#include "defines.h"

static void push_face(Universe *uni, Object3D *obj, int a, int b, int c, uint8_t wire) {
    Face *f = &uni->faces[uni->num_faces++];
    f->a = a; f->b = b; f->c = c;
    f->force_wire = wire;
    obj->num_faces++;
}

static Object3D *alloc_object(Universe *uni) {
    Object3D *obj = &uni->objects[uni->num_objects++];
    obj->vert_start = uni->num_verts;
    obj->face_start = uni->num_faces;
    obj->num_verts  = 0;
    obj->num_faces  = 0;
    obj->pos.x      = obj->pos.y      = obj->pos.z      = 0;
    obj->base_pos.x = obj->base_pos.y = obj->base_pos.z = 0;
    mat3_identity(&obj->rot);
    return obj;
}

Object3D *add_sphere(Universe *uni, fixed x, fixed y, fixed z, fixed r, int det, uint8_t col, uint8_t wire) {
    int i, j, v_base, phi, th;
    Object3D *obj;
    Vector3 *v, *n;

    if (uni->num_objects >= MAX_OBJECTS) return NULL;
    if (uni->num_verts + (det + 1) * det > MAX_VERTEX) return NULL;
    if (uni->num_faces + det * det * 2    > MAX_FACES)  return NULL;

    obj    = alloc_object(uni);
    obj->color = col;
    v_base = uni->num_verts;

    for (j = 0; j <= det; j++) {
        phi = (j * 180 / det) % 360;
        for (i = 0; i < det; i++) {
            th = (i * 360 / det) % 360;
            v  = &uni->verts[uni->num_verts];
            n  = &uni->v_normals[uni->num_verts];

            n->x = f_mul(sintab[phi], costab[th]);
            n->y = costab[phi];
            n->z = f_mul(sintab[phi], sintab[th]);
            v->x = x + f_mul(r, n->x);
            v->y = y + f_mul(r, n->y);
            v->z = z + f_mul(r, n->z);
            uni->num_verts++; obj->num_verts++;
        }
    }

    for (j = 0; j < det; j++) {
        for (i = 0; i < det; i++) {
            int a = v_base +  j      * det + i;
            int b = v_base +  j      * det + (i + 1) % det;
            int c = v_base + (j + 1) * det + i;
            int d = v_base + (j + 1) * det + (i + 1) % det;
            push_face(uni, obj, a, b, c, wire);
            push_face(uni, obj, b, d, c, wire);
        }
    }

    return obj;
}

Object3D *add_cylinder(Universe *uni, fixed x, fixed y, fixed z, fixed r, fixed h, int det, uint8_t col, uint8_t wire) {
    int i, v_base, cap_bot_center, cap_bot_rim, cap_top_center, cap_top_rim, th;
    fixed half_h, s, cs;
    Object3D *obj;

    if (uni->num_objects >= MAX_OBJECTS) return NULL;
    if (uni->num_verts + 2 + 4 * det > MAX_VERTEX) return NULL;
    if (uni->num_faces +     4 * det > MAX_FACES)  return NULL;

    obj    = alloc_object(uni);
    obj->color = col;
    v_base = uni->num_verts;
    half_h = h / 2;

    /* --- Corps --- */
    for (i = 0; i < det; i++) {
        th = (i * 360 / det) % 360;
        s  = sintab[th]; cs = costab[th];

        uni->v_normals[uni->num_verts].x = cs;
        uni->v_normals[uni->num_verts].y = 0;
        uni->v_normals[uni->num_verts].z = s;
        uni->verts[uni->num_verts].x = x + f_mul(r, cs);
        uni->verts[uni->num_verts].y = y - half_h;
        uni->verts[uni->num_verts].z = z + f_mul(r, s);
        uni->num_verts++; obj->num_verts++;

        uni->v_normals[uni->num_verts].x = cs;
        uni->v_normals[uni->num_verts].y = 0;
        uni->v_normals[uni->num_verts].z = s;
        uni->verts[uni->num_verts].x = x + f_mul(r, cs);
        uni->verts[uni->num_verts].y = y + half_h;
        uni->verts[uni->num_verts].z = z + f_mul(r, s);
        uni->num_verts++; obj->num_verts++;
    }

    for (i = 0; i < det; i++) {
        int a  = v_base + (i * 2);
        int b  = v_base + ((i * 2 + 2) % (det * 2));
        int cv = a + 1;
        int d  = b + 1;
        push_face(uni, obj, a, cv, b, wire);
        push_face(uni, obj, cv, d, b, wire);
    }

