from kallithea.lib.pidlock import DaemonLock, LockHeld

from kallithea.model.base import init_model

from kallithea.model import meta

from sqlalchemy import engine_from_config

log = logging.getLogger(__name__)

class FakeTask(object):

    """Fake a sync result to make it look like a finished task"""

    def __init__(self, result):

        self.result = result

    def failed(self):

        return False

    traceback = None # if failed

    task_id = None

def task(f_org):

    """Wrapper of celery.task.task, running async if CELERY_ON

    """

    if CELERY_ON:

        def f_async(*args, **kwargs):

            log.info('executing %s task', f_org.__name__)

            try:

                f_org(*args, **kwargs)

            finally:

                log.info('executed %s task', f_org.__name__)

        f_async.__name__ = f_org.__name__

        from kallithea.lib import celerypylons

        runner = celerypylons.task(ignore_result=True)(f_async)

        def f_wrapped(*args, **kwargs):

            t = runner.apply_async(args=args, kwargs=kwargs)

            log.info('executing task %s in async mode - id %s', f_org, t.task_id)

            return t

    else:

        def f_wrapped(*args, **kwargs):

            log.info('executing task %s in sync', f_org.__name__)

            try:

                result = f_org(*args, **kwargs)

            except Exception as e:

                raise # TODO: return this in FakeTask as with async tasks?

            return FakeTask(result)

    return f_wrapped

def __get_lockkey(func, *fargs, **fkwargs):

    params = list(fargs)

    params.extend(['%s-%s' % ar for ar in fkwargs.items()])

    func_name = str(func.__name__) if hasattr(func, '__name__') else str(func)

    lockkey = 'task_%s.lock' % \

        md5(func_name + '-' + '-'.join(map(safe_str, params))).hexdigest()

    return lockkey

def locked_task(func):

    def __wrapper(func, *fargs, **fkwargs):

        lockkey = __get_lockkey(func, *fargs, **fkwargs)

        lockkey_path = config['app_conf']['cache_dir']

        log.info('running task with lockkey %s', lockkey)

        try:

            l = DaemonLock(file_=os.path.join(lockkey_path, lockkey))

            ret = func(*fargs, **fkwargs)

            l.release()

            return ret

        except LockHeld:

            log.info('LockHeld')

            return 'Task with key %s already running' % lockkey

    return decorator(__wrapper, func)

def get_session():

    if CELERY_ON:

        engine = engine_from_config(config, 'sqlalchemy.')

        init_model(engine)

    sa = meta.Session()

    return sa

def dbsession(func):

    def __wrapper(func, *fargs, **fkwargs):

        try:

            ret = func(*fargs, **fkwargs)

            return ret