'''
Script for processing the log generated by the TPSmart app. 
Given a directory and userID will determine the latest log file, decrypt it and 
compute the time that was spent on each app.
'''

import datetime
import base64
import os
import glob
import functools
import sys
from Crypto.Cipher import AES

monthDict = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6, 'Jul': 7, 'Aug': 8, 'Sep':9, 'Oct':10, 'Nov': 11, 'Dec' : 12}


def readAndProcess(fileName):
    f = open(fileName, 'r')
    return processAppTimes(f.read().split('\n'))

def processAppTimes(fileContent):
#     fileContent = fileContent.split('\n')
    fileContent = [line.split(' ') for line in fileContent if len(line.strip()) > 0]

    # dictionary to accumulate the seconds for each application
    appDict = {}


    # for each line in the text file, extract the tokens, compute the time diff
    # and accumulate in dictionary

    maxTokenIdx = max(tokenApp, tokenMonth, tokenDay, tokenYear, tokenTime)

    isFirst = True
    for event in fileContent:
#         print("evenToken:", tokenTime)
#         print (event[tokenTime])

        if len(event) > maxTokenIdx:
            (hour, minutes, seconds) = event[tokenTime].split(':') 
            
            (year, month, day) = (int(event[tokenYear]), monthDict[event[tokenMonth]],int(event[tokenDay]))
            currDateTime = datetime.datetime(year, month, day, int(hour), int(minutes), int(seconds)) 
    #         print(event, currDateTime, event[tokenApp])
            if (not isFirst):
                timeDelta = currDateTime - prevDateTime 
    #             print(timeDelta, prevApp)
                if prevApp in appDict:
                    appDict[prevApp] = appDict[prevApp] + timeDelta.seconds 
                else:
                    appDict[prevApp] = 0 + timeDelta.seconds
            else:
                isFirst = False
            prevDateTime = currDateTime
            prevApp = event[tokenApp]

    return appDict

def decryptFileAndProcess(encryptedFName):
    key = "This is a secret"

    f = open(encryptedFName, 'rb')
    print("Decrypting the file: %s ..." % encryptedFName)
    
    cipher = AES.new(key)
    decrypted = cipher.decrypt(f.read())
    fileContent = decrypted.decode("utf-8").split("\n")

    # positions of tokens in each line

    # print("Is this a time? ", fileContent[0][tokenTime])
    # print("Is this a year month day? ", fileContent[0][tokenYear], fileContent[0][tokenMonth], fileContent[0][tokenDay])
    # print("If not, modify the token values....")
    # print(fileContent)
#     print([line for line in fileContent if len(line) > 10])
    return processAppTimes([line for line in fileContent if len(line) > 10])



def latestUserFile(searchDir, userID):
    # search_dir = "/tmp/images/"
    print("Searching dir %s for latest file of userID: %s ...." % (searchDir, userID))
    files = [f for f in glob.glob(searchDir + "/" +  userID + "-*EncrypFile*") if os.path.isfile(f)]
    return max(files, key = lambda x: os.path.getmtime(x))


'''
The main program....
'''


if len(sys.argv) != 3:
	print("Usage: " + sys.argv[0] + " (directory) (UserID)")
	print("Example: " + sys.argv[0] + " /tmp/images 1000")
	sys.exit(1)

searchDir = sys.argv[1]
userID = sys.argv[2]

(tokenApp,tokenMonth, tokenDay, tokenYear, tokenTime) = (0,3,4,7,5)
results = decryptFileAndProcess( latestUserFile(searchDir,userID))
print("Results for user", userID)
print(results)