/*
    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
#include <aghdr.h>

#ifdef DMALLOC
#include "dmalloc.h"
#endif

/*
 * provides "compound nodes" on top of base Libgraph.
 * a compound node behaves as both an ordinary node and a subgraph.
 * there are additional primitives to "hide" and "expose" its contents.
 *
 * you could think of these as hypergraphs, but there is an assymetry
 * in the operations we have chosen.  i.e. nodes "own" their edges,
 * but nodes and interior edges are "owned by" the hyperedges.
 * also the subgraphs are nested, etc.   the bottom line is that graphs
 * and hypergraphs are just sets, everything else here is convenience
 * and maintaining consistency.
 *
 * this package adds a primitive "agsplice" to move endpoints of edges.
 * this could be useful in other situations.
 */

static char	Descriptor_id[] = "AG_cmpnd";

typedef struct Agcmpnode_s {
	Agrec_t		hdr;
	Agraph_t	*subg;
	int			collapsed;
} Agcmpnode_t;

typedef struct Agcmpgraph_s {
	Agrec_t		hdr;
	Agnode_t	*node;		/* its associated node */
	Dict_t		*hidden_node_set;
} Agcmpgraph_t;

typedef struct save_e_s {
	Agnode_t	*from,*to;
} save_e_t;

typedef struct save_stack_s  {
	save_e_t	*mem;
	int			stacksize;
} save_stack_t;

typedef struct Agcmpedge_s {
	Agrec_t		hdr;
	save_stack_t stack[2];	/* IN and OUT save stacks */
} Agcmpedge_t ;
#define IN_STACK 0
#define OUT_STACK 1

static save_stack_t *save_stack_of(Agedge_t *e, Agnode_t *node_being_saved)
{
	int			i;
	Agcmpedge_t	*edgerec;
	edgerec = (Agcmpedge_t*)agbindrec(e,Descriptor_id,sizeof(*edgerec),FALSE);
	if (node_being_saved == AGHEAD(e)) i = IN_STACK;
	else i = OUT_STACK;
	return &(edgerec->stack[i]);
}

static void stackpush(save_stack_t *stk, Agnode_t *from, Agnode_t *to)
{
	int		i, osize, nsize;

	osize = (stk->stacksize) * sizeof(stk->mem);
	i = stk->stacksize++;
	nsize = (stk->stacksize) * sizeof(stk->mem);
	stk->mem = agrealloc(agraphof(from),stk->mem,osize,nsize);
	stk->mem[i].from = from;
	stk->mem[i].to = to;
}

static save_e_t stacktop(save_stack_t *stk)
{
	save_e_t	rv;
	if (stk->stacksize > 0)
		rv = stk->mem[stk->stacksize - 1];
	else
		rv.from = rv.to = NILnode;
	return rv;
}

/* note: doesn't give back mem, but stackpush() eventually does */
static save_e_t stackpop(save_stack_t *stk)
{
	save_e_t	rv;
	rv = stacktop(stk);
	if (stk->stacksize > 0) stk->stacksize--;
	return  rv;
}

typedef struct Agsplice_arg_s {
	int			head_side;
	Agnode_t	*target;
} Agsplice_arg_t ;

/* perform a splice operation on an individual edge */
static void splice(Agobj_t *obj, void *arg)
{
	Agraph_t	*g;
	Agedge_t	*e,*opp;
	Agnode_t	*target,*t,*h;
	Agedge_t	**dict_of_del, **dict_of_ins, **dict_of_relabel;
	Agsplice_arg_t *spl;

	e = (Agedge_t*)obj;
	g = agraphof(e);
	t = AGTAIL(e);
	h = AGHEAD(e);
	opp = AGOPP(e);
	spl = arg;
	target = spl->target;

