#include <stdlib.h>
#include <stdio.h>
#include <time.h>
 
FILE* world_file;
char buffer[20];
 
enum tile_type { floor , wall , robot };
enum tile_type world[50][50];
 
enum orientation { north, northeast, east, southeast, south, southwest, west, northwest};
enum orientation robot_orientation;
int x, old_x;
int y, old_y;
 
enum tile_type n,ne,e,se,s,sw,w,nw;
 
void print_world()
{
	int x, y;
	printf("N:%u NE:%u E:%u SE:%u S:%u SW:%u W:%u NW:%u\n", n, ne, e, se, s, sw, w, nw);
	for (y = 49; y >= 0; y--)
	{
		for (x = 0; x < 50; x++)
		{
			if (world[x][y] == floor)
			{
				putchar('_');
			}
			else if (world[x][y] == wall)
			{
				putchar('#');
			}
			else
			{
				putchar('!');
			}
		}
		putchar('\n');
	}
}
 
void sense()
{
	n = world[x][y + 1];
	ne = world[x + 1][y + 1];
	e = world[x + 1][y];
	se = world[x + 1][y - 1];
	s = world[x][y - 1];
	sw = world[x - 1][y - 1];
	w = world[x - 1][y];
	nw = world[x - 1][y + 1];
}
 
void plan()
{
	if (robot_orientation == north)
	{
		if (nw != wall && ne != wall && n == wall)
		{
			if (rand() % 2)				//toss a coin
			{
				robot_orientation = northwest;
			}
			else
			{
				robot_orientation = northeast;
			}
			return;
		}
		if (nw == wall && ne == wall && n != wall)
		{
			return;
		}
		if (nw == wall && ne == wall && n == wall)
		{
			if (rand() % 2 && e != wall)
			{
				robot_orientation = east;
			}
			else if (rand() % 2 && w != wall)
			{
				robot_orientation = west;
			}
			else if (rand() % 2 && se != wall)
			{
				robot_orientation = southeast;
			}
			else if (rand() % 2 && sw != wall)
			{
				robot_orientation = southwest;
			}
			else
			{
				robot_orientation = south;
			}
			return;
		}
		if (nw == wall && ne != wall)
		{
			robot_orientation = northeast;
			return;
		}
		if (ne == wall && nw != wall)
		{
			robot_orientation = northwest;
			return;
		}
	}
	else if (robot_orientation == northeast)
	{
		if (e != wall && n != wall && ne == wall)
		{
			if (rand() % 2)				//toss a coin
			{
				robot_orientation = east;
			}
			else
			{
				robot_orientation = north;
			}
			return;
		}
		if (e == wall && n == wall && ne != wall)
		{
			return;
		}
		if (e == wall && n == wall && ne == wall)
		{
			if (rand() % 2 && nw != wall)
			{
				robot_orientation = northwest;
			}
			else if (rand() % 2 && se != wall)
			{
				robot_orientation = southeast;
			}
			else if (rand() % 2 && s != wall)
			{
				robot_orientation = south;
			}
			else if (rand() % 2 && w != wall)
			{
				robot_orientation = west;
			}
			else
			{
				robot_orientation = southwest;
			}
			return;
		}
		if (n == wall && e != wall)
		{
			robot_orientation = east;
			return;
		}
		if (e == wall && n != wall)
		{
			robot_orientation = north;
			return;
		}
	}
	else if (robot_orientation == east)
	{
		if (ne != wall && se != wall && e == wall)
		{
			if (rand() % 2)				//toss a coin
			{
				robot_orientation = northeast;
			}
			else
			{
				robot_orientation = southeast;
			}
			return;
		}
		if (ne == wall && se == wall && e != wall)
		{
			return;
		}
		if (ne == wall && se == wall && e == wall)
		{
			if (rand() % 2 && n != wall)
			{
				robot_orientation = north;
			}
			else if (rand() % 2 && s != wall)
			{
				robot_orientation = south;
			}
			else if (rand() % 2 && sw != wall)
			{
				robot_orientation = southwest;
			}
			else if (rand() % 2 && nw != wall)
			{
				robot_orientation = northwest;
			}
			else
			{
				robot_orientation = west;
			}
			return;
		}
		if (ne == wall && se != wall)
		{
			robot_orientation = southeast;
			return;
		}
		if (se == wall && ne != wall)
		{
			robot_orientation = northeast;
			return;
		}
	}
	else if (robot_orientation == southeast)
	{
		if (e != wall && s != wall && se == wall)
		{
			if (rand() % 2)				//toss a coin
			{
				robot_orientation = east;
			}
			else
			{
				robot_orientation = south;
			}
			return;
		}
		if (e == wall && s == wall && se != wall)
		{
			return;
		}
		if (e == wall && s == wall && se == wall)
		{
			if (rand() % 2 && ne != wall)
			{
				robot_orientation = northeast;
			}
			else if (rand() % 2 && sw != wall)
			{
				robot_orientation = southwest;
			}
			else if (rand() % 2 && w != wall)
			{
				robot_orientation = west;
			}
			else if (rand() % 2 && n != wall)
			{
				robot_orientation = north;
			}
			else
			{
				robot_orientation = northwest;
			}
			return;
		}
		if (e == wall && s != wall)
		{
			robot_orientation = south;
			return;
		}
		if (s == wall && e != wall)
		{
			robot_orientation = east;
			return;
		}
	}
	else if (robot_orientation == south)
	{
		if (se != wall && sw != wall && s == wall)
		{
			if (rand() % 2)				//toss a coin
			{
				robot_orientation = southeast;
			}
			else
			{
				robot_orientation = southwest;
			}
			return;
		}
		if (se == wall && sw == wall && s != wall)
		{
			return;
		}
		if (se == wall && sw == wall && s == wall)
		{
			if (rand() % 2 && ne != wall)
			{
				robot_orientation = northeast;
			}
			else if (rand() % 2 && nw != wall)
			{
				robot_orientation = northwest;
			}
			else if (rand() % 2 && e != wall)
			{
				robot_orientation = east;
			}
			else if (rand() % 2 && w != wall)
			{
				robot_orientation = west;
			}
			else
			{
				robot_orientation = north;
			}
			return;
		}
		if (se == wall && sw != wall)
		{
			robot_orientation = southwest;
			return;
		}
		if (sw == wall && se != wall)
		{
			robot_orientation = southeast;
			return;
		}
	}
	else if (robot_orientation == southwest)
	{
		if (s != wall && w != wall && sw == wall)
		{
			if (rand() % 2)				//toss a coin
			{
				robot_orientation = south;
			}
			else
			{
				robot_orientation = west;
			}
			return;
		}
		if (s == wall && w == wall && sw != wall)
		{
			return;
		}
		if (s == wall && w == wall && sw == wall)
		{
			if (rand() % 2 && nw != wall)
			{
				robot_orientation = northwest;
			}
			else if (rand() % 2 && se != wall)
			{
				robot_orientation = southeast;
			}
			else if (rand() % 2 && e != wall)
			{
				robot_orientation = east;
			}
			else if (rand() % 2 && n != wall)
			{
				robot_orientation = north;
			}
			else
			{
				robot_orientation = northeast;
			}
			return;
		}
		if (s == wall && w != wall)
		{
			robot_orientation = west;
			return;
		}
		if (w == wall && s != wall)
		{
			robot_orientation = south;
			return;
		}
	}
	else if (robot_orientation == west)
	{
		if (sw != wall && nw != wall && w == wall)
		{
			if (rand() % 2)				//toss a coin
			{
				robot_orientation = southwest;
			}
			else
			{
				robot_orientation = northwest;
			}
			return;
		}
		if (sw == wall && nw == wall && w != wall)
		{
			return;
		}
		if (sw == wall && nw == wall && w == wall)
		{
			if (rand() % 2 && ne != wall)
			{
				robot_orientation = northeast;
			}
			else if (rand() % 2 && se != wall)
			{
				robot_orientation = southeast;
			}
			else if (rand() % 2 && s != wall)
			{
				robot_orientation = south;
			}
			else if (rand() % 2 && n != wall)
			{
				robot_orientation = north;
			}
			else
			{
				robot_orientation = east;
			}
			return;
		}
		if (sw == wall && nw != wall)
		{
			robot_orientation = northwest;
			return;
		}
		if (nw == wall && sw != wall)
		{
			robot_orientation = southwest;
			return;
		}
	}
	else if (robot_orientation == northwest)
	{
		if (w != wall && n != wall && nw == wall)
		{
			if (rand() % 2)				//toss a coin
			{
				robot_orientation = west;
			}
			else
			{
				robot_orientation = north;
			}
			return;
		}
		if (w == wall && n == wall && nw != wall)
		{
			return;
		}
		if (w == wall && n == wall && nw == wall)
		{
			if (rand() % 2 && ne != wall)
			{
				robot_orientation = northeast;
			}
			else if (rand() % 2 && sw != wall)
			{
				robot_orientation = southwest;
			}
			else if (rand() % 2 && s != wall)
			{
				robot_orientation = south;
			}
			else if (rand() % 2 && e != wall)
			{
				robot_orientation = east;
			}
			else
			{
				robot_orientation = southeast;
			}
			return;
		}
		if (w == wall && n != wall)
		{
			robot_orientation = north;
			return;
		}
		if (n == wall && w != wall)
		{
			robot_orientation = west;
			return;
		}
	}
}
 
