from google.appengine.ext import db
from datetime import datetime
from datetime import timedelta

class Lookup(db.Model):
    value = db.StringProperty(multiline=True)
    update_date = db.DateTimeProperty(auto_now_add=True)

    def toJSON(self):
        #return "{'value':'" + self.value + "'}"
        return "{'value':'" + self.value + "','update_date':'" + str(self.update_date) + "'}"

def create_or_update(keyname, valueTxt):
    obj = Lookup.get_by_key_name(keyname)
    if obj == None:
        obj = Lookup(key_name=keyname,value=valueTxt)
    else:
        obj.value = valueTxt
        obj.update_date = datetime.now()
    obj.put()

def get_value(keyname):
    obj = Lookup.get_by_key_name(keyname)
    if obj == None:
        return None
    else:
        return obj.value
    
def get_Lookup(keyname):
    obj = Lookup.get_by_key_name(keyname)
    if obj == None:
        return None
    else:
        return "<![CDATA[" + str(obj.to_xml()) + "]]>"

def get_LookupJSON(keyname):
    obj = Lookup.get_by_key_name(keyname)
    if obj == None:
        return None
    else:
        return str(obj.toJSON())

def deleteByKey(keyname):
    obj = Lookup.get_by_key_name(keyname)
    if obj != None:
        obj.delete()
        
#for cron job
def expireCacheEntries():
    weekago = datetime.now() - timedelta(days=7)
    query = Lookup.gql("where update_date < :1", weekago)
    for l in query:
        l.delete()

class CacheService:
    "<namespace>http://solidcoding.blogspot.com</namespace>"
    def setValue(self, key,value):
        "<op><name/><args><arg type='string'>key</arg><arg type='string'>value</arg></args><ret/></op>"
        db.run_in_transaction(create_or_update,key,value)
    
    def getValue(self, key):
        "<op><name/><args><arg type='string'>key</arg></args><ret type='string'></ret></op>"        
        return db.run_in_transaction(get_value,key)

    def getLookupAsXml(self, key):
        "<op><name/><args><arg type='string'>key</arg></args><ret type='string'></ret></op>"        
        return db.run_in_transaction(get_Lookup,key)

    def getLookupAsJSON(self, key):
        "<op><name/><args><arg type='string'>key</arg></args><ret type='string'></ret></op>"        
        return db.run_in_transaction(get_LookupJSON,key)

    def delete(self, key):
        "<op><name/><args><arg type='string'>key</arg></args><ret/></op>"        
        return db.run_in_transaction(deleteByKey,key)

    def expire(self):
        #for cron job. Not allowed to query inside a transaction. Call direct
        expireCacheEntries()