from django.db import models
from django.db.models import Sum
from django.db.models.signals import post_save, post_delete, post_init
from django.dispatch import receiver

from apps.product.validators.quota_stats_validator import QuotaStatsValidator
from apps.warehouse.models import (
    InventoryQuotaSaleTransaction,
    InventoryEntry
)
from .models import (
    QuotaDistribution,
    Quota,
    QuotaStats, OrganizationQuotaStats
)
from .services.quota_stat_service import QuotaStatsService


def recalculate_remaining_amount(quota):
    """ calculate remaining weight from distribution """
    total_distributed = quota.distributions_assigned.filter(
        parent_distribution__isnull=True,
        assigner_organization=quota.registerer_organization,
        trash=False,
    ).aggregate(
        total=Sum('weight')
    )['total'] or 0

    quota.remaining_weight = quota.quota_weight - total_distributed
    quota.quota_distributed = total_distributed
    quota.save(update_fields=["remaining_weight", "quota_distributed"])


def remaining_distribution_weight(instance: QuotaDistribution):
    """ calculate remaining & distributed weight from distribution """

    total_children_weight = instance.children.filter(trash=False).aggregate(
        total=Sum('weight')
    )['total'] or 0

    # total warehouse inventory entry
    total_entry = instance.inventory_entry.filter(trash=False).aggregate(
        total=Sum('weight')
    )['total'] or 0

    instance.remaining_weight = instance.weight - total_children_weight - total_entry
    instance.distributed = total_children_weight
    instance._from_signal = True
    instance.save(update_fields=['remaining_weight', 'distributed'])

    if instance.parent_distribution:
        remaining_distribution_weight(instance.parent_distribution)


@receiver(post_save, sender=QuotaDistribution)
@receiver(post_delete, sender=QuotaDistribution)
def update_quota_remaining(sender, instance, **kwargs):
    recalculate_remaining_amount(instance.quota)

    # if _from_signal=True prevent from maximum recursion loop
    if getattr(instance, '_from_signal', False):
        return

    # when delete object, prevent from update fields error
    # if kwargs.get('signal') == post_delete:
    if instance.trash:
        if instance.parent_distribution:
            remaining_distribution_weight(instance.parent_distribution)
    else:
        remaining_distribution_weight(instance)


