// file      : build2/target.ixx -*- C++ -*-
// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd
// license   : MIT; see accompanying LICENSE file

namespace build2
{
  // prerequisite_ref
  //
  inline bool prerequisite_ref::
  belongs (const target& t) const
  {
    const auto& p (t.prerequisites);
    return !(p.empty () || this < &p.front () || this > &p.back ());
  }

  // prerequisite_member
  //
  inline prerequisite& prerequisite_member::
  as_prerequisite (tracer& trace) const
  {
    if (target == nullptr)
      return prerequisite;

    // An ad hoc group member cannot be used as a prerequisite (use the whole
    // group instead).
    //
    assert (!target->adhoc_member ());

    // The use of the group's prerequisite scope is debatable.
    //
    scope& s (prerequisite.get ().scope);
    return s.prerequisites.insert (nullptr, key ().tk, s, trace).first;
  }

  // prerequisite_members
  //
  group_view
  resolve_group_members (action, target&); // <build2/algorithm>

  template <typename T>
  inline auto prerequisite_members_range<T>::iterator::
  operator++ () -> iterator&
  {
    if (k_ != nullptr) // Iterating over an ad hoc group.
      k_ = k_->member;
    else if (r_->members_)
    {
      // Get the target if one has been resolved and see if it's an ad hoc
      // group. If so, switch to the ad hoc mode.
      //
      target* t (g_.count != 0
                 ? j_ != 0 ? g_.members[j_ - 1] : nullptr // enter_group()
                 : i_->get ().target);
      if (t != nullptr && t->member != nullptr)
        k_ = t->member;
    }

    if (k_ == nullptr && g_.count != 0) // Iterating over a normal group.
    {
      if (g_.members == nullptr || // leave_group()
          ++j_ > g_.count)
        g_.count = 0;
    }

    if (k_ == nullptr && g_.count == 0) // Iterating over the range.
    {
      ++i_;

      if (r_->members_ && i_ != r_->e_ && i_->get ().type.see_through)
        switch_mode ();
    }

    return *this;
  }

  template <typename T>
  inline bool prerequisite_members_range<T>::iterator::
  enter_group ()
  {
    // First see if we are about to enter an ad hoc group (the same code as in
    // operator++() above).
    //
    target* t (g_.count != 0
               ? j_ != 0 ? g_.members[j_ - 1] : nullptr
               : i_->get ().target);

    if (t != nullptr && t->member != nullptr)
      k_ = t->member;
    else
    {
      // Otherwise assume it is a normal group.
      //
      g_ = resolve_group_members (r_->a_, search (*i_));

      if (g_.members == nullptr) // Members are not know.
      {
        g_.count = 0;
        return false;
      }

      if (g_.count != 0) // Group is not empty.
        j_ = 0; // Account for the increment that will follow.
    }


    return true;
  }

  template <typename T>
  inline void prerequisite_members_range<T>::iterator::
  leave_group ()
  {
    // First see if we are about to enter an ad hoc group (the same code as in
    // operator++() above).
    //
    if (k_ == nullptr)
    {
      target* t (g_.count != 0
                 ? j_ != 0 ? g_.members[j_ - 1] : nullptr
                 : i_->get ().target);
      if (t != nullptr && t->member != nullptr)
        k_ = t->member;
    }

    if (k_ != nullptr)
    {
      // Skip until the last element (next increment will reach the end).
      //
      for (; k_->member != nullptr; k_ = k_->member) ;
    }
    else
    {
      // Pretend we are on the last member of a normal group.
      //
      j_ = 0;
      g_.count = 1;
      g_.members = nullptr; // Ugly "special case signal" for operator++.
    }
  }
}