void act()
{
	world[x][y] = floor;
	switch(robot_orientation)
	{
		case north:
			y = y + 1;
			break;
		case northeast:
			x = x + 1;
			y = y + 1;
			break;
		case east:
			x = x + 1;
			break;
		case southeast:
			x = x + 1;
			y = y - 1;
			break;
		case south:
			y = y - 1;
			break;
		case southwest:
			x = x - 1;
			y = y - 1;
			break;
		case west:
			x = x - 1;
			break;
		case northwest:
			x = x - 1;
			y = y + 1;
			break;
	}
	world[x][y] = robot;
}
 
int main(int argc, char ** argv)
{
	srand(time(NULL));
	if (argc < 4)
	{
		fputs("Usage: robot <world_file> <robot_x> <robot_y>\n",stderr);
		exit(1);
	}
 
	for (x = 0; x < 50; x++)
	{
		for (y = 0; y < 50; y++)
		{
			world[x][y] = floor;
		}
	}
 
	if ((world_file = fopen(argv[1], "r")) == NULL)
	{
		fputs("Can not open world file!\n",stderr);
		exit(1);
	}
	fgets(buffer,20,world_file); //get rid of comment
	while ((fgets(buffer,20,world_file)) != NULL)
	{
		sscanf(buffer,"%u %u", &x, &y);
		world[x][y] = wall;
	}
	fclose(world_file);
 
	x = atoi(argv[2]);
	y = atoi(argv[3]);
 
	if (world[x][y] != floor)
	{
		fputs("Robot position is a wall! Aborting\n",stderr);
		exit(1);
	}
	else
	{
		world[x][y] = robot;
	}
	robot_orientation = north;
 
	sense();
	print_world();
	getchar();
 
	while (1)
	{
		sense();
		plan();
		act();
		print_world();
		getchar();
	}
 
	return(0);
}