// written in the D programming language

module samples.Pump;

import chipmunkd.chipmunk;

import samples.ChipmunkDemo;

import gameApp;

import std.math;

enum M_PI = PI;
enum M_PI_2 = PI*0.5f;

static cpSpace *space;
static cpConstraint *motor;

enum numBalls = 5;
static cpBody *balls[numBalls];

static void
update(int ticks)
{
	cpFloat coef = (2.0f + arrowDirection.y)/3.0f;
	cpFloat rate = arrowDirection.x*30.0f*coef;
	
	cpSimpleMotorSetRate(motor, rate);
	motor.maxForce = (rate ? 1000000.0f : 0.0f);

	enum int steps = 2;
	enum cpFloat dt = 1.0f/60.0f/cast(cpFloat)steps;
	
	for(int i=0; i<steps; i++){
		cpSpaceStep(space, dt);
		
		for(int j=0; j<numBalls; j++){
			cpBody *ball = balls[j];
			if(ball.p.x > 320.0f){
				ball.v = cpvzero;
				ball.p = cpv(-224.0f, 200.0f);
			}
		}
	}
}

static cpBody *
add_ball(cpVect pos)
{
	cpBody *_body = cpSpaceAddBody(space, cpBodyNew(1.0f, cpMomentForCircle(1.0f, 30, 0, cpvzero)));
	_body.p = pos;
	
	cpShape *shape = cpSpaceAddShape(space, cpCircleShapeNew(_body, 30, cpvzero));
	shape.e = 0.0f; shape.u = 0.5f;
	
	return _body;
}

static cpSpace *
init()
{
	space = cpSpaceNew();
	space.gravity = cpv(0, -600);
	
	cpBody *staticBody = &space.staticBody;
	cpShape *shape;
	
	// beveling all of the line segments slightly helps prevent things from getting stuck on cracks
	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-256,16), cpv(-256,300), 2.0f));
	shape.e = 0.0f; shape.u = 0.5f; shape.layers = 1;
	shape.layers = NOT_GRABABLE_MASK;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-256,16), cpv(-192,0), 2.0f));
	shape.e = 0.0f; shape.u = 0.5f; shape.layers = 1;
	shape.layers = NOT_GRABABLE_MASK;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-192,0), cpv(-192, -64), 2.0f));
	shape.e = 0.0f; shape.u = 0.5f; shape.layers = 1;
	shape.layers = NOT_GRABABLE_MASK;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-128,-64), cpv(-128,144), 2.0f));
	shape.e = 0.0f; shape.u = 0.5f; shape.layers = 1;
	shape.layers = NOT_GRABABLE_MASK;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-192,80), cpv(-192,176), 2.0f));
	shape.e = 0.0f; shape.u = 0.5f; shape.layers = 1;
	shape.layers = NOT_GRABABLE_MASK;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-192,176), cpv(-128,240), 2.0f));
	shape.e = 0.0f; shape.u = 0.0f; shape.layers = 1;
	shape.layers = NOT_GRABABLE_MASK;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-128,144), cpv(192,64), 2.0f));
	shape.e = 0.0f; shape.u = 0.5f; shape.layers = 1;
	shape.layers = NOT_GRABABLE_MASK;

	cpVect verts[] = [
		cpv(-30,-80),
		cpv(-30, 80),
		cpv( 30, 64),
		cpv( 30,-80),
	];

	cpBody *plunger = cpSpaceAddBody(space, cpBodyNew(1.0f, INFINITY));
	plunger.p = cpv(-160,-80);
	
	shape = cpSpaceAddShape(space, cpPolyShapeNew(plunger, 4, verts.ptr, cpvzero));
	shape.e = 1.0f; shape.u = 0.5f; shape.layers = 1;
	
	// add balls to hopper
	for(int i=0; i<numBalls; i++)
		balls[i] = add_ball(cpv(-224 + i,80 + 64*i));
	
	// add small gear
	cpBody *smallGear = cpSpaceAddBody(space, cpBodyNew(10.0f, cpMomentForCircle(10.0f, 80, 0, cpvzero)));
	smallGear.p = cpv(-160,-160);
	cpBodySetAngle(smallGear, cast(float)-M_PI_2);

	shape = cpSpaceAddShape(space, cpCircleShapeNew(smallGear, 80.0f, cpvzero));
	shape.layers = 0;
	
	cpSpaceAddConstraint(space, cpPivotJointNew2(staticBody, smallGear, cpv(-160,-160), cpvzero));

	// add big gear
	cpBody *bigGear = cpSpaceAddBody(space, cpBodyNew(40.0f, cpMomentForCircle(40.0f, 160, 0, cpvzero)));
	bigGear.p = cpv(80,-160);
	cpBodySetAngle(bigGear, cast(float)M_PI_2);
	
	shape = cpSpaceAddShape(space, cpCircleShapeNew(bigGear, 160.0f, cpvzero));
	shape.layers = 0;
	
	cpSpaceAddConstraint(space, cpPivotJointNew2(staticBody, bigGear, cpv(80,-160), cpvzero));

	// connect the plunger to the small gear.
	cpSpaceAddConstraint(space, cpPinJointNew(smallGear, plunger, cpv(80,0), cpv(0,0)));
	// connect the gears.
	cpSpaceAddConstraint(space, cpGearJointNew(smallGear, bigGear, -M_PI_2, -2.0f));
	
	
	// feeder mechanism
	cpFloat bottom = -300.0f;
	cpFloat top = 32.0f;
	cpBody *feeder = cpSpaceAddBody(space, cpBodyNew(1.0f, cpMomentForSegment(1.0f, cpv(-224.0f, bottom), cpv(-224.0f, top))));
	feeder.p = cpv(-224, (bottom + top)/2.0f);
	
	cpFloat len = top - bottom;
	cpSpaceAddShape(space, cpSegmentShapeNew(feeder, cpv(0.0f, len/2.0f), cpv(0.0f, -len/2.0f), 20.0f));
	
	cpSpaceAddConstraint(space, cpPivotJointNew2(staticBody, feeder, cpv(-224.0f, bottom), cpv(0.0f, -len/2.0f)));
	cpVect anchr = cpBodyWorld2Local(feeder, cpv(-224.0f, -160.0f));
	cpSpaceAddConstraint(space, cpPinJointNew(feeder, smallGear, anchr, cpv(0.0f, 80.0f)));

	// motorize the second gear
	motor = cpSpaceAddConstraint(space, cpSimpleMotorNew(staticBody, bigGear, 3.0f));

	return space;
}

static void
destroy()
{
	cpSpaceFreeChildren(space);
	cpSpaceFree(space);
}

chipmunkDemo Pump = {
	"Pump",
	null,
	&init,
	&update,
	&destroy,
};