"""
Quick, little script for periodically checking the relay count in the
consensus. Queries are done every couple hours and this sends an email notice
if it changes dramatically throughout the week.
"""

import time
import getpass
import smtplib
from email.mime.text import MIMEText

import util.torTools

USERNAME = "atagar1@gmail.com"
PASSWORD = ""
SENDER = "project113@nowhere.com" # evidently ignored
RECEIVER = "atagar1@gmail.com"

# size of change (+/-) at which an alert is sent
BIHOURLY_THRESHOLD = 25
DAILY_THRESHOLD = 100
WEEKLY_THRESHOLD = 250

def sendAlert(msg):
  mimeMsg = MIMEText(msg)
  mimeMsg['Subject'] = "Tor Relay Threshold Alert"
  mimeMsg['From'] = SENDER
  mimeMsg['To'] = RECEIVER

  # Send the message via our own SMTP server, but don't include the
  # envelope header.
  server = smtplib.SMTP('smtp.gmail.com:587')
  server.starttls()
  server.login(USERNAME, PASSWORD)

  server.sendmail(SENDER, [RECEIVER], mimeMsg.as_string())
  server.quit()

def getCount(conn):
  nsEntries = conn.get_network_status()
  return len(nsEntries)

if __name__ == '__main__':
  if not PASSWORD:
    PASSWORD = getpass.getpass("GMail Password: ")

  # gets the baseline count
  conn = util.torTools.connect()
  counts = [getCount(conn)] # has entries for the past week
  lastQuery = time.time()

  while True:
    # sleep for a couple hours
    while time.time() < (lastQuery + 7200):
      sleepTime = max(1, 7200 - (time.time() - lastQuery))
      time.sleep(sleepTime)

    # adds new count to the beginning
    newCount = getCount(conn)
    counts.insert(0, newCount)
    if len(counts) > 84: counts.pop()

    # check if we broke any thresholds (alert at the highest increment)
    alertType = None

    if abs(newCount - counts[1]) >= BIHOURLY_THRESHOLD:
      alertType = "hourly"

    dayMin, dayMax = min(counts[:12]), max(counts[:12])
    if (dayMax - dayMin) > DAILY_THRESHOLD:
      alertType = "daily"

    weekMin, weekMax = min(counts), max(counts)
    if (weekMax - weekMin) > WEEKLY_THRESHOLD:
      alertType = "weekly"

    lastQuery = time.time()

    # sends a notice with counts for the last week
    if alertType:
      msg = "%s threshold broken:\n" % alertType

      entryTime = lastQuery
      for countEntry in counts:
        timeLabel = time.strftime("%H:%M %m/%d/%Y", time.localtime(entryTime))
        msg += "%s - %i\n" % (timeLabel, countEntry)
        entryTime -= 7200

      sendAlert(msg)

      # clears entries so we don't repeatidly send daily/weekly alarms
      if alertType == "weekly":
        del counts[12:]
      elif alertType == "daily":
        del counts[2:]