	/* set e to variant side, opp to invariant */
	if ((e->node == h) != spl->head_side) {
		Agedge_t *t = e; e = opp; opp = t;
	}

	if (spl->head_side) {
		dict_of_relabel =  &(t->out);
		dict_of_del =  &(h->in);
		dict_of_ins =  &(target->in);
	}
	else {
		dict_of_relabel =  &(h->in);
		dict_of_del =  &(t->out);
		dict_of_ins =  &(target->out);
	}

	agdeledgeimage(g,dict_of_del,opp);
	agdeledgeimage(g,dict_of_relabel,e);
	e->node = target;
	aginsedgeimage(g,dict_of_ins,opp);
	aginsedgeimage(g,dict_of_relabel,e);
}

int agsplice(Agedge_t *e, Agnode_t *target)
{
	Agnode_t	*t,*h;
	Agraph_t	*g,*root;
	Agsplice_arg_t splice_arg;


	if ((e == NILedge) || (e->node == target)) return FAILURE;
	g = agraphof(e);
	t = AGTAIL(e);
	h = AGHEAD(e);
	splice_arg.head_side = (e->node == h);
	splice_arg.target = target;
	root = agroot(g);
	agapply(root,(Agobj_t*)e,splice,&splice_arg,TRUE);
	return SUCCESS;
}

Agnode_t *agcmpnode(Agraph_t *g, char *name)
{
	Agnode_t	*n;
	Agraph_t	*subg;
	n = agnode(g,name,TRUE);
	subg = agsubg(g,name);
	if (n && g && agassociate(n,subg)) return n;
	else return NILnode;
}

int agassociate(Agnode_t *n, Agraph_t *sub)
{
	Agcmpnode_t		*noderec;
	Agcmpgraph_t	*graphrec;

	if (agsubnode(sub,n,FALSE)) return FAILURE;	/* avoid cycles */
	noderec = agbindrec(n,Descriptor_id,sizeof(*noderec),FALSE);
	graphrec = agbindrec(sub,Descriptor_id,sizeof(*graphrec),FALSE);
	if (noderec->subg || graphrec->node) return FAILURE;
	noderec->subg = sub; graphrec->node = n;
	return SUCCESS;
}

/* a utility function for aghide */
static void delete_outside_subg(Agraph_t *g, Agnode_t *node, Agraph_t *subg)
{
	Agraph_t	*s, **subglist;
	Agnode_t	*n;
	Agcmpgraph_t *graphrec;
	Dict_t		*d;

	if ((g != subg) && (n = agsubnode(g,(Agnode_t*)node,FALSE))) {
		dtdelete(g->n_dict,n);

		graphrec = agbindrec(g,Descriptor_id,sizeof(*graphrec),FALSE);
		if ((d = graphrec->hidden_node_set) == NIL(Dict_t*)) {
			/* use name disc. to permit search for hidden node by name */
			d = graphrec->hidden_node_set
				= agdtopen(g,&Ag_node_name_disc,Dttree);
		}
		dtinsert(d,n);

		subglist = agsubglist(g);
		while ((s = *subglist++)) delete_outside_subg(s,node,subg);
	}
}
/*
 *  when we hide a compound node (make it opaque)
 *	1. hide its nodes (option)
 *	2. hide the associated subgraph (option)
 *	3. remap edges to internal nodes (option)
 */
int aghide(Agnode_t *cmpnode)
{
	Agcmpnode_t		*noderec;
	Agraph_t		*g,*subg,*root;
	Agnode_t		*n,*nn,*rootn;
	Agedge_t		*e,*opp,*f;

	g = agraphof(cmpnode);
	/* skip operation if node is not compound, or hidden */
	if (agcmpgraph_of(cmpnode) == NILgraph) return FAILURE;
	noderec = (Agcmpnode_t*)aggetrec(cmpnode,Descriptor_id,FALSE);

	subg = noderec->subg; root = agroot(g);

	/* make sure caller hasn't put a node "inside itself" */
	if ((n = agsubnode(subg,cmpnode,FALSE))) agdelnode(n);

	/* remap edges by splicing and saving previous endpt */
	for (n = agfstnode(subg); n; n = agnxtnode(n)) {
		rootn = agsubnode(root,n,FALSE);
		for (e = agfstedge(rootn); e; e = f) {
			f = agnxtedge(e,rootn);
			if (agsubedge(subg,e,FALSE)) continue;	/* an internal edge */
			opp = AGOPP(e);
			stackpush(save_stack_of(e,rootn),rootn,cmpnode);
			agsplice(opp,cmpnode);
		}
	}

