import json

from server import get_redis_conn


class Resource(object):
    __collection__ = 'generic'
    __required_keys__ = ()

    def __init__(self):
        self._db = get_redis_conn()

    def getall(self):
        ret = []

        for resource in self._db.hgetall(self.__collection__).itervalues():
            try:
                ret.append(json.loads(resource))
            except ValueError, exc:
                print_exc()

        return ret

    def get(self, resource_id):
        raw_resource = self._db.hget(self.__collection__, resource_id)

        if not raw_resource:
            return None

        resource = json.loads(raw_resource)
        return resource

    def add(self, resource_dict):
        if None in (resource_dict.get(k) for k in self.__required_keys__):
            raise ValueError(
                'Missing required fields!: {}'.format(resource_dict)
            )

        resource_dict['id'] = self._db.incr(self.__collection__ + '_ids')
        success = self._db.hset(
            self.__collection__, resource_dict['id'], json.dumps(resource_dict)
        )
        assert success, 'Failed to save!'

        return resource_dict['id']