#!/usr/bin/env python

from prometheus_client import start_http_server, Gauge
from time import sleep

from datetime import datetime
import re
import os
import sys

HTTP_PORT = 9401
BACKUP_DIRECTORY = '/srv/dropzone/'
INTERVAL = 30 * 60  # seconds

DATEREGEX = re.compile("[0-9]{4}-[0-9]{2}-[0-9]{2}")

files_touched_recently = Gauge('veeam_has_touched_files',
                               'Files have been modified in past 24h',
                               ['name'])


def isNotHidden(dirname):
    return dirname[0] != '.'


def hasDate(filename):
    return DATEREGEX.search(filename) is not None


def deltaInDays(filename):
    filedate = datetime.strptime(DATEREGEX.search(filename).group(),
                                 "%Y-%m-%d")
    return (datetime.today() - filedate).days


# Because Prometheus has no binary datatype, we use integers in a Gauge.
# Sorry, dear reader...
def hasRecentFile(deltaList):
    if 0 in deltaList or 1 in deltaList:
        return 1
    else:
        return 0


def deltaList(dirname):
    return [deltaInDays(f) for f in os.listdir(dirname) if hasDate(f)]


if __name__ == '__main__':
    if len(sys.argv) == 2:
        BACKUP_DIRECTORY = sys.argv[1]
    elif len(sys.argv) > 2:
        sys.exit("Invalid number of arguments."
                 "Usage: ./prometheus-borgbackup-exporter [backup-directory]")

    # Serve metrics over HTTP.
    print("Starting prometheus-veeam-exporter on port",
          "{}...".format(HTTP_PORT), end='')
    start_http_server(HTTP_PORT)
    print(" OK.")

    os.chdir(BACKUP_DIRECTORY)

    while True:
        try:
            print(">> Running check...")

            result = [(backupjob, hasRecentFile(deltaList(backupjob)))
                      for backupjob in os.listdir(BACKUP_DIRECTORY)
                      if isNotHidden(backupjob)]

            for job in result:
                files_touched_recently.labels(job[0]).set(job[1])

            print(" OK.")
        except Exception as e:
            print("Error! {}".format(e))

        sleep(INTERVAL)