/*
Compiler: g++
Flags: -static-libgcc -static-libstdc++ -lws2_32

TODO:
Do not send auto reply
Change card0.txt file based on information given by client

*/

#include <iostream>
#include <string>
#include "argh.h"
#include <winsock2.h>
#include <stdio.h>

#pragma comment(lib,"ws2_32.lib") //Winsock Library

void exampleMessage();

int main (int argc, char* argv[])
{
    std::string file, check; // file = card0.txt ; check = check.txt
    int port = 0; // port number to listen

    argh::parser cmdl; // command line parser
    cmdl.parse(argc, argv, argh::parser::PREFER_PARAM_FOR_UNREG_OPTION);

    if(cmdl["-h"]) // help
    {
        exampleMessage();
    }

    for(auto& param: cmdl.params())
    {
        if(!param.first.compare("f")) // card0 file
        {
            file = param.second;
        }
        if(!param.first.compare("c")) // checker file
        {
            check = param.second;
        }
        if(!param.first.compare("p")) // port
        {
            try 
            {
                port = stoi(param.second); // convert to int
                if (port < 1 || port > 65535) // validate port number
                    exampleMessage();
            }
            catch (std::invalid_argument) // failed convert
            {
                exampleMessage();
            }
        }
    }

    if(file == "" || check == "" || port == 0) // failed validation
        exampleMessage();

    std::cout << "File:\t" << file << std::endl;
    std::cout << "Check:\t" << check << std::endl;
    std::cout << "Port:\t" << port << std::endl;

    // begin socket work - copy and pasted below (http://www.binarytides.com/code-tcp-socket-server-winsock/)
    WSADATA wsa;
    SOCKET master , new_socket , client_socket[30] , s;
    struct sockaddr_in server, address;
    int max_clients = 30 , activity, addrlen, i, valread;
    char *message = "ECHO Daemon v1.0 \r\n";
     
    //size of our receive buffer, this is string length.
    int MAXRECV = 1024;
    //set of socket descriptors
    fd_set readfds;
    //1 extra for null character, string termination
    char *buffer;
    buffer =  (char*) malloc((MAXRECV + 1) * sizeof(char));
 
    for(i = 0 ; i < 30;i++)
    {
        client_socket[i] = 0;
    }
 
    printf("\nInitialising Winsock...");
    if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
    {
        printf("Failed. Error Code : %d",WSAGetLastError());
        exit(EXIT_FAILURE);
    }
     
    printf("Initialised.\n");
     
    //Create a socket
    if((master = socket(AF_INET , SOCK_STREAM , 0 )) == INVALID_SOCKET)
    {
        printf("Could not create socket : %d" , WSAGetLastError());
        exit(EXIT_FAILURE);
    }
 
    printf("Socket created.\n");
     
    //Prepare the sockaddr_in structure
    server.sin_family = AF_INET;
    server.sin_addr.s_addr = INADDR_ANY;
    server.sin_port = htons( port );
     
    //Bind
    if( bind(master ,(struct sockaddr *)&server , sizeof(server)) == SOCKET_ERROR)
    {
        printf("Bind failed with error code : %d" , WSAGetLastError());
        exit(EXIT_FAILURE);
    }
     
    puts("Bind done");
 
    //Listen to incoming connections
    listen(master , 3);
     
    //Accept and incoming connection
    puts("Waiting for incoming connections...");
     
    addrlen = sizeof(struct sockaddr_in);
     
    while(TRUE)
    {
        //clear the socket fd set
        FD_ZERO(&readfds);
  
        //add master socket to fd set
        FD_SET(master, &readfds);
         
        //add child sockets to fd set
        for (  i = 0 ; i < max_clients ; i++) 
        {
            s = client_socket[i];
            if(s > 0)
            {
                FD_SET( s , &readfds);
            }
        }
         
        //wait for an activity on any of the sockets, timeout is NULL , so wait indefinitely
        activity = select( 0 , &readfds , NULL , NULL , NULL);
    
        if ( activity == SOCKET_ERROR ) 
        {
            printf("select call failed with error code : %d" , WSAGetLastError());
            exit(EXIT_FAILURE);
        }
          
        //If something happened on the master socket , then its an incoming connection
        if (FD_ISSET(master , &readfds)) 
        {
            if ((new_socket = accept(master , (struct sockaddr *)&address, (int *)&addrlen))<0)
            {
                perror("accept");
                exit(EXIT_FAILURE);
            }
          
            //inform user of socket number - used in send and receive commands
            printf("New connection , socket fd is %d , ip is : %s , port : %d \n" , new_socket , inet_ntoa(address.sin_addr) , ntohs(address.sin_port));
        
            //send new connection greeting message
            if( send(new_socket, message, strlen(message), 0) != strlen(message) ) 
            {
                perror("send failed");
            }
              
            puts("Welcome message sent successfully");
              
            //add new socket to array of sockets
            for (i = 0; i < max_clients; i++) 
            {
                if (client_socket[i] == 0)
                {
                    client_socket[i] = new_socket;
                    printf("Adding to list of sockets at index %d \n" , i);
                    break;
                }
            }
        }
          
        //else its some IO operation on some other socket :)
        for (i = 0; i < max_clients; i++) 
        {
            s = client_socket[i];
            //if client presend in read sockets             
            if (FD_ISSET( s , &readfds)) 
            {
                //get details of the client
                getpeername(s , (struct sockaddr*)&address , (int*)&addrlen);
 
                //Check if it was for closing , and also read the incoming message
                //recv does not place a null terminator at the end of the string (whilst printf %s assumes there is one).
                valread = recv( s , buffer, MAXRECV, 0);
                 
                if( valread == SOCKET_ERROR)
                {
                    int error_code = WSAGetLastError();
                    if(error_code == WSAECONNRESET)
                    {
                        //Somebody disconnected , get his details and print
                        printf("Host disconnected unexpectedly , ip %s , port %d \n" , inet_ntoa(address.sin_addr) , ntohs(address.sin_port));
                      
                        //Close the socket and mark as 0 in list for reuse
                        closesocket( s );
                        client_socket[i] = 0;
                    }
                    else
                    {
                        printf("recv failed with error code : %d" , error_code);
                    }
                }
                if ( valread == 0)
                {
                    //Somebody disconnected , get his details and print
                    printf("Host disconnected , ip %s , port %d \n" , inet_ntoa(address.sin_addr) , ntohs(address.sin_port));
                      
                    //Close the socket and mark as 0 in list for reuse
                    closesocket( s );
                    client_socket[i] = 0;
                }
                  
                //Echo back the message that came in
                else
                {
                    //add null character, if you want to use with printf/puts or other string handling functions
                    buffer[valread] = '\0';
                    printf("%s:%d - %s \n" , inet_ntoa(address.sin_addr) , ntohs(address.sin_port), buffer);
                    send( s , buffer , valread , 0 );
                }
            }
        }
    }
     
    closesocket(s);
    WSACleanup();

    return 0;
}

void exampleMessage() // help menu
{
    std::cout << "Availble options:" << std::endl;
    std::cout << "  -f\tLocation of card0.txt file" << std::endl;
    std::cout << "  -c\tLocation of check file" << std::endl;
    std::cout << "  -p\tPort number to listen on (1-65535)" << std::endl;
    std::cout << std::endl << "Example usage: cardnet.exe -f G:\\card0.txt -c G:\\check.txt -p 4500" << std::endl;
    exit(0);

}