"""Build OSC bundles for client applications."""

from pythonosc import osc_bundle
from pythonosc import osc_message
from pythonosc.parsing import osc_types


# Shortcut to specify an immediate execution of messages in the bundle.
IMMEDIATELY = osc_types.IMMEDIATELY


class BuildError(Exception):
  """Error raised when an error occurs building the bundle."""


class OscBundleBuilder(object):
  """Builds arbitrary OscBundle instances."""

  def __init__(self, timestamp):
    """Build a new bundle with the associated timestamp.

    Args:
      - timestamp: system time represented as a floating point number of
                   seconds since the epoch in UTC or IMMEDIATELY.
    """
    self._timestamp = timestamp
    self._contents = []

  def add_content(self, content):
    """Add a new content to this bundle.

    Args:
      - content: Either an OscBundle or an OscMessage
    """
    self._contents.append(content)

  def build(self):
    """Build an OscBundle with the current state of this builder.

    Raises:
      - BuildError: if we could not build the bundle.
    """
    dgram = b'#bundle\x00'
    try:
      dgram += osc_types.write_date(self._timestamp)
      for content in self._contents:
        if (type(content) == osc_message.OscMessage
            or type(content) == osc_bundle.OscBundle):
          size = content.size
          dgram += osc_types.write_int(size)
          dgram += content.dgram
        else:
          raise BuildError(
              "Content must be either OscBundle or OscMessage"
              "found {}".format(type(content)))
      return osc_bundle.OscBundle(dgram)
    except osc_types.BuildError as be:
      raise BuildError('Could not build the bundle {}'.format(be))