#ifndef SIMULATION_H_7BF6EEA4
#define SIMULATION_H_7BF6EEA4

#include "entity.h"
#include "renderer.h"
#include <vector>
#include <deque>
#include <set>
#include <unordered_map>
#include <unordered_set>

class Level;

class Simulation {
public:

  using id_type = std::vector<Entity>::size_type;

  // Constructor
  explicit Simulation(const Level& level) : level_(level) {}

  void tick(
    double dt,
    const Uint8* keystate);

  id_type emplaceEntity();

  void deleteEntity(id_type id);

  Entity& getEntity(id_type id)
  {
    return entities_.at(id);
  }

  const Entity& getEntity(id_type id) const
  {
    return entities_.at(id);
  }

  const std::set<id_type>& getActive() const
  {
    return active_;
  }

  const Level& getLevel() const
  {
    return level_;
  }

  void setGridPos(id_type id, vec2s pos);

  static vec2s posInDir(vec2s orig, Direction dir);

private:



  const std::unordered_set<id_type>& getGridEntities(vec2s pos) const;

  bool moveEntityOnGrid(
    id_type id,
    Direction moveDir,
    bool validate = false);

  const Level& level_;

  std::vector<Entity> entities_;
  std::deque<id_type> available_;
  std::set<id_type> active_;

  mutable std::unordered_map<size_t, std::unordered_set<id_type>> gridCache_;
};

#endif /* end of include guard: SIMULATION_H_7BF6EEA4 */