    /* --- Fond bas --- */
    cap_bot_center = uni->num_verts;
    uni->v_normals[uni->num_verts].x = 0;
    uni->v_normals[uni->num_verts].y = -int_to_f(1);
    uni->v_normals[uni->num_verts].z = 0;
    uni->verts[uni->num_verts].x = x;
    uni->verts[uni->num_verts].y = y - half_h;
    uni->verts[uni->num_verts].z = z;
    uni->num_verts++; obj->num_verts++;

    cap_bot_rim = uni->num_verts;
    for (i = 0; i < det; i++) {
        th = (i * 360 / det) % 360;
        s  = sintab[th]; cs = costab[th];
        uni->v_normals[uni->num_verts].x = 0;
        uni->v_normals[uni->num_verts].y = -int_to_f(1);
        uni->v_normals[uni->num_verts].z = 0;
        uni->verts[uni->num_verts].x = x + f_mul(r, cs);
        uni->verts[uni->num_verts].y = y - half_h;
        uni->verts[uni->num_verts].z = z + f_mul(r, s);
        uni->num_verts++; obj->num_verts++;
    }

    for (i = 0; i < det; i++)
        push_face(uni, obj, cap_bot_center, cap_bot_rim + i, cap_bot_rim + (i + 1) % det, wire);

    /* --- Fond haut --- */
    cap_top_center = uni->num_verts;
    uni->v_normals[uni->num_verts].x = 0;
    uni->v_normals[uni->num_verts].y = int_to_f(1);
    uni->v_normals[uni->num_verts].z = 0;
    uni->verts[uni->num_verts].x = x;
    uni->verts[uni->num_verts].y = y + half_h;
    uni->verts[uni->num_verts].z = z;
    uni->num_verts++; obj->num_verts++;

    cap_top_rim = uni->num_verts;
    for (i = 0; i < det; i++) {
        th = (i * 360 / det) % 360;
        s  = sintab[th]; cs = costab[th];
        uni->v_normals[uni->num_verts].x = 0;
        uni->v_normals[uni->num_verts].y = int_to_f(1);
        uni->v_normals[uni->num_verts].z = 0;
        uni->verts[uni->num_verts].x = x + f_mul(r, cs);
        uni->verts[uni->num_verts].y = y + half_h;
        uni->verts[uni->num_verts].z = z + f_mul(r, s);
        uni->num_verts++; obj->num_verts++;
    }

    for (i = 0; i < det; i++)
        push_face(uni, obj, cap_top_center, cap_top_rim + (i + 1) % det, cap_top_rim + i, wire);

    return obj;
}

/* --- I/O sur Mesh dynamique (non utilisé dans le pipeline principal) --- */

void save_mesh(Mesh *m, const char *fn) {
    FILE *f = fopen(fn, "wb");
    if (!f) return;
    fwrite(&m->num_verts, sizeof(int), 1, f);
    fwrite(&m->num_faces, sizeof(int), 1, f);
    fwrite(m->verts,    sizeof(Vector3), m->num_verts, f);
    fwrite(m->v_normals,sizeof(Vector3), m->num_verts, f);
    fwrite(m->faces,    sizeof(Face),    m->num_faces, f);
    fclose(f);
}

Mesh *load_mesh(const char *fname) {
    Mesh *m;
    FILE *f = fopen(fname, "rb");
    if (!f) return NULL;
    m = (Mesh*)malloc(sizeof(Mesh));
    if (!m) return NULL;
    fread(&m->num_verts, sizeof(int), 1, f);
    fread(&m->num_faces, sizeof(int), 1, f);
    m->verts     = (Vector3*)malloc(sizeof(Vector3) * m->num_verts);
    m->v_normals = (Vector3*)malloc(sizeof(Vector3) * m->num_verts);
    m->faces     = (Face*)   malloc(sizeof(Face)    * m->num_faces);
    if (!m->verts || !m->v_normals || !m->faces) {
        free(m->verts); free(m->v_normals); free(m->faces); free(m);
        fclose(f);
        return NULL;
    }
    fread(m->verts,     sizeof(Vector3), m->num_verts, f);
    fread(m->v_normals, sizeof(Vector3), m->num_verts, f);
    fread(m->faces,     sizeof(Face),    m->num_faces, f);
    fclose(f);
    return m;
}

void free_mesh(Mesh *m) {
    if (!m) return;
    free(m->verts);
    free(m->v_normals);
    free(m->faces);
    free(m);
}