import httpx

from opengoods.adapters.openfoodfacts import OpenFoodFactsAdapter


def _product(code, lm):
    return {"code": code, "product_name": f"P{code}", "last_modified_t": lm}


def _adapter(pages):
    """Build an adapter whose search endpoint serves the given pages."""

    def handler(request: httpx.Request) -> httpx.Response:
        page = int(request.url.params.get("page", "1"))
        products = pages.get(page, [])
        return httpx.Response(200, json={"products": products, "page": page})

    client = httpx.Client(transport=httpx.MockTransport(handler))
    return OpenFoodFactsAdapter(client=client, min_interval=0)


def test_incremental_yields_only_newer_and_stops_at_watermark():
    pages = {
        1: [_product("1", 300), _product("2", 250), _product("3", 100)],
    }
    adapter = _adapter(pages)
    got = list(adapter.fetch_modified_since(200, page_size=3, max_pages=5))
    codes = [p["code"] for p in got]
    assert codes == ["1", "2"]  # 100 <= 200 stops iteration


def test_incremental_paginates_until_short_page():
    pages = {
        1: [_product("1", 900), _product("2", 800)],
        2: [_product("3", 700)],  # short page -> stop after
    }
    adapter = _adapter(pages)
    got = list(adapter.fetch_modified_since(0, page_size=2, max_pages=5))
    assert [p["code"] for p in got] == ["1", "2", "3"]


def test_incremental_empty_first_page():
    adapter = _adapter({1: []})
    assert list(adapter.fetch_modified_since(0, page_size=10, max_pages=3)) == []