#include <glad/glad.h>
#include <GLFW/glfw3.h>

#include <iostream>
#include "stb_image.h"
#include "shader.h"

#include "glm/glm.hpp"
#include "glm/gtc/matrix_transform.hpp"
#include "glm/gtc/type_ptr.hpp"

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

//
const unsigned int SCR_WIDTH = 1280;
const unsigned int SCR_HEIGHT = 720;

float factor = 0.2f;

// float vertices[] = {
//     //               //
//     -0.5f, -0.5f, 0.0f, //1.0f, 0.0f, 0.0f,     //左
//     0.5f, -0.5f, 0.0f,  //0.0f, 1.0f, 0.0f,     //右
//     0.0f, 0.5f, 0.0f//, 0.0f, 0.0f, 1.0f        //上
// };

float rectVertices[] = {
    /* 位置         */ /* 颜色        */              /* 纹理坐标 */
    0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f,   //右上角
    0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f,  //右下角
    -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, //左下角
    -0.5f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f   //左上角
};
//
unsigned int indices[] = {
    0, 1, 3, //
    1, 2, 3  //
};

int main()
{
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    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);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

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

    //
    int nrAttributes;
    glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &nrAttributes);
    std::cout << "" << nrAttributes << std::endl;

    //着色器
    Shader shader("Shader.vs", "Shader.fs");

    //
    unsigned int VBO, VAO;
    glGenVertexArrays(1, &VAO);
    glBindVertexArray(VAO);

    glGenBuffers(1, &VBO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(rectVertices), rectVertices, GL_STATIC_DRAW);

    //位置属性
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)0);
    glEnableVertexAttribArray(0);
    //颜色属性
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(3 * sizeof(float)));
    glEnableVertexAttribArray(1);
    //纹理属性
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void *)(6 * sizeof(float)));
    glEnableVertexAttribArray(2);

    //
    //unsigned int VBO1, VAO1;
    //glGenVertexArrays(1, &VAO1);
    //glBindVertexArray(VAO1);
    //
    //glGenBuffers(1, &VBO1);
    //glBindBuffer(GL_ARRAY_BUFFER, VBO1);
    //glBufferData(GL_ARRAY_BUFFER, sizeof(vertices) / 2, vertices + 9, GL_STATIC_DRAW);

    //glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void*)0);
    //glEnableVertexAttribArray(0);

    unsigned int EBO;
    glGenBuffers(1, &EBO);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    //纹理1
    unsigned int texture;
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);

    //设置纹理包装和过滤方式
    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

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

    unsigned char *data = stbi_load("awesomeface.png", &width, &height, &nrChannels, 0);
    if (data)
    {
        GLint format = (nrChannels == 3) ? GL_RGB : GL_RGBA;
        glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
        glGenerateMipmap(GL_TEXTURE_2D);
    }
    else
    {
        std::cout << "load image error" << std::endl;
    }

    stbi_image_free(data);

    //纹理2
    unsigned int texture2;
    glGenTextures(1, &texture2);
    glActiveTexture(GL_TEXTURE1);
    glBindTexture(GL_TEXTURE_2D, texture2);

    //设置纹理包装和过滤方式
    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    // int width;
    // int height;
    // int nrChannels;
    stbi_set_flip_vertically_on_load(true);

    unsigned char *data2 = stbi_load("beauty.jpg", &width, &height, &nrChannels, 0);
    if (data2)
    {
        GLint format = (nrChannels == 3) ? GL_RGB : GL_RGBA;
        glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data2);
        glGenerateMipmap(GL_TEXTURE_2D);
    }
    else
    {
        std::cout << "load image error" << std::endl;
    }

    stbi_image_free(data2);

    shader.use();
    //着色器要使用之后才能操作
    //告诉OpenGL哪个采样器属于哪个纹理单元

    //采样器1对应编号0的纹理单元
    shader.setInt("texture1", 0);
    //采样器2对应编号1的纹理单元
    shader.setInt("texture2", 1);
    // glBindTexture(GL_TEXTURE_2D, texture);

    while (!glfwWindowShouldClose(window))
    {
        processInput(window);

        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        glm::mat4 trans;
        trans = glm::scale(trans, glm::vec3(0.5f, 0.5f, 0.5f));
        // trans = glm::rotate(trans, glm::radians(90.0f), glm::vec3(0.0f, 0.0f, 1.0f));
        trans = glm::rotate(trans, (float)glfwGetTime(), glm::vec3(0.0f, 0.0f, 1.0f));
        //float timeValue = glfwGetTime();
        //float greenValue = (sin(timeValue) / 2.0f) + 0.5f;
        //float greenValue = 1.0f;
        //int outColorLocation = glGetUniformLocation(shaderProgram, "ourColor");
        //glUniform4f(outColorLocation, 0.0f, greenValue, 0.0f, 1.0f);
        //glUseProgram(shaderProgram);
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);

        /*
        * 
        * 
        */
        shader.use();
        shader.setFloat("factor", factor);
        shader.setMat4("transform", glm::value_ptr(trans));

        glBindVertexArray(VAO);
        // glDrawArrays(GL_TRIANGLES, 0, 3);
        //glUseProgram(shaderProgram1);
        //glBindVertexArray(VAO1);
        //glDrawArrays(GL_TRIANGLES, 0, 3);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glBindVertexArray(0);
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glfwTerminate();
    return 0;
}

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

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

    if (glfwGetKey(window, GLFW_KEY_UP) == GLFW_PRESS)
    {
        factor += 0.01f;
        if (factor > 1.0f)
            factor = 1.0f;
    }

    if (glfwGetKey(window, GLFW_KEY_DOWN) == GLFW_PRESS)
    {
        factor -= 0.01f;
        if (factor < 0.0f)
            factor = 0.0f;
    }
}