#!/usr/bin/env python3
"""psi2log"""

import os
from time import sleep
from ctypes import CDLL
from sys import stdout, exit
from argparse import ArgumentParser
from signal import signal, SIGTERM, SIGINT, SIGQUIT, SIGHUP


def form(num):
    """
    """
    s = str(num).split('.')
    return '{}.{:0<2}'.format(s[0], s[1])


def signal_handler(signum, frame):
    """
    """
    def signal_handler_inner(signum, frame):
        pass
    for i in sig_list:
        signal(i, signal_handler_inner)

    log('')

    lpd = len(peaks_dict)
    if lpd != 15:
        exit()

    log('Peak values:  avg10  avg60 avg300')

    log('-----------  ------ ------ ------')

    log('some cpu     {:>6} {:>6} {:>6}'.format(
        form(peaks_dict['c_some_avg10']),
        form(peaks_dict['c_some_avg60']),
        form(peaks_dict['c_some_avg300']),
    ))

    log('-----------  ------ ------ ------')

    log('some memory  {:>6} {:>6} {:>6}'.format(
        form(peaks_dict['m_some_avg10']),
        form(peaks_dict['m_some_avg60']),
        form(peaks_dict['m_some_avg300']),
    ))

    log('full memory  {:>6} {:>6} {:>6}'.format(
        form(peaks_dict['m_full_avg10']),
        form(peaks_dict['m_full_avg60']),
        form(peaks_dict['m_full_avg300']),
    ))

    log('-----------  ------ ------ ------')

    log('some io      {:>6} {:>6} {:>6}'.format(
        form(peaks_dict['i_some_avg10']),
        form(peaks_dict['i_some_avg60']),
        form(peaks_dict['i_some_avg300']),
    ))

    log('full io      {:>6} {:>6} {:>6}'.format(
        form(peaks_dict['i_full_avg10']),
        form(peaks_dict['i_full_avg60']),
        form(peaks_dict['i_full_avg300']),
    ))

    exit()


def cgroup2_root():
    """
    """
    with open(mounts) as f:
        for line in f:
            if cgroup2_separator in line:
                return line.partition(cgroup2_separator)[0].partition(' ')[2]


def mlockall():
    """
    """

    MCL_CURRENT = 1
    MCL_FUTURE = 2
    MCL_ONFAULT = 4

    CDLL('libc.so.6').mlockall(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT)


def psi_file_mem_to_metrics(psi_path):
    """
    """

    with open(psi_path) as f:
        psi_list = f.readlines()
    some_list, full_list = psi_list[0].split(' '), psi_list[1].split(' ')
    some_avg10 = some_list[1].split('=')[1]
    some_avg60 = some_list[2].split('=')[1]
    some_avg300 = some_list[3].split('=')[1]
    full_avg10 = full_list[1].split('=')[1]
    full_avg60 = full_list[2].split('=')[1]
    full_avg300 = full_list[3].split('=')[1]
    return (some_avg10, some_avg60, some_avg300,
            full_avg10, full_avg60, full_avg300)


def psi_file_cpu_to_metrics(psi_path):
    """
    """

    with open(psi_path) as f:
        psi_list = f.readlines()
    some_list = psi_list[0].split(' ')
    some_avg10 = some_list[1].split('=')[1]
    some_avg60 = some_list[2].split('=')[1]
    some_avg300 = some_list[3].split('=')[1]
    return (some_avg10, some_avg60, some_avg300)


def log(*msg):
    """
    """
    print(*msg)
    if separate_log:
        logging.info(*msg)


parser = ArgumentParser()

parser.add_argument(
    '-t',
    '--target',
    help="""target (cgroup2 or SYTSTEM_WIDE)""",
    default='SYSTEM_WIDE',
    type=str
)


parser.add_argument(
    '-p',
    '--period',
    help="""period in sec""",
    default=2,
    type=float
)


parser.add_argument(
    '-l',
    '--log',
    help="""path to log file""",
    default=None,
    type=str
)


args = parser.parse_args()

target = args.target

period = args.period

log_file = args.log


if log_file is None:
    separate_log = False
else:
    separate_log = True
    import logging

sig_list = [SIGTERM, SIGINT, SIGQUIT, SIGHUP]


for i in sig_list:
    signal(i, signal_handler)


if separate_log:
    logging.basicConfig(
        filename=log_file,
        level=logging.INFO,
        format="%(asctime)s: %(message)s")

log('Starting psi-monitor')
log('target: {}'.format(target))
log('period: {}'.format(period))
if log_file is not None:
    log('log file: {}'.format(log_file))


if not os.path.exists('/proc/pressure'):
    log('ERROR: /proc/pressure does not exist, PSI is not supported, exit')
    exit()


if target == 'SYSTEM_WIDE':

    cpu_file = "/proc/pressure/cpu"
    memory_file = "/proc/pressure/memory"
    io_file = "/proc/pressure/io"

else:

    mounts = '/proc/mounts'
    cgroup2_separator = ' cgroup2 rw,'
    cgroup2_mountpoint = cgroup2_root()

    if cgroup2_mountpoint is None:

        log('ERROR: unified cgroup hierarchy is not mounted, exit')
        exit()

    else:

        log('cgroup2 mountpoint: {}'.format(cgroup2_mountpoint))

    cpu_file = cgroup2_mountpoint + target + "/cpu.pressure"
    memory_file = cgroup2_mountpoint + target + "/memory.pressure"
    io_file = cgroup2_mountpoint + target + "/io.pressure"


mlockall()


