#ifndef toposlice_hedge_H
#define toposlice_hedge_H

/* Copyright (C) 2023 Jorge Stolfi, UNICAMP */
/* Last edited on 2023-10-04 08:16:07 by stolfi */

#include <bool.h>
#include <r3.h>
#include <vec.h>


struct hedge_face_t *left;  /* face on left side. */
    struct hedge_vert_t *org;   /* Origin vertex. */
    double bend;                /* Modifies the direction at endpoints. */
    The {bend} attribute is used when drawing the structure. 

typedef struct toposlice_hedge_face_t
  { struct hedge_arc_t *side;   /* One {arc_t} on the perimeter. */
    r3_t ctr;                   /* Nominal center, for plotting. */
    bool_t show;                /* True to draw the record. */
    int32_t id;                 /* Sequential number. */
  } toposlice_hedge_face_t;
  /* A record of the half-edge structure representing a face of the mesh.
    The {ctr} and {show} attributes are used when drawing the structure. */
    
vec_typedef(toposlice_hedge_face_vec_t, toposlice_hedge_face_vec, toposlice_hedge_face_t*);
  /* A vector of pointers to {Vace_t} records. */

typedef struct hedge_arc_t 
  { struct hedge_arc_t *twin;   /* Same edge in opposite orientation. */
    struct hedge_arc_t *next;   /* Next edge around left face. */
    struct hedge_face_t *left;  /* face on left side. */
    struct hedge_vert_t *org;   /* Origin vertex. */
    double bend;                /* Modifies the direction at endpoints. */
    int32_t id;                 /* Sequential number. */
  } hedge_arc_t;
  /* A record of the half-edge structure representing a directed edge of the mesh.
    The {bow} attribute is used when drawing the structure. */
  
vec_typedef(toposlice_hedge_arc_vec_t, toposlice_hedge_arc_vec, hedge_arc_t*);
  /* A vector of pointers to {hedge_arc_t} records.  The twin of an arc {a[i]}
    is {a[i^1]}. */
  
typedef struct toposlice_hedge_vert_t
  { struct hedge_arc_t *out;    /* One arc out the vertex. */
    r3_t pos;             /* Nominal position. */
    bool_t show;          /* True to draw the record. */
    int32_t id;                 /* Sequential number. */
  } toposlice_hedge_vert_t;
  /* A record of the half-edge structure representing a vertex of the mesh.
    The {pos} and {show} attributes are used when drawing the structure. */
  
vec_typedef(toposlice_hedge_vert_vec_t, toposlice_hedge_vert_vec, toposlice_hedge_vert_t*);
  /* A vector of pointers to {vert_t} records. */

typedef struct toposlice_hedge_t 
  { int32_t nv; toposlice_hedge_vert_vec_t V;  /* The vertices are V.e[0..nv-1]. */
    int32_t na; toposlice_hedge_arc_vec_t A;   /* The arcs are A.e[0..na-1]. */
    int32_t nf; toposlice_hedge_face_vec_t F;  /* The faces are F.e[0..nf-1]. */
  } toposlice_hedge_t;
  /* A half-edge structure. */
  
toposlice_hedge_t *toposlice_hedge_new(int32_t nf_alloc, int32_t ne_alloc, int32_t nv_alloc);
  /* Creates a new half-edge structure, with tables initially allocatde for the give
    number of faces, edges, and vertices. */

toposlice_hedge_face_t *toposlice_hedge_add_face(toposlice_hedge_t *H, double X, double Y, double Z, bool_t show);
  /* Adds to {H} a new face record {f} to the end of {H.F}, expanding it if needed.
    
    The nominal centroid {f.pos} is set to {(X,Y,Z)}, and {f.show} is set to {show}.
    The pointer {f.side} is set to {NULL}. */

toposlice_hedge_vert_t *toposlice_hedge_add_vert(toposlice_hedge_t *H, double X, double Y, double Z, bool_t show);
  /* Adds to {H} a new vertex record {v} to the end of {H.V}, expanding it if needed.
    
    The position {v.pos} is set to {(X,Y,Z)}, and {v.show} is set to {show}.
    The pointer {v.out} is set to {NULL}. */

hedge_arc_t *toposlice_hedge_add_edge
  ( toposlice_hedge_t *H,
    toposlice_hedge_vert_t *org,
    toposlice_hedge_vert_t *dst,
    toposlice_hedge_face_t *left,
    toposlice_hedge_face_t *right,
    double bend
  );
  /* Adds to {H} an edge, consisting of two {arc_t} records {a,b}, each
    the {twin} of the other, respectively from {org} to {dst} (with left
    face {left}) and from {dst} to {org} (with left face {right}). The
    arcs are added at the end of {H.A}, expanding it if needed. Returns
    the arc {a}.
    
    The pointers {org.out} and {left.side} are set to {a} while
    {dst.out} and {right.side are set to {b}. The {next} pointers of
    the two arcs are set to {NULL}; they should be eventually defined by
    the client with {hedge_set_next} below. */

void hedge_set_next(hedge_arc_t *a,hedge_arc_t *b);
  /* Sets the pointer {a.next} (which must be {NULL}) to point to {b}.  The two 
    must have the same non-{NULL} {left} face link, and that face record must
    have a non-null {side} link. */
 
void hedge_check_topology(hedge_t *H);
  /* Topological consistency checks. */

#endif