class Aws::RpcV2::Parser

def flattened_list?(shape)
  shape.is_a?(ListShape) && shape.flattened
end

def flattened_map?(shape)
  shape.is_a?(MapShape) && shape.flattened
end

def initialize(rules, query_compatible: false)
  @rules = rules
  @query_compatible = query_compatible
end

def list(ref, values, target = nil)
  target = [] if target.nil?
  values.each do |value|
    target << parse_ref(ref.shape.member, value)
  end
  target
end

def map(ref, values, target = nil)
  target = {} if target.nil?
  values.each do |key, value|
    target[key] = parse_ref(ref.shape.value, value) unless value.nil?
  end
  target
end

def parse(cbor, target = nil)
  return {} if cbor.empty?
  parse_ref(@rules, RpcV2.decode(cbor), target)
end

def parse_ref(ref, value, target = nil)
  if value.nil?
    nil
  else
    case ref.shape
    when StructureShape then structure(ref, value, target)
    when ListShape then list(ref, value, target)
    when MapShape then map(ref, value, target)
    else value
    end
  end
end

def structure(ref, values, target = nil)
  shape = ref.shape
  target = ref.shape.struct_class.new if target.nil?
  values.each do |key, value|
    member_name, member_ref = shape.member_by_location_name(key)
    if member_ref
      target[member_name] = parse_ref(member_ref, value)
    elsif shape.union && key != '__type'
      target[:unknown] = { 'name' => key, 'value' => value }
    end
  end
  # In services that were previously Query/XML, members that were
  # "flattened" defaulted to empty lists. In JSON, these values are nil,
  # which is backwards incompatible. To preserve backwards compatibility,
  # we set a default value of [] for these members.
  if @query_compatible
    ref.shape.members.each do |member_name, member_target|
      next unless target[member_name].nil?
      if flattened_list?(member_target.shape)
        target[member_name] = []
      elsif flattened_map?(member_target.shape)
        target[member_name] = {}
      end
    end
  end
  if shape.union
    # convert to subclass
    member_subclass = shape.member_subclass(target.member).new
    member_subclass[target.member] = target.value
    target = member_subclass
  end
  target
end