# Copyright 2015 Hewlett Packard Enterprise Development Company LP
#
# 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.

import logging
import os
import stat
import subprocess

import flask
import jinja2

from octavia.amphorae.backends.agent.api_server import listener
from octavia.amphorae.backends.agent.api_server import util
from octavia.common import constants as consts


BUFFER = 100

LOG = logging.getLogger(__name__)

j2_env = jinja2.Environment(loader=jinja2.FileSystemLoader(
    os.path.dirname(os.path.realpath(__file__)) + consts.AGENT_API_TEMPLATES))
template = j2_env.get_template(consts.KEEPALIVED_CONF)
check_script_template = j2_env.get_template(consts.CHECK_SCRIPT_CONF)


def upload_keepalived_config():
    stream = listener.Wrapped(flask.request.stream)

    if not os.path.exists(util.keepalived_dir()):
        os.makedirs(util.keepalived_dir())
        os.makedirs(util.keepalived_check_scripts_dir())

    conf_file = util.keepalived_cfg_path()
    flags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC
    # mode 00644
    mode = stat.S_IRUSR | stat.S_IWUSR | stat.S_IRGRP | stat.S_IROTH
    with os.fdopen(os.open(conf_file, flags, mode), 'w') as f:
        b = stream.read(BUFFER)
        while b:
            f.write(b)
            b = stream.read(BUFFER)

    file_path = util.keepalived_init_path()
    # mode 00755
    mode = (stat.S_IRWXU | stat.S_IRGRP | stat.S_IXGRP |
            stat.S_IROTH | stat.S_IXOTH)
    if not os.path.exists(file_path):
        with os.fdopen(os.open(file_path, flags, mode), 'w') as text_file:
            text = template.render(
                keepalived_pid=util.keepalived_pid_path(),
                keepalived_cmd=consts.KEEPALIVED_CMD,
                keepalived_cfg=util.keepalived_cfg_path(),
                keepalived_log=util.keepalived_log_path(),
                amphora_nsname=consts.AMPHORA_NAMESPACE
            )
            text_file.write(text)

        # Renders the Keepalived check script
        keepalived_path = util.keepalived_check_script_path()
        open_obj = os.open(keepalived_path, flags, mode)
        with os.fdopen(open_obj, 'w') as text_file:
            text = check_script_template.render(
                check_scripts_dir=util.keepalived_check_scripts_dir()
            )
            text_file.write(text)

    res = flask.make_response(flask.jsonify({
        'message': 'OK'}), 200)
    res.headers['ETag'] = stream.get_md5()

    return res


def manager_keepalived_service(action):
    action = action.lower()
    if action not in ['start', 'stop', 'reload']:
        return flask.make_response(flask.jsonify(dict(
            message='Invalid Request',
            details="Unknown action: {0}".format(action))), 400)

    cmd = ("/usr/sbin/service octavia-keepalived {action}".format(
        action=action))

    try:
        subprocess.check_output(cmd.split(), stderr=subprocess.STDOUT)
    except subprocess.CalledProcessError as e:
        LOG.debug("Failed to {0} keepalived service: {1}".format(action, e))
        return flask.make_response(flask.jsonify(dict(
            message="Failed to {0} keepalived service".format(action),
            details=e.output)), 500)

    return flask.make_response(flask.jsonify(
        dict(message='OK',
             details='keepalived {action}ed'.format(action=action))), 202)
