ah-zip-utils.H

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
 
 
# ifndef AH_ZIP_UTILS_H
# define AH_ZIP_UTILS_H
 
# include <type_traits>
# include <tuple>
# include <iterator>
# include <utility>
# include <optional>
# include <functional>
# include <ah-concepts.H>
 
namespace Aleph
{
 
// ============================================================================
// Type Traits for Container Detection
// ============================================================================
 
namespace uni_zip_detail
{
 
// Detect if type has STL-style begin()/end()
template <typename T>
struct has_stl_iterator : std::bool_constant<StlIterableContainer<T>> {};
 
// Detect if type has Aleph-style Iterator with has_curr()/get_curr()/next_ne()
// Note: We check for next_ne() which is the non-exception-throwing variant used in Aleph
template <typename T>
struct has_aleph_iterator : std::bool_constant<AlephIterable<T>> {};
 
// Get value type from container
template <typename T, typename = void>
struct container_value_type;
 
template <typename T>
struct container_value_type<T, std::enable_if_t<has_stl_iterator<T>::value>>
{
  using type = typename T::value_type;
};
 
template <typename T>
struct container_value_type<T, std::enable_if_t<
  has_aleph_iterator<T>::value && !has_stl_iterator<T>::value>>
{
  using type = std::decay_t<typename T::Item_Type>;
};
 
template <typename T>
using container_value_t = typename container_value_type<std::decay_t<T>>::type;
 
// ============================================================================
// Unified Iterator Wrapper
// ============================================================================
 
template <typename Container>
class StlIteratorWrapper
{
  typename std::decay_t<Container>::const_iterator curr_;
  typename std::decay_t<Container>::const_iterator end_;
 
public:
  using value_type = typename std::decay_t<Container>::value_type;
 
  explicit StlIteratorWrapper(const Container& c)
    : curr_(c.begin()), end_(c.end()) {}
 
  [[nodiscard]] bool has_curr() const noexcept { return curr_ != end_; }
  [[nodiscard]] bool completed() const noexcept { return curr_ == end_; }
  [[nodiscard]] auto get_curr() const { return *curr_; }
  void next() noexcept { ++curr_; }
 
  void next_ne() noexcept { next(); }
};
 
template <typename Container>
class AlephIteratorWrapper
{
  // mutable: the wrapper's const accessors forward to the Aleph iterator,
  // whose get_curr() may be non-const (e.g. the chained hash tables).
  mutable typename std::decay_t<Container>::Iterator it_;
 
public:
  using value_type = std::decay_t<typename std::decay_t<Container>::Item_Type>;
 
  explicit AlephIteratorWrapper(const Container& c)
    : it_(c) {}
 
  [[nodiscard]] bool has_curr() const noexcept { return it_.has_curr(); }
  [[nodiscard]] bool completed() const noexcept { return !it_.has_curr(); }
  [[nodiscard]] auto get_curr() const { return it_.get_curr(); }
  void next() { it_.next_ne(); }
 
  void next_ne() { next(); }
};
 
template <typename Container, typename = void>
struct IteratorWrapperSelector;
 
// STL containers (prefer STL if both interfaces exist)
template <typename Container>
struct IteratorWrapperSelector<Container, 
  std::enable_if_t<has_stl_iterator<std::decay_t<Container>>::value>>
{
  using type = StlIteratorWrapper<std::decay_t<Container>>;
};
 
// Aleph-only containers (no STL interface)
template <typename Container>
struct IteratorWrapperSelector<Container,
  std::enable_if_t<
    has_aleph_iterator<std::decay_t<Container>>::value &&
    !has_stl_iterator<std::decay_t<Container>>::value>>
{
  using type = AlephIteratorWrapper<std::decay_t<Container>>;
};
 
template <typename Container>
using iterator_wrapper_t = typename IteratorWrapperSelector<Container>::type;
 
// Static assertion helper for unsupported container types
template <typename T>
inline constexpr bool is_supported_container_v =
  has_stl_iterator<std::decay_t<T>>::value ||
  has_aleph_iterator<std::decay_t<T>>::value;
 
} // namespace uni_zip_detail
 
// ============================================================================
// Sentinel type for O(1) end()
// ============================================================================
 
struct UniZipSentinel {};
 
