/* CHANGES FROM UNIX VERSION                                                   */
/*                                                                             */
/* 1.  Changed header files.                                                   */
/* 2.  Added WSAStartUP() and WSACleanUp().                                    */
/* 3.  Used closesocket() instead of close().                                  */ 

#include <stdio.h>      /* for printf(), fprintf() */
#include <winsock.h>    /* for socket(),... */
#include <stdlib.h>     /* for exit() */

#define RCVBUFSIZE 32   /* Size of receive buffer */

void DieWithError(char *errorMessage);  /* Error handling function */

void main(int argc, char *argv[])
{
    int sock;                        /* Socket descriptor */
    struct sockaddr_in echoServAddr; /* Echo server address */
    unsigned short echoServPort;     /* Echo server port */
    char *servIP;                    /* Server IP address (dotted quad) */
    char *echoString;                /* String to send to echo server */
    char echoBuffer[RCVBUFSIZE];     /* Buffer for echo string */
    int echoStringLen;               /* Length of string to echo */
    int bytesRcvd, totalBytesRcvd;   /* Bytes read in single recv() and total bytes read */
    WSADATA wsaData;                 /* Structure for WinSock setup communication */

    if ((argc < 3) || (argc > 4))    /* Test for correct number of arguments */
    {
        fprintf(stderr, "Usage: %s <Server IP> <Echo Word> [<Echo Port>]\n", argv[0]);
        exit(1);
    }

    servIP = argv[1];             /* First arg: server IP address (dotted quad) */
    echoString = argv[2];         /* Second arg: string to echo */

    if (argc == 4)
        echoServPort = atoi(argv[3]); /* Use given port, if any */
    else
        echoServPort = 7;  /* otherwise, 7 is the well-known port for the echo service */

    if (WSAStartup(MAKEWORD(2, 0), &wsaData) != 0) /* Load Winsock 2.0 DLL */
    {
        fprintf(stderr, "WSAStartup() failed");
        exit(1);
    }

    /* Create a reliable, stream socket using TCP */
    if ((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
        DieWithError("socket() failed");

    /* Construct the server address structure */
    memset(&echoServAddr, 0, sizeof(echoServAddr));     /* Zero out structure */
    echoServAddr.sin_family      = AF_INET;             /* Internet address family */
    echoServAddr.sin_addr.s_addr = inet_addr(servIP);   /* Server IP address */
    echoServAddr.sin_port        = htons(echoServPort); /* Server port */
    /* Establish the connection to the echo server */
    if (connect(sock, (struct sockaddr *) &echoServAddr, sizeof(echoServAddr)) < 0)
        DieWithError("connect() failed");

    echoStringLen = strlen(echoString);          /* Determine input length */

    /* Send the string, including the null terminator, to the server */
    if (send(sock, echoString, echoStringLen, 0) != echoStringLen)
        DieWithError("send() sent a different number of bytes than expected");

    /* Receive the same string back from the server */
    totalBytesRcvd = 0;
    printf("Received: ");                /* Setup to print the echoed string */
    while (totalBytesRcvd < echoStringLen)
    {
        /* Receive up to the buffer size (minus 1 to leave space for 
           a null terminator) bytes from the sender */
        if ((bytesRcvd = recv(sock, echoBuffer, RCVBUFSIZE - 1, 0)) <= 0)
            DieWithError("recv() failed or connection closed prematurely");
        totalBytesRcvd += bytesRcvd;   /* Keep tally of total bytes */
        echoBuffer[bytesRcvd] = '\0';  /* Add \0 so printf knows where to stop */
        printf("%s", echoBuffer);            /* Print the echo buffer */
    }

    printf("\n");    /* Print a final linefeed */

    closesocket(sock);
    WSACleanup();  /* Cleanup Winsock */

    exit(0);
}