#pragma once

#include <boost/assert.hpp>
#include <boost/next_prior.hpp>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
#include <boost/range/empty.hpp>
#include <boost/range/iterator_range.hpp>
#include <boost/range/algorithm/mismatch.hpp>


// Mimics for_each, but with adjacent pairs.
// Precondition: rng not empty
// Postcondition: ran fn for all adjacent (x, x+1) pairs: fn(x,x+1), fn(x+2,x+3), etc.
template <typename SinglePassRange, typename BinaryFunction>
BinaryFunction for_each_adjacent(const SinglePassRange& rng, BinaryFunction fn) {
  BOOST_ASSERT(not boost::empty(rng));

  const auto sub = boost::make_iterator_range(boost::next(boost::begin(rng)), boost::end(rng));

  // Sequence side-effects and always returning true for mismatch to run through whole range
  const auto wrap = [fn](const auto& lhs, const auto& rhs) { return fn(lhs, rhs), true; };

  boost::mismatch(rng, sub, wrap);

  return fn;
}


template <typename SinglePassIterator, typename BinaryFunction>
BinaryFunction for_each_adjacent(SinglePassIterator first, SinglePassIterator last, BinaryFunction fn) {
  return for_each_adjacent(boost::make_iterator_range(first, last), fn);
}