#include "model.h"
#include "graphics.h"
#include <stdlib.h>

static void visitNode(ModelData* modelData, ModelNode* node, mat4 transform, vec_float_t* vertices, vec_uint_t* indices) {
  mat4 newTransform;

  if (!transform) {
    newTransform = mat4_init();
  } else {
    newTransform = mat4_copy(transform);
  }

  mat4_multiply(newTransform, node->transform);

  int indexOffset = vertices->length / 3;

  // Meshes
  for (int m = 0; m < node->meshes.length; m++) {
    ModelMesh* mesh = modelData->meshes.data[node->meshes.data[m]];

    // Transformed vertices
    for (int v = 0; v < mesh->vertices.length; v++) {
      ModelVertex vertex = mesh->vertices.data[v];

      float v[4] = {
        vertex.x,
        vertex.y,
        vertex.z,
        1.f
      };

      mat4_multiplyVector(newTransform, v);
      vec_pusharr(vertices, v, 3);
    }

    // Face vertex indices
    for (int f = 0; f < mesh->faces.length; f++) {
      ModelFace face = mesh->faces.data[f];

      for (int v = 0; v < face.indices.length; v++) {
        vec_push(indices, face.indices.data[v] + indexOffset);
      }
    }
  }

  for (int c = 0; c < node->children.length; c++) {
    visitNode(modelData, node->children.data[c], newTransform, vertices, indices);
  }
}

Model* lovrModelCreate(const char* filename) {
  Model* model = malloc(sizeof(model));
  model->modelData = lovrModelDataCreate(filename);

  vec_float_t vertices;
  vec_init(&vertices);

  vec_uint_t indices;
  vec_init(&indices);

  visitNode(model->modelData, model->modelData->root, NULL, &vertices, &indices);

  BufferFormat format;
  BufferAttribute position = { .name = "position", .type = BUFFER_FLOAT, .size = 3 };
  vec_init(&format);
  vec_push(&format, position);

  model->buffer = lovrBufferCreate(vertices.length / 3, &format, BUFFER_TRIANGLES, BUFFER_STATIC);
  lovrBufferSetVertices(model->buffer, vertices.data, vertices.length / 3);
  lovrBufferSetVertexMap(model->buffer, indices.data, indices.length);

  vec_deinit(&vertices);
  vec_deinit(&indices);
  return model;
}

void lovrModelDestroy(Model* model) {
  lovrModelDataDestroy(model->modelData);
  lovrBufferDestroy(model->buffer);
  free(model);
}

void lovrModelDraw(Model* model, float x, float y, float z, float size, float angle, float ax, float ay, float az) {
  lovrGraphicsPush();
  lovrGraphicsTransform(x, y, z, size, size, size, angle, ax, ay, az);
  lovrBufferDraw(model->buffer);
  lovrGraphicsPop();
}