"""Open Food Facts Lookup-Client."""

from __future__ import annotations

import json

import httpx

from .config import get_settings

settings = get_settings()


def _guess_base_unit(quantity: str | None) -> str:
    """Rät die Basiseinheit aus dem OFF-Feld 'quantity' (z.B. '500 g', '1 l')."""
    if not quantity:
        return "piece"
    q = quantity.lower()
    if "ml" in q or "cl" in q or "l" in q or "liter" in q:
        return "milliliter"
    if "kg" in q or " g" in q or "gramm" in q or q.strip().endswith("g"):
        return "gram"
    return "piece"


def lookup_barcode(barcode: str) -> dict | None:
    """Fragt Open Food Facts nach einem Barcode.

    Gibt ein vorbefülltes Produkt-Dict zurück oder None, wenn nicht gefunden.
    """
    # v0-API: liefert bei Treffer status=1 + product, bei Nicht-Treffer status=0
    # (HTTP 200). Die v2-API hat kein status-Feld und antwortet mit HTTP 404,
    # weshalb wir bewusst v0 nutzen.
    url = f"{settings.off_base_url}/api/v0/product/{barcode}.json"
    try:
        resp = httpx.get(
            url,
            timeout=settings.off_timeout_seconds,
            headers={"User-Agent": "Project-Good-Selfhosted/1.0"},
            follow_redirects=True,
        )
    except httpx.HTTPError:
        return None

    if resp.status_code != 200:
        return None

    try:
        data = resp.json()
    except ValueError:
        return None
    if data.get("status") != 1:
        return None

    product = data.get("product", {})
    name = (
        product.get("product_name_de")
        or product.get("product_name")
        or product.get("generic_name")
        or ""
    ).strip()
    if not name:
        return None

    categories = product.get("categories") or ""
    category_tags = product.get("categories_tags") or []

    return {
        "barcode": barcode,
        "name": name,
        "brand": (product.get("brands") or "").strip() or None,
        "image_url": product.get("image_front_url") or product.get("image_url") or None,
        "base_unit": _guess_base_unit(product.get("quantity")),
        "quantity_text": product.get("quantity"),
        "category_suggestion": categories.split(",")[0].strip() if categories else None,
        "category_tags": category_tags,
        "source": "off",
        "off_raw": json.dumps(product)[:20000],
    }