records.py

from copy import deepcopy

from .logger import logger
from .operations import build_operation
from .utils import extract_id, get_by_path


class Record(object):

    # if a subclass has a list of ids that should be update when child records are removed, it should specify the key here
    child_list_key = None

    def __init__(self, client, id, *args, **kwargs):
        self._client = client
        self._id = extract_id(id)
        self._callbacks = []
        if self._client._monitor is not None:
            self._client._monitor.subscribe(self)

    @property
    def id(self):
        return self._id

    @property
    def role(self):
        return self._client._store.get_role(self._table, self.id)

    def _str_fields(self):
        """
        Determines the list of fields to include in the __str__ representation. Override and extend this in subclasses.
        """
        return ["id"]

    def __str__(self):
        return ", ".join(
            [
                "{}={}".format(field, repr(getattr(self, field)))
                for field in self._str_fields()
                if getattr(self, field, "")
            ]
        )

    def __repr__(self):
        return "<{} ({})>".format(self.__class__.__name__, self)

    def refresh(self):
        """
        Update the cached data for this record from the server (data for other records may be updated as a side effect).
        """
        self._get_record_data(force_refresh=True)

    def _convert_diff_to_changelist(self, difference, old_val, new_val):
        changed_values = set()
        for operation, path, values in deepcopy(difference):
            path = path.split(".") if isinstance(path, str) else path
            if operation in ["add", "remove"]:
                path.append(values[0][0])
            while isinstance(path[-1], int):
                path.pop()
            changed_values.add(".".join(map(str, path)))
        return [
            (
                "changed_value",
                path,
                (get_by_path(path, old_val), get_by_path(path, new_val)),
            )
            for path in changed_values
        ]

    def add_callback(self, callback, callback_id=None, extra_kwargs={}):
        assert callable(
            callback
        ), "The callback must be a 'callable' object, such as a function."
        callback_obj = self._client._store.add_callback(
            self, callback, callback_id=callback_id, extra_kwargs=extra_kwargs
        )
        self._callbacks.append(callback_obj)
        return callback_obj

    def remove_callbacks(self, callback_or_callback_id_prefix=None):
        if callback_or_callback_id_prefix is None:
            for callback_obj in list(self._callbacks):
                self._client._store.remove_callbacks(
                    self._table, self.id, callback_or_callback_id_prefix=callback_obj
                )
            self._callbacks = []
        else:
            self._client._store.remove_callbacks(
                self._table,
                self.id,
                callback_or_callback_id_prefix=callback_or_callback_id_prefix,
            )
            if callback_or_callback_id_prefix in self._callbacks:
                self._callbacks.remove(callback_or_callback_id_prefix)

    def _get_record_data(self, force_refresh=False):
        return self._client.get_record_data(
            self._table, self.id, force_refresh=force_refresh
        )

    def get(self, path=[], default=None, force_refresh=False):
        """
        Retrieve cached data for this record. The `path` is a list (or dot-delimited string) the specifies the field
        to retrieve the value for. If no path is supplied, return the entire cached data structure for this record.
        If `force_refresh` is set to True, we force_refresh the data cache from the server before reading the values.
        """
        return get_by_path(
            path, self._get_record_data(force_refresh=force_refresh), default=default
        )

    def set(self, path, value):
        """
        Set a specific `value` (under the specific `path`) on the record's data structure on the server.
        """
        self._client.submit_transaction(
            build_operation(id=self.id, path=path, args=value, table=self._table)
        )

    def __eq__(self, other):
        return self.id == other.id

    def __ne__(self, other):
        return self.id != other.id

    def __hash__(self):
        return hash(self.id)