from apps.herd.services.services import rancher_quota_weight, get_rancher_statistics
from rest_framework.exceptions import APIException
from apps.warehouse.models import (
    InventoryEntry,
    InventoryQuotaSaleTransaction,
    InventoryQuotaSaleItem,
    ExtraSale,
    QuotaPreSaleItem
)
from apps.product.models import QuotaDistribution
from apps.core.models import SystemConfig
from django.db.models import Sum
import typing


def get_total_sold(rancher, inventory_entry: InventoryEntry = None, distribution: QuotaDistribution = None):
    """
    """
    if inventory_entry:
        return (
                InventoryQuotaSaleTransaction.objects.filter(
                    inventory_entry=inventory_entry,
                    rancher=rancher
                ).aggregate(total=Sum('weight'))['total'] or 0
        )

    elif distribution:
        return (
                InventoryQuotaSaleTransaction.objects.filter(
                    inventory_entry=inventory_entry,
                    rancher=rancher
                ).aggregate(total=Sum('weight'))['total'] or 0
        )


def can_buy_from_inventory(rancher, inventory_entry: InventoryEntry = None, distribution: QuotaDistribution = None):
    """
    """
    if SystemConfig.get("IGNORE_ALL_RANCHER_PURCHASE_LIMITS") == "true":
        return True

    if rancher.ignore_purchase_limit:
        return True

    if inventory_entry:
        # check if quota is open and acceptable to sale
        if inventory_entry.distribution.quota.is_in_valid_time():
            quota_weight = rancher_quota_weight(rancher, inventory_entry=inventory_entry)  # {total, by_type}
        else:
            return False

    elif distribution:
        # check if quota is open and acceptable to sale
        if distribution.quota.is_in_valid_time():
            quota_weight = rancher_quota_weight(rancher, distribution=distribution)  # {total, by_type}
        else:
            return False

    total_allowed = quota_weight['total']  # noqa

    total_sold = get_total_sold(inventory_entry, rancher)

    return total_sold < total_allowed


def create_extra_sale(
        sale_item: InventoryQuotaSaleItem,
        transaction: InventoryQuotaSaleTransaction
) -> typing.Any:
    """
    :param sale_item
    :param transaction
    create extra sale for items that weight are
    more than distribution warehouse balance
    """

    if sale_item.quota_distribution.free_sale:
        if sale_item.weight > sale_item.quota_distribution.warehouse_balance:
            # calculate extra weight between item weight and warehouse balance
            extra_weight = sale_item.weight - sale_item.quota_distribution.warehouse_balance
            extra_sale = ExtraSale.objects.create(  # create extra sale
                transaction=transaction,
                sale_item=sale_item,
                distribution=sale_item.quota_distribution,
                weight=extra_weight
            )

            # set distribution warehouse balance to 0 because we have extra sale
            sale_item.quota_distribution.warehouse_balance = 0
            sale_item.quota_distribution.free_sale_balance += extra_weight
            sale_item.quota_distribution.save()

            # set transaction as free sale
            transaction.free_sale_state = True
            transaction.save()

            # set sale item as extra sale
            sale_item.is_extra = True
            sale_item.save()

            return extra_sale
        pass
    pass


def create_pre_sale(
        transaction: InventoryQuotaSaleTransaction,
        sale_item: InventoryQuotaSaleItem
) -> typing.Any:
    """
    :param transaction
    :param sale_item
    Create pre_sale for distributions
    """

    if sale_item.quota_distribution.pre_sale:
        try:
            # create pre sale
            pre_sale = QuotaPreSaleItem.objects.create(
                transaction=transaction,
                sale_item=sale_item,
                distribution=sale_item.quota_distribution,
                weight=sale_item.weight
            )

            # set transaction as pre sale
            transaction.pre_sale_state = True
            transaction.save()

            # set sale item as pre sale
            sale_item.is_pre_sale = True
            sale_item.quota_distribution.pre_sale_balance += sale_item.weight
            sale_item.save()

            return pre_sale
        except APIException as e:
            pass
    pass