import math
import re
import time

from util import hook, urlnorm, timesince

url_re = re.compile(r'([a-zA-Z]+://|www\.)[^ ]*')

expiration_period = 60 * 60 * 24  # 1 day

rate_limit_period = 60 * 3 # 3 minutes
rate_limit_count = 3

ignored_urls = [urlnorm.normalize("http://google.com")]


def db_connect(bot, server):
    "check to see that our db has the the seen table and return a dbection."
    db = bot.get_db_connection(server)
    db.execute("create table if not exists urlhistory"
                 "(chan, url, nick, time)")
    db.commit()
    return db


def insert_history(db, chan, url, nick):
    now = time.time()
    db.execute("insert into urlhistory(chan, url, nick, time) "
                 "values(?,?,?,?)", (chan, url, nick, time.time()))
    db.commit()


def get_history_duration(db, chan, url, duration):
    db.execute("delete from urlhistory where time < ?",
                 (time.time() - duration,))
    return db.execute("select nick, time from urlhistory where "
            "chan=? and url=? order by time desc", (chan, url)).fetchall()


def get_history(db, chan, url):
    return get_history_duration(db, chan, url, expiration_period)


def get_recent_links_count(db, chan, url):
    return len(get_history_duration(db, chan, url, rate_limit_period))
   

def nicklist(nicks):
    nicks = sorted(dict(nicks), key=unicode.lower)
    if len(nicks) <= 2:
        return ' and '.join(nicks)
    else:
        return ', and '.join((', '.join(nicks[:-1]), nicks[-1]))


def format_reply(history):
    if not history:
        return

    last_nick, recent_time = history[0]
    last_time = timesince.timesince(recent_time)

    if len(history) == 1:
        return "%s linked that %s ago." % (last_nick, last_time)

    hour_span = math.ceil((time.time() - history[-1][1]) / 3600)
    hour_span = '%.0f hours' % hour_span if hour_span > 1 else 'hour'

    hlen = len(history)
    ordinal = ["once", "twice", "%d times" % hlen][min(hlen, 3) - 1]

    if len(dict(history)) == 1:
        last = "last linked %s ago" % last_time
    else:
        last = "last linked by %s %s ago" % (last_nick, last_time)

    return "that url has been posted %s in the past %s by %s (%s)." % (ordinal,
            hour_span, nicklist(history), last)


@hook.command(hook=r'(.*)', prefix=False)
def urlinput(inp, nick='', chan='', server='', reply=None, bot=None):
    m = url_re.search(inp.encode('utf8'))
    if not m:
        return

    # URL detected
    db = db_connect(bot, server)
    url = urlnorm.normalize(m.group(0))
    if url not in ignored_urls:
        history = get_history(db, chan, url)
        recent_history = get_recent_links_count(db, chan, url)
        insert_history(db, chan, url, nick)
        if nick not in dict(history) and recent_history < rate_limit_count:
            return format_reply(history)