"""Scaling must never present an unscaled line as scaled.

The original implementation read the structured `quantity` field and string-replaced
`str(quantity)` into the display text. Against the live library that silently did
nothing twice over: unparsed recipes store `quantity: 0.0` with the real amount only
in the text, and `str(800.0)` == "800.0" never matches "800 g kycklinglårfilé".
The result was a confident wrong answer — the worst kind for a shopping list.
"""
from __future__ import annotations

from decimal import Decimal

import pytest

from mealie_mcp.normalize import format_amount, scale_line
from mealie_mcp.server import scale_ingredients


class TestFormatAmount:
    def test_whole_numbers_lose_the_decimal(self):
        assert format_amount(Decimal("1200")) == "1200"

    def test_fractions_use_the_swedish_decimal_comma(self):
        assert format_amount(Decimal("1.5")) == "1,5"

    def test_rounds_to_one_decimal(self):
        assert format_amount(Decimal("0.66")) == "0,7"


class TestScaleLine:
    def test_scales_a_leading_gram_amount(self):
        assert scale_line("800 g kycklinglårfilé", Decimal("1.5")) == ("1200 g kycklinglårfilé", True)

    def test_scales_a_swedish_decimal_amount(self):
        assert scale_line("4,7 dl basmatiris", Decimal("2")) == ("9,4 dl basmatiris", True)

    def test_scales_a_discrete_item(self):
        assert scale_line("1 klyfta vitlök", Decimal("3")) == ("3 klyfta vitlök", True)

    def test_line_without_an_amount_is_reported_as_unscaled(self):
        assert scale_line("salt", Decimal("2")) == ("salt", False)

    def test_parenthetical_line_without_amount_is_untouched(self):
        assert scale_line("smör (att steka i)", Decimal("2")) == ("smör (att steka i)", False)

    def test_does_not_touch_a_number_that_is_not_leading(self):
        # "Cheddar 40%" must not become "Cheddar 80%".
        assert scale_line("cheddar 40% fetthalt", Decimal("2")) == ("cheddar 40% fetthalt", False)


class TestScaleIngredients:
    def _recipe(self, **overrides):
        recipe = {
            "name": "Provencalsk kycklinggryta",
            "recipeYield": "",
            "recipeServings": 4.0,
            "recipeYieldQuantity": 0.0,
            "recipeIngredient": [
                # Verified live shape: unparsed rows carry quantity 0.0.
                {"display": "800 g kycklinglårfilé", "quantity": 0.0},
                {"display": "salt", "quantity": 0.0},
                {"display": "1 klyfta vitlök", "quantity": 0.0},
            ],
        }
        recipe.update(overrides)
        return recipe

    def test_scales_from_recipe_servings_when_yield_is_empty(self, monkeypatch):
        monkeypatch.setattr("mealie_mcp.server.get_recipe", lambda _s: self._recipe())
        result = scale_ingredients("x", 6)
        assert result["factor"] == 1.5
        assert result["ingredients"][0] == "1200 g kycklinglårfilé"
        assert result["ingredients"][2] == "1,5 klyfta vitlök"

    def test_lines_without_amounts_are_listed_not_hidden(self, monkeypatch):
        monkeypatch.setattr("mealie_mcp.server.get_recipe", lambda _s: self._recipe())
        assert scale_ingredients("x", 6)["unscaled"] == ["salt"]

    def test_falls_back_to_a_numeric_leading_recipe_yield(self, monkeypatch):
        recipe = self._recipe(recipeServings=0.0, recipeYield="4 portioner")
        monkeypatch.setattr("mealie_mcp.server.get_recipe", lambda _s: recipe)
        assert scale_ingredients("x", 8)["factor"] == 2.0

    def test_refuses_to_guess_without_serving_metadata(self, monkeypatch):
        recipe = self._recipe(recipeServings=0.0, recipeYield="", recipeYieldQuantity=0.0)
        monkeypatch.setattr("mealie_mcp.server.get_recipe", lambda _s: recipe)
        with pytest.raises(ValueError, match="serving metadata"):
            scale_ingredients("x", 6)


class TestRanges:
    """Live data: 'Provencalsk kycklinggryta' stores '1-1,5 msk koncentrerad kycklingfond'."""

    def test_both_ends_of_a_range_are_scaled(self):
        assert scale_line("1-1,5 msk koncentrerad kycklingfond", Decimal("1.5")) == (
            "1,5-2,3 msk koncentrerad kycklingfond",
            True,
        )

    def test_integer_range_stays_readable(self):
        assert scale_line("2-3 dl vatten", Decimal("2")) == ("4-6 dl vatten", True)

    def test_en_dash_range_is_handled(self):
        assert scale_line("1–2 st lök", Decimal("2")) == ("2-4 st lök", True)


class TestMixedFractions:
    """Live data: 'tortillakebab-pa-grillen' stores '1 1/2 msk tomatpuré'."""

    def test_mixed_number_scales_as_one_value(self):
        # Naively scaling the leading "1" would yield "2 1/2 msk" instead of "3".
        assert scale_line("1 1/2 msk tomatpuré", Decimal("2")) == ("3 msk tomatpuré", True)

    def test_bare_fraction_scales(self):
        assert scale_line("1/2 tsk salt", Decimal("3")) == ("1,5 tsk salt", True)

    def test_mixed_number_is_readable_not_mangled(self):
        from mealie_mcp.normalize import looks_mangled

        assert not looks_mangled("1 1/2 msk tomatpuré")

    def test_duplicated_unit_is_still_mangled(self):
        from mealie_mcp.normalize import looks_mangled

        assert looks_mangled("2 dl dl grädde")