class Grape::Validations::AttributesIterator

def do_each(params_to_process, original_params, parent_indices = [], &block)
  params_to_process.each_with_index do |resource_params, index|
    # when we get arrays of arrays it means that target element located inside array
    # we need this because we want to know parent arrays indices
    if resource_params.is_a?(Array)
      do_each(resource_params, original_params, [index] + parent_indices, &block)
      next
    end
    if @scope.type == Array
      next unless original_params.is_a?(Array) # do not validate content of array if it isn't array
      store_indices(@scope, index, parent_indices)
    elsif original_params.is_a?(Array)
      # Lateral scope (no @element) whose params resolved to an array —
      # delegate index tracking to the nearest array-typed ancestor so
      # that full_name produces the correct bracketed index.
      target = @scope.nearest_array_ancestor
      store_indices(target, index, parent_indices) if target
    end
    yield_attributes(resource_params, &block)
  end
end

def each(params, &)
  original_params = @scope.params(params)
  # because we need recursion for nested arrays
  do_each(Array.wrap(original_params), original_params, &)
end

def initialize(attrs, scope)
  @attrs = attrs
  @scope = scope
end

def skip?(val)
  val == Grape::DSL::Parameters::EmptyOptionalValue
end

def store_indices(target_scope, index, parent_indices)
  # No tracker means we're outside a ParamScopeTracker.track block (e.g.
  # a unit test that invokes a validator directly). Index tracking is
  # skipped — full_name will produce bracket-less names — but validation
  # continues rather than crashing.
  tracker = ParamScopeTracker.current or return
  parent_scope = target_scope.parent
  parent_indices.each do |parent_index|
    break unless parent_scope
    tracker.store_index(parent_scope, parent_index)
    parent_scope = parent_scope.parent
  end
  tracker.store_index(target_scope, index)
end

def yield_attributes(_resource_params)
  raise NotImplementedError
end