log('----------------------------------------------------------------------'
    '--------------------------------------------')
log(' some cpu pressure   || some memory pressure | full memory pressure ||'
    '  some io pressure    |  full io pressure')
log('---------------------||----------------------|----------------------||'
    '----------------------|---------------------')
log(' avg10  avg60 avg300 ||  avg10  avg60 avg300 |  avg10  avg60 avg300 ||'
    '  avg10  avg60 avg300 |  avg10  avg60 avg300')
log('------ ------ ------ || ------ ------ ------ | ------ ------ ------ ||'
    ' ------ ------ ------ | ------ ------ ------')


peaks_dict = dict()


while True:

    if not os.path.exists(cpu_file):
        log('ERROR: cpu pressure file does not exist:    {}'.format(cpu_file))
        sleep(period)
        continue

    if not os.path.exists(memory_file):
        log('ERROR: memory pressure file does not exist: {}'.format(
            memory_file))
        sleep(period)
        continue

    if not os.path.exists(io_file):
        log('ERROR: io pressure file does not exist:     {}'.format(cpu_file))
        sleep(period)
        continue

    (c_some_avg10, c_some_avg60, c_some_avg300
     ) = psi_file_cpu_to_metrics(cpu_file)

    (m_some_avg10, m_some_avg60, m_some_avg300,
     m_full_avg10, m_full_avg60, m_full_avg300
     ) = psi_file_mem_to_metrics(memory_file)

    (i_some_avg10, i_some_avg60, i_some_avg300,
     i_full_avg10, i_full_avg60, i_full_avg300
     ) = psi_file_mem_to_metrics(io_file)

    log('{:>6} {:>6} {:>6} || {:>6} {:>6} {:>6} | {:>6} {:>6} {:>6} || {:>6}'
        ' {:>6} {:>6} | {:>6} {:>6} {:>6}'.format(

            c_some_avg10, c_some_avg60, c_some_avg300,

            m_some_avg10, m_some_avg60, m_some_avg300,
            m_full_avg10, m_full_avg60, m_full_avg300,

            i_some_avg10, i_some_avg60, i_some_avg300,
            i_full_avg10, i_full_avg60, i_full_avg300

        ))

    c_some_avg10 = float(c_some_avg10)
    if ('c_some_avg10' not in peaks_dict or
            peaks_dict['c_some_avg10'] < c_some_avg10):
        peaks_dict['c_some_avg10'] = c_some_avg10

    c_some_avg60 = float(c_some_avg60)
    if ('c_some_avg60' not in peaks_dict or
            peaks_dict['c_some_avg60'] < c_some_avg60):
        peaks_dict['c_some_avg60'] = c_some_avg60

    c_some_avg300 = float(c_some_avg300)
    if ('c_some_avg300' not in peaks_dict or
            peaks_dict['c_some_avg300'] < c_some_avg300):
        peaks_dict['c_some_avg300'] = c_some_avg300

    #######################################################################

    m_some_avg10 = float(m_some_avg10)
    if ('m_some_avg10' not in peaks_dict or
            peaks_dict['m_some_avg10'] < m_some_avg10):
        peaks_dict['m_some_avg10'] = m_some_avg10

    m_some_avg60 = float(m_some_avg60)
    if ('m_some_avg60' not in peaks_dict or
            peaks_dict['m_some_avg60'] < m_some_avg60):
        peaks_dict['m_some_avg60'] = m_some_avg60

    m_some_avg300 = float(m_some_avg300)
    if ('m_some_avg300' not in peaks_dict or
            peaks_dict['m_some_avg300'] < m_some_avg300):
        peaks_dict['m_some_avg300'] = m_some_avg300

    m_full_avg10 = float(m_full_avg10)
    if ('m_full_avg10' not in peaks_dict or
            peaks_dict['m_full_avg10'] < m_full_avg10):
        peaks_dict['m_full_avg10'] = m_full_avg10

    m_full_avg60 = float(m_full_avg60)
    if ('m_full_avg60' not in peaks_dict or
            peaks_dict['m_full_avg60'] < m_full_avg60):
        peaks_dict['m_full_avg60'] = m_full_avg60

    m_full_avg300 = float(m_full_avg300)
    if ('m_full_avg300' not in peaks_dict or
            peaks_dict['m_full_avg300'] < m_full_avg300):
        peaks_dict['m_full_avg300'] = m_full_avg300

    #######################################################################

    i_some_avg10 = float(i_some_avg10)
    if ('i_some_avg10' not in peaks_dict or
            peaks_dict['i_some_avg10'] < i_some_avg10):
        peaks_dict['i_some_avg10'] = i_some_avg10

    i_some_avg60 = float(i_some_avg60)
    if ('i_some_avg60' not in peaks_dict or
            peaks_dict['i_some_avg60'] < i_some_avg60):
        peaks_dict['i_some_avg60'] = i_some_avg60

    i_some_avg300 = float(i_some_avg300)
    if ('i_some_avg300' not in peaks_dict or
            peaks_dict['i_some_avg300'] < i_some_avg300):
        peaks_dict['i_some_avg300'] = i_some_avg300

    i_full_avg10 = float(i_full_avg10)
    if ('i_full_avg10' not in peaks_dict or
            peaks_dict['i_full_avg10'] < i_full_avg10):
        peaks_dict['i_full_avg10'] = i_full_avg10

    i_full_avg60 = float(i_full_avg60)
    if ('i_full_avg60' not in peaks_dict or
            peaks_dict['i_full_avg60'] < i_full_avg60):
        peaks_dict['i_full_avg60'] = i_full_avg60

    i_full_avg300 = float(i_full_avg300)
    if ('i_full_avg300' not in peaks_dict or
            peaks_dict['i_full_avg300'] < i_full_avg300):
        peaks_dict['i_full_avg300'] = i_full_avg300

    stdout.flush()
    sleep(period)