#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <locale.h>

#include <glib.h>

#include <g3dviewer_plugin.h>

G3DObject *obj_createobject(G3DModel *model, const char *name);
int obj_tryloadmat(G3DModel *model, const char *filename);

int plugin_load(const char *filename, G3DModel *model)
{
  FILE *f;
  char line[2048], oname[128], matname[128], matfile[1024];
  G3DObject *object = NULL;
  G3DMaterial *material = NULL;
  double x,y,z;
#if 0
  unsigned int v1,v2,v3,v4, vd;
#endif
  int num_v, v_off = 1, v_cnt = 0;

  setlocale(LC_NUMERIC, "C");

  g_return_val_if_fail(model != NULL, EXIT_FAILURE);

  f = fopen(filename, "r");
  if(f == NULL)
  {
    g_warning("can't open file '%s'", filename);
    return EXIT_FAILURE;
  }

  strncpy(matfile, filename, strlen(filename) - 3);
  matfile[strlen(filename)-3] = '\0';
  strcat(matfile, "mtl");
  obj_tryloadmat(model, matfile);

  object = obj_createobject(model, "(default)");

  while(!feof(f))
  {
    fgets(line, 2048, f);
    g_strchomp(line);
    if(strlen(line) > 0)
    {
      switch(line[0])
      {
        case '#': 
        case '\n': continue; break;
        case 'g': /* object */
          if(strlen(line) == 1)
          {
          }
          else if(sscanf(line, "g %s", oname) == 1)
          {
#if 0
            object = obj_createobject(model, oname);
            v_off += v_cnt;
            v_cnt = 1;
#endif
          }
          else g_printerr("parse error in line: %s\n", line);
          break;
        case 'v': /* vertex */
          if(strncmp(line, "vn ", 3) == 0)
          {
            /* normal ? */
          }
          else if(strncmp(line, "vt ", 3) == 0)
          {
            /* ?? */
          }
          else if(sscanf(line, "v %lf %lf %lf", &x, &y, &z) == 3)
          {
            if(object == NULL)
            {
              object = obj_createobject(model, "(noname)");
            }
            object->vertex_count++;
            object->vertices = g_realloc(object->vertices, 
              object->vertex_count * 3 * sizeof(GLfloat));
            object->vertices[v_cnt*3+0] = x;
            object->vertices[v_cnt*3+1] = y;
            object->vertices[v_cnt*3+2] = z;
            v_cnt++;
          } 
          else g_printerr("parse error in line: %s\n", line);
          break;
        case 'f': /* face */
          if(strncmp("f ", line, 2) == 0)
          {
            G3DFace *face;
            gchar **vertex, **vstrs = g_strsplit(line, " ", 0);
            int i;

            num_v = 0;
            if(object == NULL)
            {
              g_printerr("error: face before object\n");
              fclose(f);
              return EXIT_FAILURE;
            }
            face = g_new0(G3DFace, 1);
            if(material != NULL) face->material = material;
            else face->material = g_slist_nth_data(object->materials, 0);

            /* find number of vertices in line */
            vertex = vstrs;
            while(*vertex != NULL) { num_v++; vertex++; }
            face->num_vertices = num_v - 1;

			/* next one if # of vertices < 3 */
			if(face->num_vertices < 3)
				continue;

            /* read vertices */
            face->index_vertex = g_malloc((num_v-1) * sizeof(int));
            for(i=1; i<num_v; i++)
            {
              unsigned long int index = strtoul(vstrs[i], NULL, 10);

              face->index_vertex[i-1] = index - v_off;
            }
            g_strfreev(vstrs);
            object->faces = g_slist_prepend(object->faces, face);
          } 
          else g_printerr("parse error in line: %s\n", line);
          break;
        case 'u': /* usemat? */
        case 'm':
        case 's':
          if(sscanf(line, "usemtl %s", matname) == 1)
          {
            /* sets new active material from named list */
            GSList *mlist = model->materials;
            while(mlist != NULL)
            {
              G3DMaterial *mat = (G3DMaterial*)mlist->data;
              if(strcmp(matname, mat->name) == 0)
              {
                material = mat;
                break;
              }
              mlist = mlist->next;
            }
          }
          else if(sscanf(line, "mtllib %s", matfile) == 1)
          {
            /* loads external material library */
            if(obj_tryloadmat(model, matfile) != EXIT_SUCCESS)
            {
              g_printerr("error loading material library '%s'\n", matfile);
            }
          }
          break;
        default:
          g_printerr("unknown type of line: %s\n", line);
      }
    }
  }
  fclose(f);
  return EXIT_SUCCESS;
}

char *plugin_description(void)
{
  return g_strdup(
    "Import plugin for Maya .obj files\n");
}

char **plugin_extensions(void)
{
  return g_strsplit("obj", ":", 0);
}

/*****************************************************************************/

G3DObject *obj_createobject(G3DModel *model, const char *name)
{
  G3DObject *object;
  G3DMaterial *material = g3d_new_G3DMaterial();

  object = g_new0(G3DObject, 1);
  object->name = g_strdup(name);
  model->objects = g_slist_append(model->objects, object);
  object->materials = g_slist_append(object->materials, material);
  return object;
}

/*****************************************************************************/
/* material file ops                                                         */
/*****************************************************************************/

int obj_tryloadmat(G3DModel *model, const char *filename)
{
  FILE *f;
  G3DMaterial *material = NULL;

  f = fopen(filename, "r");
  if(f == NULL)
  {
#if DEBUG > 1
    g_printerr("obj_tryloadmat: loading '%s' failed: %s\n", filename, 
               strerror(errno));
#endif
    return EXIT_FAILURE;
  }
#if DEBUG > 0
  g_printerr("loading material library %s\n", filename);
#endif
  while(!feof(f))
  {
    char line[2048];
    float r,g,b, t1,t2, ni;
    int tf, ns, il;
   
    fgets(line, 2048, f);
    if(strlen(line))
    {
      char mname[128];

      if(line[0] == '#') continue;   /* comments */
      if(line[0] == '\n') continue;  /* empty lines */

      if(sscanf(line, "newmtl %s", mname) == 1)
      {
        /* new material */
        material = g3d_new_G3DMaterial();
        material->name = g_strdup(mname);
        model->materials = g_slist_append(model->materials, material);
      }
      else if(sscanf(line, " Kd %f %f %f", &r, &g, &b) == 3)
      {
        /* material color? */
        if(material != NULL)
        {
          material->r = r;
          material->g = g;
          material->b = b;
        }
      }
      else if(sscanf(line, " Ks %f %f %f", &r, &g, &b) == 3)
      {
        /* ?? */
      }
      else if(sscanf(line, " Tf %f %f %d", &t1, &t2, &tf) == 3)
      {
        /* transparency ?? */
        if(material != NULL)
        {
          if(tf == 1) material->a = 1.0 - t1;
        }
      }
      else if(sscanf(line, " Ns %d Ni %f", &ns, &ni) == 2)
      {
        /* ?? */
      }
      else if(sscanf(line, " illum %d", &il) == 1)
      {
        /* ?? */
      }
      else
      {
        g_printerr("unknown type of line: %s", line);
      }
    }
  }
  return EXIT_SUCCESS;
}