#include"gl_window.hpp"
#include"gl_shader.hpp"

#include<glm/glm.hpp>
#include<glm/gtc/type_ptr.hpp>
#include<glm/gtc/matrix_transform.hpp>
#include<opencv2/opencv.hpp>


static constexpr int numVAOs = 1;
static constexpr int numVBOs = 2;

class MainWindow : public glWindow {
    GLuint renderingProgram;
    GLuint vao[numVAOs];
    GLuint vbo[numVBOs];
    ShaderProgram program;

    float cameraX, cameraY, cameraZ;
    float cube_x, cube_y, cube_z;
    GLuint mv_loc, proj_loc;
    int width, height;
    float aspect;
    glm::mat4 p_mat, v_mat, m_mat, mv_mat, r_mat;
    GLuint texture;
    
public:
    
    virtual void init() override {
        renderingProgram = createShaderProgram();
        cameraX = 0;
        cameraY = 0;
        cameraZ = 8.0f;
        cube_x = 0.0f;
        cube_y = -2.0f;
        cube_z = 0.0f;

        GLfloat vertices[] = { -1.0f, -1.0f, 1.0f, // front face
            1.0f, 1.0f, 1.0f,
            -1.0f, 1.0f, 1.0f,
            
            -1.0f, -1.0f, 1.0f,
            1.0f, -1.0f, 1.0f,
            1.0f, 1.0f, 1.0f,
            
            -1.0f, -1.0f, -1.0f, // left side
            -1.0f, -1.0f, 1.0f,
            -1.0f, 1.0f, -1.0f,
            
            -1.0f, 1.0f, -1.0f,
            -1.0f, -1.0f, 1.0f,
            -1.0f, 1.0f, 1.0f,
            
            -1.0f, 1.0f, -1.0f, // top
            -1.0f, 1.0f, 1.0f,
            1.0f, 1.0f, 1.0f,
            
            1.0f, 1.0f, 1.0f,
            1.0f, 1.0f, -1.0f,
            -1.0f, 1.0f, -1.0f,
            
            -1.0f, -1.0f, -1.0f, // bottom
            -1.0f, -1.0f, 1.0f,
            1.0f, -1.0f, 1.0f,
            
            1.0f, -1.0f, 1.0f,
            1.0f, -1.0f, -1.0f,
            -1.0f, -1.0f, -1.0f,
            
            1.0f, -1.0f, -1.0f, // right
            1.0f, -1.0f, 1.0f,
            1.0f, 1.0f, -1.0f,
            
            1.0f, 1.0f, -1.0f,
            1.0f, -1.0f, 1.0f,
            1.0f, 1.0f, 1.0f,
            
            -1.0f, -1.0f, -1.0f, // back face
            1.0f, 1.0f, -1.0f,
            -1.0f, 1.0f, -1.0f,
            
            -1.0f, -1.0f, -1.0f,
            1.0f, -1.0f, -1.0f,
            1.0f, 1.0f, -1.0f,
        };
        
        GLfloat texCoords[] = {
            0, 0, // front
            1, 1,
            0, 1,
            
            0, 0,
            1, 0,
            1, 1,
            
            0, 0, // left
            1, 0,
            0, 1,
            
            0, 1,
            1, 0,
            1, 1,
            
            0,0, // top
            0,1,
            1,1,
            
            1, 1,
            1, 0,
            0, 0,
            
            0, 0,// bottom
            0, 1,
            1, 1,
            
            1,1,
            1,0,
            0,0,
            
            0,0,// right
            1,0,
            0,1,
            
            0,1,
            1,0,
            1,1,
            
            0,0, // back
            1,1,
            0,1,
            
            0,0,
            1,0,
            1,1
        };
        
        glGenVertexArrays(1, vao);
        glBindVertexArray(vao[0]);
        glGenBuffers(numVBOs, vbo);
        glBindBuffer(GL_ARRAY_BUFFER, vbo[0]);
        glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
        glBindBuffer(GL_ARRAY_BUFFER, vbo[1]);
        glBufferData(GL_ARRAY_BUFFER, sizeof(texCoords), texCoords, GL_STATIC_DRAW);
        
