#include "camera.h"
#include "glad/glad.h"
#include "shader.h"
#include "stb_image.h"
#include <GLFW/glfw3.h>
#include <cmath>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <iostream>

// settings
const unsigned int SCR_WIDTH = 600;
const unsigned int SCR_HEIGHT = 600;

// 四边形顶点
float vertices[] = {
    //       ---- 位置 ----    -- 法向量--   - 纹理坐标 -
    0.2f,  0.4f,  0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, // 右上
    0.2f,  -0.4f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, // 右下
    -0.2f, -0.4f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, // 左下
    -0.2f, 0.4f,  0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f  // 左上
};

// 索引
unsigned int indices[] = {
    0, 1, 3, // 第一个三角形
    1, 2, 3  // 第二个三角形
};

float deltaTime, lastTime;
Camera camera = Camera(SCR_HEIGHT / 2.0f, SCR_HEIGHT / 2.0f);

// lighting
glm::vec3 lightPos(1.2f, 1.0f, 2.0f);

void framebuffer_size_callback(GLFWwindow *window, int width, int height);
void processInput(GLFWwindow *window);
void mouse_callback(GLFWwindow *window, double xpos, double ypos);
void scroll_callback(GLFWwindow *window, double xoffset, double yoffset);

int main() {

  // 设置 glfw
  glfwInit();
  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

  // 创建窗口
  GLFWwindow *window =
      glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
  if (window == NULL) {
    std::cout << "Failed to create GLFW window" << std::endl;
    glfwTerminate();
    return -1;
  }

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

  // 加载glad
  if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
    std::cout << "Failed to initialize GLAD" << std::endl;
    return -1;
  }

  // 创建着色器程序
  Shader shader = Shader("src/tex.vs", "src/tex.fs");

  unsigned int VAO, VBO, EBO;
  // 创建顶点数组对象
  glGenVertexArrays(1, &VAO);
  glBindVertexArray(VAO);

  // 创建顶点缓冲对象
  glGenBuffers(1, &VBO);
  glBindBuffer(GL_ARRAY_BUFFER, VBO);
  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

  // 创建索引缓冲对象
  glGenBuffers(1, &EBO);
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
  glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,
               GL_STATIC_DRAW);

  // 顶点属性
  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)0);
  glEnableVertexAttribArray(0);
  // 法向量属性
  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float),
                        (void *)(3 * sizeof(float)));
  glEnableVertexAttribArray(1);
  // 纹理坐标属性
  glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float),
                        (void *)(6 * sizeof(float)));
  glEnableVertexAttribArray(2);

  // 创建纹理
  unsigned int texture;
  glGenTextures(1, &texture);
  glBindTexture(GL_TEXTURE_2D, texture);
  // 设置纹理环绕方式
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  // 设置纹理过滤方式
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
                  GL_LINEAR_MIPMAP_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

  // 加载并生成纹理
  // 图片翻转y轴
  stbi_set_flip_vertically_on_load(true);
  int width, height, nrChannels;
  unsigned char *data =
      stbi_load("resources/bf-half.png", &width, &height, &nrChannels, 0);
  if (data) {

    // note that the awesomeface.png has transparency and thus an alpha channel,
    // so make sure to tell OpenGL the data type is of GL_RGBA
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA,
                 GL_UNSIGNED_BYTE, data);
    glGenerateMipmap(GL_TEXTURE_2D);
  } else {
    std::cout << "Failed to load texture" << std::endl;
  }
  stbi_image_free(data);

  // 激活着色器
  shader.use();
  // 绑定纹理
  shader.setInt("tex", 0);
  // // 直射光
  shader.setVec3("dirLight.direction", 2.0f, 0.0f, 0.0f);
  shader.setVec3("dirLight.ambient", 0.2f, 0.2f, 0.2f);
  shader.setVec3("dirLight.diffuse", 0.6f, 0.6f, 0.6f);
  shader.setVec3("dirLight.specular", 0.7f, 0.7f, 0.7f);
  // 点光源
  shader.setVec3("pointLighs.position", glm::vec3(-0.5f, -2.0f, -0.5f));
  shader.setVec3("pointLight.ambient", 0.2f, 0.2f, 0.2f);
  shader.setVec3("pointLight.diffuse", 3.0f, 3.0f, 3.0f);
  shader.setVec3("pointLight.specular", 3.0f, 3.0f, 3.0f);
  shader.setFloat("pointLight.constant", 1.0f);
  shader.setFloat("pointLight.linear", 0.00014f);
  shader.setFloat("pointLight.quadratic", 0.0000007f);

