class Aws::Json::Parser

def initialize(rules)
  @rules = rules
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)
  end
  target
end

def parse(json, target = nil)
  parse_ref(@rules, Json.load(json), 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)
    when TimestampShape then time(value)
    when BlobShape then Base64.decode64(value)
    when BooleanShape then value.to_s == 'true'
    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
      target[:unknown] = { 'name' => key, 'value' => value }
    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

def time(value)
  value.is_a?(Numeric) ? Time.at(value) : Time.parse(value)
end