// client.c -- open an internet socket and talk into it.

/*  Derived from isockt.c (C) 1991 Blair P. Houghton, All Rights Reserved,
 copying and distribution permitted with copyright intact.
 Modified in 1993 to remove pre-ANSI code by Michael J. Fischer
 Modified 2010 to improve style and clarity by Michael J. Fischer and Alice E. Fischer
 */

#include "tools.h"

// Shorter names for system structures
typedef struct sockaddr_in  sockInfo;
typedef struct sockaddr     sockUnion;
typedef struct hostent      hostInfo;

// -----------------------------------------------------------------------------
// Data to send to remote server
const char* const line[] = { "Politeness, by Alan Alexander Milne\n",
		"When people ask me,", "I always tell them:",
		"\"Quite well, thank you, I'm very glad to say.\"",
		"If people ask me,", "I always answer,",
		"\"Quite well, thank you, how are you to-day?\"", "I always answer,",
		"I always tell them,", "If they ask me", "Politely.....",
		"BUT SOMETIMES\n", "I wish\n", "That they wouldn't.\n" };
const int nLines = sizeof line / sizeof line[0];

// -----------------------------------------------------------------------------
// Prototypes
void openConnection(const char* host, int port, FILE** remoteInP,
		FILE** remoteOutP);

// -----------------------------------------------------------------------------
// arg 1 is remote host; arg 2 is port number of listener on remote host
int main(int argc, char *argv[]) {
	char buf[BUFSIZ + 1];
	int k, nBytes, status;
	char* ret;
	FILE* remoteIn;
	FILE* remoteOut;

	// collect command line arguments
	const char* prog = argv[0];
	if (argc != 3)
		fatal("usage: %s hostname portno\n", prog);
	const char* hostName = argv[1];
	int port = atoi(argv[2]);

	// open socket connection
	openConnection(hostName, port, &remoteIn, &remoteOut);

	// wait for server to acknowledge the connection.
	ret = fgets(buf, BUFSIZ, remoteIn);
	if (!ret)
		fatalp("%s: Error while reading from socket.", prog);
	printf("%s", buf);

	// write lines of text, one per second, until message is complete.
	for (k = 0; k < nLines; k++) {
		sleep(1);
		printf("Writing to socket: %s\n", line[k]);
		nBytes = fprintf(remoteOut, "%s\n", line[k]);
		if (nBytes <= 0)
			fatalp("%s: Error while writing to socket.", prog);
		fflush(remoteOut); // force line to go out
	}

	// Close socket streams
	status = fclose(remoteIn);
	if (status)
		fatalp("Error closing input stream on socket");
	status = fclose(remoteOut);
	if (status)
		fatalp("Error closing output stream on socket");
	exit(0);
}

// -----------------------------------------------------------------------------
// Opens a connection to given host and port.
// Returns open streams for reading and writing to the connection.
// Both streams should be closed when done with the connection.
// All errors result in an error message followed by termination.
void openConnection(const char* hostName, int port, FILE** remoteInP,
		FILE** remoteOutP) {
	int status;

	// Make a net socket, using stream mode, with protocol irrelevant ( == 0 )
	int sockFd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockFd < 0)
		fatalp("Can't to create socket");

	// get host IP address
	hostInfo* remoteHost = gethostbyname(hostName);
	if (remoteHost == NULL)
		fatalp("unknown host: %s\n", hostName);

	// create an address structure for the peer socket
	sockInfo peer;
	peer.sin_family = AF_INET;
	memmove(&peer.sin_addr, remoteHost->h_addr_list[0], remoteHost->h_length);
	peer.sin_port = htons(port);

	// connect local socket to its peer
	status = connect(sockFd, (sockUnion*) &peer, sizeof peer);
	if (status < 0)
		fatalp("connection to %s refused.", hostName);

	// create buffered input and output streams on the new socket
	// we use dup() so that each stream has its own file descriptor
	*remoteOutP = fdopen(sockFd, "w");
	if (!*remoteOutP)
		fatalp("Can't create output stream");
	int sockFd2 = dup(sockFd);
	if (sockFd2 < 0)
		fatalp("Can't duplicate socket file descriptor");
	*remoteInP = fdopen(dup(sockFd), "r");
	if (!*remoteOutP)
		fatalp("Can't create input stream");
}