/*
    This software may only be used by you under license from AT&T Corp.
    ("AT&T").  A copy of AT&T's Source Code Agreement is available at
    AT&T's Internet website having the URL:
    <http://www.research.att.com/sw/tools/graphviz/license/source.html>
    If you received this software without first entering into a license
    with AT&T, you have an infringing copy of this software and cannot use
    it without violating AT&T's intellectual property rights.
*/
#pragma prototyped

/* classify edges for mincross/nodepos/splines, using given ranks */

#include "dot.h"


void class2(graph_t* g)
{
	int		c;
	node_t	*n,*t,*h;
	edge_t	*e,*prev,*opp;

	GD_nlist(g) = NULL;

	GD_n_nodes(g) = 0;	/* new */

	mark_clusters(g);
	for (c = 1; c <= GD_n_cluster(g); c++)
		build_skeleton(g,GD_clust(g)[c]);
	for (n = agfstnode(g); n; n = agnxtnode(g,n))
		for (e = agfstout(g,n); e; e = agnxtout(g,e)) {
			if (ND_weight_class(e->head) <= 2) ND_weight_class(e->head)++;
			if (ND_weight_class(e->tail) <= 2) ND_weight_class(e->tail)++;
	}

	for (n = agfstnode(g); n; n = agnxtnode(g,n)) {
		if ((ND_clust(n) == NULL) && (n == UF_find(n))) {fast_node(g,n); GD_n_nodes(g)++;}
		prev = NULL;
		for (e = agfstout(g,n); e; e = agnxtout(g,e)) {

				/* already processed */
			if (ED_to_virt(e)) continue;

				/* edges involving sub-clusters of g */
			if (is_cluster_edge(e)) {
				/* following is new cluster multi-edge code */
				if (mergeable(prev,e)) {
					if (ED_to_virt(prev)) { 
						merge_chain(g,e,ED_to_virt(prev),FALSE);
						other_edge(e);
					}
					else if (ND_rank(e->tail) == ND_rank(e->head)) {
						merge_oneway(e,prev);
						other_edge(e);
					}
					/* else is an intra-cluster edge */
					continue;
				}
				interclrep(g,e);
				prev = e;
				continue;
			}
				/* merge multi-edges */
			if (prev && (e->tail == prev->tail) && (e->head == prev->head)) {
				if (ND_rank(e->tail) == ND_rank(e->head)) {
					merge_oneway(e,prev);
					other_edge(e);
					continue;
				}
				if ((ED_label(e) == NULL) && (ED_label(prev) == NULL) && ports_eq(e,prev)) {
					if (Concentrate) 
						ED_edge_type(e) = IGNORED;
					else{
					merge_chain(g,e,ED_to_virt(prev),TRUE);
					other_edge(e);
					}
					continue;
				}
				/* parallel edges with different labels fall through here */
			}

				/* self edges */
			if (e->tail == e->head) {
				other_edge(e);
				prev = e;
				continue;
			}

			t = UF_find(e->tail);
			h = UF_find(e->head);

				/* non-leader leaf nodes */
			if ((e->tail != t) || (e->head != h)) {
					/* ### need to merge stuff */
				continue;	
			}


				/* flat edges */
			if (ND_rank(e->tail) == ND_rank(e->head)) {
				flat_edge(g,e);
				prev = e;
				continue;
			}

				/* forward edges */
			if (ND_rank(e->head) > ND_rank(e->tail)) {
				make_chain(g,e->tail,e->head,e);
				prev = e;
				continue;
			}

				/* backward edges */
			else {
				/*other_edge(e);*/
				    /* avoid when opp==e in undirected graph */
				if ((opp = agfindedge(g,e->head,e->tail))&&(opp!=e)) {
					/* shadows a forward edge */
					if (ED_to_virt(opp) == NULL)
						make_chain(g,opp->tail,opp->head,opp);
					if ((ED_label(e) == NULL) && (ED_label(opp) == NULL) && ports_eq(e,opp)) {
						if (Concentrate) {
							ED_edge_type(e) = IGNORED;
							ED_conc_opp_flag(opp) = TRUE;
						}
						else{	/* see above.  this is getting out of hand */
						other_edge(e);
						merge_chain(g,e,ED_to_virt(opp),TRUE);
						}
						continue;
					}
				}
				make_chain(g,e->head,e->tail,e);
				prev = e;
			}
		}
	}
	/* since decompose() is not called on subgraphs */
	if (g != g->root) {
		GD_comp(g).list = ALLOC(1,GD_comp(g).list,node_t*);
		GD_comp(g).list[0] = GD_nlist(g);
	}
}

