import time, HTMLParser, urllib2, urllib
from datetime import datetime
from threading import Timer

sign_in_url = "https://vbc.mitglobalnet.net/index.php"
ping_page = "http://www.nathanvangheem.com/give_me_something.html"
redirect_page = "http://welcome.mit/".rstrip('/')
last_opened_page = '__saved_last_opened.html'
user_agent = "	Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1) Gecko/20090624 Firefox/3.5"
username = "blah"
password = "pass"
interval_to_check = 70 #amount of time in seconds to check if you're logged in

post_vars = {
    'passwd' : password,
    'username' : username,
    'remember' : 'no'
}

def print_time():
    n = datetime.now()
    print n.ctime(),

class MyParser(HTMLParser.HTMLParser):
    "A simple parser class."
    
    def __init__(self):
        HTMLParser.HTMLParser.__init__(self)
        self.input_tags = {}
    
    def get_attr(self, name, attrs):
        for n, v in attrs:
            if n == name:
                return v
                
        return None
    
    def handle_starttag(self, tag, attrs):
        if tag == 'input':
            name = self.get_attr('name', attrs)
            value = self.get_attr('value', attrs)
            self.input_tags[name] = value

    def parse(self, s):
        "Parse the given string 's'."
        self.feed(s)
        self.close()

def write_to_file(page_data):
    fi = open(last_opened_page, 'w')
    fi.write(page_data)
    fi.close()

def count_down(sec):
    
    while sec > 0:
        print str(sec),
        time.sleep(1)
        sec -= 1

def get_page(url, data=None, prev_headers=None):
    headers = {
        'User-Agent' : user_agent,
        'Accept' : "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
        'Accept-Language' : "en,fr;q=0.7,en-us;q=0.3",
        'Accept-Charset' : "ISO-8859-1,utf-8;q=0.7,*;q=0.7",
        'Keep-Alive' : '300'
    }
    
    if prev_headers:
        # extract my session id by loading a page from the site
        cookie = prev_headers.getheader("Set-Cookie").split(' ')[0]
        headers["Cookie"] = cookie

    if data:
        req = urllib2.Request(url, urllib.urlencode(data), headers=headers)
    else:
        req = urllib2.Request(url, headers=headers)
        
    
    try_again = True
    page = None
    while try_again:
        try:
            page = urllib2.urlopen(req)
        except urllib2.HTTPError, e:
            print e
        except urllib2.URLError, e:
            print 'lost connection, trying again in.. ',
            count_down(5)
        else:
            try_again = False
        
    page.raw_html = page.read()
    write_to_file(page.raw_html)
    return page

def get_parser(page):
    parser = MyParser()
    parser.parse(page.raw_html)
    return parser

def check(reconnect_count):
    print_time()
    page = get_page(ping_page)
    
    if page.url.rstrip('/') != ping_page:
        #got redirected, let's log in...
        print '--not logged in... logging in.',
        page = get_page(sign_in_url)
        parser = get_parser(page)
        
        input_tags = parser.input_tags
        input_tags.update(post_vars)
        
        login_page = get_page(sign_in_url, input_tags, page.headers)
        
        reconnect_count += 1
        print '--reconnected %s times' % reconnect_count
        
        if "Log out" not in login_page.raw_html:
            print "logging in did NOT work!"
    else:
        print 'logged in.'
    
    Timer(float(interval_to_check), check, [reconnect_count]).start()

check(0)