  // 开启深度测试
  glEnable(GL_DEPTH_TEST);

  // 循环渲染
  while (!glfwWindowShouldClose(window)) {

    // 计算帧时间差
    float currentFrame = glfwGetTime();
    deltaTime = currentFrame - lastTime;
    lastTime = currentFrame;

    // 处理输入
    processInput(window);

    // 初始化
    glClearColor(0.3f, 0.3f, 0.3f, 0.3f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // 绑定纹理
    glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture);

    glm::mat4 view = camera.GetViewMatrix();
    glm::mat4 projection =
        glm::perspective(glm::radians(camera.Zoom),
                         (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);

    // 绘制三角形
    shader.use();
    glBindVertexArray(VAO);

    shader.setVec3("viewPos", camera.Position);
    shader.setMat4("view", view);
    shader.setMat4("projection", projection);

    // 设置材质
    shader.setVec3("material.ambient", 1.0f, 0.5f, 0.31f);
    shader.setVec3("material.diffuse", 1.0f, 0.5f, 0.31f);
    shader.setVec3("material.specular", 0.5f, 0.5f, 0.5f);
    shader.setFloat("material.shininess", 4.0f);
    glm::mat4 trans(1.0f);
    trans = glm::rotate(trans, glm::radians(-90.0f), glm::vec3(1.0, 0.0, 0.0));
    trans = glm::rotate(trans, float(-sin((float)glfwGetTime())),
                        glm::vec3(0.0, 1.0, 0.0));
    trans = glm::translate(trans, glm::vec3(-0.2, 0.0, 0.0));
    shader.setMat4("trans", trans);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    // 设置材质
    shader.setVec3("material.ambient", 1.0f, 0.5f, 0.31f);
    shader.setVec3("material.diffuse", 0.75f, 0.6f, 0.23f);
    shader.setVec3("material.specular", 0.62f, 0.55f, 0.37f);
    shader.setFloat("material.shininess", 64.0f);
    trans = glm::mat4(1.0f);
    trans = glm::rotate(trans, glm::radians(-90.0f), glm::vec3(1.0, 0.0, 0.0));
    trans = glm::rotate(trans, float(sin((float)glfwGetTime())),
                        glm::vec3(0.0, 1.0, 0.0));
    trans = glm::translate(trans, glm::vec3(0.2, 0.0, 0.0));
    trans = glm::rotate(trans, glm::radians(180.0f), glm::vec3(0.0, 1.0, 0.0));
    shader.setMat4("trans", trans);
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

    // 检查并调用事件，交换缓冲
    glfwSwapBuffers(window);
    glfwPollEvents();
  }

  // 释放资源
  glfwTerminate();
  return 0;
}

// 处理输入
void processInput(GLFWwindow *window) {
  if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
    glfwSetWindowShouldClose(window, true);
  if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
    camera.ProcessKeyboard(FORWARD, deltaTime);
  if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
    camera.ProcessKeyboard(BACKWARD, deltaTime);
  if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
    camera.ProcessKeyboard(LEFT, deltaTime);
  if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
    camera.ProcessKeyboard(RIGHT, deltaTime);
  if (glfwGetKey(window, GLFW_KEY_SPACE) == GLFW_PRESS)
    camera.ProcessKeyboard(UP, deltaTime);
}

// 窗口大小改变时回调该函数
void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
  glViewport(0, 0, width, height);
}

void mouse_callback(GLFWwindow *window, double xpos, double ypos) {
  camera.ProcessMouseMovement(xpos, ypos);
}

void scroll_callback(GLFWwindow *window, double xoffset, double yoffset) {
  camera.ProcessMouseScroll(yoffset);
}