class Aws::Json::Builder

def encode(blob)
  Base64.strict_encode64(String === blob ? blob : blob.read)
end

def format(ref, value)
  case ref.shape
  when StructureShape then structure(ref, value)
  when ListShape      then list(ref, value)
  when MapShape       then map(ref, value)
  when TimestampShape then timestamp(ref, value)
  when BlobShape      then encode(value)
  else value
  end
end

def initialize(rules)
  @rules = rules
end

def list(ref, values)
  member_ref = ref.shape.member
  values.collect { |value| format(member_ref, value) }
end

def map(ref, values)
  value_ref = ref.shape.value
  values.each.with_object({}) do |(key, value), data|
    data[key] = format(value_ref, value)
  end
end

def structure(ref, values)
  shape = ref.shape
  values.each_pair.with_object({}) do |(key, value), data|
    if shape.member?(key) && !value.nil?
      member_ref = shape.member(key)
      member_name = member_ref.location_name || key
      data[member_name] = format(member_ref, value)
    end
  end
end

def timestamp(ref, value)
  case ref['timestampFormat'] || ref.shape['timestampFormat']
  when 'iso8601' then value.utc.iso8601
  when 'rfc822' then value.utc.httpdate
  else
    # rest-json and jsonrpc default to unixTimestamp
    value.to_i
  end
end

def to_json(params)
  Json.dump(format(@rules, params))
end