#ifndef SPROUT_NUMERIC_FIT_ADJACENT_DIFFERENCE_HPP
#define SPROUT_NUMERIC_FIT_ADJACENT_DIFFERENCE_HPP

#include <sprout/config.hpp>
#include <sprout/iterator/distance.hpp>
#include <sprout/container/traits.hpp>
#include <sprout/container/functions.hpp>
#include <sprout/numeric/fixed/adjacent_difference.hpp>
#include <sprout/algorithm/fit/result_of.hpp>
#include <sprout/sub_array/sub_array.hpp>
#include <sprout/sub_array/sub.hpp>
#include <sprout/iterator/type_traits/category.hpp>

namespace sprout {
	namespace fit {
		namespace detail {
			template<typename InputIterator, typename Result>
			inline SPROUT_CONSTEXPR typename sprout::fit::result_of::algorithm<Result>::type
			adjacent_difference_impl(
				InputIterator first, InputIterator last, Result const& result,
				typename sprout::container_traits<Result>::difference_type offset
				)
			{
				return sprout::sub_copy(
					sprout::get_internal(sprout::fixed::adjacent_difference(first, last, result)),
					offset,
					offset + sprout::fit_size(result, sprout::distance(first, last))
					);
			}
		}	// namespace detail
		//
		// adjacent_difference
		//
		template<typename InputIterator, typename Result>
		inline SPROUT_CONSTEXPR typename sprout::fit::result_of::algorithm<Result>::type
		adjacent_difference(InputIterator first, InputIterator last, Result const& result) {
			static_assert(sprout::is_forward_iterator<InputIterator>::value, "Sorry, not implemented.");
			return sprout::fit::detail::adjacent_difference_impl(first, last, result, sprout::internal_begin_offset(result));
		}

		namespace detail {
			template<typename InputIterator, typename Result, typename BinaryOperation>
			inline SPROUT_CONSTEXPR typename sprout::fit::result_of::algorithm<Result>::type
			adjacent_difference_impl(
				InputIterator first, InputIterator last, Result const& result, BinaryOperation binary_op,
				typename sprout::container_traits<Result>::difference_type offset
				)
			{
				return sprout::sub_copy(
					sprout::get_internal(sprout::fixed::adjacent_difference(first, last, result, binary_op)),
					offset,
					offset + NS_SSCRISK_CEL_OR_SPROUT::min(sprout::distance(first, last), sprout::size(result))
					);
			}
		}	// namespace detail
		//
		// adjacent_difference
		//
		template<typename InputIterator, typename Result, typename BinaryOperation>
		inline SPROUT_CONSTEXPR typename sprout::fit::result_of::algorithm<Result>::type
		adjacent_difference(InputIterator first, InputIterator last, Result const& result, BinaryOperation binary_op) {
			static_assert(sprout::is_forward_iterator<InputIterator>::value, "Sorry, not implemented.");
			return sprout::fit::detail::adjacent_difference_impl(first, last, result, binary_op, sprout::internal_begin_offset(result));
		}
	}	// namespace fit
}	// namespace sprout

#endif	// #ifndef SPROUT_NUMERIC_FIT_ADJACENT_DIFFERENCE_HPP
