#!/usr/bin/python
# -*- coding: utf-8 -*-


import re
import sys
import time
import datetime
from os import listdir
from os import path

a_dir = "d:\\"


def get_active_file():
    files = listdir(a_dir)
    files = filter(lambda x: x.startswith('info'), files)
    files = [path.join(a_dir, file) for file in files]
    files = sorted(files, key=lambda log_file: path.getmtime(log_file))
    if len(files):
        return files.pop()
    else:
        print 'No file for parse found!\n'
        raise SystemExit(1)


def get_lines(file, lines=10000):
    total_lines_wanted = lines
    BLOCK_SIZE = 1024
    file.seek(0, 2)
    block_end_byte = file.tell()
    lines_to_go = total_lines_wanted
    block_number = -1
    blocks = []     # blocks of size BLOCK_SIZE, in reverse order starting from the end of the file
    while lines_to_go > 0 and block_end_byte > 0:
        if (block_end_byte - BLOCK_SIZE > 0):  # read the last block we haven't yet read
            file.seek(block_number * BLOCK_SIZE, 2)
            blocks.append(file.read(BLOCK_SIZE))
        else:
            file.seek(0, 0)                            # file too small, start from begining
            blocks.append(file.read(block_end_byte))   # only read what was not read
        lines_found = blocks[-1].count('\n')
        lines_to_go -= lines_found
        block_end_byte -= BLOCK_SIZE
        block_number -= 1
    all_read_text = ''.join(reversed(blocks))
    return list(reversed(all_read_text.splitlines()[-total_lines_wanted:]))


def get_pe_stats(receiver_id, metric_count):
    metrics_hash = {}
    date_exp = re.compile('^(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2})\.\d{3}')
    time_arr = []
    index = 0
    lines_to_parse = get_lines(open(get_active_file()))
    for current_line in lines_to_parse:
        if "statistics for receiver {0}".format(receiver_id) in current_line:
            time_arr.append(
                time.mktime(datetime.datetime.strptime(date_exp.findall(current_line)[0], "%Y-%m-%d %H:%M:%S").timetuple()))
            if len(time_arr) >= 2:
                break
            lines_to_check = lines_to_parse[index - metric_count:index]
            for line_with_metric in lines_to_check:
                metric, value = line_with_metric.split(':')
                metric = metric.replace(' ', '')
                metrics_hash[metric] = float(value)
        else:
            index += 1
    time_step = int(time_arr[0] - time_arr[1])

    return metrics_hash

# receiver = sys.argv[1]
# metric = sys.argv[2]
# type = sys.argv[3]

receiver = 2
metric = 'qdrops'
type = 'dpdk'

if type == 'pcap':
    metric_count = 12
elif type == 'dpdk':
    metric_count = 20
else:
    print 'Wrong type of PE component specified!'
    raise SystemExit(1)

metrics = get_pe_stats(receiver, metric_count)
print metrics