// ============================================================================
// Unified Zip Iterator
// ============================================================================
 
template <typename... Containers>
class UniZipIterator
{
  static_assert((uni_zip_detail::is_supported_container_v<Containers> && ...),
    "All containers must have either STL (begin/end) or Aleph (Iterator) interface");
 
public:
  using value_type = std::tuple<uni_zip_detail::container_value_t<Containers>...>;
 
private:
  std::tuple<uni_zip_detail::iterator_wrapper_t<Containers>...> iters_;
 
  template <size_t... Is>
  [[nodiscard]] bool has_curr_impl(std::index_sequence<Is...>) const noexcept
  {
    return (... && std::get<Is>(iters_).has_curr());
  }
 
  template <size_t... Is>
  [[nodiscard]] bool any_has_curr_impl(std::index_sequence<Is...>) const noexcept
  {
    return (... || std::get<Is>(iters_).has_curr());
  }
 
  template <size_t... Is>
  [[nodiscard]] bool all_completed_impl(std::index_sequence<Is...>) const noexcept
  {
    return (... && std::get<Is>(iters_).completed());
  }
 
  template <size_t... Is>
  [[nodiscard]] auto get_curr_impl(std::index_sequence<Is...>) const
  {
    return std::make_tuple(std::get<Is>(iters_).get_curr()...);
  }
 
  template <size_t... Is>
  void next_impl(std::index_sequence<Is...>)
  {
    (std::get<Is>(iters_).next(), ...);
  }
 
public:
  static constexpr size_t num_containers = sizeof...(Containers);
 
  explicit UniZipIterator(const Containers&... cs)
    : iters_(uni_zip_detail::iterator_wrapper_t<Containers>(cs)...) {}
 
  [[nodiscard]] bool has_curr() const noexcept
  {
    return has_curr_impl(std::make_index_sequence<num_containers>{});
  }
 
  [[nodiscard]] bool any_has_curr() const noexcept
  {
    return any_has_curr_impl(std::make_index_sequence<num_containers>{});
  }
 
  [[nodiscard]] bool all_completed() const noexcept
  {
    return all_completed_impl(std::make_index_sequence<num_containers>{});
  }
 
  [[nodiscard]] bool completed() const noexcept
  {
    return all_completed();
  }
 
  [[nodiscard]] auto get_curr() const
  {
    return get_curr_impl(std::make_index_sequence<num_containers>{});
  }
 
  void next()
  {
    next_impl(std::make_index_sequence<num_containers>{});
  }
 
  void next_ne() { next(); }
 
  // STL iterator interface for range-based for
  [[nodiscard]] auto operator*() const { return get_curr(); }
 
  UniZipIterator& operator++()
  {
    next();
    return *this;
  }
 
  [[nodiscard]] bool operator==(UniZipSentinel) const noexcept
  {
    return !has_curr();
  }
 
  [[nodiscard]] bool operator!=(UniZipSentinel s) const noexcept
  {
    return !(*this == s);
  }
 
  [[nodiscard]] bool operator==(const UniZipIterator& other) const noexcept
  {
    // Both at end (any container exhausted)
    return !has_curr() && !other.has_curr();
  }
 
  [[nodiscard]] bool operator!=(const UniZipIterator& other) const noexcept
  {
    return !(*this == other);
  }
};
 
template <typename... Containers>
class UniZipView
{
  std::tuple<const std::decay_t<Containers>&...> containers_;
 
public:
  using iterator = UniZipIterator<std::decay_t<Containers>...>;
  using sentinel = UniZipSentinel;
  using value_type = typename iterator::value_type;
 
  explicit UniZipView(const Containers&... cs)
    : containers_(cs...) {}
 
  [[nodiscard]] iterator begin() const
  {
    return std::apply([](const auto&... cs) {
      return iterator(cs...);
    }, containers_);
  }
 
  [[nodiscard]] sentinel end() const noexcept
  {
    return sentinel{};
  }
 
  [[nodiscard]] bool empty() const
  {
    return !begin().has_curr();
  }
 
  [[nodiscard]] size_t size() const
  {
    size_t count = 0;
    for (auto it = begin(); it != end(); ++it)
      ++count;
    return count;
  }
};
 
// ============================================================================
// Factory Functions
// ============================================================================
 
template <typename... Containers>
[[nodiscard]] auto uni_zip(const Containers&... cs)
{
  static_assert(sizeof...(Containers) >= 2,
                "uni_zip requires at least 2 containers");
  return UniZipView<Containers...>(cs...);
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_it(const Containers&... cs)
{
  return UniZipIterator<std::decay_t<Containers>...>(cs...);
}
 