	/* hide nodes by deleting from the parent set.  what if they also
	   belong to a sibling subg?  weird. possible bug. */
	for (n = agfstnode(subg); n; n = nn) {
		nn = agnxtnode(n);
		delete_outside_subg(root,n,subg);
	}

	/* hide subgraph is easy */
	agdelsubg(agparent(subg),subg);

	noderec->collapsed = TRUE;
	g->desc.has_cmpnd = TRUE;
	return SUCCESS;
}

/* utility function for agexpose */
static void insert_outside_subg(Agraph_t *g, Agnode_t *node, Agraph_t *subg)
{
	Agraph_t	*s, **subglist;
	Agnode_t	*n;
	Agcmpgraph_t *graphrec;

	if ((g != subg) && ((n = agsubnode(g,(Agnode_t*)node,FALSE)) == NILnode)) {
		graphrec = (Agcmpgraph_t*) aggetrec(g,Descriptor_id,FALSE);
		if (graphrec && ((n = (Agnode_t*)dtsearch(graphrec->hidden_node_set,node))))
			dtinsert(g->n_dict,n);

		subglist = agsubglist(g);
		while ((s = *subglist++)) delete_outside_subg(s,node,subg);
	}
}

int agexpose(Agnode_t *cmpnode)
{
	Agcmpnode_t		*noderec;
	Agcmpedge_t		*edgerec;
	Agraph_t		*g,*subg,*root;
	Agnode_t		*n,*rootcmp;
	Agedge_t		*e,*f;
	save_stack_t	*stk;
	save_e_t		sav;
	int				i;

	g = agraphof(cmpnode);

	/* skip if this is not a collapsed subgraph */
	noderec = (Agcmpnode_t*)aggetrec(cmpnode,Descriptor_id,FALSE);
	if ((noderec == NIL(Agcmpnode_t*) || NOT(noderec->collapsed)))
		return FAILURE;

	/* undo aghide (above) in reverse order.  first, expose subgraph */
	subg = noderec->subg;
	agsubgrec_insert(agsubgrec(agparent(subg)),subg);

	/* re-insert nodes */
	for (n = agfstnode(subg); n; n = agnxtnode(n))
		insert_outside_subg(g,n,subg);

	/* re-splice the affected edges */
	root = agroot(g); rootcmp = agsubnode(root,cmpnode,FALSE);
	for (e = agfstedge(rootcmp); e; e = f) {
		f = agnxtedge(e,rootcmp);
		if ((edgerec = (Agcmpedge_t*)aggetrec(e,Descriptor_id,FALSE))) {
			/* anything interesting on either stack? */
			for (i = 0; i < 2; i++) {
				stk = &(edgerec->stack[i]);
				sav = stacktop(stk);
				if (sav.to && (AGID(sav.to) == AGID(cmpnode))) {
					if (e->node != sav.to) e = AGOPP(e);
					agsplice(e,sav.from);
					stackpop(stk);
					continue;
				}
			}
		}
	}
	noderec->collapsed = FALSE;
	return SUCCESS;
}

Agraph_t *agcmpgraph_of(Agnode_t *n) 
{
	Agcmpnode_t		*noderec;
	noderec = (Agcmpnode_t*) aggetrec(n,Descriptor_id,FALSE);
	if (noderec && NOT(noderec->collapsed)) return noderec->subg;
	else return NILgraph;
}

Agnode_t *agcmpnode_of(Agraph_t *g)
{
	Agcmpgraph_t	*graphrec;
	graphrec = (Agcmpgraph_t*) aggetrec(g,Descriptor_id,FALSE);
	if (graphrec) return graphrec->node; else return NILnode;
}

Agnode_t *agfindhidden(Agraph_t *g, char *name)
{
	Agcmpgraph_t	*graphrec;
	Agnode_t		key;

	graphrec = (Agcmpgraph_t*) aggetrec(g,Descriptor_id,FALSE);
	if (graphrec) {
		key.name = name;
		return (Agnode_t*) dtsearch(graphrec->hidden_node_set,&key);
	}
	else return NILnode;
}