import re
import time
import praw
import datetime

CONFIG_INTERVAL      = 6 * 3600 # Number of seconds between updating
CONFIG_CLIENT_ID     = "" # Client ID from /prefs/apps
CONFIG_CLIENT_SECRET = "" # Client secret from /prefs/apps
CONFIG_USERNAME      = "" # Username for the bot account
CONFIG_PASSWORD      = "" # Password for the bot account
CONFIG_SUBREDDIT     = "" # Subreddit(s) the script runs on
CONFIG_SCRIPTHOST    = "" # Your Reddit username
CONFIG_USER_AGENT    = "catsubtracker 1.0 for /r/%s, hosted by /u/%s" \
                       %(CONFIG_SUBREDDIT, CONFIG_SCRIPTHOST)
CONFIG_WIKIPAGE      = "" # The name of the wiki page to check/edit

catmatch = r'indexing\s[0-9]*\scategories'
submatch = r'categories\sand\s[0-9]*\ssubreddits'
datemtch = r'Last updated [0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2} UTC'
pformat  = 'The directory is currently indexing %d' + \
           ' categories and %d subreddits. (Last updated %s UTC)'

def get_counts(body):
    _catmatch = r'###\s*[^\s]*'
    _submatch = r'/r/[^\s]*'
    return (len(re.findall(_catmatch, body)),
            len(re.findall(_submatch, body)))

def get_old_counts(body):
    if 'The directory is currently' in body:
        return (int(re.findall(catmatch, body)[0].split(' ')[1]),
                int(re.findall(submatch, body)[0].split(' ')[2]))
    else:
        return (0, 0)

def gen_new_page(body, cats, subs):
    datestr = datetime.datetime.utcnow().strftime('%Y-%m-%d %H:%M')
    base = re.sub(catmatch, 'indexing %d categories'%cats, body)
    base = re.sub(submatch, 'categories and %d subreddits'%subs, base)
    base = re.sub(datemtch, 'Last updated %s UTC'%datestr, base)
    if base == body:
        base += '\r\n\r\n-------\r\n\r\n%s'%(pformat%(cats, subs, datestr))
    return base

def log(msg):
    print('[%s] %s'%(time.ctime(), msg))

def main():
    reddit = praw.Reddit(client_id = CONFIG_CLIENT_ID,
                         client_secret = CONFIG_CLIENT_SECRET,
                         username = CONFIG_USERNAME,
                         password = CONFIG_PASSWORD,
                         user_agent = CONFIG_USER_AGENT)
    while True:
        log('Loading wiki page...')
        wikipage = reddit.subreddit(CONFIG_SUBREDDIT).wiki[CONFIG_WIKIPAGE]
        cats, subs = get_counts(wikipage.content_md)
        ocats, osubs = get_old_counts(wikipage.content_md)
        if cats != ocats or subs != osubs:
            log('Directory has been updated! Editing...')
            new_page = gen_new_page(wikipage.content_md, cats, subs)
            wikipage.edit(new_page, 'Category / sub count updated.')
            log('Directory edited.')
        else:
            log('No changes were detected.')
        log('Sleeping for %d hours.'%(CONFIG_INTERVAL / 3600))
        time.sleep(CONFIG_INTERVAL)

if __name__ == '__main__':
    main()