#include "include/object.h"

#include "include/math.h"
#include <math.h>
#include <assimp/cimport.h>
#include <assimp/scene.h>
#include <assimp/postprocess.h>

static int load_vertices(struct model *m, struct aiMesh *ms) {
    m->vertices_num = ms->mNumVertices;
    int len = m->vertices_num * sizeof(struct aiVector3D);
    m->vertices = malloc(len);
    if (m->vertices == NULL) {
        return -1;
    }

    memset(m->vertices, 0, len);
    memcpy(m->vertices, ms->mVertices, len);
    return 0;
}

static int load_indices(struct model *m, struct aiMesh *ms) {
    for (int face_index = 0; face_index < ms->mNumFaces; face_index++) {
        struct aiFace *face = &(ms->mFaces[face_index]);
        long start = m->indices_num;

        m->indices_num += face->mNumIndices;
        m->indices = (unsigned int *) realloc(m->indices, sizeof(unsigned int)*m->indices_num);
        if (m->indices == NULL) {
            return -1;
        }

        memcpy(&m->indices[start], face->mIndices, sizeof(unsigned int)*face->mNumIndices);
    }
    return 0;
}

static int load_normals(struct model *m, struct aiMesh *ms) {
    m->normals_num = ms->mNumVertices;
    int len = m->vertices_num * sizeof(struct aiVector3D); 
    m->normals = malloc(len);
    if (m->vertices == NULL) {
        return -1;
    }
    memset(m->normals, 0, len);
    memcpy(m->normals, ms->mNormals, len);
    return 0;
}

struct model *load_model(const char *path) {
    int ret = 0; 
    struct model *nm = malloc(sizeof(struct model));
    if (nm == NULL) {
        return NULL;
    }

    memset(nm, 0, sizeof(struct model));

    const struct aiScene *scene = aiImportFile(path, aiProcess_Triangulate);
    if (scene == NULL) {
        free(nm);
        return NULL;
    }

    for (int mesh_index = 0; mesh_index < scene->mNumMeshes; mesh_index++) {
        struct aiMesh *mesh = scene->mMeshes[mesh_index];

        ret = load_vertices(nm, mesh);
        if (ret < 0) {
            free(nm);
            aiReleaseImport(scene);
            return NULL;
        }

        ret = load_indices(nm, mesh);
        if (ret < 0) {
            free(nm->vertices);
            free(nm);
            aiReleaseImport(scene);
            return NULL;
        }

        ret = load_normals(nm, mesh);
        if (ret < 0) {
            free(nm->vertices);
            free(nm->indices);
            free(nm);
            aiReleaseImport(scene);
            return NULL;
        }
    }

    return nm;
}

struct object *create_object(struct object **o, float mass, struct model *model) {
    struct object *no = malloc(sizeof(struct object));
    if (no == NULL) {
        return NULL;
    }
    memset(no, 0, sizeof(struct object));

    no->mass = mass;
    no->scale = 1.0f;
    no->model = model;
    glm_vec4_one(no->position);
    glm_vec3_one(no->color);

    for (int i = 0; i < 3; i++) {
        no->color[i] = 0.5f + (fabs(frand48()) / 2);
    }

    if (*o == NULL) {
        *o = no;
        return no;
    }

    struct object *previous_object = *o;
    no->next = previous_object;
    *o = no;

    return no;
}