#include <sys/types.h>          /* See NOTES */
#include <sys/socket.h>
#include <netinet/ip.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>

//Creating a simple server: Four main things:
//
//1. Create a socket with socket()
//
//2. Bind an address to the socket() (assign a port number)
//
//3. Set socket to listening mode with listen()
//   (This activates the socket, and others can try to connect.)
//
//4. Accept incoming connections with accept()


int main( int argc, char* argv[] ){

	if ( argc != 2 ){
		printf("Usage: ./server (port number)\n");
		return 0;
	}
	int portNum = atoi( argv[1] );

	//Step 1: Create a socket
	int sockFD = socket( AF_INET, SOCK_STREAM, 0 );
	if( sockFD == -1 ){
		perror("Could not create socket");
		return -1;
	}

	//Step 2: Bind port number to socket
	struct sockaddr_in address;
	//Initializes address structure to zero
	memset( &address, 0, sizeof( struct sockaddr_in ) );
	address.sin_family = AF_INET;
	address.sin_port = htons( portNum );
	address.sin_addr.s_addr = htonl(INADDR_ANY);

	int retVal = bind( sockFD,
			   (struct sockaddr*) &address,
			   sizeof(struct sockaddr_in));
	if( retVal == -1 ){
		perror("Could not bind socket");
		return -1;
	}

	//Step 3: Set the port to listening mode
	retVal = listen( sockFD, 5 );
	if( retVal == -1 ){
		perror("Could not listen to socket");
		return -1;
	}

	//Step 4: Accept incoming client connections
	int clientFD = accept( sockFD, NULL, 0 );
	if( clientFD == -1 ){
		perror("Could not accept connection");
		return -1;
	}

	//Now we're at the point where we can read or write
	//from/to the clientFD

	char buffer[ 1024 ];
	//memset( buffer, 0, 1024 );
	for( int i = 0; i < 256; i++ ){
		buffer[i] = i;
	}

	int bytesRead = read( clientFD, buffer, 1024 );
	buffer[bytesRead] = '\0';

	printf("I got '%s' from the client socket.\n", buffer );

	FILE* sockStream = fdopen( clientFD, "r+");

	fgets( buffer, 1024, sockStream );

	printf("The I got '%s' from the client afterwards.\n", buffer );

	return  0;
}