#pragma once

#include "utility.h"
#include <Entities/Entity.h>

class EntityView;

class EntityViewIterator
{
  friend class EntityView;

  EntityViewIterator(EntityIndex);

  EntityViewIterator& operator++();

  EntityViewIterator operator++(int);

  EntityViewIterator& operator--();

  EntityViewIterator operator--(int);

  Entity operator*();

  Entity operator[](int);
  Entity* operator->();

  bool operator==(EntityViewIterator);
  bool operator!=(EntityViewIterator);

private:
  Entity m_currentEntity;
};

class EntityViewConstIterator
{
  friend class EntityView;
  
  EntityViewConstIterator(EntityIndex index);

  EntityViewConstIterator& operator++();

  EntityViewConstIterator operator++(int);

  EntityViewConstIterator& operator--();

  EntityViewConstIterator operator--(int);

  const Entity operator*();

  const Entity operator[](int index);

  const Entity* operator->();


  bool operator==(EntityViewConstIterator);
  bool operator!=(EntityViewConstIterator);

private:
  Entity m_currentEntity;
};

class EntityView
{
public:
  friend class EntityManager;
  EntityView() = delete;
  EntityView(EntityIndex, EntityIndex);

  using iterator = EntityViewIterator;
  using const_iterator = EntityViewConstIterator;

  iterator begin() { return iterator(m_start); }
  iterator end()   { return iterator(m_start + m_size); }



  const_iterator cbegin() const { return const_iterator(m_start); }
  const_iterator cend()   const { return const_iterator(m_start + m_size); }
private:
  EntityIndex m_start;
  EntityIndex m_size;
};