#define _USE_MATH_DEFINES
#include <math.h>
#include "dbc.hpp"
#include <print>
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <vector>
#include <functional>
#include "shader.hpp"
#include <stb_image.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include "data.hpp"
#include "model.hpp"
#include "camera.hpp"

void framebuffer_size_callback(GLFWwindow *window, int width, int height);

const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;

const float AMBIENT_LEVEL = 0.25f;

struct Config {
  Shader shader;
  Shader lightShader;
  std::vector<Model> models;

  Lighting light{
    .directional={
      .direction={-0.2f, -1.0f, -0.3f},
      .ambient={0.2f, 0.2f, 0.2f},
      .diffuse={0.8f, 0.8f, 0.8f},
      .specular={1.0f, 1.0f, 1.0f},
    },
    .positioned={
      {
        .position={1.2f, 1.0f, 2.0f},
        .direction={-0.2f, -1.0f, -0.3f},
        .ambient={0.2f, 0.2f, 0.2f},
        .diffuse={0.8f, 0.8f, 0.8f},
        .specular={1.0f, 1.0f, 1.0f},
        .constant=1.0f,
        .linear=0.09f,
        .quadratic=0.032f,
        .cutOff=12.5f,
        .outerCutOff=17.5f,
      },
      {
        .position={-1.2f, -1.0f, -2.0f},
        .direction={0.2f, 1.0f, 0.3f},
        .ambient={0.2f, 0.2f, 0.2f},
        .diffuse={0.8f, 0.8f, 0.8f},
        .specular={1.0f, 1.0f, 1.0f},
        .constant=1.0f,
        .linear=0.09f,
        .quadratic=0.032f,
        .cutOff=12.5f,
        .outerCutOff=17.5f,
      },
    },
    .spot={
      .position={2.2f, 1.0f, 2.0f},
      .direction={0.0f, 0.0f, -1.0f},
      .ambient={0.2f, 0.2f, 0.2f},
      .diffuse={0.8f, 0.8f, 0.8f},
      .specular={1.0f, 1.0f, 1.0f},
      .constant=1.0f,
      .linear=0.09f,
      .quadratic=0.032f,
      .cutOff=12.5f,
      .outerCutOff=17.5f,
    },
  };

  glm::vec3 cubePos{2.0f, 0.0f, 0.0f};
  Camera camera{
    .pos={2.2f, 1.0f, 2.0f},
    .movementSpeed=2.0f
  };

  Material cubeMaterial{
    .ambient = {1.0f, 0.5f, 0.31f},
    .shininess = 32.0f,
    .diffuseMap = 0,
    .specularMap = 0,
  };

  float deltaTime = 0.0f;
  float lastFrame = 0.0f;

  void updateDelta() {
    float currentFrame = glfwGetTime();
    deltaTime = currentFrame - lastFrame;
    lastFrame = currentFrame;
  }
};

void init_glfw() {
  glfwInit();
  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
}

void framebuffer_size_callback(GLFWwindow *, int width, int height) {
  glViewport(0, 0, width, height);
}

void mouse_callback(GLFWwindow *window, double xpos, double ypos) {
  Camera* camera = static_cast<Camera*>(glfwGetWindowUserPointer(window));
  camera->mouse_move(xpos, ypos);
}

void scroll_callback(GLFWwindow *window, double xoffset, double yoffset) {
  Camera* camera = static_cast<Camera*>(glfwGetWindowUserPointer(window));
  camera->mouse_scroll(xoffset, yoffset);
}

