import smtplib
import string
import os
from time import strftime
import sys

#Settings
TO_ADDRESS = 'detinationEmailAddress.com'
SMTP_SERVER = 'smtpEmailServer'

SMTP_USERNAME = "sourceEmail@email.com"
SMTP_PASSWORD = "EmailPassword"

SUBJECT = "OpenCanary Alert"

EMAILTEMPLATE = """From: OpenCanary RPi <sourceEmail@email.com>
Subject: OpenCanary Alert from RPi

New Events
"""

NEWLINE = "\n\r"
SOURCELOGFILE = '/var/tmp/opencanary-tmp.log'

# very basic code to send a simple email to the defined recipient
def  SendEmail(emailText):
  emailSent = False
  try:
    emailMessage = EMAILTEMPLATE + emailText
    server = smtplib.SMTP(SMTP_SERVER,587)
    server.ehlo()
    server.starttls()
    server.login(SMTP_USERNAME, SMTP_PASSWORD)
    server.sendmail(SMTP_USERNAME, TO_ADDRESS, emailMessage)
    server.quit()
    emailSent = True
  except:
    print("Error sending Emails - Log not Emptied")
  return emailSent

# utility to find the value for a given source parameter.
# sample of event string elements is
# , "node_id": "opencanary-1", "src_host": "192.168.0.11", "src_port": "37284"}
# the string to check should be of the format "src_port"

def findParam(sourceEvent,checkString):
    result = ""
    fullCheckString = '"'+checkString+'": "'
    startChar = sourceEvent.find(fullCheckString)
    if(startChar>0):
        startChar +=len(fullCheckString)
        endChar =sourceEvent.find('"',startChar)
        if(endChar>0):
            result = sourceEvent[startChar:endChar]
        else:
            print("no matching end \n")
    return result


#basic parser for each line of text to see if it is one of the whitelisted events that do not need reporting

def CheckLine (sourceEvent):
     sendTheEmail = True
     print("checking line > {}\n",sourceEvent)

     sourceIP        = findParam(sourceEvent,"src_host")
     destinationPort = findParam(sourceEvent,"dst_port")
     sourcePort      = findParam(sourceEvent,"src_port")
     print("source IP: {}   destination port: {} \n".format(sourceIP,destinationPort))
     #better code would be to use a config file, but for now lets just add some simple cases

     if(sourceIP =="127.0.0.1"):
         if(destinationPort=="631"):
             #local port on Rpi  doing a regular check of the printer port
             sendTheEmail = False
     else:
         if(sourceIP == "192.168.0.13"):
             if(destinationPort == "445") or (destinationPort == "139" ):
                 #mac mini doing a regular port check on these 2 ports
                 sendTheEmail = False
         else:
             if(sourceIP == "192.168.0.15"):
                 if(destinationPort == "139"):
                      #main PC on wired network
                      sendTheEmail = False
     displayCommand = "{0}:{1} > {2}  ".format (sourceIP,sourcePort,destinationPort)

     if (sendTheEmail):
         displayCommand += '\033[31;40m UNKNOWN \033[37;40m\n'
     else:
         displayCommand += '\033[32;40m Ignored \033[37;40m\n'

# change this tty to tty1 if you are using a dedicated screen hat
# tty will just display to the active screen you are logged on to.
     f = open("/dev/tty", "w")
     f.write(displayCommand)
     f.close()
     return sendTheEmail

#main code starts here
localText = ""


file2 = open(SOURCELOGFILE,'r')
count  =0
for line in file2:
    if (CheckLine(line.strip())==True):
        count +=1
        localText += "Event {}: {}".format(count,line.strip())
        localText += NEWLINE
    else:
        print("ignoring line\n\r")
file2.close

if (count >0):
    emailsSent= SendEmail (localText)
    if(emailsSent):
      #this is a bit crude but acts as a simple emptying of the source file
      # Only clear the log if the email was sent
      # if not the log will remain and next time it will re-try
      file2 = open(SOURCELOGFILE,'w')
      file2.writelines([])
      file2.close