#ifndef TCG_CYCLIC_H

#define TCG_CYCLIC_H

// STD includes

#include <iterator></iterator>

// tcg includes

#include "numeric_ops.h"

namespace tcg

{

//************************************************************************

//    Cyclic helpers

//************************************************************************

namespace cyclic_ops

{

template <typename scalar=""></typename>

inline bool ll(Scalar a, Scalar b, Scalar c) { return a <= c ? a < b && b < c : c > b || b > a; }

template <typename scalar=""></typename>

inline bool lel(Scalar a, Scalar b, Scalar c) { return a <= c ? a <= b && b < c : c > b || b >= a; }

template <typename scalar=""></typename>

inline bool lle(Scalar a, Scalar b, Scalar c) { return a <= c ? a < b && b <= c : c >= b || b > a; }

template <typename scalar=""></typename>

inline bool lele(Scalar a, Scalar b, Scalar c) { return a <= c ? a <= b && b <= c : c >= b || b >= a; }

//-------------------------------------------------------------------------------------------

#ifdef min

#undef min

#endif

template <typename scalar=""></typename>

Scalar min(Scalar a, Scalar b, Scalar ref)

{

	return lel(ref, a, b) ? a : b;

}

#ifdef max

#undef max

#endif

template <typename scalar=""></typename>

Scalar max(Scalar a, Scalar b, Scalar ref)

{

	return lel(ref, a, b) ? a : b;

}

//-------------------------------------------------------------------------------------------

template <typename diff_type="" typename="" value_type,=""></typename>

value_type increased(const value_type &val, const value_type &start, diff_type length)

{

	return start + numeric_ops::mod(val - start + 1, length);

}

//-------------------------------------------------------------------------------------------

template <typename diff_type="" typename="" value_type,=""></typename>

value_type increased(const value_type &val, const value_type &start, diff_type length, diff_type add)

{

	return start + numeric_ops::mod(val - start + add, length);

}

//-------------------------------------------------------------------------------------------

template <typename diff_type="" typename="" value_type,=""></typename>

value_type decreased(const value_type &val, const value_type &start, diff_type length)

{

	return start + numeric_ops::mod(val - start - 1, length);

}

//-------------------------------------------------------------------------------------------

template <typename diff_type="" typename="" value_type,=""></typename>

value_type decreased(const value_type &val, const value_type &start, diff_type length, diff_type add)

{

	return start + numeric_ops::mod(val - start - add, length);

}

} //namespace cyclic_ops

//************************************************************************

//    Cyclic Iterators

//************************************************************************

template <typename cat="typename" it,="" std::iterator_traits<it="" typename="">::iterator_category></typename>

class cyclic_iterator;

//------------------------------------------------------------------------------------------

template <typename it=""></typename>

class cyclic_iterator<it, std::forward_iterator_tag=""></it,>

	: public std::iterator

						   typename std::iterator_traits<it>::value_type,</it>

						   typename std::iterator_traits<it>::difference_type,</it>

						   typename std::iterator_traits<it>::pointer,</it>

						   typename std::iterator_traits<it>::reference></it>

{

protected:

	It m_it, m_begin, m_end;

	int m_lap;

public:

	cyclic_iterator() : m_lap(0) {}

	cyclic_iterator(const It &it, const It &begin, const It &end, int lap = 0)

		: m_it(it), m_begin(begin), m_end(end), m_lap(lap) {}

	cyclic_iterator &operator++()

	{

		if (++m_it == m_end)

			++m_lap, m_it = m_begin;

		return *this;

	}

	cyclic_iterator operator++(int)

	{

		cyclic_iterator it(*this);

		operator++();

		return it;

	}

	typename cyclic_iterator::reference operator*() { return *m_it; }

	typename cyclic_iterator::pointer operator->() { return m_it.operator->(); }

	bool operator==(const cyclic_iterator &it) const { return m_it == it.m_it && m_lap == it.m_lap; }

	bool operator!=(const cyclic_iterator &it) const { return !operator==(it); }

};

//------------------------------------------------------------------------------------------

template <typename it=""></typename>

class cyclic_iterator<it, std::bidirectional_iterator_tag=""></it,>

	: public std::iterator

						   typename std::iterator_traits<it>::value_type,</it>

						   typename std::iterator_traits<it>::difference_type,</it>

						   typename std::iterator_traits<it>::pointer,</it>

						   typename std::iterator_traits<it>::reference></it>

{

protected:

