class ElasticAPM::Traceparent

def self.from_transaction(transaction)
  new.tap do |t|
    t.trace_id = SecureRandom.hex(16)
    t.recorded = transaction.sampled?
  end
end

def self.parse(header)
  raise InvalidTraceparentHeader unless header.length == 55
  raise InvalidTraceparentHeader unless header[0..1] == VERSION
  new.tap do |t|
    t.version, t.trace_id, t.span_id, t.flags =
      header.split('-').tap do |values|
        values[-1] = Util.hex_to_bits(values[-1])
      end
    raise InvalidTraceparentHeader if HEX_REGEX =~ t.trace_id
    raise InvalidTraceparentHeader if HEX_REGEX =~ t.span_id
  end
end

def flags
  format('0000000%d', recorded? ? 1 : 0)
end

def flags=(flags)
  @flags = flags
  self.recorded = flags[7] == '1'
end

def hex_flags
  format('%02x', flags.to_i(2))
end

def initialize
  @version = VERSION
end

def to_header(span_id: nil)
  span_id ||= self.span_id
  format('%s-%s-%s-%s', version, trace_id, span_id, hex_flags)
end