# The contents of this file are subject to the Common Public Attribution
# License Version 1.0. (the "License"); you may not use this file except in
# compliance with the License. You may obtain a copy of the License at
# http://code.reddit.com/LICENSE. The License is based on the Mozilla Public
# License Version 1.1, but Sections 14 and 15 have been added to cover use of
# software over a computer network and provide for limited attribution for the
# Original Developer. In addition, Exhibit A has been modified to be consistent
# with Exhibit B.
#
# Software distributed under the License is distributed on an "AS IS" basis,
# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
# the specific language governing rights and limitations under the License.
#
# The Original Code is reddit.
#
# The Original Developer is the Initial Developer.  The Initial Developer of
# the Original Code is reddit Inc.
#
# All portions of the code written by reddit are Copyright (c) 2006-2012 reddit
# Inc. All Rights Reserved.
###############################################################################

from datetime import datetime
from utils import tup
import pytz

def make_last_modified():
    last_modified = datetime.now(pytz.timezone('GMT'))
    last_modified = last_modified.replace(microsecond = 0)
    return last_modified

def last_modified_key(thing, action):
    return 'last_%s_%s' % (str(action), thing._fullname)

def last_modified_date(thing, action, set_if_empty = True):
    """Returns the date that should be sent as the last-modified header."""
    from pylons import g
    cache = g.permacache

    key = last_modified_key(thing, action)
    last_modified = cache.get(key)
    if not last_modified and set_if_empty:
        #if there is no last_modified, add one
        last_modified = make_last_modified()
        cache.set(key, last_modified)
    return last_modified

def set_last_modified(thing, action):
    from pylons import g
    key = last_modified_key(thing, action)
    g.permacache.set(key, make_last_modified())

def last_modified_multi(things, action):
    from pylons import g
    cache = g.permacache

    things = tup(things)
    keys = dict((last_modified_key(thing, action), thing) for thing in things)

    last_modified = cache.get_multi(keys.keys())
    return dict((keys[k], v) for k, v in last_modified.iteritems())
