from typing import List

from pycs.database.Database import Database
from pycs.frontend.notifications.NotificationList import NotificationList
from pycs.interfaces.MediaFileList import MediaFileList
from pycs.interfaces.MediaLabel import MediaLabel


class MediaStorage:
    """
    helper class for pipelines to interact with database entities
    """

    def __init__(self, db: Database, project_id: int, notifications: NotificationList = None):
        self.__db = db
        self.__project_id = project_id
        self.__notifications = notifications

        self.__project = self.__db.project(self.__project_id)
        self.__collections = self.__project.collections()

    def labels(self) -> List[MediaLabel]:
        """
        receive a list of labels

        :return: list of labels
        """
        label_list = self.__project.labels()
        label_dict = {la.identifier: MediaLabel(la) for la in label_list}
        result = []

        for label in label_list:
            medial_label = label_dict[label.identifier]

            if label.parent_id is not None:
                medial_label.parent = label_dict[label.parent_id]
                medial_label.parent.children.append(medial_label)

            result.append(medial_label)

        return result

    def labels_tree(self) -> List[MediaLabel]:
        """
        receive a tree of labels

        :return: list of root-level labels (parent is None)
        """
        return list(filter(
            lambda ml: ml.parent is None,
            self.labels()
        ))

    def files(self) -> MediaFileList:
        """
        get a FileList object to filter and receive MediaFile elements

        :return: FileList
        """
        return MediaFileList(self.__project, self.__notifications)