import logging
from datetime import datetime

from boto3.dynamodb.conditions import Attr, And

from lib_b2b.change import ChangeRecord
from lib_b2b.errors import VersionConflictError
from lib_b2b.order import Order
from lib_b2b.order_change import OrderChangeRequest, SimpleOrderPredicate, OrderStatusChangeDataProvider
from lib_b2b.order_status import OrderStatus
from lib_b2b.policy import Policy

logger = logging.getLogger(__name__)


class OrderReprocessChangeRequest(OrderChangeRequest):
    # TODO: - Move these policies to be data driven
    _policy = Policy(
        name='reprocess_change_policy',
        subject=Policy.SUBJECT_ALL,
        predicates=[
            SimpleOrderPredicate(
                lambda o: o.status is OrderStatus.REJECTED,
                'Cannot reprocess unless the order is Rejected.')
        ]
    )

    def __init__(self, on_behalf_of: str, change_data_provider: OrderStatusChangeDataProvider):
        super().__init__(on_behalf_of, OrderReprocessChangeRequest._policy)
        self.change_data_provider = change_data_provider

    def will_change(self, order: Order) -> bool:
        return self.change_data_provider.new_status is not order.status and self.change_data_provider.new_status is OrderStatus.RECEIVED

    def apply(self, order: Order):
        try:
            self.changeable_object = order
            if super().permitted(order):
                if self.will_change(order):
                    before_status = order.status
                    expressions1 = [
                        Attr('order_status').ne(OrderStatus.RECEIVED.value),
                        Attr('order_status').ne(OrderStatus.SHIPPED.value)
                    ]
                    conditions1 = And(*expressions1)
                    expressions2 = [
                        Attr('order_status').ne(OrderStatus.PARTIALLY_SHIPPED.value),
                        Attr('order_status').ne(OrderStatus.CANCELLED.value)
                    ]
                    conditions2 = And(*expressions2)
                    conditions3 = And(*[conditions1, conditions2])
                    order.set_status(self.change_data_provider.new_status,
                                     conditions3,
                                     version=self.change_data_provider.version())
                    order.record(
                        ChangeRecord(before=before_status.value, after=self.change_data_provider.new_status.value,
                                     description="Order was reprocessed", when=datetime.now(), who=self.on_behalf_of)
                    )

        except ValueError as ve:
            raise VersionConflictError(str(ve))