module PryStackExplorer

def bindings_equal?(b1, b2)
  (b1.eval('self').equal?(b2.eval('self'))) &&
    (b1.eval('__method__') == b2.eval('__method__')) &&
    (b1.eval('local_variables').map { |v| b1.eval("#{v}") }.equal?(
     b2.eval('local_variables').map { |v| b2.eval("#{v}") }))
end

def clear_frame_managers(_pry_)
  pop_frame_manager(_pry_) until frame_managers(_pry_).empty?
  frame_hash.delete(_pry_) # this line should be unnecessary!
end

def create_and_push_frame_manager(bindings, _pry_, options={})
  fm = FrameManager.new(bindings, _pry_)
  frame_hash[_pry_].push fm
  push_helper(fm, options)
  fm
end

def frame_hash
  Thread.current[:__pry_frame_managers__] ||= Hash.new { |h, k| h[k] = [] }
end

def frame_manager(_pry_)
  frame_hash[_pry_].last
end

def frame_managers(_pry_)
  frame_hash[_pry_]
end

def pop_frame_manager(_pry_)
  return if frame_managers(_pry_).empty?
  popped_fm = frame_managers(_pry_).pop
  pop_helper(popped_fm, _pry_)
  popped_fm
end

def pop_helper(popped_fm, _pry_)
  if frame_managers(_pry_).empty?
    if _pry_.binding_stack.empty?
      _pry_.binding_stack.push popped_fm.prior_binding
    else
      _pry_.binding_stack[-1] = popped_fm.prior_binding
    end
    frame_hash.delete(_pry_)
  else
    frame_manager(_pry_).refresh_frame(false)
  end
  # restore backtrace
  _pry_.backtrace = popped_fm.prior_backtrace
end

def push_helper(fm, options={})
  options = {
    :initial_frame => 0
  }.merge!(options)
  fm.change_frame_to(options[:initial_frame], false)
end