/*
 * connect.c - Connect paths
 *
 * Written 2010-2012, 2015 by Werner Almesberger
 * Copyright 2010-2012, 2015 Werner Almesberger
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */


#include <stdlib.h>
#include <math.h>

#include "util.h"
#include "path.h"


static void path_reverse_inplace(struct path *path)
{
	struct point *points = NULL, *p, *next;

	path->last = path->first;
	for (p = path->first; p; p = next) {
		next = p->next;
		p->next = points;
		points = p;
	}
	path->first = points;
}


static int attr_eq(const struct path *a, const struct path *b)
{
	return a->r_tool == b->r_tool && a->outside == b->outside &&
	    a->notch == b->notch;
}


struct path *path_connect(struct path *path)
{
	struct path **a, **b;
	struct path *tmp;

again:
	for (a = &path; *a; a = &(*a)->next)
		for (b = &(*a)->next; *b; b = &(*b)->next) {
			if (!attr_eq(*a, *b))
				continue;
			if (points_eq((*a)->last, (*b)->last))
				path_reverse_inplace(*b);
			if (points_eq((*a)->last, (*b)->first)) {
				(*a)->last->next = (*b)->first->next;
				(*a)->last = (*b)->last;
				free((*b)->first);
				tmp = *b;
				*b = tmp->next;
				free(tmp);
				goto again;
			}
			if (points_eq((*a)->first, (*b)->first))
				path_reverse_inplace(*b);
			if (points_eq((*a)->first, (*b)->last)) {
				(*b)->last->next = (*a)->first->next;
				(*b)->last = (*a)->last;
				free((*a)->first);
				tmp = *a;
				*a = tmp->next;
				free(tmp);
				goto again;
			}
		}
	return path;
}