# -*- coding: utf-8 -*-
'''
Beacon to monitor memory usage.

.. versionadded:: 2016.3.0

:depends: python-psutil
'''

# Import Python libs
from __future__ import absolute_import, unicode_literals
import logging
import re
from salt.ext.six.moves import map

# Import Third Party Libs
try:
    import psutil
    HAS_PSUTIL = True
except ImportError:
    HAS_PSUTIL = False

log = logging.getLogger(__name__)

__virtualname__ = 'memusage'


def __virtual__():
    if HAS_PSUTIL is False:
        return False
    else:
        return __virtualname__


def validate(config):
    '''
    Validate the beacon configuration
    '''
    # Configuration for memusage beacon should be a list of dicts
    if not isinstance(config, list):
        return False, ('Configuration for memusage '
                       'beacon must be a list.')
    else:
        _config = {}
        list(map(_config.update, config))

        if 'percent' not in _config:
            return False, ('Configuration for memusage beacon '
                           'requires percent.')

    return True, 'Valid beacon configuration'


def beacon(config):
    '''
    Monitor the memory usage of the minion

    Specify thresholds for percent used and only emit a beacon
    if it is exceeded.

    .. code-block:: yaml

        beacons:
          memusage:
            - percent: 63%
    '''
    ret = []

    _config = {}
    list(map(_config.update, config))

    _current_usage = psutil.virtual_memory()

    current_usage = _current_usage.percent
    monitor_usage = _config['percent']
    if '%' in monitor_usage:
        monitor_usage = re.sub('%', '', monitor_usage)
    monitor_usage = float(monitor_usage)
    if current_usage >= monitor_usage:
        ret.append({'memusage': current_usage})
    return ret