// trace around a square

Box box;
P2D lineEnd;

//P2D pointA;
P2D pointB;
P2D pointC;

// angles
float A;
float B;
float C;

// sides
float a;
float b;
float c;

float angle;

int then;
int now;
float elapsed;

boolean paused;

PFont font;

void setup() {
	size(200,200);
	noSmooth();
	stroke(255);
	strokeWeight(1);
	fill(255,120,0);
	font = loadFont("04b-08-8.vlw");
	textFont(font);
	
	box = new Box();
		
	pointB = new P2D();
	pointC = new P2D();
	C = radians(90);
	angle = 0.0f;
	
	then = millis();		// used for pausing
	paused = false;			// if you press UP or DOWN it resumes a "demo" mode
}

void draw() {
	background(255,120,0);
	stroke(255,80);
	fill(255,255,255,40);
	rect(box.x, box.y, box.h, box.w);
	fill(255);
	text("Angle: " + angle, 0, 8);
	text("Distance: " + (int)c, 0, 16);
	text("Use UP/DOWN to move if you want.", 0, height - 1);
	
	if (paused == true) {
		now = millis();
		elapsed = ((now - then) / 1000.0f);
		if (elapsed >= 2) {
			paused = false;
		}
	}
	
	//angle = 140.0f;
	
	if (! paused) {
		angle++;
	}
	// increment this
	//A = radians(angle++);

	if (angle >= 0.0f && angle < 45.0f) {
			A = radians(angle);
	} else if (angle >= 45.0f && angle < 90.0f) {
			A = radians(90.0f - angle);
	} else if (angle >= 90.0f && angle < 135.0f) {
			A = radians(135.0f - angle);
	} else if (angle >= 135.0f && angle < 180.0f) {
			A = radians(180.0f - angle);
	} else if (angle >= 180.0f && angle < 225.0f) {
			A = radians(225.0f - angle);
	} else if (angle >= 225.0f && angle < 270.0f) {
			A = radians(270.0f - angle);
	} else if (angle >= 270.0f && angle < 315.0f) {
			A = radians(315.0f - angle);
	} else if (angle >= 315.0f && angle < 360.0f) {
			A = radians(360.0f - angle);
	}
	
	// solve angle B
	// all triangles are 180º and we know C is 90
	B = radians(180 - C - A);

	// b is known
	b = box.h / 2;

	// TOA tan(A) = opposite (a) / adjacent (b)
	a = tan(A) * b;	

	// SOH sin(A) = opposite (a) / hypotenuse (c)
	//c = a / sin(radians(angle));

	c = sqrt(abs(a*a) + abs(b*b));
	
	// 1st octet
	if (angle < 45.0f) {
		pointC.x = box.center.x;
		pointC.y = box.center.y - b;

		pointB.x = pointC.x + a;
		pointB.y = pointC.y;
	}	
	
	// 2nd octet
	if (angle >= 45.0f && angle < 90.0f) {
		pointC.x = box.center.x + b;
		pointC.y = box.center.y;

		pointB.x = box.center.x + b;
		pointB.y = box.center.y - a;
	}
	
	// 3rd octet
	if (angle >= 90.0f && angle < 135.0f) {
		pointC.x = box.center.x + b;
		pointC.y = box.center.y;

		pointB.x = box.center.x + b;
		pointB.y = box.center.y + (b - a);
	}
	
	// 4th octet
	if (angle >= 135.0f && angle < 180.0f) {
		pointC.x = box.center.x;
		pointC.y = box.center.y + b;

		pointB.x = box.center.x + a;
		pointB.y = box.center.y + b;
	}

	// 5th octet
	if (angle >= 180.0f && angle < 225.0f) {
		pointC.x = box.center.x;
		pointC.y = box.center.y + b;

		pointB.x = box.center.x - (b - a);
		pointB.y = box.center.y + b;
	}
	
	// 6th octet
	if (angle >= 225.0f && angle < 270.0f) {
		pointC.x = box.center.x - b;
		pointC.y = box.center.y;

		pointB.x = box.center.x - b;
		pointB.y = box.center.y + a;
	}

	// 7th octet
	if (angle >= 270.0f && angle < 315.0f) {
		pointC.x = box.center.x - b;
		pointC.y = box.center.y;

		pointB.x = box.center.x - b;
		pointB.y = box.center.y - (b-a);
	}
	
	// 8th octet
	if (angle >= 315.0f && angle <= 360.0f) {
		pointC.x = box.center.x;
		pointC.y = box.center.y - b;

		pointB.x = pointC.x - a;
		pointB.y = pointC.y;
	}
	
	// if value is past limit, flip value to fake continuity
	if (angle > 360.0f) {
		angle = 0.0f;
	}

	// if value is pas limit, flip value to fake continuity	
	if (angle < 0.0f) {
		angle = 360.0f;
	}


	stroke(180,80,20);	
	// adjacent
	line(box.center.x, box.center.y, pointC.x, pointC.y);

	stroke(255);	
	// opposite
	fill(255,255,255,120);
	rect(pointB.x-8, pointB.y-8, 16, 16);
	line(pointC.x, pointC.y, pointB.x, pointB.y);

	stroke(180,80,20);	
	// hypotenuse
	line(box.center.x, box.center.y, pointB.x, pointB.y);
}

void keyPressed() {
	if (keyCode == UP) {
		//debug();
		paused = true;
		then = millis();
		angle++;
	}
	if (keyCode == DOWN) {
		//debug();
		paused = true;
		then = millis();
		angle--;
	}
}

void debug() {
		println("angle:" + angle + " RAD:" + A + " a:" + a + " b:" + b);	
}

/*
int B(int C, int A) {
	return 180 - C - A;
}

float a(int A, int b) {
	return tan(A) * b;
}*/


// quick and dirty
class Box {
	public float x;
	public float y;
	public float h;
	public float w;
	public P2D center;
	
	public Box() {
		x = 25;
		y = 25;
		h = 150;
		w = 150;
		
		center = new P2D(x + (w/2), y + (h/2));
	}
}

class P2D {
	public float x;
	public float y;
	
	public P2D(float x, float y) {
		this.x=x;
		this.y=y;
	}
	public P2D() {
		
	}
}