/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/


/* clusteredges.c:
 * Written by Emden R. Gansner
 *
 * Code for handling spline edges around clusters.
 */

/* uses PRIVATE interface */
#define FDP_PRIVATE 1

#include "config.h"
#include <assert.h>
#include <fdpgen/clusteredges.h>
#include <fdpgen/fdp.h>
#include <limits.h>
#include <neatogen/neatoprocs.h>
#include <pathplan/vispath.h>
#include <pack/pack.h>
#include <stdbool.h>
#include <util/alloc.h>
#include <util/list.h>

typedef LIST(Ppoly_t *) objlist_t;

#if defined(DEBUG) && DEBUG > 1
static void dumpObj(Ppoly_t * p)
{
    Ppoint_t pt;
    for (size_t j = 0; j < p->pn; j++) {
	pt = p->ps[j];
	fprintf(stderr, " %.5g %.5g", pt.x, pt.y);
    }
    fputs("\n", stderr);
}

static void dumpObjlist(const objlist_t *l) {
    for (size_t i = 0; i < LIST_SIZE(l); i++) {
	dumpObj(LIST_GET(l, i));
    }
}
#endif

/* makeClustObs:
 * Create an obstacle corresponding to a cluster's bbox.
 */
static Ppoly_t *makeClustObs(graph_t * g, expand_t* pm)
{
    Ppoly_t *obs = gv_alloc(sizeof(Ppoly_t));
    boxf bb;
    boxf newbb;
    Ppoint_t ctr;

    bb = GD_bb(g);
    obs->pn = 4;
    obs->ps = gv_calloc(4, sizeof(Ppoint_t));

    ctr.x = (bb.UR.x + bb.LL.x) / 2.0;
    ctr.y = (bb.UR.y + bb.LL.y) / 2.0;

    if (pm->doAdd) {
	newbb.UR.x = bb.UR.x + pm->x;
	newbb.UR.y = bb.UR.y + pm->y;
	newbb.LL.x = bb.LL.x - pm->x;
	newbb.LL.y = bb.LL.y - pm->y;
    }
    else {
	double deltax = pm->x - 1.0;
	double deltay = pm->y - 1.0;
	newbb.UR.x = pm->x * bb.UR.x - deltax * ctr.x;
	newbb.UR.y = pm->y * bb.UR.y - deltay * ctr.y;
	newbb.LL.x = pm->x * bb.LL.x - deltax * ctr.x;
	newbb.LL.y = pm->y * bb.LL.y - deltay * ctr.y;
    }

    /* CW order */
    obs->ps[0].x = newbb.LL.x;
    obs->ps[0].y = newbb.LL.y;
    obs->ps[1].x = newbb.LL.x;
    obs->ps[1].y = newbb.UR.y;
    obs->ps[2].x = newbb.UR.x;
    obs->ps[2].y = newbb.UR.y;
    obs->ps[3].x = newbb.UR.x;
    obs->ps[3].y = newbb.LL.y;

    return obs;
}

/* addGraphObjs:
 * Add all top-level clusters and nodes with g as their smallest
 * containing graph to the list l.
 * Don't add any objects equal to tex or hex.
 * Return the list.
 */
static void
addGraphObjs(objlist_t *l, graph_t *g, void *tex, void *hex, expand_t *pm) {
    node_t *n;
    graph_t *sg;
    int i;

    for (n = agfstnode(g); n; n = agnxtnode(g, n)) {
	if (PARENT(n) == g && n != tex && n != hex && !IS_CLUST_NODE(n)) {
	    LIST_APPEND(l, makeObstacle(n, pm, false));
	}
    }
    for (i = 1; i <= GD_n_cluster(g); i++) {
	sg = GD_clust(g)[i];
	if (sg != tex && sg != hex) {
	    LIST_APPEND(l, makeClustObs(sg, pm));
	}
    }
}

/* raiseLevel:
 * Add barrier objects for node n, in graph *gp of level maxlvl, up to
 * level minlvl. 
 * Assume maxlvl > minlvl.
 * Return appended list, plus pass back last cluster processed in gp.
 */
static void
raiseLevel(objlist_t *l, int maxlvl, void *ex, int minlvl, graph_t **gp,
	   expand_t* pm)
{
    graph_t *g = *gp;
    int i;

    for (i = maxlvl; i > minlvl; i--) {
	addGraphObjs(l, g, ex, NULL, pm);
	ex = g;
	g = GPARENT(g);
    }
    *gp = ex;
}

