# vim: tabstop=4 shiftwidth=4 softtabstop=4

#    Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

from tempfile import TemporaryFile

from devstack import component as comp
from devstack import log as logging
from devstack import settings
from devstack import shell as sh

LOG = logging.getLogger("devstack.components.rabbit")

# So far these are distro independent..
START_CMD = ['service', "rabbitmq-server", "start"]
STOP_CMD = ['service', "rabbitmq-server", "stop"]
STATUS_CMD = ['service', "rabbitmq-server", "status"]
RESTART_CMD = ['service', "rabbitmq-server", "restart"]
PWD_CMD = ['rabbitmqctl', 'change_password', 'guest']

# Default password (guest)
RESET_BASE_PW = ''

# How long we wait for rabbitmq to start up before doing commands on it
WAIT_ON_TIME = settings.WAIT_ALIVE_SECS

# Config keys we warm up so u won't be prompted later
WARMUP_PWS = ['rabbit']

# Partial of rabbit user prompt
PW_USER_PROMPT = 'the rabbit user'


class RabbitUninstaller(comp.PkgUninstallComponent):
    def __init__(self, *args, **kargs):
        comp.PkgUninstallComponent.__init__(self, *args, **kargs)
        self.runtime = RabbitRuntime(*args, **kargs)

    def pre_uninstall(self):
        try:
            self.runtime.restart()
            LOG.info("Attempting to reset the rabbit-mq guest password to \"%s\"", RESET_BASE_PW)
            cmd = PWD_CMD + [RESET_BASE_PW]
            sh.execute(*cmd, run_as_root=True)
        except IOError:
            LOG.warn(("Could not reset the rabbit-mq password. You might have to manually "
                      "reset the password to \"%s\" before the next install") % (RESET_BASE_PW))


class RabbitInstaller(comp.PkgInstallComponent):
    def __init__(self, *args, **kargs):
        comp.PkgInstallComponent.__init__(self, *args, **kargs)
        self.runtime = RabbitRuntime(*args, **kargs)

    def warm_configs(self):
        for pw_key in WARMUP_PWS:
            self.pw_gen.get_password(pw_key, PW_USER_PROMPT)

    def _setup_pw(self):
        LOG.info("Setting up your rabbit-mq guest password.")
        self.runtime.restart()
        passwd = self.pw_gen.get_password("rabbit", PW_USER_PROMPT)
        cmd = PWD_CMD + [passwd]
        sh.execute(*cmd, run_as_root=True)
        LOG.info("Restarting so that your rabbit-mq guest password is reflected.")
        self.runtime.restart()

    def post_install(self):
        comp.PkgInstallComponent.post_install(self)
        self._setup_pw()


class RabbitRuntime(comp.EmptyRuntime):
    def __init__(self, *args, **kargs):
        comp.EmptyRuntime.__init__(self, *args, **kargs)

    def start(self):
        if self.status() != comp.STATUS_STARTED:
            self._run_cmd(START_CMD)
            return 1
        else:
            return 0

    def status(self):
        # This has got to be the worst status output.
        #
        # I have ever seen (its like a weird mix json+crap)
        run_result = sh.execute(*STATUS_CMD,
                        check_exit_code=False,
                        run_as_root=True)
        if not run_result:
            return comp.STATUS_UNKNOWN
        (sysout, stderr) = run_result
        combined = str(sysout) + str(stderr)
        combined = combined.lower()
        if combined.find('nodedown') != -1 or combined.find("unable to connect to node") != -1:
            return comp.STATUS_STOPPED
        elif combined.find('running_applications') != -1:
            return comp.STATUS_STARTED
        else:
            return comp.STATUS_UNKNOWN

    def _run_cmd(self, cmd, check_exit=True):
        # This seems to fix one of the bugs with rabbit mq starting and stopping
        # not cool, possibly connected to the following bugs:
        #
        # See: https://bugs.launchpad.net/ubuntu/+source/rabbitmq-server/+bug/878597
        # See: https://bugs.launchpad.net/ubuntu/+source/rabbitmq-server/+bug/878600
        #
        # RHEL seems to have this bug also...
        #
        # TODO: Move to distro dir...
        with TemporaryFile() as f:
            return sh.execute(*cmd, run_as_root=True,
                        stdout_fh=f, stderr_fh=f,
                        check_exit_code=check_exit)

    def restart(self):
        LOG.info("Restarting rabbit-mq.")
        self._run_cmd(RESTART_CMD)
        LOG.info("Please wait %s seconds while it starts up." % (WAIT_ON_TIME))
        sh.sleep(WAIT_ON_TIME)
        return 1

    def stop(self):
        if self.status() != comp.STATUS_STOPPED:
            self._run_cmd(STOP_CMD)
            return 1
        else:
            return 0