from decimal import Decimal

from .models import Item


class PricingSuggestionService:
    def suggest_for_item(self, item: Item):
        recent_comp = (
            Item.objects.filter(status=Item.Status.SOLD, category=item.category)
            .exclude(sold_price__isnull=True)
            .order_by("-sold_at", "-created_at")
            .values_list("sold_price", flat=True)[:5]
        )
        recent_prices = list(recent_comp)

        if recent_prices:
            average_price = sum(recent_prices) / len(recent_prices)
            return {
                "price": average_price.quantize(Decimal("0.01")),
                "source": "Recent sold comps",
                "notes": f"Based on {len(recent_prices)} recent sold items in {item.category}.",
            }

        if item.estimated_resale_price is not None:
            return {
                "price": item.estimated_resale_price,
                "source": "Item estimate",
                "notes": "Using the item's existing estimated resale price.",
            }

        if item.template and item.template.default_estimated_resale_price is not None:
            return {
                "price": item.template.default_estimated_resale_price,
                "source": "Template default",
                "notes": "Using the template's default resale estimate.",
            }

        fallback = (item.purchase_price * Decimal("1.75")).quantize(Decimal("0.01"))
        return {
            "price": fallback,
            "source": "Purchase-price fallback",
            "notes": "No sold comps yet; using a purchase-price multiple as a starting point.",
        }