// ============================================================================
// Functional Operations
// ============================================================================
 
template <typename Pred, typename... Containers>
[[nodiscard]] bool uni_zip_all(Pred&& pred, const Containers&... cs)
{
  auto& pred_ref = pred;  // Preserve as lvalue to avoid invalidating in loop
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    if (!pred_ref(it.get_curr()))
      return false;
  return true;
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] bool uni_zip_all_eq(Pred&& pred, const Containers&... cs)
{
  auto& pred_ref = pred;
  auto it = uni_zip_it(cs...);
  for (; it.has_curr(); it.next())
    if (!pred_ref(it.get_curr()))
      return false;
  return it.all_completed();  // All containers exhausted = equal length
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] bool uni_zip_exists(Pred&& pred, const Containers&... cs)
{
  auto& pred_ref = pred;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    if (pred_ref(it.get_curr()))
      return true;
  return false;
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] bool uni_zip_any(Pred&& pred, const Containers&... cs)
{
  return uni_zip_exists(std::forward<Pred>(pred), cs...);
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] bool uni_zip_none(Pred&& pred, const Containers&... cs)
{
  return !uni_zip_exists(std::forward<Pred>(pred), cs...);
}
 
template <typename Op, typename... Containers>
void uni_zip_for_each(Op&& op, const Containers&... cs)
{
  auto& op_ref = op;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    op_ref(it.get_curr());
}
 
template <typename Op, typename... Containers>
void uni_zip_for_each_indexed(Op&& op, const Containers&... cs)
{
  auto& op_ref = op;
  size_t idx = 0;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next(), ++idx)
    op_ref(idx, it.get_curr());
}
 
template <typename T, typename Op, typename... Containers>
[[nodiscard]] T uni_zip_foldl(T init, Op&& op, const Containers&... cs)
{
  auto& op_ref = op;
  T acc = std::move(init);
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    acc = op_ref(std::move(acc), it.get_curr());
  return acc;
}
 
template <typename T, typename Op, typename... Containers>
[[nodiscard]] T uni_zip_reduce(T init, Op&& op, const Containers&... cs)
{
  return uni_zip_foldl(std::move(init), std::forward<Op>(op), cs...);
}
 
template <typename Op, typename... Containers>
[[nodiscard]] auto uni_zip_map(Op&& op, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
  using ResultType = std::decay_t<decltype(op(std::declval<TupleType>()))>;
 
  auto& op_ref = op;
  std::vector<ResultType> result;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    result.push_back(op_ref(it.get_curr()));
  return result;
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] auto uni_zip_filter(Pred&& pred, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  auto& pred_ref = pred;
  std::vector<TupleType> result;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    {
      auto t = it.get_curr();
      if (pred_ref(t))
        result.push_back(t);
    }
  return result;
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] auto uni_zip_find_first(Pred&& pred, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  auto& pred_ref = pred;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    {
      auto t = it.get_curr();
      if (pred_ref(t))
        return std::optional<TupleType>(t);
    }
  return std::optional<TupleType>{};
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] size_t uni_zip_count(Pred&& pred, const Containers&... cs)
{
  auto& pred_ref = pred;
  size_t count = 0;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    if (pred_ref(it.get_curr()))
      ++count;
  return count;
}
 
template <typename... Containers>
[[nodiscard]] size_t uni_zip_length(const Containers&... cs)
{
  size_t count = 0;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    ++count;
  return count;
}
 
template <typename... Containers>
[[nodiscard]] bool uni_zip_equal_length(const Containers&... cs)
{
  auto it = uni_zip_it(cs...);
  while (it.has_curr())
    it.next();
  return it.all_completed();  // All exhausted = equal length
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_nth(size_t n, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  size_t i = 0;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next(), ++i)
    if (i == n)
      return std::optional<TupleType>(it.get_curr());
  return std::optional<TupleType>{};
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_take(size_t n, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  std::vector<TupleType> result;
  result.reserve(n);
  size_t count = 0;
  for (auto it = uni_zip_it(cs...); it.has_curr() && count < n; it.next(), ++count)
    result.push_back(it.get_curr());
  return result;
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_drop(size_t n, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  std::vector<TupleType> result;
  auto it = uni_zip_it(cs...);
 
