#include <iostream>
#include <GL/glut.h>

static int day = 0;
static int year = 0;
static int months = 0;
static bool hidden = true;
static float dz = 0;
static float dx = 0;
static float dy = 0;

void init(void)
{
	glClearColor(0.0,0.0,0.0,0.0);
	glColor3f(1.0,1.0,1.0);
}

void display(void)
{
	glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	if(hidden)
	glEnable(GL_DEPTH_TEST);
	else
	glDisable(GL_DEPTH_TEST);

	glPushMatrix();

	glEnable(GL_LIGHTING);
	glEnable(GL_LIGHT0);
	GLfloat lightPos[] = {dx,dy,dz,1.0};
	glLightfv(GL_LIGHT0,GL_POSITION,lightPos);

	GLfloat mDiffs[] = {1.0,1.0,0.0,1.0};
	glMaterialfv(GL_FRONT,GL_DIFFUSE,mDiffs);
	//sun
	glRotatef(year,0.0,1.0,0.0);
	glColor3f(1.0, 1.0,0.0);
	glutSolidSphere(1.0, 20, 16);
	//earth
	//glColor3f(0.0, 0.0,1.0);
	GLfloat mDiffe[] = {0.0,0.0,1.0,1.0};
	glMaterialfv(GL_FRONT,GL_DIFFUSE,mDiffe);
	glTranslatef(2.0,0.0,0.0);
	glRotatef(day,0.0,1.0,0.0);
	glutSolidSphere(0.2, 10, 8);

	//moon
	GLfloat mDiff[] = {1.0,1.0,1.0,1.0};
	glMaterialfv(GL_FRONT,GL_DIFFUSE,mDiff);
	//glColor3f(1.0, 1.0,1.0);
	glRotatef(months,1.0,0.0,0.0);
	glTranslatef(0.0,0.5,0.0);
	glutSolidSphere(0.1, 10, 8);

	glPopMatrix();
	glutSwapBuffers();

}

void reshape (int w, int h)
{
	glViewport (0,0, (GLsizei) w, (GLsizei)h);
	glMatrixMode (GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt(0.0,0.0,5.0,	0.0,0.0,0.0,	0.0,1.0,0.0);
}


void specialKey(int key, int x, int y)
  {

	   switch(key)
	   {

        case GLUT_KEY_UP:
			dz-=0.25;
			std::cout<<"X:Y:Z = "<<dx<<":"<<dy<<":"<<dz<<std::endl;
			glutPostRedisplay();
          break;
        case GLUT_KEY_DOWN:
			dz+=0.25;
			std::cout<<"X:Y:Z = "<<dx<<":"<<dy<<":"<<dz<<std::endl;
			glutPostRedisplay();
          break;

	}
  }

void keyboard(unsigned char key, int x, int y)
{
	switch(key)
	{
		case 'd':
				day = (day + 15) % 360;
				glutPostRedisplay();
				break;
		case 'D':
				day = (day - 15) % 360;
				glutPostRedisplay();
				break;
		case 'y':
				year = (year + 30) % 360;
				glutPostRedisplay();
				break;
		case 'Y':
				year = (year - 30) % 360;
				glutPostRedisplay();
				break;

		case 'm':
				months = (months + 12) % 360;
				glutPostRedisplay();
				break;
		case 'M':
				months = (months - 12) % 360;
				glutPostRedisplay();
				break;
		case 'a':
				day = (day + 15) % 360;
				year = (year + 5) % 360;
				months = (months + 5) % 360;
				glutPostRedisplay();
				break;
		case 'h':
				hidden = !hidden;
				glutPostRedisplay();
				break;

		case 27:
				exit(0);
				break;
		default:
				break;
	}
}

int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB| GLUT_DEPTH);
	glutInitWindowSize(600, 600);
	glutInitWindowPosition(50, 200);
	glutCreateWindow("OpenGL-XI");
	glutDisplayFunc(display);
	glutReshapeFunc(reshape);
	glutKeyboardFunc(keyboard);
	glutSpecialFunc(specialKey);
	init();
	glutMainLoop();
	return(0);
}