class Aws::Query::ParamBuilder

def apply(ref, params)
  structure(ref, params, '')
end

def blob(value)
  value = value.read unless String === value
  Base64.strict_encode64(value)
end

def flat?(ref)
  ref.shape.flattened
end

def format(ref, value, prefix)
  case ref.shape
  when StructureShape then structure(ref, value, prefix + '.')
  when ListShape      then list(ref, value, prefix)
  when MapShape       then map(ref, value, prefix)
  when BlobShape      then set(prefix, blob(value))
  when TimestampShape then set(prefix, timestamp(ref, value))
  else set(prefix, value.to_s)
  end
end

def initialize(param_list)
  @params = param_list
end

def list(ref, values, prefix)
  member_ref = ref.shape.member
  if values.empty?
    set(prefix, '')
    return
  end
  if flat?(ref)
    if name = query_name(member_ref)
      parts = prefix.split('.')
      parts.pop
      parts.push(name)
      prefix = parts.join('.')
    end
  else
    prefix += '.' + (member_ref.location_name || 'member')
  end
  values.each.with_index do |value, n|
    format(member_ref, value, "#{prefix}.#{n+1}")
  end
end

def map(ref, values, prefix)
  key_ref = ref.shape.key
  value_ref = ref.shape.value
  prefix += '.entry' unless flat?(ref)
  key_name = "%s.%d.#{query_name(key_ref, 'key')}"
  value_name  = "%s.%d.#{query_name(value_ref, 'value')}"
  values.each.with_index do |(key, value), n|
    format(key_ref, key, key_name % [prefix, n + 1])
    format(value_ref, value, value_name % [prefix, n + 1])
  end
end

def query_name(ref, default = nil)
  ref.location_name || default
end

def set(name, value)
  params.set(name, value)
end

def structure(ref, values, prefix)
  shape = ref.shape
  values.each_pair do |name, value|
    next if value.nil?
    member_ref = shape.member(name)
    format(member_ref, value, prefix + query_name(member_ref))
  end
end

def timestamp(ref, value)
  case ref['timestampFormat'] || ref.shape['timestampFormat']
  when 'unixTimestamp' then value.to_i
  when 'rfc822' then value.utc.httpdate
  else
    # query defaults to iso8601
    value.utc.iso8601
  end
end