#!/usr/bin/env python
#Author: Shriphani Palakodety
#Mail: spalakod@purdue.edu

#An attempt to replicate Steve Lambert's self-control application for windows.

import sys
import time
import os

machine_hosts_location = ""

if os.name == "nt":
    machine_hosts_location = "C:\Windows\System32\drivers\etc\hosts"
elif os.name == "posix":
    machine_hosts_location = "/etc/hosts"
else:
    sys.exit(1)  #else, this app cannot really help you

class App:
    def __init__(self, urlList=[], path="list.txt", hosts=machine_hosts_location):
        self.UrlList = urlList
        self.Path = path
        self.HostsFile = hosts
        self.StartTime = time.time()  #get no. of seconds since epoch
        self.StartMarker = "# Inserted by WinSelfControl! DO NOT EDIT OR CHANGE CONTENTS"
        self.EndMarker = "# End of WinSelfControl Section ! Edit away after this line"

    def confirm(self, duration):
        '''Prints out a list of domains to be blocked'''

        print "The following domains will be blocked for the next %s minutes", duration
        f = open(self.path, "r")
        for new_line in f:
            print f
        
        f.close()


    def addNewTLD(self, tldname):
        '''Take new TLD and block it'''
        pass  #this won't come in use till I attach a GUI to it.
        


    def beginControl(self, duration):
        '''add blacklisted dudes to hosts file for user specified time'''

        #read in blacklisted domains
        f = open(self.Path, "r")
        for new_line in f:
            self.UrlList.append(new_line)
        f.close()

        #write to hosts file
        hosts = open(self.HostsFile, "a")
        
        #first insert markers so I can detect where to remove from
        hosts.write(self.StartMarker + "\n\n\n")

        #next put in the entries
        for domain in self.UrlList:
            hosts.write("127.0.0.1\t"+domain+"\n")

        #next close our section
        hosts.write("\n\n\n"+self.EndMarker)
        hosts.close()

        #call timeOut
        self.timeOut(duration)


    #this is currently super necessary. I will write this tomorrow
    def endControl(self):
        '''remove blacklisted sites from hosts file'''
        
        #first open file to see where the lines added by this app are.
        hostsInStream = open(self.HostsFile, "r")

        #read in text till our blacklisted section
        content = []  #hold content that was present beforehand

        self_content = False

        for new_line in hostsInStream:
            if new_line.find(self.StartMarker) == -1 and not self_content:
                content.append(new_line)
                
            else:
                self_content = True
            
            if self_content and new_line.find(self.EndMarker) > -1:
                self_content = False
        hostsInStream.close()

        #write back original file content
        hostsOutStream = open(self.HostsFile, "w")
        for line in content:
            hostsOutStream.write(line)
        hostsOutStream.close()



    def timeOut(self, duration):
        '''count down for <duration> minutes'''
        curTime = time.time()
        passed = (curTime - self.StartTime)/60.0        
        while passed < duration:
            curTime = time.time()
            passed = (curTime - self.StartTime)/60.0        
            #print passed
            #pass

        #now, kick out the entries from the hosts file.
        self.endControl()

    def usage(self):
        '''tell the user how to use this app'''
        print "Usage: selfcontrol <duration in minutes>"

if __name__ == "__main__":
    
    #initalize the App object
    appInstance = App()    #start with a blank urllist
    
    #perform sanity checks and complain etc.
    if len(sys.argv) < 2:
        appInstance.usage()

    else:
        duration = float(sys.argv[1])

        appInstance.beginControl(duration)

        #need to get time to work