# Copyright (C) 2008 by the Free Software Foundation, Inc.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
# USA.

"""Various test helpers."""

from __future__ import with_statement

__metaclass__ = type
__all__ = [
    'TestableMaster',
    'digest_mbox',
    'get_queue_messages',
    'make_testable_runner',
    ]


import os
import time
import errno
import mailbox
import subprocess

from datetime import datetime, timedelta

from mailman.bin.master import Loop as Master
from mailman.configuration import config
from mailman.queue import Switchboard


WAIT_INTERVAL = timedelta(seconds=3)



def make_testable_runner(runner_class):
    """Create a queue runner that runs until its queue is empty.

    :param runner_class: An IRunner
    :return: A runner instance.
    """

    class EmptyingRunner(runner_class):
        """Stop processing when the queue is empty."""

        def _doperiodic(self):
            """Stop when the queue is empty."""
            self._stop = (len(self._switchboard.files) == 0)

    return EmptyingRunner()



class _Bag:
    def __init__(self, **kws):
        for key, value in kws.items():
            setattr(self, key, value)


def get_queue_messages(queue):
    """Return and clear all the messages in the given queue.

    :param queue: An ISwitchboard or a string naming a queue.
    :return: A list of 2-tuples where each item contains the message and
        message metadata.
    """
    if isinstance(queue, basestring):
        queue = Switchboard(queue)
    messages = []
    for filebase in queue.files:
        msg, msgdata = queue.dequeue(filebase)
        messages.append(_Bag(msg=msg, msgdata=msgdata))
        queue.finish(filebase)
    return messages



def digest_mbox(mlist):
    """The mailing list's pending digest as a mailbox.

    :param mlist: The mailing list.
    :return: The mailing list's pending digest as a mailbox.
    """
    path = os.path.join(mlist.full_path, 'digest.mbox')
    return mailbox.mbox(path)



class TestableMaster(Master):
    """A testable master loop watcher."""

    def __init__(self, event):
        super(TestableMaster, self).__init__(
            restartable=False, config_file=config.filename)
        self._event = event
        self._started_kids = None

    def loop(self):
        """Wait until all the qrunners are actually running before looping."""
        starting_kids = set(self._kids)
        while starting_kids:
            for pid in self._kids:
                try:
                    os.kill(pid, 0)
                    starting_kids.remove(pid)
                except OSError, error:
                    if error.errno == errno.ESRCH:
                        # The child has not yet started.
                        pass
                    raise
        # Keeping a copy of all the started child processes for use by the
        # testing environment, even after all have exited.
        self._started_kids = set(self._kids)
        # Let the blocking thread know everything's running.
        self._event.set()
        super(TestableMaster, self).loop()

    @property
    def qrunner_pids(self):
        """The pids of all the child qrunner processes."""
        for pid in self._started_kids:
            yield pid