#
# Service facade for gnuviech-admin tool backend
# (c) 2006 Jan Dittberner <jan@dittberner.info>
# $Id$
#
from SessionManager import *
from DomainManager import *
import Settings
import psycopg2

class ServiceFacade:
    """
    This class implements the facade to the services provided by the
    gnuviech admin backend.
    """
    def __init__(self):
        connstr = 'host=%(dbhost)s user=%(dbuser)s ' + \
                  'password=%(dbpassword)s dbname=%(dbname)s'
        dbconn = psycopg2.connect(connstr % Settings.DBSETTINGS)
        self.sessionManager = SessionManager(dbconn)
        self.domainManager = DomainManager(dbconn)

    def _dispatch(self, method, params):
        try:
            func = getattr(self, method)
        except AttributeError:
            raise Exception('method "%s" is not supported' % method)
        else:
            if method != 'login' and method != 'logout':
                sessionid = params[0]
                try:
                    session = self.sessionManager.getSession(sessionid)
                except InvalidSessionError:
                    return ""
                nparams = [session]
                for item in params[1:]:
                    nparams.append(item)
                params = nparams
                self.sessionManager.updateSession(sessionid)
            return func(*params)

    def login(self, login, password):
        """
        Logs in the user specified by the given login and password.
        The method creates a session and returns the session id which
        has to be sent back by subsequent requests. If the login is
        invalid the returned id is 0
        """
        try:
            return self.sessionManager.newSession(login, password)
        except InvalidLoginError, ile:
            return 0

    def logout(self, sessionid):
        self.sessionManager.deleteSession(sessionid)
        return 0

    def listdomains(self, session):
        """
        Lists the domains the given session may see.
        """
        return self.domainManager.listDomains(session)