#include "mesh.hpp"
#include "dbc.hpp"
#include "config.hpp"

void Mesh::draw(Shader &shader, bool with_textures) {
  if(with_textures) {
    apply_textures(shader);
  }

  glBindVertexArray(VAO);
  glDrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0);
  glBindVertexArray(0);
}

void Mesh::apply_textures(const Shader& shader) {
  int texture_i = 1;
  bool has_height = false;

  for(auto& texture : textures) {
    texture.uniform_id = glGetUniformLocation(shader.ID, texture.target.c_str());
    if(texture.uniform_id == -1) continue;

    if(texture.target.starts_with("texture_height")) {
      has_height = true;
    }

    glActiveTexture(GL_TEXTURE0 + texture_i);
    glBindTexture(GL_TEXTURE_2D, texture.id);
    glUniform1i(texture.uniform_id, texture_i);

    texture_i++;
  }

  // quick hack to avoid applying height/normal to things without one
  shader.setBool("hasHeight", has_height);
}

void Mesh::setup_mesh() {
  glGenVertexArrays(1, &VAO);
  glGenBuffers(1, &VBO);
  glGenBuffers(1, &EBO);

  glBindVertexArray(VAO);
  glBindBuffer(GL_ARRAY_BUFFER, VBO);
  glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(Vertex), vertices.data(), GL_STATIC_DRAW);

  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
  glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(unsigned int), indices.data(), GL_STATIC_DRAW);

  // this matches the locations in the vertex shader
  glEnableVertexAttribArray(0);
  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, position));

  glEnableVertexAttribArray(1);
  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, normal));

  glEnableVertexAttribArray(2);
  glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, tex_coords));

  glEnableVertexAttribArray(3);
  glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, tangent));

  glEnableVertexAttribArray(4);
  glVertexAttribPointer(4, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, bitangent));

  // bone ids
  glEnableVertexAttribArray(5);
  glVertexAttribIPointer(5, 4, GL_INT, sizeof(Vertex), (void*)offsetof(Vertex, bone_ids));

  // bone weights
  glEnableVertexAttribArray(6);
  glVertexAttribPointer(6, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void*)offsetof(Vertex, weights));
}