/*  ADMesh -- process triangulated solid meshes
 *  Copyright (C) 1995, 1996  Anthony D. Martin <amartin@engr.csulb.edu>
 *  Copyright (C) 2013, 2014  several contributors, see AUTHORS
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.

 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.

 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *  Questions, comments, suggestions, etc to
 *           https://github.com/admesh/admesh/issues
 */

#include <stdlib.h>
#include <string.h>

#include "stl.h"

void
stl_invalidate_shared_vertices(stl_file *stl) {
  if (stl->error) return;

  if (stl->v_indices != NULL) {
    free(stl->v_indices);
    stl->v_indices = NULL;
  }
  if (stl->v_shared != NULL) {
    free(stl->v_shared);
    stl->v_shared = NULL;
  }
}

void
stl_generate_shared_vertices(stl_file *stl) {
  int i;
  int j;
  int first_facet;
  int direction;
  int facet_num;
  int vnot;
  int next_edge;
  int pivot_vertex;
  int next_facet;
  int reversed;

  if (stl->error) return;

  /* make sure this function is idempotent and does not leak memory */
  stl_invalidate_shared_vertices(stl);

  stl->v_indices = (v_indices_struct*)
                   calloc(stl->stats.number_of_facets, sizeof(v_indices_struct));
  if(stl->v_indices == NULL) perror("stl_generate_shared_vertices");
  stl->v_shared = (stl_vertex*)
                  calloc((stl->stats.number_of_facets / 2), sizeof(stl_vertex));
  if(stl->v_shared == NULL) perror("stl_generate_shared_vertices");
  stl->stats.shared_malloced = stl->stats.number_of_facets / 2;
  stl->stats.shared_vertices = 0;

  for(i = 0; i < stl->stats.number_of_facets; i++) {
    stl->v_indices[i].vertex[0] = -1;
    stl->v_indices[i].vertex[1] = -1;
    stl->v_indices[i].vertex[2] = -1;
  }


  for(i = 0; i < stl->stats.number_of_facets; i++) {
    first_facet = i;
    for(j = 0; j < 3; j++) {
      if(stl->v_indices[i].vertex[j] != -1) {
        continue;
      }
      if(stl->stats.shared_vertices == stl->stats.shared_malloced) {
        stl->stats.shared_malloced += 1024;
        stl->v_shared = (stl_vertex*)realloc(stl->v_shared,
                                             stl->stats.shared_malloced * sizeof(stl_vertex));
        if(stl->v_shared == NULL) perror("stl_generate_shared_vertices");
      }

      stl->v_shared[stl->stats.shared_vertices] =
        stl->facet_start[i].vertex[j];

      direction = 0;
      reversed = 0;
      facet_num = i;
      vnot = (j + 2) % 3;

      for(;;) {
        if(vnot > 2) {
          if(direction == 0) {
            pivot_vertex = (vnot + 2) % 3;
            next_edge = pivot_vertex;
            direction = 1;
          } else {
            pivot_vertex = (vnot + 1) % 3;
            next_edge = vnot % 3;
            direction = 0;
          }
        } else {
          if(direction == 0) {
            pivot_vertex = (vnot + 1) % 3;
            next_edge = vnot;
          } else {
            pivot_vertex = (vnot + 2) % 3;
            next_edge = pivot_vertex;
          }
        }
        stl->v_indices[facet_num].vertex[pivot_vertex] =
          stl->stats.shared_vertices;

        next_facet = stl->neighbors_start[facet_num].neighbor[next_edge];
        if(next_facet == -1) {
          if(reversed) {
            break;
          } else {
            direction = 1;
            vnot = (j + 1) % 3;
            reversed = 1;
            facet_num = first_facet;
          }
        } else if(next_facet != first_facet) {
          vnot = stl->neighbors_start[facet_num].
                 which_vertex_not[next_edge];
          facet_num = next_facet;
        } else {
          break;
        }
      }
      stl->stats.shared_vertices += 1;
    }
  }
}

void
stl_write_off(stl_file *stl, char *file) {
  int i;
  FILE      *fp;
  char      *error_msg;

  if (stl->error) return;

