#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# This file is part of Checkbox.
#
# Copyright 2014 Canonical Ltd.
#
# Authors:
#    Brendan Donegan <brendan.donegan@canonical.com>
#    Jeff Lane <jeff.lane@canonical.com>
#    Sylvain Pineau <sylvain.pineau@canonical.com>
#
# Checkbox is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3,
# as published by the Free Software Foundation.
#
# Checkbox 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Checkbox.  If not, see <http://www.gnu.org/licenses/>.

import os
import sys
from subprocess import check_output, PIPE

from checkbox_support.parsers.lshwjson import LshwJsonParser
from checkbox_support.parsers.meminfo import MeminfoParser


class LshwJsonResult:

    memory_reported = 0
    banks_reported = 0

    def addHardware(self, hardware):
        if hardware['id'] == 'memory':
            self.memory_reported += int(hardware.get('size', 0))
        elif 'bank' in hardware['id']:
            self.banks_reported += int(hardware.get('size', 0))


def get_installed_memory_size():
    lshw = LshwJsonParser(check_output(['lshw', '-json'],
                          universal_newlines=True,
                          stderr=PIPE))
    result = LshwJsonResult()
    lshw.run(result)

    if result.memory_reported:
        return result.memory_reported
    else:
        return result.banks_reported


class MeminfoResult:

    memtotal = 0

    def setMemory(self, memory):
        self.memtotal = memory['total']


def get_visible_memory_size():
    parser = MeminfoParser(open('/proc/meminfo'))
    result = MeminfoResult()
    parser.run(result)

    return result.memtotal


def get_threshold(installed_memory):
    GB = 1024**3
    if installed_memory <= 2 * GB:
        return 25
    elif installed_memory <= 6 * GB:
        return 20
    else:
        return 10


def main():
    if os.geteuid() != 0:
        print("This script must be run as root.", file=sys.stderr)
        return 1

    installed_memory = get_installed_memory_size()
    visible_memory = get_visible_memory_size()
    threshold = get_threshold(installed_memory)

    difference = installed_memory - visible_memory
    try:
        percentage = difference / installed_memory * 100
    except ZeroDivisionError:
        print("Results:")
        print("\t/proc/meminfo reports:\t%s kB" % (visible_memory / 1024),
              file=sys.stderr)
        print("\tlshw reports:\t%s kB" % (installed_memory / 1024),
              file=sys.stderr)
        print("\nFAIL: Either lshw or /proc/meminfo returned a memory size "
              "of 0 kB", file=sys.stderr)
        return 1

    if percentage <= threshold:
        print("Results:")
        print("\t/proc/meminfo reports:\t%s kB" % (visible_memory / 1024))
        print("\tlshw reports:\t%s kB" % (installed_memory / 1024))
        print("\nPASS: Meminfo reports %d bytes less than lshw, a "
              "difference of %.2f%%. This is less than the "
              "%d%% variance allowed." % (difference, percentage, threshold))
        return 0
    else:
        print("Results:", file=sys.stderr)
        print("\t/proc/meminfo reports:\t%s kB" % (visible_memory / 1024),
              file=sys.stderr)
        print("\tlshw reports:\t%s kB" % (installed_memory / 1024),
              file=sys.stderr)
        print("\nFAIL: Meminfo reports %d bytes less than lshw, "
              "a difference of %.2f%%. Only a variance of %d%% in "
              "reported memory is allowed." %
              (difference, percentage, threshold), file=sys.stderr)
        return 1

if __name__ == "__main__":
    sys.exit(main())
