#include <iostream>
#include <stdlib.h>

#ifdef __APPLE__
#   include <OpenGL/OpenGL.h>
#   include <GLUT/glut.h>
#else
#   include <GL/glut.h>
#endif
#include "../easylogging++.h"

#include "imageloader.h"

INITIALIZE_EASYLOGGINGPP

using namespace std;

const float BOX_SIZE = 7.0f; //The length of each side of the cube
float _angle = 0;            //The rotation of the box
GLuint _textureId;           //The OpenGL id of the texture

void handleKeypress(unsigned char key, int x, int y) {
    switch (key) {
        case 27: //Escape key
            exit(0);
    }
}

//Makes the image into a texture, and returns the id of the texture
GLuint loadTexture(Image* image) {
    VLOG(1) << "Loading texture from image...";
    GLuint textureId;
    glGenTextures(1, &textureId);
    glBindTexture(GL_TEXTURE_2D, textureId);
    glTexImage2D(GL_TEXTURE_2D,
                 0,
                 GL_RGB,
                 image->width, image->height,
                 0,
                 GL_RGB,
                 GL_UNSIGNED_BYTE,
                 image->pixels);
    return textureId;
}

void initRendering() {
    VLOG(1) << "Initializing rendering";
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_NORMALIZE);
    glEnable(GL_COLOR_MATERIAL);
    
    Image* image = loadBMP("vtr.bmp");
    _textureId = loadTexture(image);
    delete image;
}

void handleResize(int w, int h) {
    VLOG(1) << "Resizing to [" << w << " x " << h << "]";
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45.0, (float)w / (float)h, 1.0, 200.0);
}

void drawScene() {
    VLOG(3) << "Drawing scene...";
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    
    glTranslatef(0.0f, 0.0f, -20.0f);
    
    GLfloat ambientLight[] = {0.3f, 0.3f, 0.3f, 1.0f};
    glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambientLight);
    
    GLfloat lightColor[] = {0.7f, 0.7f, 0.7f, 1.0f};
    GLfloat lightPos[] = {-2 * BOX_SIZE, BOX_SIZE, 4 * BOX_SIZE, 1.0f};
    glLightfv(GL_LIGHT0, GL_DIFFUSE, lightColor);
    glLightfv(GL_LIGHT0, GL_POSITION, lightPos);
    
    glRotatef(-_angle, 1.0f, 1.0f, 0.0f);
    
    glBegin(GL_QUADS);
    
    //Top face
    glColor3f(1.0f, 1.0f, 0.0f);
    glNormal3f(0.0, 1.0f, 0.0f);
    glVertex3f(-BOX_SIZE / 2, BOX_SIZE / 2, -BOX_SIZE / 2);
    glVertex3f(-BOX_SIZE / 2, BOX_SIZE / 2, BOX_SIZE / 2);
    glVertex3f(BOX_SIZE / 2, BOX_SIZE / 2, BOX_SIZE / 2);
    glVertex3f(BOX_SIZE / 2, BOX_SIZE / 2, -BOX_SIZE / 2);
    
    //Bottom face
    glColor3f(1.0f, 0.0f, 1.0f);
    glNormal3f(0.0, -1.0f, 0.0f);
    glVertex3f(-BOX_SIZE / 2, -BOX_SIZE / 2, -BOX_SIZE / 2);
    glVertex3f(BOX_SIZE / 2, -BOX_SIZE / 2, -BOX_SIZE / 2);
    glVertex3f(BOX_SIZE / 2, -BOX_SIZE / 2, BOX_SIZE / 2);
    glVertex3f(-BOX_SIZE / 2, -BOX_SIZE / 2, BOX_SIZE / 2);
    
