/*
 * area-poly2d.c - Area fill (using libpoly2d)
 *
 * Written 2012, 2015 by Werner Almesberger
 * Copyright 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 <stdio.h>
#include <math.h>

#include "poly2d.h"

#include "path.h"
#include "area.h"


static void fill_path(const struct path *paths, double z, double overlap,
    struct path ***res)
{
	const struct path *path;
	double r_tool = 0;
	struct p2d *polys;
	struct p2d *fill;

	for (path = paths; path; path = path->next)
		if (path->first && path->first->z == z)
			r_tool = path->r_tool;

	polys = paths_to_polys_z(paths, z, z);

	fill = p2d_area(polys, r_tool, 2*r_tool-overlap);
	p2d_free_all(polys);

	**res = polys_to_paths(fill, r_tool, z);
	while (**res)
		*res = &(**res)->next;
	p2d_free_all(fill);
}


struct path *area(const struct path *paths, double overlap)
{
	double z = HUGE_VAL, best_z;
	const struct path *path;
	struct path *res = NULL, **last = &res;
	unsigned n = 0, bad = 0;

	for (path = paths; path; path = path->next) {
		bad += !path_is_closed(path);
		n++;
	}
	if (bad) {
		fprintf(stderr, "%u/%u open paths\n", bad, n);
		exit(1);
	}
	while (1) {
		best_z = -HUGE_VAL;
		for (path = paths; path; path = path->next) {
			if (path->first->z >= z)
				continue;
			if (best_z >= path->first->z)
				continue;
			best_z = path->first->z;
		}
		if (best_z == -HUGE_VAL)
			break;
		fill_path(paths, best_z, overlap, &last);
		z = best_z;
	}
	return res;
}