        glfwGetFramebufferSize(win(), &width, &height);
        aspect = (float)width/(float)height;
        
        p_mat = glm::perspective(1.0472f, aspect, 0.1f, 1000.0f);
        
        glGenTextures(1, &texture);
        glBindTexture(GL_TEXTURE_2D, texture);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        cv::Mat frame;
        frame = cv::imread("texture.png");
        if(frame.empty()) {
            std::cerr << "Error: could not load texture..\n";
            exit(EXIT_FAILURE);
        }
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, frame.cols, frame.rows, 0, GL_RGB, GL_UNSIGNED_BYTE, frame.ptr());
    }
    
    virtual void update(double timeval) override {
        glClearColor(0.0, 0.0, 0.0, 1.0);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glUseProgram(renderingProgram);
        
        mv_loc = glGetUniformLocation(renderingProgram, "mv_matrix");
        proj_loc = glGetUniformLocation(renderingProgram,"proj_matrix");
        
        GLuint samp = glGetUniformLocation(renderingProgram,"samp");
        
        
        v_mat = glm::translate(glm::mat4(1.0f), glm::vec3(-cameraX, cameraY, -cameraZ));
        
        m_mat = glm::translate(glm::mat4(1.0f), glm::vec3(sin(0.35f * timeval)*2.0f, cos(0.52f*timeval)*2.0f, sin(0.7f*timeval)*2.0f));
        
        r_mat = glm::rotate(glm::mat4(1.0f), 1.75f*(float)timeval,glm::vec3(0.0f, 1.0f, 0.0f));
        r_mat = glm::rotate(r_mat, 1.75f*(float)timeval,glm::vec3(1.0f, 0.0f, 0.0f));
        r_mat = glm::rotate(r_mat, 1.75f*(float)timeval, glm::vec3(0.0f, 0.0f, 1.0f));
        
        m_mat = m_mat * r_mat;
        mv_mat = v_mat * m_mat;
        
        glUniformMatrix4fv(mv_loc, 1, GL_FALSE, glm::value_ptr(mv_mat));
        glUniformMatrix4fv(proj_loc, 1, GL_FALSE, glm::value_ptr(p_mat));
        
        glUniformMatrix4fv(mv_loc, 1, GL_FALSE, glm::value_ptr(mv_mat));
        glUniformMatrix4fv(proj_loc, 1, GL_FALSE, glm::value_ptr(p_mat));
        
        glBindBuffer(GL_ARRAY_BUFFER, vbo[0]);
        glVertexAttribPointer(0,3,GL_FLOAT, GL_FALSE,0,0);
        glEnableVertexAttribArray(0);
        
        glBindBuffer(GL_ARRAY_BUFFER, vbo[1]);
        glVertexAttribPointer(1,2,GL_FLOAT,GL_FALSE,0,0);
        glEnableVertexAttribArray(1);
        
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture);
        
        glUniform1i(samp, 0);
        
        glEnable(GL_DEPTH_TEST);
        glEnable(GL_LEQUAL);
        
        glDrawArrays(GL_TRIANGLES,0,36);
    }

    GLuint createShaderProgram() {
        GLuint vfProgram = program.createProgramFromFile("vertex.glsl", "frag.glsl");
        return vfProgram;
    }

    void keypress(int key, int scancode, int action, int mode) {
        if(key == GLFW_KEY_ESCAPE)
            exit(EXIT_SUCCESS);
    }
};

MainWindow main_window;

void key_callback(GLFWwindow *window, int key, int scancode, int action, int mode) {
    main_window.keypress(key, scancode, action, mode);
    std::cout << "keypress: " << key << "\n";
}

int main(int argc, char **argv) {
    if(!glfwInit()) {
        exit(EXIT_FAILURE);
    }
    main_window.create("Test", 1280, 720);
    std::cout << "GL Version: " << glGetString(GL_VERSION) << "\n";
    glfwSetKeyCallback(main_window.win(), key_callback);
    main_window.loop();
    return 0;
}