from zephyr.models import Message
from zephyr.lib.cache import cache_with_key, djcache

MESSAGE_CACHE_SIZE = 25000

def message_cache_key(message_id):
    return "message:%d" % (message_id,)

def cache_save_message(message):
    djcache.set(message_cache_key(message.id), (message,), timeout=3600*24)

@cache_with_key(message_cache_key)
def cache_get_message(message_id):
    return Message.objects.select_related("client", "sender").get(id=message_id)

# Called on Tornado startup to ensure our message cache isn't empty
def populate_message_cache():
    max_message_id = 0
    min_message_id = 0
    messages_for_memcached = {}
    for m in Message.objects.select_related("sender", "client").all().order_by(
        "-id")[0:MESSAGE_CACHE_SIZE]:
        max_message_id = max(m.id, max_message_id)
        min_message_id = min(m.id, min_message_id)
        messages_for_memcached[message_cache_key(m.id)] = (m,)

    djcache.set_many(messages_for_memcached, timeout=3600*24)
    return max_message_id, min_message_id