GLFWwindow* create_window() {
  GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
  dbc::check(window != NULL, "failed to open window");

  glfwMakeContextCurrent(window);

  glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

  auto good = gladLoadGLLoader((GLADloadproc)glfwGetProcAddress);
  dbc::check(good, "failed to load GLAD");

  glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
  glfwSetCursorPosCallback(window, mouse_callback);
  glfwSetScrollCallback(window, scroll_callback);

  return window;
}


void processInput(GLFWwindow *window, Config& config) {
  if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
    glfwSetWindowShouldClose(window, true);
  }

  if(glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) {
    config.camera.forward();
  }

  if(glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
    config.camera.back();
  }

  if(glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
    config.camera.left();
  }

  if(glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
    config.camera.right();
  }

  if(glfwGetKey(window, GLFW_KEY_L) == GLFW_PRESS) {
    config.light.directional.adjust(-0.01f);
  }

  if(glfwGetKey(window, GLFW_KEY_P) == GLFW_PRESS) {
    config.light.directional.adjust(0.01f);
  }
}

unsigned int load_texture(const std::string& image_file) {
  unsigned int texture_id;
  glGenTextures(1, &texture_id);
  glBindTexture(GL_TEXTURE_2D, texture_id);

  // set the texture wrapping parameters
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

  // set texture filtering parameters
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

  int width = 0;
  int height = 0;
  int nrChannels = 0;
  stbi_set_flip_vertically_on_load(true);

  unsigned char *data = stbi_load(image_file.c_str(), &width, &height, &nrChannels, 0);

  dbc::check(data != nullptr, std::format("Failed to load texture: {}", image_file));

  dbc::check(nrChannels == 3 || nrChannels == 4,
      std::format("Image {} has invalid channels {} should be 3 or 4.", image_file, nrChannels));

  auto rgb_or_a = nrChannels == 3 ? GL_RGB : GL_RGBA;

  glTexImage2D(GL_TEXTURE_2D, 0, rgb_or_a, width, height, 0, rgb_or_a, GL_UNSIGNED_BYTE, data);
  glGenerateMipmap(GL_TEXTURE_2D);

  stbi_image_free(data);

  return texture_id;
}

Config setup() {
  glEnable(GL_DEPTH_TEST);

  Config config{
    .shader={"shaders/14-vert.glsl", "shaders/14-frag.glsl"},
    .lightShader={"shaders/14-vert.glsl", "shaders/14-lightsource.frag.glsl"},
    .models={
      {"assets", "crate.obj"}
    },
  };

  // REFACTOR: really this should be done somewhere else
  for(auto& model : config.models) {
    model.connect_shader(config.shader);
  }

  return config;
}

void draw_models(Config& config, size_t model_i, size_t model_pos, glm::mat4& projection, glm::mat4& view)
{
  glm::vec3 objectColor = {1.0, 0.94, 0.78};
  config.shader.apply_material(config.cubeMaterial);

  float time = glfwGetTime();
  glm::mat4 model = glm::mat4(1.0f);
  model = glm::translate(model, popcorn_positions[model_pos]);
  model = glm::rotate(model, glm::radians(time * 10.0f), glm::vec3(1.0f, 0.3f, 0.5f));

  config.shader.setMat4("model", model);

  config.models[model_i].draw(config.shader);
}

void render(GLFWwindow* window, Config& config) {
  glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  config.shader.use();

  // time is used for fake 3d rotation
  float time = glfwGetTime();

  config.camera.update(config.deltaTime);

  glm::mat4 view = config.camera.look_at();
  glm::mat4 projection = glm::mat4(1.0f);

  // fov, aspect, near plane, far plane
  projection = glm::perspective(glm::radians(config.camera.fov), (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);

  config.shader.use();
  config.shader.setMat4("view", view);
  config.shader.setMat4("projection", projection);
  config.shader.setVec3("viewPos", config.camera.pos);

  config.light.spot.position = config.camera.pos;
  config.light.spot.direction = config.camera.front;
  config.shader.apply_lighting(config.light);

  for(size_t i = 0; i < CUBE_COUNT; i++) {
    draw_models(config, 0, i, projection, view);
  }

  glfwSwapBuffers(window);
  glfwPollEvents();
}

void cleanup(Config& config) {
  config.shader.cleanup();
}

int main() {
  init_glfw();

  auto window = create_window();
  auto config = setup();

  glfwSetWindowUserPointer(window, &config.camera);

  while(!glfwWindowShouldClose(window)) {
    processInput(window, config);
    render(window, config);
    config.updateDelta();
  }

  cleanup(config);

  glfwTerminate();

  return 0;
}