	It m_it, m_begin, m_end;

	int m_lap;

public:

	cyclic_iterator() : m_lap(0) {}

	cyclic_iterator(const It &it, const It &begin, const It &end, int lap = 0)

		: m_it(it), m_begin(begin), m_end(end), m_lap(lap) {}

	cyclic_iterator &operator++()

	{

		if (++m_it == m_end)

			++m_lap, m_it = m_begin;

		return *this;

	}

	cyclic_iterator &operator--()

	{

		if (m_it == m_begin)

			--m_lap, m_it = m_end;

		--m_it;

		return *this;

	}

	cyclic_iterator operator++(int)

	{

		cyclic_iterator it(*this);

		operator++();

		return it;

	}

	cyclic_iterator operator--(int)

	{

		cyclic_iterator it(*this);

		operator--();

		return it;

	}

	typename cyclic_iterator::reference operator*() { return *m_it; }

	typename cyclic_iterator::pointer operator->() { return m_it.operator->(); }

	bool operator==(const cyclic_iterator &it) const { return m_it == it.m_it && m_lap == it.m_lap; }

	bool operator!=(const cyclic_iterator &it) const { return !operator==(it); }

};

//------------------------------------------------------------------------------------------

template <typename it=""></typename>

class cyclic_iterator<it, std::random_access_iterator_tag=""></it,>

	: public std::iterator

						   typename std::iterator_traits<it>::value_type,</it>

						   typename std::iterator_traits<it>::difference_type,</it>

						   typename std::iterator_traits<it>::pointer,</it>

						   typename std::iterator_traits<it>::reference></it>

{

protected:

	It m_it, m_begin, m_end;

	int m_lap;

	typename cyclic_iterator::difference_type m_count;

public:

	cyclic_iterator() : m_lap(0), m_count(0) {}

	cyclic_iterator(const It &it, const It &begin, const It &end, int lap = 0)

		: m_it(it), m_begin(begin), m_end(end), m_lap(lap), m_count(m_end - m_begin) {}

	cyclic_iterator &operator++()

	{

		if (++m_it == m_end)

			++m_lap, m_it = m_begin;

		return *this;

	}

	cyclic_iterator &operator--()

	{

		if (m_it == m_begin)

			--m_lap, m_it = m_end;

		--m_it;

		return *this;

	}

	cyclic_iterator operator++(int)

	{

		cyclic_iterator it(*this);

		operator++();

		return it;

	}

	cyclic_iterator operator--(int)

	{

		cyclic_iterator it(*this);

		operator--();

		return it;

	}

	cyclic_iterator &operator+=(const typename cyclic_iterator::difference_type &val)

	{

		m_lap += (val + (m_it - m_begin)) / m_count;

		m_it = cyclic_ops::increased(m_it, m_begin, m_count, val);

		return *this;

	}

	cyclic_iterator &operator-=(const typename cyclic_iterator::difference_type &val)

	{

		m_lap -= (val + (m_end - m_it)) / m_count;

		m_it = cyclic_ops::decreased(m_it, m_begin, m_count, val);

		return *this;

	}

	typename cyclic_iterator::difference_type operator-(const cyclic_iterator &it) const

	{

		assert(m_begin == it.m_begin && m_end == it.m_end);

		return m_it - it.m_it + m_lap * m_count - it.m_lap * it.m_count;

	}

	cyclic_iterator operator+(const typename cyclic_iterator::difference_type &val) const

	{

		cyclic_iterator it(*this);

		it += val;

		return it;

	}

	cyclic_iterator operator-(const typename cyclic_iterator::difference_type &val) const

	{

		cyclic_iterator it(*this);

		it -= val;

		return it;

	}

	typename cyclic_iterator::reference operator*() const { return *m_it; }

	typename cyclic_iterator::pointer operator->() const { return m_it.operator->(); }

	bool operator==(const cyclic_iterator &it) const { return m_it == it.m_it && m_lap == it.m_lap; }

	bool operator!=(const cyclic_iterator &it) const { return !operator==(it); }

	bool operator<(const cyclic_iterator &it) const { return m_lap < it.m_lap || m_it < it.m_it; }

	bool operator>(const cyclic_iterator &it) const { return m_lap > it.m_lap || m_it > it.m_it; }

	bool operator<=(const cyclic_iterator &it) const { return m_lap <= it.m_lap || m_it <= it.m_it; }

	bool operator>=(const cyclic_iterator &it) const { return m_lap >= it.m_lap || m_it >= it.m_it; }

};

} //namespace tcg

#endif //TCG_CYCLIC_H