/*
 * hiq.c -- Solution for HiQ code test "Simulator for radio controlled cars."
 *
 * Copyright (C) 2018 Andreas Forsgren <andreas@sparcy.net>
 * All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#define	VERSION	1

static char *prgpath, *prgname;

static void usage(FILE *output, int help)
{
	fprintf(output, "usage: %s -h | <width> <height> <x> <y> <heading> "
	    "[command...] | -v\n", prgpath);
	if (help) {
		fprintf(output, "usage: %s 8 6 2 3 north          # 8x6 "
		    "room & pos. 2,3 & face north\n", prgpath);
		fprintf(output, "usage: %s 8 6 2 3 n fffrfflbb    # same & "
		    "move/rot. f*3>r>f*2>l>b*2\n", prgpath);
		fprintf(output, "usage: %s -v                     # display "
		    "version\n", prgpath);
	}
}

static void version(void)
{
	printf("%d\n", VERSION);
}

int main(int argc, char *argv[])
{
	int width, height, x, y;
	char head, *cmd = "";

	prgpath = argv[0];
	prgname = strrchr(prgpath, '/');
	if (prgname != NULL)
		prgname++;
	else
		prgname = prgpath;

	if (argc == 2) {
		if (strcmp(argv[1], "-h") == 0)
			usage(stdout, 1);
		else if (strcmp(argv[1], "-v") == 0)
			version();
		else {
			fprintf(stderr, "%s: unknown argument '%s'\n", prgname,
			    argv[1]);

			return 1;
		}

		return 0;
	} else if (argc == 6 || argc == 7) {
		width = atoi(argv[1]);
		if (width < 1) {
			fprintf(stderr, "%s: width must be >= 1\n", prgname);

			return 1;
		}
		height = atoi(argv[2]);
		if (height < 1) {
			fprintf(stderr, "%s: height must be >= 1\n", prgname);

			return 1;
		}
		x = atoi(argv[3]);
		if (x < 1 || x > width) {
			fprintf(stderr, "%s: x must be >= 1 and <= width\n",
			    prgname);

			return 1;
		}
		y = atoi(argv[4]);
		if (y < 1 || y > height) {
			fprintf(stderr, "%s: y must be >= 1 and <= height\n",
			    prgname);

			return 1;
		}
		head = *argv[5];
		/* Just grabbing the 1st character is a nice feature as the
		   user can specify e.g. north and it will work as expected. */
		if (head != 'n' && head != 's' && head != 'w' && head != 'e') {
			fprintf(stderr, "%s: invalid heading %c\n", prgname,
			    head);

			return 1;
		}
		if (argc == 7)
			cmd = argv[6];
	} else {
		usage(stderr, 0);

		return 1;
	}

	do {
#ifdef DEBUG
		fprintf(stderr, "%s: debug: width=%d height=%d x=%d y=%d "
		    "head=%c cmd='%c'\n", prgname, width, height, x, y, head,
		    *cmd);
#endif
		switch (*cmd) {
		    case '\0':
			break;
		    case 'f':
		    case 'b':
			switch (head) {
			    case 'n': if (*cmd == 'f') y++; else y--; break;
			    case 's': if (*cmd == 'f') y--; else y++; break;
			    case 'w': if (*cmd == 'f') x--; else x++; break;
			    case 'e': if (*cmd == 'f') x++; else x--; break;
			}

			break;
		    case 'l':
		    case 'r':
			switch (head) {
			    case 'n': head = (*cmd == 'l') ? 'w' : 'e'; break;
			    case 's': head = (*cmd == 'l') ? 'e' : 'w'; break;
			    case 'w': head = (*cmd == 'l') ? 's' : 'n'; break;
			    case 'e': head = (*cmd == 'l') ? 'n' : 's'; break;
			}

			break;
		    default:
			fprintf(stderr, "%s: unknown command '%c'\n", prgname,
			    *cmd);

			return 1;
		}
		if (x < 1 || x > width || y < 1 || y > height) {
			fprintf(stderr, "%s: invalid position x=%d y=%d "
			    "reached when heading %c and last command '%c' "
			    "(\"wall hit\")\n", prgname, x, y, head, *cmd);

			return 1;
		}
	} while (*cmd++ != '\0');
	printf("%d %d %c\n", x, y, head);

	return 0;
}