#include "model.h"

#include "log.h"
#include "resources.h"
#include "stb_ds.h"
#include "font.h"
#include "gameobject.h"

//#include "diffuse.sglsl.h"
#include "unlit.sglsl.h"

#include "render.h"

#include "HandmadeMath.h"

#include "math.h"
#include "time.h"

#define CGLTF_IMPLEMENTATION
#include <cgltf.h>

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

#include "texture.h"

#include "sokol/sokol_gfx.h"

static void processnode();
static void processmesh();
static void processtexture();

static sg_shader model_shader;
static sg_pipeline model_pipe;

struct bone_weights {
  char b1;
  char b2;
  char b3;
  char b4;
};

struct mesh_v {
  HMM_Vec3 pos;
  struct uv_n uv;
  uint32_t norm;
  struct bone_weights bones;
};

void model_init() {
  model_shader = sg_make_shader(unlit_shader_desc(sg_query_backend()));

  model_pipe = sg_make_pipeline(&(sg_pipeline_desc){
    .shader = model_shader,
    .layout = {
      .attrs = {
        [0].format = SG_VERTEXFORMAT_FLOAT3,
	      [1].format = SG_VERTEXFORMAT_USHORT2N,
	      [1].buffer_index = 1,
        [2].format = SG_VERTEXFORMAT_FLOAT3,
        [2].buffer_index = 2
      },
    },
    .index_type = SG_INDEXTYPE_UINT16,
    .cull_mode = SG_CULLMODE_FRONT,
    .depth.write_enabled = true,
    .depth.compare = SG_COMPAREFUNC_LESS_EQUAL
  });
}

cgltf_attribute *get_attr_type(cgltf_primitive *p, cgltf_attribute_type t)
{
  for (int i = 0; i < p->attributes_count; i++) {
    if (p->attributes[i].type == t)
      return &p->attributes[i];
  }

  return NULL;
}

unsigned short pack_short_texcoord(float x, float y)
{
  unsigned short s;
  char xc = x*255;
  char yc = y*255;
  return (((unsigned short)yc) << 8) | xc;
}

unsigned short pack_short_tex(float c) { return c * USHRT_MAX; }

uint32_t pack_int10_n2(float *norm)
{
  /*float x = norm[0];
  float y = norm[1];
  float z = norm[2];
  const uint32_t xs = x < 0;
  const uint32_t ys = y < 0;
  const uint32_t zs = z < 0;
  uint32_t vi =
      zs << 29 | ((uint32_t)(z * 511 + (zs << 9)) & 511) << 20 |
      ys << 19 | ((uint32_t)(y * 511 + (ys << 9)) & 511) << 10 |
      xs << 9  | ((uint32_t)(x * 511 + (xs << 9)) & 511);
  return vi;
  int16_t ni[3];
  printf("accessing norm %g,%g,%g\n", norm[0], norm[1], norm[2]);

  for (int i = 0; i < 3; i++) 
    ni[i] = (int16_t)(norm[i]*512.0f);

  uint32_t combined = (((uint32_t)ni[2]) << 20) | (((uint32_t)ni[1]) << 10) | ((uint32_t)ni[0]);
  return combined;
uint32_t ni[3];
    for (int i = 0; i < 3; i++) {
    ni[i] = fabs(norm[i]) * 511.0 + 0.5;
    ni[i] = (ni[i] > 511) ? 511 : ni[i];
    ni[i] = ( norm[i] < 0.0 ) ? -ni[i] : ni[i];
  }

  return (ni[0] | ( (ni[1]) << 10) | ( (ni[2] << 20) | ( (0 & 0x3) << 30)));*/

      // Pack the floats into a 32-bit unsigned integer
    uint32_t packedValue = 0;
    packedValue |= (uint32_t)((int32_t)(norm[0] * 0x1ff) & 0x3ff) << 20;
    packedValue |= (uint32_t)((int32_t)(norm[1] * 0x1ff) & 0x3ff) << 10;
    packedValue |= (uint32_t)((int32_t)(norm[2] * 0x1ff) & 0x3ff);
    //packedValue |= (uint32_t)((int32_t)(0 * 0x1ff) & 0x3ff) >> 8;

    return packedValue;
}

void mesh_add_material(mesh *mesh, cgltf_material *mat)
{
  if (!mat) return;
  
