from abc import ABC, abstractmethod

from atlas_um.helpers.filtering import QueryFiltering
from atlas_um.helpers.ordering import QueryOrdering
from atlas_um.helpers.pagination import APIQueryPagination


class BaseAPIFacade(ABC):
    """
    Base interface to deal with list-like data in list endpoints.
    """

    def __eq__(self, other):
        try:
            return self.items == other.items
        except AttributeError:
            return False

    @property
    @abstractmethod
    def items(self):
        pass

    @property
    @abstractmethod
    def limit(self):
        pass

    @property
    @abstractmethod
    def offset(self):
        pass

    @property
    @abstractmethod
    def count(self):
        pass

    @property
    @abstractmethod
    def previous(self):
        pass

    @property
    @abstractmethod
    def next(self):
        pass


class APIQueryFacade(BaseAPIFacade):
    """
    Helper class to apply filtering, ordering and pagination
    to query, used in API views.
    """

    query_filtering_class = QueryFiltering
    query_ordering_class = QueryOrdering
    query_pagination_class = APIQueryPagination

    def __init__(
        self,
        query,
        allowed_fields=None,
        filter_string="",
        fields_mapping=None,
        limit=None,
        offset=None,
    ):
        self._allowed_fields = allowed_fields
        self._filter_string = filter_string
        self._fields_mapping = fields_mapping
        self._limit = limit
        self._offset = offset
        self._query_filtering = self.query_filtering_class(
            query,
            allowed_fields=self._allowed_fields,
            filter_string=self._filter_string,
            fields_mapping=self._fields_mapping,
        )
        self._query_ordering = self.query_ordering_class(
            self._query_filtering.query,
            allowed_fields=self._allowed_fields,
            order_string=self._filter_string,
            fields_mapping=self._fields_mapping,
        )
        self._query_pagination = self.query_pagination_class(
            self._query_ordering.query, self._limit, self._offset
        )

    @property
    def query(self):
        return self._query_pagination.query

    @property
    def items(self):
        return self._query_pagination.items

    @property
    def limit(self):
        return self._query_pagination.limit

    @property
    def offset(self):
        return self._query_pagination.offset

    @property
    def count(self):
        return self._query_pagination.count

    @property
    def previous(self):
        return self._query_pagination.previous

    @property
    def next(self):
        return self._query_pagination.next