  for (size_t i = 0; i < n && it.has_curr(); ++i)
    it.next();
 
  for (; it.has_curr(); it.next())
    result.push_back(it.get_curr());
  return result;
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] auto uni_zip_take_while(Pred&& pred, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  auto& pred_ref = pred;
  std::vector<TupleType> result;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    {
      auto t = it.get_curr();
      if (!pred_ref(t))
        break;
      result.push_back(t);
    }
  return result;
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] auto uni_zip_drop_while(Pred&& pred, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  auto& pred_ref = pred;
  std::vector<TupleType> result;
  auto it = uni_zip_it(cs...);
 
  for (; it.has_curr() && pred_ref(it.get_curr()); it.next())
    /* skip */;
 
  for (; it.has_curr(); it.next())
    result.push_back(it.get_curr());
  return result;
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_first(const Containers&... cs)
{
  return uni_zip_nth(0, cs...);
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_last(const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  std::optional<TupleType> result;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    result = it.get_curr();
  return result;
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] auto uni_zip_partition(Pred&& pred, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  auto& pred_ref = pred;
  std::vector<TupleType> matching, non_matching;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    {
      auto t = it.get_curr();
      if (pred_ref(t))
        matching.push_back(t);
      else
        non_matching.push_back(t);
    }
  return std::make_pair(std::move(matching), std::move(non_matching));
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_to_vector(const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  std::vector<TupleType> result;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    result.push_back(it.get_curr());
  return result;
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] bool uni_zip_traverse(Pred&& pred, const Containers&... cs)
{
  auto& pred_ref = pred;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    if (!pred_ref(it.get_curr()))
      return false;
  return true;
}
 
// ============================================================================
// ML-style Additional Operations
// ============================================================================
 
template <typename Op, typename... Containers>
[[nodiscard]] auto uni_zip_mapi(Op&& op, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
  using ResultType = std::decay_t<decltype(op(size_t{}, std::declval<TupleType>()))>;
 
  auto& op_ref = op;
  std::vector<ResultType> result;
  size_t idx = 0;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next(), ++idx)
    result.push_back(op_ref(idx, it.get_curr()));
  return result;
}
 
template <typename Pred, typename... Containers>
[[nodiscard]] auto uni_zip_filteri(Pred&& pred, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  auto& pred_ref = pred;
  std::vector<TupleType> result;
  size_t idx = 0;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next(), ++idx)
    {
      auto t = it.get_curr();
      if (pred_ref(idx, t))
        result.push_back(t);
    }
  return result;
}
 
template <typename T, typename Op, typename... Containers>
[[nodiscard]] auto uni_zip_scan_left(T init, Op&& op, const Containers&... cs)
{
  auto& op_ref = op;
  std::vector<T> result;
  result.push_back(init);
 
  T acc = std::move(init);
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    {
      acc = op_ref(std::move(acc), it.get_curr());
      result.push_back(acc);
    }
  return result;
}
 
template <typename Op, typename... Containers>
[[nodiscard]] auto uni_zip_find_mapi(Op&& op, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
  using OptType = std::decay_t<decltype(op(size_t{}, std::declval<TupleType>()))>;
 
  auto& op_ref = op;
  size_t idx = 0;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next(), ++idx)
    {
      auto result = op_ref(idx, it.get_curr());
      if (result)
        return result;
    }
  return OptType{};
}
 
template <typename Eq, typename... Containers>
[[nodiscard]] bool uni_zip_equal_by(Eq&& eq, const Containers&... cs)
{
  auto& eq_ref = eq;
  auto it = uni_zip_it(cs...);
  for (; it.has_curr(); it.next())
    if (!eq_ref(it.get_curr()))
      return false;
  return it.all_completed();  // All exhausted = equal length
}
 
template <typename Tuple, typename... Containers>
[[nodiscard]] bool uni_zip_mem(const Tuple& target, const Containers&... cs)
{
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    if (it.get_curr() == target)
      return true;
  return false;
}
 
template <typename Key, typename... Containers>
[[nodiscard]] auto uni_zip_assoc(const Key& key, const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    {
      auto t = it.get_curr();
      if (std::get<0>(t) == key)
        return std::optional<TupleType>(t);
    }
  return std::optional<TupleType>{};
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_min(const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  auto it = uni_zip_it(cs...);
  if (!it.has_curr())
    return std::optional<TupleType>{};
 