    //Left face
    glNormal3f(-1.0, 0.0f, 0.0f);
    glColor3f(0.0f, 1.0f, 1.0f);
    glVertex3f(-BOX_SIZE / 2, -BOX_SIZE / 2, -BOX_SIZE / 2);
    glVertex3f(-BOX_SIZE / 2, -BOX_SIZE / 2, BOX_SIZE / 2);
    glColor3f(0.0f, 0.0f, 1.0f);
    glVertex3f(-BOX_SIZE / 2, BOX_SIZE / 2, BOX_SIZE / 2);
    glVertex3f(-BOX_SIZE / 2, BOX_SIZE / 2, -BOX_SIZE / 2);
    
    //Right face
    glNormal3f(1.0, 0.0f, 0.0f);
    glColor3f(1.0f, 0.0f, 0.0f);
    glVertex3f(BOX_SIZE / 2, -BOX_SIZE / 2, -BOX_SIZE / 2);
    glVertex3f(BOX_SIZE / 2, BOX_SIZE / 2, -BOX_SIZE / 2);
    glColor3f(0.0f, 1.0f, 0.0f);
    glVertex3f(BOX_SIZE / 2, BOX_SIZE / 2, BOX_SIZE / 2);
    glVertex3f(BOX_SIZE / 2, -BOX_SIZE / 2, BOX_SIZE / 2);
    
    glEnd();
    
    glEnable(GL_TEXTURE_2D);
    glBindTexture(GL_TEXTURE_2D, _textureId);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glColor3f(1.0f, 1.0f, 1.0f);
    glBegin(GL_QUADS);
    
    //Front face
    glNormal3f(0.0, 0.0f, 1.0f);
    glTexCoord2f(0.0f, 0.0f);
    glVertex3f(-BOX_SIZE / 2, -BOX_SIZE / 2, BOX_SIZE / 2);
    glTexCoord2f(1.0f, 0.0f);
    glVertex3f(BOX_SIZE / 2, -BOX_SIZE / 2, BOX_SIZE / 2);
    glTexCoord2f(1.0f, 1.0f);
    glVertex3f(BOX_SIZE / 2, BOX_SIZE / 2, BOX_SIZE / 2);
    glTexCoord2f(0.0f, 1.0f);
    glVertex3f(-BOX_SIZE / 2, BOX_SIZE / 2, BOX_SIZE / 2);
    
    //Back face
    glNormal3f(0.0, 0.0f, -1.0f);
    glTexCoord2f(0.0f, 0.0f);
    glVertex3f(-BOX_SIZE / 2, -BOX_SIZE / 2, -BOX_SIZE / 2);
    glTexCoord2f(1.0f, 0.0f);
    glVertex3f(-BOX_SIZE / 2, BOX_SIZE / 2, -BOX_SIZE / 2);
    glTexCoord2f(1.0f, 1.0f);
    glVertex3f(BOX_SIZE / 2, BOX_SIZE / 2, -BOX_SIZE / 2);
    glTexCoord2f(0.0f, 1.0f);
    glVertex3f(BOX_SIZE / 2, -BOX_SIZE / 2, -BOX_SIZE / 2);
    
    glEnd();
    glDisable(GL_TEXTURE_2D);
    
    glutSwapBuffers();
}

//Called every 25 milliseconds
void update(int value) {
    _angle += 1.0f;
    if (_angle > 360) {
        _angle -= 360;
    }
    VLOG(3) << "Updating ... [angle: " << _angle << "]";
    glutPostRedisplay();
    glutTimerFunc(25, update, 0);
}

int main(int argc, char** argv) {

    START_EASYLOGGINGPP(argc, argv);

    LOG(INFO) << "Source base taken from http://www.muflihun.com";

    LOG_IF(!VLOG_IS_ON(1), INFO) << "Try using --v=1 or --v=2 or --verbose command line arguments as well";

    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(400, 400);
    
    glutCreateWindow("Great Cube Sample");
    initRendering();
    
    glutDisplayFunc(drawScene);
    glutKeyboardFunc(handleKeypress);
    glutReshapeFunc(handleResize);
    glutTimerFunc(25, update, 0);
    
    glutMainLoop();
    return 0;
}