# def update_product_stats(instance: OrganizationQuotaStats):
#     """ update all stats of product  """
#
#     user = get_current_user()  # get user object
#     if not isinstance(user, AnonymousUser):
#         organization = get_organization_by_user(user)
#         # QuotaStatsValidator.validate_assigner_has_enough(
#         #     organization,
#         #     distribution.quota,
#         #     distribution.weight,
#         #     allow_zero=True
#         # )
#
#         stat, created = ProductStats.objects.get_or_create(
#             organization=organization,
#             product=instance,
#             sale_unit=instance.quota.sale_unit.unit
#         )
#
#         # number of quotas
#
#         org_quota_stat = OrganizationQuotaStats.objects.filter(
#             organization=organization,
#             quota__product=instance.quota.product,
#         )
#
#         quotas_count = org_quota_stat.count()  # noqa
#
#         product_stat_data = org_quota_stat.aggregate(
#             total_quotas_weight=models.Sum('total_amount'),
#             active_quotas_weight=models.Sum('active_quotas_weight', filter=Q(quota__is_closed=False)),
#             closed_quotas_weight=models.Sum('closed_quotas_weight', filter=Q(quota__is_closed=True)),
#             total_remaining_quotas_weight=models.Sum('remaining_amount'),
#             total_distributed=models.Sum('quota_distributed'),
#             total_warehouse_entry=models.Sum('inventory_received'),
#             total_sold=models.Sum('total_sold'),
#         )
#         # quota = Quota.objects.filter(
#         #     Q(
#         #         distributions_assigned__in=QuotaDistribution.objects.filter(
#         #             Q(assigned_organization=organization) |
#         #             Q(assigner_organization=organization) &
#         #             Q(parent_distribution__isnull=True)
#         #
#         #         )
#         #     ) |
#         #     Q(registerer_organization=organization),
#         #     product=instance
#         # ).distinct()
#         #
#         # quotas_count = quota.count()  # noqa
#         #
#         # total_quotas_weight = quota.aggregate(  # noqa
#         #     total=models.Sum('quota_weight')
#         # )['total'] or 0
#         #
#         # # total weight of product that assigned in quota
#         # active_quotas_weight = quota.filter(is_closed=False).aggregate(
#         #     total=models.Sum('quota_weight')
#         # )['total'] or 0
#         #
#         # closed_quotas_weight = quota.filter(is_closed=True).aggregate(  # noqa
#         #     total=models.Sum('quota_weight')
#         # )['total'] or 0
#         #
#         # # total remaining weight of product quotas
#         # total_remaining_quotas_weight = quota.filter(is_closed=False).aggregate(  # noqa
#         #     total=models.Sum('remaining_weight')
#         # )['total'] or 0
#         #
#         # received_distribution_weight = QuotaDistribution.objects.filter(
#         #     quota__product_id=instance.id,
#         #     quota__is_closed=False,
#         #     quota__sale_unit=distribution.quota.sale_unit,
#         #     assigned_organization=organization,
#         #     parent_distribution__isnull=True
#         # )
#         #
#         # received_distribution_number = received_distribution_weight.count()
#         #
#         # received_distribution_weight = received_distribution_weight.aggregate(
#         #     total_weight=models.Sum('weight')
#         # )['total_weight'] or 0
#         #
#         # # product total distributed weight from quota
#         # given_distribution_weight = QuotaDistribution.objects.filter(
#         #     quota__product_id=instance.id,
#         #     quota__is_closed=False,
#         #     quota__sale_unit=distribution.quota.sale_unit,
#         #     assigner_organization=organization,
#         #     parent_distribution__isnull=True
#         # )
#         #
#         # given_distribution_number = given_distribution_weight.count()
#         # given_distribution_weight = given_distribution_weight.aggregate(
#         #     total_weight=models.Sum('weight')
#         # )['total_weight'] or 0
#         #
#         # if received_distribution_weight > 0:
#         #     distribution_weight_balance = received_distribution_weight - given_distribution_weight
#         # else:
#         #     distribution_weight_balance = given_distribution_weight
#         #
#         # # total sold of product from quota
#         # total_sold = QuotaDistribution.objects.filter(
#         #     quota__product_id=instance.id,
#         #     quota__is_closed=False,
#         #     quota__sale_unit=distribution.quota.sale_unit,
#         #     assigned_organization=organization
#         # ).aggregate(total_sold=models.Sum('been_sold'))['total_sold'] or 0
#         #
#         # # total entry from product to inventory
#         # total_warehouse_entry = QuotaDistribution.objects.filter(
#         #     quota__product_id=instance.id,
#         #     quota__is_closed=False,
#         #     quota__sale_unit=distribution.quota.sale_unit,
#         #     assigned_organization=organization
#         # ).aggregate(total_entry=models.Sum('warehouse_entry'))['total_entry'] or 0
#
#         # stat.quotas_number = quotas_count
#         # stat.active_quotas_weight = active_quotas_weight
#         # stat.closed_quotas_weight = closed_quotas_weight
#         # stat.total_quota_weight = total_quotas_weight
#         # stat.total_quota_remaining = total_remaining_quotas_weight
#         # stat.total_remaining_distribution_weight = distribution_weight_balance
#         # stat.received_distribution_weight = received_distribution_weight
#         # stat.given_distribution_weight = given_distribution_weight
#         # stat.received_distribution_number = received_distribution_number
#         # stat.given_distribution_number = given_distribution_number
#         # stat.total_warehouse_entry = total_warehouse_entry
#         # stat.total_sold = total_sold
#         # stat.save(update_fields=[
#         #     "quotas_number",
#         #     "active_quotas_weight",
#         #     "closed_quotas_weight",
#         #     "total_quota_weight",
#         #     "total_quota_remaining",
#         #     "total_remaining_distribution_weight",
#         #     "received_distribution_weight",
#         #     "given_distribution_weight",
#         #     "received_distribution_number",
#         #     "total_warehouse_entry",
#         #     "total_sold",
#         # ])


def update_quota_stats(instance: Quota):
    """ update all stats of quota """

    if hasattr(instance, 'stats'):
        stat = instance.stats
    else:
        stat = QuotaStats.objects.create(quota=instance)

    total_distributed = instance.quota_distributed
    total_remaining = instance.remaining_weight

    # total entry to inventory from quota
    total_inventory = InventoryEntry.objects.filter(
        distribution__quota=instance
    ).aggregate(
        total_inventory=models.Sum('weight')
    )['total_inventory'] or 0

