#include <u.h>
#include <libc.h>
#include <bio.h>
#include <draw.h>

#include "rushhour.h"

static char buf[1024];

static void
consumeline(Biobuf *b)
{
	while(Bgetc(b) != '\n')
		;
}

static char*
readline(Biobuf *b)
{
	char *p, *e;
	int c;

	p = buf;
	e = buf + sizeof(buf) - 1; /* -1 for final \n */
	while((c = Bgetc(b)) != '\n' )
		if (p < e)
			*(p++) = c;
	*p = '\0';
	return buf;
}

static void
setlevel(int lnum, int x, int y, int e)
{
	levels[lnum].board[x][y] = e;
	if (levels[lnum].length[e] == 0)
		levels[lnum].orient[e] = -1 - y;
	else if (levels[lnum].orient[e] < 0)
		if (levels[lnum].orient[e] == -1 -y)
			levels[lnum].orient[e] = OHoriz;
		else
			levels[lnum].orient[e] = OVert;
	levels[lnum].length[e]++;
	switch(e) {
	case CarX:
		if (levels[lnum].us == Empty)
			levels[lnum].us =  e;
		break;
	case CarY:
		if (levels[lnum].us == Empty)
			levels[lnum].us =  e;
		break;
	case CarZ:
		if (levels[lnum].us == Empty || levels[lnum].us == CarX)
			levels[lnum].us =  e;
		break;
	}
}

/* parse a level file */
int
loadlevels(char *path)
{
	Biobuf *b;
	int x, y, lnum, i;
	char c;
		
	if(path == nil)
		return -1;

	b = Bopen(path, OREAD);
	if(b == nil) {
		fprint(2, "cannot load levels: %r\n");
		return -1;
	}

	for (i=0; i < numlevels; i++)
		free(levels[i].name);
	memset(levels, 0, Maxlevels*sizeof(Level));
	
	x = Off;
	y = Off;
	lnum = 0;

	while((c = Bgetc(b)) > 0) {
		switch(c)  {
		case ';':
			consumeline(b); 
			break;
		case ':':
			levels[lnum].name = estrdup(readline(b));	/* at most one name for a level */
			break;
		case '\n':
			levels[lnum].index = lnum;
			levels[lnum].done = 0;
			x = Off;
			y++;
			levels[lnum].max.y = y;

			c = Bgetc(b);
			if(c == '\n' || c == Beof) {
				/* end of level */
				if(++lnum == Maxlevels)
					goto Done;

				x = Off;
				y = Off;
				levels[lnum].win = Pt(Off,Off);
			} else
				Bungetc(b);
			break;
		case '#':
			levels[lnum].board[x][y] = Wall;
			x++;
			break;
		case '.':
		case '@': /* used to be goal (exit); need no longer be specially marked */
			levels[lnum].board[x][y] = Empty;
			x++;
			break;
		case 'x':
			setlevel(lnum, x, y, CarX);
			x++;
			break;
		case 'y':
			setlevel(lnum, x, y, CarY);
			x++;
			break;
		case 'z':
			setlevel(lnum, x, y, CarZ);
			x++;
			break;
		case 'a':
			setlevel(lnum, x, y, CarA);
			x++;
			break;
		case 'b':
			setlevel(lnum, x, y, CarB);
			x++;
			break;
		case 'c':
			setlevel(lnum, x, y, CarC);
			x++;
			break;
		case 'd':
			setlevel(lnum, x, y, CarD);
			x++;
			break;
		case 'e':
			setlevel(lnum, x, y, CarE);
			x++;
			break;
		case 'f':
			setlevel(lnum, x, y, CarF);
			x++;
			break;
		case 'g':
			setlevel(lnum, x, y, CarG);
			x++;
			break;
		case 'h':
			setlevel(lnum, x, y, CarH);
			x++;
			break;
		case 'i':
			setlevel(lnum, x, y, CarI);
			x++;
			break;
		case 'j':
			setlevel(lnum, x, y, CarJ);
			x++;
			break;
		case 'k':
			setlevel(lnum, x, y, CarK);
			x++;
			break;
		case 'l':
			setlevel(lnum, x, y, CarL);
			x++;
			break;
		case 'm':
			setlevel(lnum, x, y, CarM);
			x++;
			break;
		case 'n':
			setlevel(lnum, x, y, CarN);
			x++;
			break;
		case 'o':
			setlevel(lnum, x, y, TruckO);
			x++;
			break;
		case 'p':
			setlevel(lnum, x, y, TruckP);
			x++;
			break;
		case 'q':
			setlevel(lnum, x, y, TruckQ);
			x++;
			break;
		case 'r':
			setlevel(lnum, x, y, TruckR);
			x++;
			break;
		case 's':
			setlevel(lnum, x, y, TruckS);
			x++;
			break;
		case 't':
			setlevel(lnum, x, y, TruckT);
			x++;
			break;
		case 'u':
			setlevel(lnum, x, y, TruckU);
			x++;
			break;
		case 'v':
			setlevel(lnum, x, y, TruckV);
			x++;
			break;
		default:
			fprint(2, "impossible character for level %d: %c\n", lnum+1, c);
			return -1;
		}
		if(x > levels[lnum].max.x)
			levels[lnum].max.x = x;
		levels[lnum].max.y = y;
	}
Done:
	Bterm(b);

	level = levels[0];
	numlevels = lnum;

	return lnum;
}