#include <GL/freeglut.h>
#include <math.h>
#include <vector>
#include <glm/vec2.hpp>

using namespace std;
using namespace glm;

double Y_AXIS = 5;
double aspectRatio = 1;
int points_num = 5;
vec2 center = vec2(2.5,2.4);
double innerR = .3;
double outerR = 1;
double startAngle = 0;
double direction = 1;
double moveSpeed = .05;

double w = 2.0; // angular velocity 	
int FPS = 60; // frames per sec 	
double alpha = w/FPS ;		

vector<vec2> inner;
vector<vec2> outer;

void draw(GLenum mode, vector<vec2> points)
{
	glColor3f(1.0, 1.0, 1.0);
	glBegin(mode);
	for(int i = 0; i < points.size(); i++) 
		glVertex2d(points[i].x, points[i].y);
	glEnd();
}

vector<vec2> createCircle(int points_num, vec2 center, double startAngle, double r)
{
	vector<vec2> points;	
	double dA = M_PI * 2 / points_num;
	double angle = startAngle;
	for (int i = 0; i < points_num; i++)
	{
		points.push_back(vec2(center.x + r*cos(angle), center.y + r*sin(angle)));
		angle += dA;
	}
	
	return points;
}

vector<vec2> createStar(int points_num, vec2 center, double innerR, double outerR, double startAngle)
{
	vector<vec2> points;
	double dA = M_PI * 2 / points_num;
	double angle = startAngle;
	for (int i = 0; i < points_num; i++)
	{
		points.push_back(vec2(center.x + innerR*cos(angle), center.y + innerR*sin(angle)));
		angle += dA / 2;
		points.push_back(vec2(center.x + outerR*cos(angle), center.y + outerR*sin(angle)));
		angle += dA / 2;
		points.push_back(vec2(center.x + innerR*cos(angle), center.y + innerR*sin(angle)));
	}
	
	return points;
}

void display()
{
	glClear(GL_COLOR_BUFFER_BIT);
	glColor3f(1.0, 1.0, 1.0);

	draw(GL_POLYGON, inner);
	draw(GL_TRIANGLES, outer);

	glFlush();
	glutPostRedisplay();
}

void timer(int v)	
{	     	
	startAngle += direction*alpha;

	inner = createCircle(points_num, center, startAngle, innerR);
	outer = createStar(points_num, center, innerR, outerR, startAngle);

	glutTimerFunc(1000/FPS, timer, v);	
	glutPostRedisplay();	
}

void init()
{
	glClearColor (0.0, 0.0, 0.0, 0.0);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(0.0, Y_AXIS*aspectRatio, 0.0, Y_AXIS, -1.0, 1.0);
}

void mouseClick(int button, int state, int x, int y)
{
	if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) points_num++;
   else if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN && points_num>2)	points_num--;
}

void keyboardClick(unsigned char key, int x, int y)
{
	switch (key)
	{
		case 'a':
			if (center.x - moveSpeed>outerR)
				center = vec2(center.x - moveSpeed, center.y);
			break;
		case 's':
			if (center.y - moveSpeed>outerR)
				center = vec2(center.x, center.y - moveSpeed);
			break;
		case 'd':
			if (center.x + moveSpeed<=Y_AXIS*aspectRatio-outerR)
				center = vec2(center.x + moveSpeed, center.y);
			break;
		case 'w':
			if (center.y + moveSpeed<=Y_AXIS - outerR)
				center = vec2(center.x, center.y + moveSpeed);
			break;
		case ' ':
			direction *= -1;
			break;
	}
}
	

int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize (500, 500);
	glutInitWindowPosition (100, 100);
	glutCreateWindow ("ZvezdaGLM");
	init();
	
	inner = createCircle(points_num, center, startAngle, innerR);
	outer = createStar(points_num, center, innerR, outerR, startAngle);

	glutDisplayFunc(display);
	glutTimerFunc(100, timer, 0);	

	glutMouseFunc(mouseClick);
	glutKeyboardFunc(keyboardClick);

	glutMainLoop();
    
	return 0;
}