#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include <sys/socket.h>
#include <sys/types.h> // BSD compatible
#include <arpa/inet.h>
#include <unistd.h>

#include <errno.h>
#include <netdb.h>

#define SERVER "::1"
#define PORT 49000

#define COMMAND_BUFFER 256

char* printable(char *str) {
	char *ret = strdup(str);

	for (int i = strlen(ret); i >= 0; i--) {
		if (ret[i] == '\r' || ret[i] == '\n') {
			ret[i] = '\0';
		}
	}

	return ret;
}

void sendCommand(int sock, char *cmd) {
	char bytesToSend[COMMAND_BUFFER];
	memset(bytesToSend, 0, COMMAND_BUFFER);

	strcpy(&bytesToSend[0], "CMND");
	strcpy(&bytesToSend[5], cmd);

	int numBytesSend = send(sock, bytesToSend, 5 + strlen(cmd), 0);
	if (numBytesSend >= 0) {
		//printf("Send %d bytes to %s:%d: %s\n", numBytesSend, SERVER, PORT, printable(bytesToSend));
	} else {
		fprintf(stderr, "Failed to send message to %s:%d (%d): %s", SERVER, PORT, errno, strerror(errno));
		exit(EXIT_FAILURE);
	}
}

int main(int argc, char *argv[]) {
	int xplaneSocket;
	struct sockaddr_in6 xplaneAddress;

	int err;

	// check argument
	if (argc != 2 || (strcmp(argv[1], "up") != 0 && strcmp(argv[1], "down") != 0)) {
		fprintf(stderr, "Usage: %s <up|down>\n", argv[0]);
		exit(EXIT_FAILURE);
	}

	// create socket
	xplaneSocket = socket(AF_INET6, SOCK_DGRAM, 0);
	if (xplaneSocket == -1) {
		fprintf(stderr, "Error creating socket (%d): %s\n", errno, strerror(errno));
		exit(EXIT_FAILURE);
	}

	// prepare address struct
	xplaneAddress.sin6_family = AF_INET6;
	xplaneAddress.sin6_port = htons(PORT);
	inet_pton(AF_INET6, SERVER, &xplaneAddress.sin6_addr.s6_addr);

	// connect to xplane
	err = connect(xplaneSocket, (struct sockaddr *)&xplaneAddress, sizeof(xplaneAddress));
	if (err) {
		fprintf(stderr, "Error connecting %s:%d (%d): %s\n", SERVER, PORT, err, gai_strerror(err));
		exit(EXIT_FAILURE);
	}

	// send payload
	if (strcmp(argv[1], "up") == 0) {
		sendCommand(xplaneSocket, "sim/autopilot/heading_up");
	} else if (strcmp(argv[1], "down") == 0) {
		sendCommand(xplaneSocket, "sim/autopilot/heading_down");
	} else {
		exit(EXIT_FAILURE);
	}

	// bye bye (and no, I don't care about error anymore; I'll exit anyway?!)
	close(xplaneSocket);
	exit(EXIT_SUCCESS);
}