#ifndef physics_hpp
#define physics_hpp

#include "asset.hpp"
#include "maths.hpp"

#include <tuple>

struct Arena;
struct Line_Renderer;
struct World;

struct Manifold {
	static constexpr int max_contacts = 16;
	v3f contacts[max_contacts];
	int contact_count;
	v3f normal;
};

struct Rigidbody;
struct Int_Collider {
	Rigidbody* rb;
	Int_Collider* next;
	int vert_count;
	int face_count;
	v3f* verts;
	v3f* faces;

	bool collide(const Int_Collider& other) const;
};

struct Collider : Asset {
	struct Face {
		v3f normal;
		int vert_count;
		uint16_t* verts;
	};
	int face_count;
	int vert_count;
	Face* faces;
	v3f* verts;
	m3f moment;

	void debug_render(
		Line_Renderer& lr,
		const m4f& t,
		const v3f& c
	);
	Int_Collider* transform(const m4f& m, Arena* a) const;
};

struct Rigidbody {
	v3f prev_pos, pos;
	v3f vel, avel;
	v3f force;
	v3f torque;
	v4f prev_rot, rot;
	float inv_mass;
	Collider* col;
	int colliding;

	void init(Collider* c, const v3f& p, const v4f& r, float mass);
	void set_pos(const v3f& p);
	void set_rot(const v4f& r);
	void set_mass(float m);
	void add_force(const v3f& f);
	void add_force(const v3f& f, const v3f& p);
	void add_impulse(const v3f& f);
	void add_impulse(const v3f& f, const v3f& p);
	void add_torque(const v3f& t);
};

Collider* make_box(Arena* a, const v3f& size);

void physics_update(World& w, Arena* a, float ts);
void physics_debug(World& w, Line_Renderer& lr);

#endif