/*
    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

/*
 *	build edge_t concentrators for parallel edges with a common endpoint
 */

#include	"dot.h"


#define		UP		0
#define		DOWN	1

static boolean
samedir(edge_t *e,edge_t *f)
{
	edge_t	*e0,*f0;

	for (e0 = e; ED_edge_type(e0) != NORMAL; e0 = ED_to_orig(e0));
	for (f0 = f; ED_edge_type(f0) != NORMAL; f0 = ED_to_orig(f0));
	if (ED_conc_opp_flag(e0)) return FALSE;
	if (ED_conc_opp_flag(f0)) return FALSE;
	return ((ND_rank(f0->tail) - ND_rank(f0->head))
		*(ND_rank(e0->tail) - ND_rank(e0->head)) > 0);
}

boolean
downcandidate(node_t* v)
{
	return ((ND_node_type(v) == VIRTUAL) && (ND_in(v).size == 1) && (ND_out(v).size == 1) &&(ND_label(v) == NULL));
}

boolean
bothdowncandidates(node_t *u, node_t *v)
{
	edge_t	*e,*f;
	e = ND_in(u).list[0];
	f = ND_in(v).list[0];
	if (downcandidate(v) && (e->tail == f->tail)) {
		return samedir(e,f) && (portcmp(ED_tail_port(e),ED_tail_port(f))==0);
	}
	return FALSE;
}

boolean
upcandidate(node_t* v)
{
	return ((ND_node_type(v) == VIRTUAL) && (ND_out(v).size == 1) && (ND_in(v).size == 1) && (ND_label(v) == NULL));
}

boolean
bothupcandidates(node_t *u, node_t *v)
{
	edge_t	*e,*f;
	e = ND_out(u).list[0];
	f = ND_out(v).list[0];
	if (upcandidate(v) && (e->head == f->head)) {
		return samedir(e,f) && (portcmp(ED_head_port(e),ED_head_port(f))==0);
	}
	return FALSE;
}

void mergevirtual(graph_t *g, int r, int lpos, int rpos, int dir)
{
	int		i,k;
	node_t	*left,*right;
	edge_t	*e,*f,*e0;

	left = GD_rank(g)[r].v[lpos];
	/* merge all right nodes into the leftmost one */
	for (i = lpos + 1; i <= rpos; i++) {
		right = GD_rank(g)[r].v[i];
		if (dir == DOWN) {
			while ((e = ND_out(right).list[0])) {
				for (k = 0; (f = ND_out(left).list[k]); k++)
					if (f->head == e->head) break;
				if (f == NULL) f = virtual_edge(left,e->head,e);
				while ((e0 = ND_in(right).list[0])) {
					merge_oneway(e0,f);
					/*ED_weight(f) += ED_weight(e0);*/
					delete_fast_edge(e0);
				}
				delete_fast_edge(e);
			}
		}
		else {
			while ((e = ND_in(right).list[0])) {
				for (k = 0; (f = ND_in(left).list[k]); k++)
					if (f->tail == e->tail) break;
				if (f == NULL) f = virtual_edge(e->tail,left,e);
				while ((e0 = ND_out(right).list[0])) {
					merge_oneway(e0,f);
					delete_fast_edge(e0);
				}
				delete_fast_edge(e);
			}
		}
		assert(ND_in(right).size + ND_out(right).size == 0);
		delete_fast_node(g,right);
	}
	k = lpos + 1;
	i = rpos + 1;
	while (i < GD_rank(g)[r].n) {
		node_t	*n;
		n = GD_rank(g)[r].v[k] = GD_rank(g)[r].v[i];
		ND_order(n) = k;
		k++; i++;
	}
	GD_rank(g)[r].n = k;
	GD_rank(g)[r].v[k] = NULL;
}

void dot_concentrate(graph_t* g)
{
	int		c,r,leftpos,rightpos;
	node_t	*left,*right;

	if (GD_maxrank(g) - GD_minrank(g) <= 1) return;
	/* this is the downward looking pass. r is a candidate rank. */
	for (r = 1; GD_rank(g)[r+1].n; r++) {
		for (leftpos = 0; leftpos < GD_rank(g)[r].n; leftpos++) {
			left = GD_rank(g)[r].v[leftpos];
			if (downcandidate(left) == FALSE) continue;
			for (rightpos = leftpos + 1; rightpos < GD_rank(g)[r].n; rightpos++) {
				right = GD_rank(g)[r].v[rightpos];
				if (bothdowncandidates(left,right) == FALSE) break;
			}
			if (rightpos - leftpos > 1)
				mergevirtual(g,r,leftpos,rightpos-1,DOWN);
		}
	}
	/* this is the corresponding upward pass */
	while (r > 0) {
		for (leftpos = 0; leftpos < GD_rank(g)[r].n; leftpos++) {
			left = GD_rank(g)[r].v[leftpos];
			if (upcandidate(left) == FALSE) continue;
			for (rightpos = leftpos + 1; rightpos < GD_rank(g)[r].n; rightpos++) {
				right = GD_rank(g)[r].v[rightpos];
				if (bothupcandidates(left,right) == FALSE) break;
			}
			if (rightpos - leftpos > 1)
				mergevirtual(g,r,leftpos,rightpos-1,UP);
		}
		r--;
	}
	for (c = 1; c <= GD_n_cluster(g); c++)
		rebuild_vlists(GD_clust(g)[c]);
}

void infuse(graph_t* g, node_t* n)
{
	node_t	*lead;

	lead = GD_rankleader(g)[ND_rank(n)];
	if ((lead == NULL) || (ND_order(lead) > ND_order(n)))
		GD_rankleader(g)[ND_rank(n)] = n;
}

void rebuild_vlists(graph_t* g)
{
	int		c,i,r,maxi;
	node_t	*n,*lead;
	edge_t	*e,*rep;

	for (r = GD_minrank(g); r <= GD_maxrank(g); r++)
		GD_rankleader(g)[r] = NULL;

	for (n = agfstnode(g); n; n = agnxtnode(g,n)) {
		infuse(g,n);
		for (e = agfstout(g,n); e; e = agnxtout(g,e)) {
			for (rep = e; ED_to_virt(rep); rep = ED_to_virt(rep));
			while (ND_rank(rep->head) < ND_rank(e->head)) {
				infuse(g,rep->head);
				rep = ND_out(rep->head).list[0];
			}
		}
	}

	for (r = GD_minrank(g); r <= GD_maxrank(g); r++) {
		lead = GD_rankleader(g)[r];
		if(ND_rank(g->root)[r].v[ND_order(lead)] != lead)
			abort();
		GD_rank(g)[r].v = ND_rank(g->root)[r].v + GD_rankleader(g)[r]->u.order;
		maxi = -1;
		for (i = 0; i < GD_rank(g)[r].n; i++) {
			if ((n = GD_rank(g)[r].v[i]) == NULL) break;
			if (ND_node_type(n) == NORMAL) {
				if (agcontains(g,n)) maxi = i;
				else break;
			}
			else {
				edge_t	*e;
				for (e = ND_in(n).list[0]; e && ED_to_orig(e); e = ED_to_orig(e));
				if (e && (agcontains(g,e->tail)) && agcontains(g,e->head))
					maxi = i;
			}
		}
		if (maxi == -1)
			agerr(AGWARN, "degenerate concentrated rank %s,%d\n",g->name,r);
		GD_rank(g)[r].n = maxi + 1;
	}

	for (c = 1; c <= GD_n_cluster(g); c++)
		rebuild_vlists(GD_clust(g)[c]);
}