from __future__ import annotations

from typing import TYPE_CHECKING

if TYPE_CHECKING:  # pragma: no cover
    from typing import List
    from sheerkarete.join_node import JoinNode
    from sheerkarete.common import WME


class AlphaMemory:

    def __init__(self, key, condition, items=None, successors=None):
        """
        Stores a set of WMEs (items). If activating an activated wme does not
        exist, then it addes it. It also right activates all of its successors,
        which correspond to beta nodes.
        :param items: set of WMEs that match this memory
        :param successors: list of JoinNode
        """
        self.key = key
        self.condition = condition
        self.items: List[WME] = items if items else []
        self.successors: List[JoinNode] = successors if successors else []
        self.reference_count = 0

    def activation(self, wme: WME) -> None:
        """
        Adds the WME to the alpha memory and then right activates the children
        in the beta network. Note, these are activated in reversed order to
        prevent duplicate matches.
        """
        if not self.condition.test(wme):
            return

        self.items.append(wme)
        wme.amems.append(self)
        for child in reversed(self.successors):
            child.right_activation(wme)