"""Basic feature store for GraphBolt."""

from typing import Dict, Tuple

import torch

from ..feature_store import Feature, FeatureStore

__all__ = ["BasicFeatureStore"]


class BasicFeatureStore(FeatureStore):
    r"""Basic feature store."""

    def __init__(self, features: Dict[Tuple[str, str, str], Feature]):
        r"""Initiate a basic feature store.


        Parameters
        ----------
        features : Dict[Tuple[str, str, str], Feature]
            The dict of features served by the feature store, in which the key
            is tuple of (domain, type_name, feature_name).

        Returns
        -------
        The feature stores.
        """
        super().__init__()
        self._features = features

    def read(
        self,
        domain: str,
        type_name: str,
        feature_name: str,
        ids: torch.Tensor = None,
    ):
        """Read from the feature store.

        Parameters
        ----------
        domain : str
            The domain of the feature such as "node", "edge" or "graph".
        type_name : str
            The node or edge type name.
        feature_name : str
            The feature name.
        ids : torch.Tensor, optional
            The index of the feature. If specified, only the specified indices
            of the feature are read. If None, the entire feature is returned.

        Returns
        -------
        torch.Tensor
            The read feature.
        """
        return self._features[(domain, type_name, feature_name)].read(ids)

    def update(
        self,
        domain: str,
        type_name: str,
        feature_name: str,
        value: torch.Tensor,
        ids: torch.Tensor = None,
    ):
        """Update the feature store.

        Parameters
        ----------
        domain : str
            The domain of the feature such as "node", "edge" or "graph".
        type_name : str
            The node or edge type name.
        feature_name : str
            The feature name.
        value : torch.Tensor
            The updated value of the feature.
        ids : torch.Tensor, optional
            The indices of the feature to update. If specified, only the
            specified indices of the feature will be updated. For the feature,
            the `ids[i]` row is updated to `value[i]`. So the indices and value
            must have the same length. If None, the entire feature will be
            updated.
        """
        self._features[(domain, type_name, feature_name)].update(value, ids)

    def __len__(self):
        """Return the number of features."""
        return len(self._features)