    # total sale of distributions from quota
    total_sale = instance.distributions_assigned.filter(
        quota__is_closed=False
    ).aggregate(total_sale=models.Sum('been_sold'))['total_sale'] or 0

    stat.total_distributed = total_distributed
    stat.remaining = total_remaining
    stat.total_inventory = total_inventory
    stat.total_sale = total_sale
    stat.save(update_fields=[
        "total_distributed",
        "remaining",
        "total_inventory",
        "total_sale",
    ])


@receiver([post_save, post_delete], sender=QuotaDistribution)
@receiver([post_save, post_delete], sender=InventoryQuotaSaleTransaction)
def update_stats_on_change(sender, instance, **kwargs):
    if sender == QuotaDistribution:
        # update_product_stats(instance.quota.product, instance)
        update_quota_stats(instance.quota)

        # if _from_signal=True prevent from maximum recursion loop
        if getattr(instance, 'stat_from_signal', False):
            return


@receiver(post_init, sender=QuotaDistribution)
def store_original_weight(sender, instance, **kwargs):
    pass


@receiver(post_init, sender=QuotaDistribution)
def distribution_pre_save(sender, instance, **kwargs):
    if instance.pk:
        instance._is_update = True
        instance._old_weight = instance.weight
    else:
        instance._is_update = False


@receiver(post_save, sender=QuotaDistribution)
def update_stats_after_save(sender, instance, created, **kwargs):
    if getattr(instance, 'stat_from_signal', False):
        return

    if instance.trash:
        return

    if not instance._is_update:  # noqa
        QuotaStatsService.apply_distribution(instance)

    else:
        QuotaStatsService.update_distribution(instance, instance._old_weight)  # noqa

    instance.stat_from_signal = True


@receiver(post_save, sender=QuotaDistribution)
def delete_stats_after_soft_delete(sender, instance, **kwargs):
    if getattr(instance, 'stat_from_signal', False):
        return

    if instance.trash:
        QuotaStatsService.delete_distribution(instance)

    instance.stat_from_signal = True


@receiver(post_save, sender=Quota)
def organization_quota_stats(sender, instance: Quota, created: bool, **kwargs):
    """
    set total received distributions for every organization
    """

    from apps.warehouse.models import InventoryQuotaSaleItem
    if getattr(instance, 'stat_from_signal', False):
        return
    org_quota_stat, created = OrganizationQuotaStats.objects.get_or_create(
        quota=instance,
        organization=instance.registerer_organization,
        stat_type='quota'
    )
    org_quota_stat.total_amount = instance.quota_weight
    org_quota_stat.total_distributed = instance.quota_distributed
    org_quota_stat.sold_amount = InventoryQuotaSaleItem.objects.filter(
        quota_distribution__quota=instance,
        transaction__transaction_status='success'
    ).aggregate(
        total=Sum('weight')
    )['total'] or 0
    org_quota_stat.remaining_amount = org_quota_stat.total_amount - org_quota_stat.total_distributed

    # validate total_amount & distributed with remaining in update
    QuotaStatsValidator.validate_quota_weight_update(org_quota_stat.remaining_amount)

    org_quota_stat.save(update_fields=['total_amount', 'total_distributed', 'sold_amount', 'remaining_amount'])

    # delete quota
    if instance.trash:
        org_quota_stat.soft_delete()

    # prevent from maximum recursion loop
    instance.stat_from_signal = True
#
#
# @receiver(post_save, sender=QuotaDistribution)
# def update_quota_stats_on_distribution(sender, instance: QuotaDistribution, created, **kwargs):
#     if getattr(instance, 'one_time_loop_flag', False):
#         return
#
#     if instance.trash:
#         return
#
#     org = instance.assigned_organization
#     quota = instance.quota
#
#     stats, _ = OrganizationQuotaStats.objects.get_or_create(
#         quota=quota,
#         organization=org,
#     )
#     stats.distributions.add(instance)
#     stats.update_amount(main_quota=True)
#     instance.one_time_loop_flag = True
#
#
# @receiver(post_save, sender=QuotaDistribution)
# def handle_quota_stats_soft_delete_on_distribution(sender, instance: QuotaDistribution, created, **kwargs):
#     if getattr(instance, 'one_time_loop_flag', False):
#         return
#
#     if instance.trash:
#         org = instance.assigned_organization
#         quota = instance.quota
#
#         stats_qs = OrganizationQuotaStats.objects.filter(
#             quota=quota,
#             organization=org,
#         )
#
#         if stats_qs:
#             for stats in stats_qs:
#                 stats.distributions.remove(instance)
#                 stats.update_amount(main_quota=True)
#
#     instance.one_time_loop_flag = True