#!/usr/bin/env python
# encoding: utf-8
"""
Profile system performance
Created by Niall Kavanagh <ntk@restdevices.com> on 2/5/2015
"""

from __future__ import print_function
import argparse
import time
import datetime
import re


def profile_memory():
    profile = {}

    pattern = re.compile('^(.+):\s*(.+)$')

    with open('/proc/meminfo') as f:
        for line in f:
            match = pattern.match(line)
            if match:
                profile[match.group(1)] = match.group(2)

    return profile


def profile_load():
    profile = {}

    pattern = re.compile('^(\S+)\s+(\S+)\s+(\S+)\s+')

    with open('/proc/loadavg') as f:
        for line in f:
            match = pattern.match(line)
            if match:
                profile['LoadAvg1'] = match.group(1)
                profile['LoadAvg5'] = match.group(2)
                profile['LoadAvg15'] = match.group(3)

    return profile


def profile_processes():
    profile = {}

    # this pattern will not match lot of multi-field lines
    pattern = re.compile('^(\S+)\s+(\d+)$')

    with open('/proc/stat') as f:
        for line in f:
            match = pattern.match(line)
            if match:
                profile[match.group(1)] = match.group(2)

    return profile


def profile_system(metrics):
    memory = profile_memory()
    load = profile_load()
    processes = profile_processes()

    profiles = [memory, load, processes]

    ts = time.time()
    profile = {
        'Time': datetime.datetime.fromtimestamp(ts)
        .strftime('%Y-%m-%d %H:%M:%S')
    }

    for metric in metrics:
        for p in profiles:
            if metric in p:
                profile[metric] = p[metric]

    return profile


def main():
    # default profile metrics TODO arg for this
    metrics = [
        'Time',
        'MemTotal',
        'MemFree',
        'LoadAvg1',
        'procs_running',
        'procs_blocked'
    ]

    # command line args
    parser = argparse.ArgumentParser(description='Profiles system performance \
                                     and outputs CSV.')

    parser.add_argument('--duration', default=60, type=int,
                        help='number of seconds to profile for')

    parser.add_argument('--frequency', default=5, type=int,
                        help='how often to sample')

    args = parser.parse_args()

    print(','.join(metrics))

    for i in range(0, args.duration/args.frequency):
        profile = profile_system(metrics)
        values = []

        for metric in metrics:
            values.append(profile[metric])

        print(','.join(values))

        time.sleep(args.frequency)

if __name__ == '__main__':
    main()