# 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__ = [
    'Watcher',
    '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.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 Watcher:
    """A doctest stand-in for the queue file watcher."""

    def __init__(self):
        self.exe = os.path.join(config.BIN_DIR, 'mailmanctl')
        self.returncode = None
        self.stdout = None
        self.stderr = None
        self.pid = None

    def start(self):
        """Start the watcher and wait until it actually starts."""
        process = subprocess.Popen(
            (self.exe, '-C', config.filename, '-q', 'start'))
        stdout, stderr = process.communicate()
        # Wait until the pid file exists.
        until = datetime.now() + WAIT_INTERVAL
        while datetime.now() < until:
            try:
                with open(config.PIDFILE) as f:
                    pid = int(f.read().strip())
                    break
            except IOError, error:
                if error.errno == errno.ENOENT:
                    time.sleep(0.1)
                else:
                    raise
        else:
            # This will usually cause the doctest to fail.
            return 'Time out'
        # Now wait until the process actually exists.
        until = datetime.now() + WAIT_INTERVAL
        while datetime.now() < until:
            try:
                os.kill(pid, 0)
                break
            except OSError, error:
                if error.errno == errno.ESRCH:
                    time.sleep(0.1)
                else:
                    raise
        else:
            return 'Time out'
        self.returncode = process.returncode
        self.stdout = stdout
        self.stderr = stderr
        self.pid = pid

    def stop(self):
        """Stop the watcher and wait until it actually stops."""
        process = subprocess.Popen(
            (self.exe, '-C', config.filename, '-q', 'stop'))
        stdout, stderr = process.communicate()
        # Now wait until the process stops.
        until = datetime.now() + WAIT_INTERVAL
        while datetime.now() < until:
            try:
                os.kill(self.pid, 0)
                time.sleep(0.1)
            except OSError, error:
                if error.errno == errno.ESRCH:
                    break
                else:
                    raise
        else:
            return 'Time out'
        self.returncode = process.returncode
        self.stdout = stdout
        self.stderr = stderr