  if (mat && mat->has_pbr_metallic_roughness) {
    cgltf_image *img = mat->pbr_metallic_roughness.base_color_texture.texture->image;
     if (img->buffer_view) {
       cgltf_buffer_view *buf = img->buffer_view;
       mesh->bind.fs.images[0] = texture_fromdata(buf->buffer->data, buf->size)->id;
     } else
       mesh->bind.fs.images[0] = texture_from_file(img->uri)->id;
   } else
     mesh->bind.fs.images[0] = texture_from_file("icons/moon.gif")->id; 
    
   mesh->bind.fs.samplers[0] = std_sampler;
}

sg_buffer texcoord_floats(float *f, int verts, int comp)
{
  int n = verts*comp;
  unsigned short packed[n];
  for (int i = 0; i < n; i++)
    packed[i] = pack_short_tex(f[i]);

  return sg_make_buffer(&(sg_buffer_desc){
    .data = SG_RANGE(packed),
    .label = "tex coord vert buffer",
  });
}

sg_buffer normal_floats(float *f, int verts, int comp)
{
  return sg_make_buffer(&(sg_buffer_desc){
    .data.ptr = f,
    .data.size = sizeof(*f)*verts*comp
  });
  uint32_t packed_norms[verts];
  for (int v = 0, i = 0; v < verts; v++, i+= comp)
    packed_norms[v] = pack_int10_n2(f+i);

  return sg_make_buffer(&(sg_buffer_desc){
    .data = SG_RANGE(packed_norms),
    .label = "normal vert buffer",
  });
}

HMM_Vec3 index_to_vert(uint32_t idx, float *f)
{
  return (HMM_Vec3){f[idx*3], f[idx*3+1], f[idx*3+2]};
}

void mesh_add_primitive(mesh *mesh, cgltf_primitive *prim)
{
  uint16_t *idxs;
  if (prim->indices) {
    int c = prim->indices->count;
    idxs = malloc(sizeof(*idxs)*c);
    memcpy(idxs, cgltf_buffer_view_data(prim->indices->buffer_view), sizeof(uint16_t) * c);

    mesh->bind.index_buffer = sg_make_buffer(&(sg_buffer_desc){
    .data.ptr = idxs,
    .data.size = sizeof(uint16_t) * c,
    .type = SG_BUFFERTYPE_INDEXBUFFER,
    .label = "mesh index buffer",
  });

    mesh->idx_count = c;
  } else {
    YughWarn("Model does not have indices. Generating them.");
    int c = prim->attributes[0].data->count;

    mesh->idx_count = c;
    idxs = malloc(sizeof(*idxs)*c);
    
    for (int z = 0; z < c; z++)
      idxs[z] = z;

    mesh->bind.index_buffer = sg_make_buffer(&(sg_buffer_desc){
	.data.ptr = idxs,
	.data.size = sizeof(uint16_t) * c,
	.type = SG_BUFFERTYPE_INDEXBUFFER});
  }
  free(idxs);

  printf("adding material\n");
  mesh_add_material(mesh, prim->material);
  int has_norm = 0;  

  for (int k = 0; k < prim->attributes_count; k++) {
    cgltf_attribute attribute = prim->attributes[k];

    int n = cgltf_accessor_unpack_floats(attribute.data, NULL, 0); /* floats per vertex x num elements. In other words, total floats pulled */
    int comp = cgltf_num_components(attribute.data->type);
    int verts = n/comp;
    float vs[n];
    cgltf_accessor_unpack_floats(attribute.data, vs, n);

    switch (attribute.type) {
      case cgltf_attribute_type_position:
      mesh->bind.vertex_buffers[0] = sg_make_buffer(&(sg_buffer_desc){
        .data.ptr = vs,
        .data.size = sizeof(float) * n,
        .label = "mesh vert buffer"
        });
      break;

    case cgltf_attribute_type_normal:
      has_norm = 1;
      YughInfo("Found normals.");
      mesh->bind.vertex_buffers[2] = normal_floats(vs, verts, comp);
      break;

    case cgltf_attribute_type_tangent:
      break;

    case cgltf_attribute_type_color:
      break;

    case cgltf_attribute_type_weights:
      break;

    case cgltf_attribute_type_joints:
      break;

    case cgltf_attribute_type_texcoord:
      mesh->bind.vertex_buffers[1] = texcoord_floats(vs, verts, comp); /*sg_make_buffer(&(sg_buffer_desc){
        .data.ptr = vs,
        .data.size=sizeof(*vs)*verts*comp
      });*/
      break;
    case cgltf_attribute_type_invalid:
      YughWarn("Invalid type.");
      break;
      
