"""Feed importer: normalize -> validate -> upsert.

NEVER auto-publishes products: new products are created with status 'imported'
only. Invalid items (missing sku/title, non-positive cost, negative inventory)
are skipped and logged to audit_logs.
"""
from decimal import Decimal

from app.engines.suppliers.base import build_adapter
from app.models import AuditLog, Product, SupplierProduct


def validate(item):
    problems = []
    if not (item.get("sku") or "").strip():
        problems.append("missing sku")
    if not (item.get("title") or "").strip():
        problems.append("missing title")
    try:
        cost = float(item.get("cost") or 0)
        if cost <= 0:
            problems.append("non-positive cost")
    except (TypeError, ValueError):
        problems.append("invalid cost")
    try:
        inventory = int(float(item.get("inventory") or 0))
        if inventory < 0:
            problems.append("negative inventory")
    except (TypeError, ValueError):
        problems.append("invalid inventory")
    return problems


def import_feed(db, supplier, feed_type=None, data_or_url=""):
    """Import a supplier feed into products + supplier_products.

    Returns summary dict: {supplier, received, imported, updated, skipped: [...]}
    """
    adapter = build_adapter(supplier, data_or_url=data_or_url)
    items = adapter.get_products()

    summary = {
        "supplier": supplier.name,
        "supplier_id": str(supplier.id),
        "received": len(items),
        "imported": 0,
        "updated": 0,
        "skipped": [],
    }

    for item in items:
        problems = validate(item)
        if problems:
            reason = "; ".join(problems)
            summary["skipped"].append({"sku": item.get("sku"), "reason": reason})
            db.add(
                AuditLog(
                    actor="importer",
                    action="import_skipped",
                    entity="product",
                    entity_id=item.get("sku"),
                    detail={"supplier": supplier.name, "reason": reason},
                )
            )
            continue

        product = db.query(Product).filter(Product.sku == item["sku"]).first()
        if product is None:
            product = Product(sku=item["sku"], status="imported")
            db.add(product)
            summary["imported"] += 1
        else:
            summary["updated"] += 1

        # set all required fields BEFORE flushing (title is NOT NULL in schema)
        product.title = item["title"]
        product.description = item.get("description") or product.description
        product.category = item.get("category") or product.category
        product.brand = item.get("brand") or product.brand
        product.cost = Decimal(str(item["cost"]))

        if item.get("image_url"):
            images = list(product.images or [])
            if item["image_url"] not in images:
                images.append(item["image_url"])
            product.images = images

        db.flush()  # product.id available now

        sp = (
            db.query(SupplierProduct)
            .filter(
                SupplierProduct.supplier_id == supplier.id,
                SupplierProduct.supplier_sku == item["sku"],
            )
            .first()
        )
        if sp is None:
            sp = SupplierProduct(
                supplier_id=supplier.id,
                supplier_sku=item["sku"],
                product_id=product.id,
            )
            db.add(sp)
            db.flush()
        else:
            sp.product_id = product.id

        sp.supplier_cost = Decimal(str(item["cost"]))
        sp.supplier_inventory = int(item.get("inventory") or 0)
        sp.shipping_cost = Decimal(str(item.get("shipping_cost") or 0))
        sp.shipping_time = item.get("shipping_time")

    db.commit()
    return summary