/* GLMgroup: Structure that defines a group in a model.
 */
typedef struct _GRRLIB_Group {
  char*                 name;		/* name of this group */
  u32                   numtriangles;	/* number of triangles in this group */
  u32*                  triangles;		/* array of triangle indices */
  u32                   material;           /* index to material for group */
  struct _GRRLIB_Group* next;		/* pointer to next group in model */
} GRRLIB_Group;


/* GLMmodel: Structure that defines a model.
 */
typedef struct {
  char*    pathname;			/* path to this model */
  char*    mtllibname;			/* name of the material library */

  u32   numvertices;			/* number of vertices in model */
  guVector* vertices;			/* array of vertices  */

  u32   numnormals;			/* number of normals in model */
  guVector* normals;			/* array of normals */

  u32   numtexcoords;		/* number of texcoords in model */
  guVector* texcoords;			/* array of texture coordinates */

  u32   numfacetnorms;		/* number of facetnorms in model */
  guVector* facetnorms;			/* array of facetnorms */

  u32       numtriangles;		/* number of triangles in model */
  //GLMtriangle* triangles;		/* array of triangles */

  //u32       nummaterials;		/* number of materials in model */
  //GLMmaterial* materials;		/* array of materials */

  u32       numgroups;		/* number of groups in model */
  GRRLIB_Group*    groups;			/* linked list of groups */

  //GLfloat position[3];			/* position of the model */

} GRRLIB_Model;

static void GRRLIB_FirstPass(GRRLIB_Model* model, FILE* file)
{
    u32    numvertices;		/* number of vertices in model */
    u32    numnormals;		/* number of normals in model */
    u32    numtexcoords;		/* number of texcoords in model */
    u32    numtriangles;		/* number of triangles in model */
    GRRLIB_Group* group;			/* current group */
    unsigned  v, n, t;
    char      buf[128];

    numvertices = numnormals = numtexcoords = numtriangles = 0;

    while(fscanf(file, "%s", buf) != EOF) {
        switch(buf[0]) {
            case '#':				/* comment */
                fgets(buf, sizeof(buf), file);
                break;
            case 'v':				/* v, vn, vt */
                switch(buf[1]) {
                case '\0':			/* vertex */
                    fgets(buf, sizeof(buf), file);
                    numvertices++;
                    break;
                case 'n':				/* normal */
                    fgets(buf, sizeof(buf), file);
                    numnormals++;
                break;
                case 't':				/* texcoord */
                    fgets(buf, sizeof(buf), file);
                    numtexcoords++;
                    break;
                default:
                    exit(1);
                    break;
                }
                break;
            case 'm':
                fgets(buf, sizeof(buf), file);
                sscanf(buf, "%s %s", buf, buf);
                model->mtllibname = strdup(buf);
                //_glmReadMTL(model, buf);
                break;
            case 'u':
                fgets(buf, sizeof(buf), file);
                break;
            case 'g':				/* group */
                fgets(buf, sizeof(buf), file);
                sscanf(buf, "%s", buf);
                //group = _glmAddGroup(model, buf);
                break;
            case 'f':				/* face */
                v = n = t = 0;
                fscanf(file, "%s", buf);
                /* can be one of %d, %d//%d, %d/%d, %d/%d/%d %d//%d */
                if (strstr(buf, "//")) {
                    /* v//n */
                    sscanf(buf, "%d//%d", &v, &n);
                    fscanf(file, "%d//%d", &v, &n);
                    fscanf(file, "%d//%d", &v, &n);
                    numtriangles++;
                    /*
                    group->numtriangles++;
                    while(fscanf(file, "%d//%d", &v, &n) > 0) {
                        numtriangles++;
                        group->numtriangles++;
                    }*/
                } else if (sscanf(buf, "%d/%d/%d", &v, &t, &n) == 3) {
                    /* v/t/n */
                    fscanf(file, "%d/%d/%d", &v, &t, &n);
                    fscanf(file, "%d/%d/%d", &v, &t, &n);
                    numtriangles++;
                    /*
                    group->numtriangles++;
                    while(fscanf(file, "%d/%d/%d", &v, &t, &n) > 0) {
                        numtriangles++;
                        group->numtriangles++;
                    }*/
                } else if (sscanf(buf, "%d/%d", &v, &t) == 2) {
                    /* v/t */
                    fscanf(file, "%d/%d", &v, &t);
                    fscanf(file, "%d/%d", &v, &t);
                    numtriangles++;
                    /*
                    group->numtriangles++;
                    while(fscanf(file, "%d/%d", &v, &t) > 0) {
                        numtriangles++;
                        group->numtriangles++;
                    }*/
                } else {
                    /* v */
                    fscanf(file, "%d", &v);
                    fscanf(file, "%d", &v);
                    numtriangles++;
                    /*
                    group->numtriangles++;
                    while(fscanf(file, "%d", &v) > 0) {
                        numtriangles++;
                        group->numtriangles++;
                    }*/
                }
                break;
            default:
                fgets(buf, sizeof(buf), file);
                break;
        }
    }

    model->numvertices  = numvertices;
    model->numnormals   = numnormals;
    model->numtexcoords = numtexcoords;
    model->numtriangles = numtriangles;

}

GRRLIB_Model* GRRLIB_ReadOBJ(char* filename)
{
    GRRLIB_Model* model;
    FILE*     file;

    file = fopen(filename, "r");
    if (!file) {
        exit(1);
    }

    model = (GRRLIB_Model*)malloc(sizeof(GRRLIB_Model));
    model->pathname      = strdup(filename);
    model->mtllibname    = NULL;
    model->numvertices   = 0;
    model->vertices      = NULL;
    model->numnormals    = 0;
    model->normals       = NULL;
    model->numtexcoords  = 0;
    model->texcoords     = NULL;
    model->numfacetnorms = 0;
    model->facetnorms    = NULL;
    model->numtriangles  = 0;

    // Get a count of the number of stuff
    GRRLIB_FirstPass(model, file);

    // allocate memory
    model->vertices = (guVector*)malloc(sizeof(guVector) * 3 * (model->numvertices + 1));
    //model->triangles = (GLMtriangle*)malloc(sizeof(GLMtriangle) * model->numtriangles);
    if (model->numnormals) {
        model->normals = (guVector*)malloc(sizeof(guVector) * 3 * (model->numnormals + 1));
    }
    if (model->numtexcoords) {
        model->texcoords = (guVector*)malloc(sizeof(guVector) * 2 * (model->numtexcoords + 1));
    }





    fclose(file);

    return model;
}