node_t	*
label_vnode(graph_t* g, edge_t* orig)
{
	node_t		*v;
	pointf		dimen;

	dimen = ED_label(orig)->dimen;
	v = virtual_node(g);
	ND_label(v) = ED_label(orig);
	ND_lw_i(v) = GD_nodesep(v->graph);
	if (!ED_label_ontop(orig)) {
		if (GD_left_to_right(g)) {
			ND_ht_i(v) = POINTS(dimen.x); ND_rw_i(v) = POINTS(dimen.y);
		}
		else {
			ND_ht_i(v) = POINTS(dimen.y); ND_rw_i(v) = POINTS(dimen.x);
		}
	}
	return v;
}

node_t	*
plain_vnode(graph_t* g, edge_t* orig)
{
	node_t		*v;
	orig = orig;
	v = virtual_node(g);
	incr_width(g,v);
	return v;
}

void incr_width(graph_t* g, node_t* v)
{
	int width = GD_nodesep(g) / 2;
	ND_lw_i(v) += width;
	ND_rw_i(v) += width;
}

void make_chain(graph_t *g, node_t *from, node_t *to, edge_t *orig)
{
	int		r,label_rank;
	node_t	*u,*v;
	edge_t	*e;

	u = from;
	if (ED_label(orig)) label_rank = (ND_rank(from) + ND_rank(to)) / 2;
	else label_rank = -1;
	assert(ED_to_virt(orig) == NULL);
	for (r = ND_rank(from) + 1; r <= ND_rank(to); r++) {
		if (r < ND_rank(to)) {
			if (r == label_rank) v = label_vnode(g,orig);
			else v = plain_vnode(g,orig);
			ND_rank(v) = r;
		}
		else v = to;
		e = virtual_edge(u,v,orig);
		virtual_weight(e);
		u = v;
	}
	assert(ED_to_virt(orig) != NULL);
}

void merge_chain(graph_t *g, edge_t	*e, edge_t *f, int flag)
{
	edge_t		*rep;
	int			lastrank = MAX(ND_rank(e->tail),ND_rank(e->head));

	assert(ED_to_virt(e) == NULL);
	ED_to_virt(e) = f;
	rep = f;
	do {
			/* interclust multi-edges are not counted now */
		if (flag) ED_count(rep) += ED_count(e);
		ED_xpenalty(rep) += ED_xpenalty(e);
		ED_weight(rep) += ED_weight(e);
		if (ND_rank(rep->head) == lastrank) break;
		incr_width(g,rep->head);
		rep = ND_out(rep->head).list[0];
	} while (rep);
}

node_t	*
leader_of(graph_t* g, node_t* v)
{
	graph_t	*clust;
	node_t	*rv;

	if (ND_ranktype(v) != CLUSTER) {
		/*assert(v == UF_find(v));  could be leaf, so comment out */
		rv = UF_find(v);
	}
	else {
		clust = ND_clust(v);
		rv = GD_rankleader(clust)[ND_rank(v)];
	}
	return rv;
}

void interclrep(graph_t* g, edge_t* e)
{
	node_t		*t,*h;
	edge_t		*ve;

	t = leader_of(g,e->tail);
	h = leader_of(g,e->head);
	if (ND_rank(t) > ND_rank(h)) {node_t *t0 = t; t = h; h = t0;}
	if (ND_clust(t) != ND_clust(h)) {
		if ((ve = find_fast_edge(t,h))) {
			merge_chain(g,e,ve,TRUE);
			return;
		}
		if (ND_rank(t) == ND_rank(h)) return;
		make_chain(g,t,h,e);

		/* mark as cluster edge */
		for (ve = ED_to_virt(e); ve && (ND_rank(ve->head) <= ND_rank(h));
			ve = ND_out(ve->head).list[0]) ED_edge_type(ve) = CLUSTER_EDGE;
	}
	/* else ignore intra-cluster edges at this point */
}

int is_cluster_edge(edge_t* e)
{
	return ((ND_ranktype(e->tail)==CLUSTER) || (ND_ranktype(e->head)==CLUSTER));
}

int mergeable(edge_t *e, edge_t *f)
{
	if (e && f && (e->tail == f->tail) && (e->head == f->head) &&
		(ED_label(e) == ED_label(f)) && ports_eq(e,f))
			return TRUE;
	return FALSE;
}