// written in the D programming language

module samples.Player;

import chipmunkd.chipmunk;

import samples.ChipmunkDemo;

import gameApp;

static cpSpace *space;

struct PlayerStruct {
	cpFloat u;
	cpShape *shape;
	cpVect groundNormal;
	cpArray *groundShapes;
}

PlayerStruct playerInstance;

static cpBool
begin(cpArbiter *arb, cpSpace *space, void *ignore)
{
	mixin(CP_ARBITER_GET_SHAPES!("arb", "a", "b"));
	PlayerStruct *player = cast(PlayerStruct *)a.data;
	
	cpVect n = cpvneg(cpArbiterGetNormal(arb, 0));
	if(n.y > 0.0f){
		cpArrayPush(player.groundShapes, b);
	}
	
	return cpTrue;
}

static cpBool
preSolve(cpArbiter *arb, cpSpace *space, void *ignore)
{
	mixin(CP_ARBITER_GET_SHAPES!("arb", "a", "b"));
	PlayerStruct *player = cast(PlayerStruct *)a.data;
	
	if(cpArbiterIsFirstContact(arb)){
		a.u = player.u;
		
		// pick the most upright jump normal each frame
		cpVect n = cpvneg(cpArbiterGetNormal(arb, 0));
		if(n.y >= player.groundNormal.y){
			player.groundNormal = n;
		}
	}
	
	return cpTrue;
}

static void
separate(cpArbiter *arb, cpSpace *space, void *ignore)
{
	mixin(CP_ARBITER_GET_SHAPES!("arb", "a", "b"));
	PlayerStruct *player = cast(PlayerStruct *)a.data;
	
	cpArrayDeleteObj(player.groundShapes, b);
	
	if(player.groundShapes.num == 0){
		a.u = 0.0f;
		player.groundNormal = cpvzero;
	}
}

static void
playerUpdateVelocity(cpBody *_body, cpVect gravity, cpFloat damping, cpFloat dt)
{
	cpBodyUpdateVelocity(_body, gravity, damping, dt);
	_body.v.y = cpfmax(_body.v.y, -700);
	_body.v.x = cpfclamp(_body.v.x, -400, 400);
}


static void
update(int ticks)
{
	static int lastJumpState = 0;
	int jumpState = (arrowDirection.y > 0.0f);
	
	cpBody *_body = playerInstance.shape._body;
	
	cpVect groundNormal = playerInstance.groundNormal;
	if(groundNormal.y > 0.0f){
		playerInstance.shape.surface_v = cpvmult(cpvperp(groundNormal), 400.0f*arrowDirection.x);
		if(arrowDirection.x) cpBodyActivate(_body);
	} else {
		playerInstance.shape.surface_v = cpvzero;
	}
	
	// apply jump
	if(jumpState && !lastJumpState && cpvlengthsq(groundNormal)){
//		body.v = cpvmult(cpvslerp(groundNormal, cpv(0.0f, 1.0f), 0.5f), 500.0f);
		_body.v = cpvadd(_body.v, cpvmult(cpvslerp(groundNormal, cpv(0.0f, 1.0f), 0.75f), 500.0f));
		cpBodyActivate(_body);
	}
	
	if(playerInstance.groundShapes.num == 0){
		cpFloat air_accel = _body.v.x + arrowDirection.x*(2000.0f);
		_body.f.x = _body.m*air_accel;
//		body.v.x = cpflerpconst(body.v.x, 400.0f*arrowDirection.x, 2000.0f/60.0f);
	}
	
	enum int steps = 3;
	enum cpFloat dt = 1.0f/60.0f/cast(cpFloat)steps;
	
	for(int i=0; i<steps; i++){
		cpSpaceStep(space, dt);
	}
	
	lastJumpState = jumpState;
}

static cpSpace *
init()
{
	cpResetShapeIdCounter();
	
	space = cpSpaceNew();
	space.iterations = 10;
	space.gravity = cpv(0, -1500);

	cpBody *_body;
	cpBody *staticBody = &space.staticBody;
	cpShape *shape;
	
	// Create segments around the edge of the screen.
	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,-240), cpv(-320,240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	shape.collision_type = 2;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(320,-240), cpv(320,240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	shape.collision_type = 2;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,-240), cpv(320,-240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	shape.collision_type = 2;
	
	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-320,240), cpv(320,240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	shape.collision_type = 2;
	
	// add some other segments to play with
	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-220,-200), cpv(-220,240), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	shape.collision_type = 2;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(0,-240), cpv(320,-200), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	shape.collision_type = 2;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(200,-240), cpv(320,-100), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	shape.collision_type = 2;

	shape = cpSpaceAddShape(space, cpSegmentShapeNew(staticBody, cpv(-220,-80), cpv(200,-80), 0.0f));
	shape.e = 1.0f; shape.u = 1.0f;
	shape.layers = NOT_GRABABLE_MASK;
	shape.collision_type = 2;
	
	// Set up the player
	cpFloat radius = 15.0f;
	_body = cpSpaceAddBody(space, cpBodyNew(10.0f, INFINITY));
	_body.p = cpv(0, -220);
	_body.velocity_func = &playerUpdateVelocity;

	shape = cpSpaceAddShape(space, cpCircleShapeNew(_body, radius, cpvzero));
	shape.e = 0.0f; shape.u = 2.0f;
	shape.collision_type = 1;
	
	playerInstance.u = shape.u;
	playerInstance.shape = shape;
	playerInstance.groundShapes = cpArrayNew(0);
	shape.data = &playerInstance;
	
	cpSpaceAddCollisionHandler(space, 1, 2, &begin, &preSolve, null, &separate, null);
	
	return space;
}

static void
destroy()
{
	cpSpaceFreeChildren(space);
	cpSpaceFree(space);
	
	cpArrayFree(playerInstance.groundShapes);
}

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