  TupleType min_val = it.get_curr();
  it.next();
 
  for (; it.has_curr(); it.next())
    {
      auto t = it.get_curr();
      if (t < min_val)
        min_val = t;
    }
  return std::optional<TupleType>(min_val);
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_max(const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  auto it = uni_zip_it(cs...);
  if (!it.has_curr())
    return std::optional<TupleType>{};
 
  TupleType max_val = it.get_curr();
  it.next();
 
  for (; it.has_curr(); it.next())
    {
      auto t = it.get_curr();
      if (t > max_val)
        max_val = t;
    }
  return std::optional<TupleType>(max_val);
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_min_max(const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
  using ResultType = std::optional<std::pair<TupleType, TupleType>>;
 
  auto it = uni_zip_it(cs...);
  if (!it.has_curr())
    return ResultType{};
 
  TupleType min_val = it.get_curr();
  TupleType max_val = min_val;
  it.next();
 
  for (; it.has_curr(); it.next())
    {
      auto t = it.get_curr();
      if (t < min_val) min_val = t;
      if (t > max_val) max_val = t;
    }
  return ResultType(std::make_pair(min_val, max_val));
}
 
// ============================================================================
// Unzip Operations (returns DynList for mixed containers)
// ============================================================================
 
} // end namespace Aleph
 
// Need DynList for unzip operations
# include <htlist.H>
 
namespace Aleph
{
 
template <typename Container>
[[nodiscard]] auto uni_unzip(const Container& c)
{
  using PairType = uni_zip_detail::container_value_t<Container>;
  using T1 = std::decay_t<decltype(std::declval<PairType>().first)>;
  using T2 = std::decay_t<decltype(std::declval<PairType>().second)>;
 
  DynList<T1> firsts;
  DynList<T2> seconds;
 
  if constexpr (uni_zip_detail::has_stl_iterator<std::decay_t<Container>>::value)
    {
      for (const auto& p : c)
        {
          firsts.append(p.first);
          seconds.append(p.second);
        }
    }
  else
    {
      for (auto it = c.get_it(); it.has_curr(); it.next_ne())
        {
          const auto& p = it.get_curr();
          firsts.append(p.first);
          seconds.append(p.second);
        }
    }
 
  return std::make_pair(std::move(firsts), std::move(seconds));
}
 
namespace uni_unzip_detail
{
 
template <typename Tuple, size_t... Is>
auto make_dynlist_tuple(std::index_sequence<Is...>)
{
  return std::make_tuple(DynList<std::tuple_element_t<Is, Tuple>>()...);
}
 
template <typename Tuple, typename ResultTuple, size_t... Is>
void append_tuple_elements(const Tuple& t, ResultTuple& result, std::index_sequence<Is...>)
{
  ((std::get<Is>(result).append(std::get<Is>(t))), ...);
}
 
} // namespace uni_unzip_detail
 
template <typename Container>
[[nodiscard]] auto uni_unzip_tuple(const Container& c)
{
  using TupleType = uni_zip_detail::container_value_t<Container>;
  constexpr size_t N = std::tuple_size_v<TupleType>;
 
  auto result = uni_unzip_detail::make_dynlist_tuple<TupleType>(
    std::make_index_sequence<N>{});
 
  if constexpr (uni_zip_detail::has_stl_iterator<std::decay_t<Container>>::value)
    {
      for (const auto& t : c)
        uni_unzip_detail::append_tuple_elements(t, result,
          std::make_index_sequence<N>{});
    }
  else
    {
      for (auto it = c.get_it(); it.has_curr(); it.next_ne())
        uni_unzip_detail::append_tuple_elements(it.get_curr(), result,
          std::make_index_sequence<N>{});
    }
 
  return result;
}
 
template <typename... Containers>
[[nodiscard]] auto uni_zip_to_dynlist(const Containers&... cs)
{
  using TupleType = typename UniZipIterator<std::decay_t<Containers>...>::value_type;
 
  DynList<TupleType> result;
  for (auto it = uni_zip_it(cs...); it.has_curr(); it.next())
    result.append(it.get_curr());
  return result;
}
 
} // end namespace Aleph
 
# endif // AH_ZIP_UTILS_H