    case cgltf_attribute_type_custom:
      break;
    case cgltf_attribute_type_max_enum:
      break;
    }
  }

  if (!has_norm) {
    YughInfo("Making normals.");
    cgltf_attribute *pa = get_attr_type(prim, cgltf_attribute_type_position);
    int n = cgltf_accessor_unpack_floats(pa->data, NULL,0);
    int comp = 3;
    int verts = n/comp;
    uint32_t face_norms[verts];
    float ps[n];
    cgltf_accessor_unpack_floats(pa->data,ps,n);

    for (int i = 0; i < verts; i+=3) {
      HMM_Vec3 a = index_to_vert(i,ps);
      HMM_Vec3 b = index_to_vert(i+1,ps);
      HMM_Vec3 c = index_to_vert(i+2,ps);
      HMM_Vec3 norm = HMM_NormV3(HMM_Cross(HMM_SubV3(b,a), HMM_SubV3(c,a)));
      uint32_t packed_norm = pack_int10_n2(norm.Elements);
      face_norms[i] = face_norms[i+1] = face_norms[i+2] = packed_norm;
     }
     
     mesh->bind.vertex_buffers[2] = sg_make_buffer(&(sg_buffer_desc){
       .data.ptr = face_norms,
       .data.size = sizeof(uint32_t) * verts});
  }
}

void model_add_cgltf_mesh(model *model, cgltf_mesh *gltf_mesh)
{
  mesh mesh = {0};

  for (int i = 0; i < gltf_mesh->primitives_count; i++)
    mesh_add_primitive(&mesh, &gltf_mesh->primitives[i]);

  arrput(model->meshes,mesh);
}

void model_add_cgltf_anim(model *model, cgltf_animation *anim)
{

}

void model_add_cgltf_skin(model *model, cgltf_skin *skin)
{
  
}

void model_process_node(model *model, cgltf_node *node)
{
  if (node->has_matrix)
    memcpy(model->matrix.Elements, node->matrix, sizeof(float)*16);

  if (node->mesh)
    model_add_cgltf_mesh(model, node->mesh);

  if (node->skin)
    model_add_cgltf_skin(model, node->skin);
}

void model_process_scene(model *model, cgltf_scene *scene)
{
  for (int i = 0; i < scene->nodes_count; i++)
    model_process_node(model, scene->nodes[i]);
}

struct model *model_make(const char *path)
{
  YughInfo("Making the model from %s.", path);
  cgltf_options options = {0};
  cgltf_data *data = NULL;
  cgltf_result result = cgltf_parse_file(&options, path, &data);

  if (result) {
    YughError("CGLTF could not parse file %s, err %d.", path, result);
    return NULL;
  }

  result = cgltf_load_buffers(&options, data, path);

  if (result) {
    YughError("CGLTF could not load buffers for file %s, err %d.", path, result);
    return NULL;
  }

  struct model *model = calloc(1, sizeof(*model));

  if (data->scenes_count == 0 || data->scenes_count > 1) return NULL;
  model_process_scene(model, data->scene);

  for (int i = 0; i < data->meshes_count; i++)
    model_add_cgltf_mesh(model, &data->meshes[i]);

  for (int i = 0; i < data->animations_count; i++)
    model_add_cgltf_anim(model, &data->animations[i]);

  return model;
}

void model_free(model *m)
{

}

void model_draw_go(model *model, gameobject *go, gameobject *cam)
{
  HMM_Mat4 view = t3d_go2world(cam);
  HMM_Mat4 proj = HMM_Perspective_RH_NO(20, 1, 0.01, 10000);
  HMM_Mat4 vp = HMM_MulM4(proj, view);
  
  vs_p_t vs_p;
  memcpy(vs_p.vp, vp.Elements, sizeof(float)*16);
  memcpy(vs_p.model, t3d_go2world(go).Elements, sizeof(float)*16);
  
  sg_apply_pipeline(model_pipe);
  sg_apply_uniforms(SG_SHADERSTAGE_VS, SLOT_vs_p, SG_RANGE_REF(vs_p));
  
  for (int i = 0; i < arrlen(model->meshes); i++) {
    sg_apply_bindings(&model->meshes[i].bind);
    sg_draw(0, model->meshes[i].idx_count, 1);    
  }
}

void material_free(material *mat)
{

}