/*
 Źródło: https://www.geeksforgeeks.org/tcp-server-client-implementation-in-c/
 $ gcc serwer_0.c -o serwer_0
 
*/
 
#include <stdio.h> 
#include <netdb.h> 
#include <netinet/in.h> 
#include <stdlib.h> 
#include <string.h> 
#include <sys/socket.h> 
#include <sys/types.h> 
#include <ctype.h>
 
// #include <fcntl.h>
#include <unistd.h>
 
#define MAX 80 
#define PORT 8081 
#define SA struct sockaddr 
 
// Function designed for chat between client and server. 
void func(int sockfd) 
{ 
	char buff[MAX]; 
	int n; 
	// infinite loop for chat 
	for (;;) { 
		bzero(buff, MAX); 
 
		// read the message from client and copy it in buffer 
		read(sockfd, buff, sizeof(buff));
		
		// print buffer which contains the client contents 
		int i = 0;
   
		while(buff[i]) {
			buff[i] = toupper(buff[i]);
			i++;
		}

		printf("From client: %s\t To client : ", buff); 
		//bzero(buff, MAX); 
		//n = 0; 
		// copy server message in the buffer 
		//while ((buff[n++] = getchar()) != '\n') 
		//	; 
 
		// and send that buffer to client 
		write(sockfd, buff, sizeof(buff)); 
 
		// if msg contains "Exit" then server exit and chat ended. 
		if (strncmp("EXIT", buff, 4) == 0) { 
			printf("Server Exit...\n"); 
			break; 
		} 
	} 
} 
 
// Driver function 
int main() 
{ 
	int sockfd, connfd, len; 
	struct sockaddr_in servaddr, cli; 
 
	// socket create and verification 
	sockfd = socket(AF_INET, SOCK_STREAM, 0); 
	if (sockfd == -1) { 
		printf("socket creation failed...\n"); 
		exit(0); 
	} 
	else
		printf("Socket successfully created..\n"); 
	bzero(&servaddr, sizeof(servaddr)); 
 
	// assign IP, PORT 
	servaddr.sin_family = AF_INET; 
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY); 
	servaddr.sin_port = htons(PORT);
 
	// Binding newly created socket to given IP and verification 
	if ((bind(sockfd, (SA*)&servaddr, sizeof(servaddr))) != 0) { 
		printf("socket bind failed...\n"); 
		exit(0); 
	} 
	else
		printf("Socket successfully binded..\n"); 
 
	// Now server is ready to listen and verification 
	if ((listen(sockfd, 5)) != 0) { 
		printf("Listen failed...\n"); 
		exit(0); 
	} 
	else
		printf("Server listening..\n"); 
	len = sizeof(cli); 
 
	// Accept the data packet from client and verification 
	connfd = accept(sockfd, (SA*)&cli, &len); 
	if (connfd < 0) { 
		printf("server acccept failed...\n"); 
		exit(0); 
	} 
	else
		printf("server acccept the client...\n"); 
 
	// Function for chatting between client and server 
	func(connfd); 
 
	// After chatting close the socket 
	close(sockfd); 
}