from django.db.models import Avg
from django.utils import timezone

from graph.models import Transaction, MonthlyTransaction
from market.models import Product


def create_transaction(post):
    transaction = Transaction.objects.create(
        product=post.product, price=post.price
    )
    return transaction


def get_average_price(transactions):
    average = transactions.aggregate(Avg("price"))["price__avg"] or 0
    return round(average, -2)


def create_monthly_transaction():
    year = timezone.now().year
    month = timezone.now().month
    products = Product.objects.all()
    for product in products:
        if MonthlyTransaction.objects.filter(
            product=product, year=year, month=month
        ).exists():
            continue
        transactions = Transaction.objects.filter(product=product)
        if transactions:
            price = get_average_price(transactions)
            MonthlyTransaction.objects.create(
                product=product,
                year=year,
                month=month,
                price=price,
            )


def create_monthly_transaction_by_product(product):
    year = timezone.now().year
    month = timezone.now().month
    if MonthlyTransaction.objects.filter(
        product=product, year=year, month=month
    ).exists():
        return
    transactions = Transaction.objects.filter(product=product)
    if transactions:
        price = get_average_price(transactions)
        MonthlyTransaction.objects.create(
            product=product,
            year=year,
            month=month,
            price=price,
        )