# -*- coding: utf-8 -*-
#
# This file is part of Glances.
#
# Copyright (C) 2014 Nicolargo <nicolas@nicolargo.com>
#
# Glances is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Glances 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 Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
Glances swap memory plugin
"""

import psutil

from glances.plugins.glances_plugin import GlancesPlugin

# SNMP OID
# Total Swap Size: .1.3.6.1.4.1.2021.4.3.0
# Available Swap Space: .1.3.6.1.4.1.2021.4.4.0
snmp_oid = { 'total': '1.3.6.1.4.1.2021.4.3.0',
             'free': '1.3.6.1.4.1.2021.4.4.0' }


class Plugin(GlancesPlugin):
    """
    Glances's swap memory Plugin

    stats is a dict
    """

    def __init__(self, args=None):
        GlancesPlugin.__init__(self, args=args)

        # We want to display the stat in the curse interface
        self.display_curse = True
        # Set the message position
        # It is NOT the curse position but the Glances column/line
        # Enter -1 to right align
        self.column_curse = 3
        # Enter -1 to diplay bottom
        self.line_curse = 1

        # Init the stats
        self.reset()        

    def reset(self):
        """
        Reset/init the stats
        """
        self.stats = {}

    def update(self, input='local'):
        """
        Update MEM (SWAP) stats using the input method
        Input method could be: local (mandatory) or snmp (optionnal)
        """

        # Reset stats
        self.reset()

        if input == 'local':
            # Update stats using the standard system lib
            # Grab SWAP using the PSUtil swap_memory method
            sm_stats = psutil.swap_memory()

            # Get all the swap stats (copy/paste of the PsUtil documentation)
            # total: total swap memory in bytes
            # used: used swap memory in bytes
            # free: free swap memory in bytes
            # percent: the percentage usage
            # sin: the number of bytes the system has swapped in from disk (cumulative)
            # sout: the number of bytes the system has swapped out from disk (cumulative)
            for swap in ['total', 'used', 'free', 'percent',
                         'sin', 'sout']:
                if hasattr(sm_stats, swap):
                    self.stats[swap] = getattr(sm_stats, swap)
        elif input == 'snmp':
            # Update stats using SNMP
            self.stats = self.set_stats_snmp(snmp_oid=snmp_oid)
            for key in self.stats.iterkeys():
                self.stats[key] = float(self.stats[key]) * 1024

            # used=total-free
            self.stats['used'] = self.stats['total'] - self.stats['free']

            # percent: the percentage usage calculated as (total - available) / total * 100.
            self.stats['percent'] = float((self.stats['total'] - self.stats['free']) / self.stats['total'] * 100)

        return self.stats

    def msg_curse(self, args=None):
        """
        Return the dict to display in the curse interface
        """
        # Init the return message
        ret = []

        # Only process if stats exist...
        if self.stats == {}:
            return ret

        # Build the string message
        # Header
        msg = "{0:7} ".format(_("SWAP"))
        ret.append(self.curse_add_line(msg, "TITLE"))
        # Percent memory usage
        msg = "{0}".format(format(self.stats['percent'] / 100, '>6.1%'))
        ret.append(self.curse_add_line(msg))
        # New line
        ret.append(self.curse_new_line())
        # Total memory usage
        msg = "{0:8}".format(_("total:"))
        ret.append(self.curse_add_line(msg))
        msg = "{0:>6}".format(self.auto_unit(self.stats['total']))
        ret.append(self.curse_add_line(msg))
        # New line
        ret.append(self.curse_new_line())
        # Used memory usage
        msg = "{0:8}".format(_("used:"))
        ret.append(self.curse_add_line(msg))
        msg = "{0:>6}".format(self.auto_unit(self.stats['used']))
        ret.append(self.curse_add_line(
            msg, self.get_alert_log(self.stats['used'], max=self.stats['total'])))
        # New line
        ret.append(self.curse_new_line())
        # Free memory usage
        msg = "{0:8}".format(_("free:"))
        ret.append(self.curse_add_line(msg))
        msg = "{0:>6}".format(self.auto_unit(self.stats['free']))
        ret.append(self.curse_add_line(msg))

        return ret