSACleanup();
#else // unix
    // wondering why we need slightly different implementations of this?
    // ask ms.
    SOCKET client = -1, Listener = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    sockaddr_in addr{};
    addr.sin_addr.s_addr = INADDR_ANY;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(uint16_t(Port));
    if (bind(Listener, (sockaddr*)&addr, sizeof(addr)) != 0){
        error(Sec("Can't bind socket! ") + std::string(strerror(errno)));
        std::this_thread::sleep_for(std::chrono::seconds(5));
        _Exit(-1);
    }
    if(Listener == -1){
        error(Sec("Invalid listening socket"));
        return;
    }
    if(listen(Listener,SOMAXCONN)){
        error(Sec("listener failed ")+ std::string(strerror(errno)));
        return;
    }
    info(Sec("Vehicle event network online"));
    do{
        try {
            client = accept(Listener, nullptr, nullptr);
            if(client == -1){
                warn(Sec("Got an invalid client socket on connect! Skipping..."));
                continue;
            }
            std::thread ID(Identify,client);
            ID.detach();
        } catch (const std::exception& e) {
            error(Sec("fatal: ") + std::string(e.what()));
        }
    }while(client);

    debug("all ok, arrived at " + std::string(__func__) + ":" + std::to_string(__LINE__));
    closesocket(client);
#endif // WIN32
}