/* objectList:
 * Create array of all objects (nodes and clusters) to be avoided
 * when routing edge e. Make sure it never adds the endpoints of the
 * edge, or any graph containing the endpoints.
 * Return the list.
 * Assume e is not a loop.
 */
static objlist_t objectList(edge_t *ep, expand_t *pm) {
    node_t *h = aghead(ep);
    node_t *t = agtail(ep);
    graph_t *hg = PARENT(h);
    graph_t *tg = PARENT(t);
    int hlevel;
    int tlevel;
    void *hex;			/* Objects to be excluded from list */
    void *tex;
    objlist_t list = {0};

    /* If either endpoint is a cluster node, we move up one level */
    if (IS_CLUST_NODE(h)) {
	hex = hg;
	hg = GPARENT(hg);
    } else
	hex = h;
    if (IS_CLUST_NODE(t)) {
	tex = tg;
	tg = GPARENT(tg);
    } else
	tex = t;

    hlevel = LEVEL(hg);
    tlevel = LEVEL(tg);
    if (hlevel > tlevel) {
	raiseLevel(&list, hlevel, hex, tlevel, &hg, pm);
	hex = hg;
	hg = GPARENT(hg);
    } else if (tlevel > hlevel) {
	raiseLevel(&list, tlevel, tex, hlevel, &tg, pm);
	tex = tg;
	tg = GPARENT(tg);
    }

    /* hg and tg always have the same level */
    while (hg != tg) {
	addGraphObjs(&list, hg, NULL, hex, pm);
	addGraphObjs(&list, tg, tex, NULL, pm);
	hex = hg;
	hg = GPARENT(hg);
	tex = tg;
	tg = GPARENT(tg);
    }
    addGraphObjs(&list, tg, tex, hex, pm);

    return list;
}

/* compoundEdges:
 * Construct edges as splines, avoiding clusters when required.
 * We still don't implement spline multiedges, so we just copy
 * one spline to all the other edges.
 * Returns 0 on success. Failure indicates the obstacle configuration
 * for some edge had overlaps.
 */
int compoundEdges(graph_t * g, expand_t* pm, int edgetype)
{
    (void)edgetype;

    node_t *n;
    node_t *head;
    edge_t *e;
    edge_t *e0;
    vconfig_t *vconfig = NULL;
    int rv = 0;

    for (n = agfstnode(g); n; n = agnxtnode(g, n)) {
	for (e = agfstout(g, n); e; e = agnxtout(g, e)) {
	    head = aghead(e);
	    if (n == head && ED_count(e)) {	/* self arc */
		makeSelfArcs(e, GD_nodesep(g));
	    } else if (ED_count(e)) {
		objlist_t objl = objectList(e, pm);
		assert(LIST_SIZE(&objl) <= INT_MAX);
		LIST_SYNC(&objl);
		if (Plegal_arrangement(LIST_FRONT(&objl), (int)LIST_SIZE(&objl))) {
		    vconfig = Pobsopen(LIST_FRONT(&objl), (int)LIST_SIZE(&objl));
		    if (!vconfig) {
			agwarningf("compoundEdges: could not construct obstacles - falling back to straight line edges\n");
			rv = 1;
			LIST_FREE(&objl);
			continue;
		    }
		}
		else {
		    if (rv == 0) {
			expand_t margin = sepFactor(g);
			int pack = getPack (g, CL_OFFSET, CL_OFFSET); 
			agwarningf("compoundEdges: nodes touch - falling back to straight line edges\n");
			if (pack <= pm->x || pack <= pm->y)
			    agerr(AGPREV, "pack value %d is smaller than esep (%.03f,%.03f)\n", pack, pm->x, pm->y);
			else if (margin.x <= pm->x || margin.y <= pm->y)
			    agerr(AGPREV, "sep value (%.03f,%.03f) is smaller than esep (%.03f,%.03f)\n",  
				margin.x, margin.y, pm->x, pm->y);
			rv = 1;
		    }
		    LIST_FREE(&objl);
		    continue;
		}

		/* For efficiency, it should be possible to copy the spline
		 * from the first edge to the rest. However, one has to deal
		 * with change in direction, different arrowheads, labels, etc.
		 */
		for (e0 = e; e0; e0 = ED_to_virt(e0)) {
		    ED_path(e0) = getPath(e0, vconfig, false);
		    assert(LIST_SIZE(&objl) <= INT_MAX);
		    LIST_SYNC(&objl);
		    makeSpline(e0, LIST_FRONT(&objl), (int)LIST_SIZE(&objl), false);
		}
		LIST_FREE(&objl);
	    }
	}
    }
    if (vconfig != NULL) {
	Pobsclose(vconfig);
    }
    return rv;
}