  /* Open the file */
  fp = fopen(file, "w");
  if(fp == NULL) {
    error_msg = (char*)
                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
            file);
    perror(error_msg);
    free(error_msg);
    stl->error = 1;
    return;
  }

  fprintf(fp, "OFF\n");
  fprintf(fp, "%d %d 0\n",
          stl->stats.shared_vertices, stl->stats.number_of_facets);

  for(i = 0; i < stl->stats.shared_vertices; i++) {
    fprintf(fp, "\t%f %f %f\n",
            stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
  }
  for(i = 0; i < stl->stats.number_of_facets; i++) {
    fprintf(fp, "\t3 %d %d %d\n", stl->v_indices[i].vertex[0],
            stl->v_indices[i].vertex[1], stl->v_indices[i].vertex[2]);
  }
  fclose(fp);
}

void
stl_write_vrml(stl_file *stl, char *file) {
  int i;
  FILE      *fp;
  char      *error_msg;

  if (stl->error) return;

  /* Open the file */
  fp = fopen(file, "w");
  if(fp == NULL) {
    error_msg = (char*)
                malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing",
            file);
    perror(error_msg);
    free(error_msg);
    stl->error = 1;
    return;
  }

  fprintf(fp, "#VRML V1.0 ascii\n\n");
  fprintf(fp, "Separator {\n");
  fprintf(fp, "\tDEF STLShape ShapeHints {\n");
  fprintf(fp, "\t\tvertexOrdering COUNTERCLOCKWISE\n");
  fprintf(fp, "\t\tfaceType CONVEX\n");
  fprintf(fp, "\t\tshapeType SOLID\n");
  fprintf(fp, "\t\tcreaseAngle 0.0\n");
  fprintf(fp, "\t}\n");
  fprintf(fp, "\tDEF STLModel Separator {\n");
  fprintf(fp, "\t\tDEF STLColor Material {\n");
  fprintf(fp, "\t\t\temissiveColor 0.700000 0.700000 0.000000\n");
  fprintf(fp, "\t\t}\n");
  fprintf(fp, "\t\tDEF STLVertices Coordinate3 {\n");
  fprintf(fp, "\t\t\tpoint [\n");

  for(i = 0; i < (stl->stats.shared_vertices - 1); i++) {
    fprintf(fp, "\t\t\t\t%f %f %f,\n",
            stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
  }
  fprintf(fp, "\t\t\t\t%f %f %f]\n",
          stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
  fprintf(fp, "\t\t}\n");
  fprintf(fp, "\t\tDEF STLTriangles IndexedFaceSet {\n");
  fprintf(fp, "\t\t\tcoordIndex [\n");

  for(i = 0; i < (stl->stats.number_of_facets - 1); i++) {
    fprintf(fp, "\t\t\t\t%d, %d, %d, -1,\n", stl->v_indices[i].vertex[0],
            stl->v_indices[i].vertex[1], stl->v_indices[i].vertex[2]);
  }
  fprintf(fp, "\t\t\t\t%d, %d, %d, -1]\n", stl->v_indices[i].vertex[0],
          stl->v_indices[i].vertex[1], stl->v_indices[i].vertex[2]);
  fprintf(fp, "\t\t}\n");
  fprintf(fp, "\t}\n");
  fprintf(fp, "}\n");
  fclose(fp);
}

void stl_write_obj (stl_file *stl, char *file) {
  int i;
  FILE* fp;

  if (stl->error) return;

  /* Open the file */
  fp = fopen(file, "w");
  if (fp == NULL) {
    char* error_msg = (char*)malloc(81 + strlen(file)); /* Allow 80 chars+file size for message */
    sprintf(error_msg, "stl_write_ascii: Couldn't open %s for writing", file);
    perror(error_msg);
    free(error_msg);
    stl->error = 1;
    return;
  }

  for (i = 0; i < stl->stats.shared_vertices; i++) {
    fprintf(fp, "v %f %f %f\n", stl->v_shared[i].x, stl->v_shared[i].y, stl->v_shared[i].z);
  }
  for (i = 0; i < stl->stats.number_of_facets; i++) {
    fprintf(fp, "f %d %d %d\n", stl->v_indices[i].vertex[0]+1, stl->v_indices[i].vertex[1]+1, stl->v_indices[i].vertex[2]+1);
  }

  fclose(fp);
}