/* Simple program to demonstrate a basic UDP client.
 * Repeatedly asks for words from stdin, and sends each word to the server.
 * If a response is received, then print out the length of the word.
 * 
 * Compile using "cc -o wordlen-client wordlen-client.c"
 * 
 * Written by Carey Williamson, February 2022
 */
 
/* Include files */
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>

/* Manifest constants */
#define MAX_BUFFER_SIZE 40
/* #define DEBUG 1 */

// Configure IP address and port of server here
//#define SERVER_IP "127.0.0.1"   /* loopback interface */
//#define SERVER_IP "136.159.5.25"  /* csx1.cpsc.ucalgary.ca */
#define SERVER_IP "136.159.5.27"  /* csx3.cpsc.ucalgary.ca */
#define SERVER_PORT 44101   /* must match the server's actual port!! */

int main(void)
  {
    struct sockaddr_in si_server;
    struct sockaddr *server;
    int s, i, len;
    char mybuffer[MAX_BUFFER_SIZE];
    int bytesin, bytesout;

    s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if( s < 0 )
      {
	printf("wordlen-client: socket() call failed!\n");
	return -1;
      }
      
    memset((char *) &si_server, 0, sizeof(si_server));
    si_server.sin_family = AF_INET;
    si_server.sin_port = htons(SERVER_PORT);
    server = (struct sockaddr *) &si_server;
    len = sizeof(si_server);

    if (inet_pton(AF_INET, SERVER_IP, &si_server.sin_addr)==0)
      {
	printf("wordlen-client: inet_pton() failed\n");
	return -1;
      }

    printf("Welcome! I am the UDP-based word length client!!\n");

    /* loop until the user enters "bye" */
    for( ; ; )
      {
	/* clear my outgoing buffer to be safe */
	bzero(mybuffer, MAX_BUFFER_SIZE);

 	printf("Enter a word to send to the server (or \"bye\" to exit): ");
	scanf("%s", mybuffer);

	if(strncmp(mybuffer, "bye", 3) == 0)
	  break;
		
	bytesout =  sendto(s, mybuffer, strlen(mybuffer), 0, server, sizeof(si_server));
	if( bytesout < 0 )
	  {
	    printf("wordlen-client: sendto() failed\n");
	    return -1;
	  }
#ifdef DEBUG
	else printf("Sent %d bytes '%s' to word length server...\n", bytesout, mybuffer);
#endif

	/* clear my incoming buffer to be safe */
	bzero(mybuffer, MAX_BUFFER_SIZE);

	bytesin = recvfrom(s, mybuffer, MAX_BUFFER_SIZE, 0, server, &len);
	if( bytesin < 0 )
	  {
	    printf("wordlen-client: recvfrom() failed!\n");
	    return -1;
	  }
#ifdef DEBUG
	else printf("Got %d bytes '%s' from word length server...\n", bytesin, mybuffer);
#endif
	mybuffer[bytesin] = '\0';    // proper null-termination of string

	printf("Answer: That word has %s letters!\n", mybuffer);
      }
    close(s);
    return 0;
  }