#ifndef SIMULATION_H
#define SIMULATION_H

#include <igl/opengl/glfw/Viewer.h>
#include "RigidObject.h"

/*
 * Base class for different kinds of simulation. Provides methods for
 * controlling the simulation and rendering it in a Gui.
 */
class Simulation {
public:
	Simulation() {}

	virtual ~Simulation() {}

	/*
	 * Initialize the necessary class variables at the beginning of the
	 * simulation.
	 */
	virtual void init() {}

	/*
	 * Reset class variables to reset the simulation.
	 */
	void reset() {
		m_time = 0.0;
		m_step = 0;
		resetMembers();
	}

	/*
	 * Update the rendering data structures. This method will be called in
	 * alternation with advance(). This method blocks rendering in the
	 * viewer, so do *not* do extensive computation here (leave it to
	 * advance()).
	 */
	virtual void updateRenderGeometry() = 0;

	/*
	 * Performs one simulation step of length m_dt. This method *must* be
	 * thread-safe with respect to renderRenderGeometry() (easiest is to not
	 * touch any rendering data structures at all). You have to update the time
	 * variables at the end of each step if they are necessary for your
	 * simulation.
	 */
	virtual bool advance() = 0;

	/*
	 * Perform any actual rendering here. This method *must* be thread-safe with
	 * respect to advance(). This method runs in the same thread as the
	 * viewer and blocks user IO, so there really should not be any extensive
	 * computation here or the UI will lag/become unresponsive (the whole reason
	 * the simulation itself is in its own thread.)
	 */
	virtual void renderRenderGeometry(igl::opengl::glfw::Viewer &viewer) = 0;

	void setTimestep(double t) { m_dt = t; }

	double getTime() const { return m_time; }

	unsigned long getStep() const { return m_step; }

	std::vector<RigidObject> &getObjects() { return m_objects; }

protected:
	/*
	 * Reset class variables specific to a certain simulation. Is called by
	 * Simulation::reset().
	 */
	virtual void resetMembers() = 0;

	std::vector<RigidObject>
		m_objects;             // vector of all objects in the simulation
	double m_dt = 0.0;         // length of timestep
	double m_time = 0.0;       // current time
	unsigned long m_step = 0;  // number of performed steps in simulation
};

#endif