#!/usr/bin/env python
# coding=utf-8

# (C) Copyright 2017 Hewlett Packard Enterprise Development LP
# (C) Copyright 2018 FUJITSU LIMITED
#
# 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 glob
import json
import logging
import os
import sys
import time

from requests import RequestException
from requests import Session

LOG_LEVEL = logging.getLevelName(os.environ.get('LOG_LEVEL', 'INFO'))
logging.basicConfig(level=LOG_LEVEL)

logger = logging.getLogger(__name__)

GRAFANA_URL = os.environ.get('GRAFANA_URL', 'http://localhost:3000')
GRAFANA_USERNAME = os.environ.get('GRAFANA_USERNAME', 'mini-mon')
GRAFANA_PASSWORD = os.environ.get('GRAFANA_PASSWORD', 'password')
GRAFANA_USERS = [{'user': GRAFANA_USERNAME, 'password': GRAFANA_PASSWORD, 'email': ''}]

DASHBOARDS_DIR = sys.argv[1]


def retry(retries=5, delay=2.0, exc_types=(RequestException,)):
    def decorator(func):
        def f_retry(*args, **kwargs):
            for i in range(retries):
                try:
                    return func(*args, **kwargs)
                except exc_types as exc:
                    if i < retries - 1:
                        logger.debug('Caught exception, retrying...',
                                     exc_info=True)
                        time.sleep(delay)
                    else:
                        logger.exception('Failed after %d attempts', retries)
                        if isinstance(exc, RequestException):
                            logger.debug('Response was: %r', exc.response.text)

                        raise
        return f_retry
    return decorator

def create_login_payload():
    if os.environ.get('GRAFANA_USERS'):
        try:
            json.loads(os.environ.get('GRAFANA_USERS'))
        except ValueError:
            print("Invalid type GRAFANA_USERS")
            raise
        grafana_users = json.loads(os.environ.get('GRAFANA_USERS'))
    else:
        grafana_users = GRAFANA_USERS
    return grafana_users

@retry(retries=24, delay=5.0)
def login(session, user):
    r = session.post('{url}/login'.format(url=GRAFANA_URL),
                     json=user,
                     timeout=5)
    r.raise_for_status()

def create_dashboard_payload(json_path):
    with open(json_path, 'r') as f:
        dashboard = json.load(f)
        dashboard['id'] = None

        return {
            'dashboard': dashboard,
            'overwrite': True
        }

def main():
    for user in create_login_payload():
        logging.info('Opening a Grafana session...')
        session = Session()
        login(session, user)

        for path in sorted(glob.glob('{dir}/*.json'.format(dir=DASHBOARDS_DIR))):
            logging.info('Creating dashboard from file: {path}'.format(path=path))
            r = session.post('{url}/api/dashboards/db'.format(url=GRAFANA_URL),
                             json=create_dashboard_payload(path))
            logging.debug('Response: %r', r.json())
            r.raise_for_status()

        logging.info('Ending %r session...', user.get('user'))
        session.get('{url}/logout'.format(url=GRAFANA_URL))

    logging.info('Finished successfully.')


if __name__ == '__main__':
    main()