"""SupplierAdapter abstract base class + registry."""
from abc import ABC, abstractmethod

# Registry of adapter_type string -> adapter class. Populated by register_adapter.
ADAPTERS = {}


class SupplierAdapter(ABC):
    """Normalized interface every supplier feed must implement.

    Product dict shape (used by the importer):
        {sku, title, description, category, brand, cost, inventory,
         shipping_cost, shipping_time, image_url}
    """

    adapter_type = "base"

    def __init__(self, supplier, data_or_url=""):
        self.supplier = supplier
        self.data_or_url = data_or_url

    @abstractmethod
    def get_products(self):
        """Return list of normalized product dicts."""

    @abstractmethod
    def get_inventory(self):
        """Return list of {'supplier_sku': str, 'inventory': int}."""

    @abstractmethod
    def get_price(self, sku):
        """Return current supplier cost for sku (number) or None."""

    @abstractmethod
    def create_order(self, items):
        """Place an order at the supplier; return {'ref': str, ...}."""

    @abstractmethod
    def get_order_status(self, ref):
        """Return status string for a supplier order ref."""

    @abstractmethod
    def get_tracking(self, ref):
        """Return {'tracking': str, 'carrier': str} or None."""

    @abstractmethod
    def cancel_order(self, ref):
        """Cancel a supplier order; return status dict."""


def register_adapter(cls):
    ADAPTERS[cls.adapter_type] = cls
    return cls


def build_adapter(supplier, data_or_url=""):
    cls = ADAPTERS.get(supplier.adapter_type)
    if cls is None:
        # lazy-import concrete adapters so their @register_adapter side effects run
        from app.engines.suppliers import csv_adapter, printful, sample  # noqa: F401

        cls = ADAPTERS.get(supplier.adapter_type)
    if cls is None:
        raise ValueError(f"unknown adapter_type '{supplier.adapter_type}' for supplier {supplier.name}")
    return cls(supplier, data_or_url=data_or_url)