FunkyJuiceRecipes/tests/test_calculations.py

from __future__ import annotations

import math
import pytest

from funkyjuicerecipes.logic.calculations import (
    compute_breakdown,
    breakdown_for_view,
)


def test_readme_style_example_120ml_nic_in_pg():
    bd = compute_breakdown(
        size_ml=120,
        base_pg_pct=30.0,
        base_vg_pct=70.0,
        nic_target_mg_per_ml=3.0,
        nic_strength_mg_per_ml=100.0,
        nic_base="PG",
        flavors=[
            {"name": "Vanilla", "base": "PG", "pct": 8.0},
            ("Strawberry", "VG", 4.0),
        ],
    )

    # Percentages
    assert bd.pg_pct == pytest.approx(19.0)
    assert bd.vg_pct == pytest.approx(66.0)
    assert bd.nic_pct == pytest.approx(3.0)

    # mL calculations
    assert bd.pg_ml == pytest.approx(22.8)
    assert bd.vg_ml == pytest.approx(79.2)
    assert bd.nic_ml == pytest.approx(3.6)

    names = [f.name for f in bd.flavors]
    assert names == ["Vanilla", "Strawberry"]
    amounts = {f.name: f.ml for f in bd.flavors}
    assert amounts["Vanilla"] == pytest.approx(9.6)
    assert amounts["Strawberry"] == pytest.approx(4.8)
    assert bd.flavor_prep_ml == pytest.approx(14.4)

    # Rounded view (1 decimal) should match obvious roundings
    v = breakdown_for_view(bd)
    assert v.pg_ml == pytest.approx(22.8)
    assert v.vg_ml == pytest.approx(79.2)
    assert v.nic_ml == pytest.approx(3.6)
    assert {f.name: f.ml for f in v.flavors}["Vanilla"] == pytest.approx(9.6)
    assert {f.name: f.ml for f in v.flavors}["Strawberry"] == pytest.approx(4.8)
    assert v.flavor_prep_ml == pytest.approx(14.4)


def test_nic_in_vg_changes_pg_vg_split():
    bd = compute_breakdown(
        size_ml=120,
        base_pg_pct=30.0,
        base_vg_pct=70.0,
        nic_target_mg_per_ml=3.0,
        nic_strength_mg_per_ml=100.0,
        nic_base="VG",
        flavors=[
            {"name": "Vanilla", "base": "PG", "pct": 8.0},
            ("Strawberry", "VG", 4.0),
        ],
    )
    assert bd.pg_pct == pytest.approx(22.0)
    assert bd.vg_pct == pytest.approx(63.0)
    assert bd.pg_ml == pytest.approx(26.4)
    assert bd.vg_ml == pytest.approx(75.6)


@pytest.mark.parametrize(
    "base_pg,base_vg",
    [
        (70.0, 30.0),
        (70.0000001, 29.9999999),  # tolerance
    ],
)
def test_base_pg_vg_sum_to_100_with_tolerance(base_pg, base_vg):
    bd = compute_breakdown(
        size_ml=60,
        base_pg_pct=base_pg,
        base_vg_pct=base_vg,
        nic_target_mg_per_ml=0.0,
        nic_strength_mg_per_ml=100.0,
        nic_base="PG",
        flavors=[],
    )
    assert bd.pg_pct + bd.vg_pct + bd.nic_pct + sum(f.pct for f in bd.flavors) == pytest.approx(100.0)


def test_excessive_flavor_or_negative_pg_raises():
    # This combination would push PG negative (base PG 10, nic 10 PG, flavor PG 5 => PG becomes -5)
    with pytest.raises(ValueError):
        compute_breakdown(
            size_ml=30,
            base_pg_pct=10.0,
            base_vg_pct=90.0,
            nic_target_mg_per_ml=10.0,
            nic_strength_mg_per_ml=100.0,
            nic_base="PG",
            flavors=[("Whatever", "PG", 5.0)],
        )

    # Flavors sum > 100 should also fail via negative VG/PG after deduction
    with pytest.raises(ValueError):
        compute_breakdown(
            size_ml=30,
            base_pg_pct=50.0,
            base_vg_pct=50.0,
            nic_target_mg_per_ml=0.0,
            nic_strength_mg_per_ml=100.0,
            nic_base="PG",
            flavors=[("A", "PG", 60.0), ("B", "VG", 50.0)],
        )


def test_input_variants_tuple_and_mapping_supported():
    bd = compute_breakdown(
        size_ml=10,
        base_pg_pct=50.0,
        base_vg_pct=50.0,
        nic_target_mg_per_ml=0.0,
        nic_strength_mg_per_ml=100.0,
        nic_base="PG",
        flavors=[
            {"name": "X", "base": "PG", "pct": 5.0},
            ("Y", "VG", 5.0),
        ],
    )


def test_50mg_stock_requires_more_nic_volume_and_changes_pg_vg_split():
    # With 50 mg/mL stock, to reach 3 mg/mL target we need 6% nic volume.
    bd = compute_breakdown(
        size_ml=120,
        base_pg_pct=30.0,
        base_vg_pct=70.0,
        nic_target_mg_per_ml=3.0,
        nic_strength_mg_per_ml=50.0,
        nic_base="PG",
        flavors=[
            {"name": "Vanilla", "base": "PG", "pct": 8.0},
            ("Strawberry", "VG", 4.0),
        ],
    )
    # Now nic_pct (volume) is 6%
    assert bd.nic_pct == pytest.approx(6.0)
    # PG is further reduced by extra 3% vs the 100 mg/mL case
    # Base pg 30 - flavor PG 8 - nic 6 = 16
    assert bd.pg_pct == pytest.approx(16.0)
    # VG remains 70 - flavor VG 4 = 66
    assert bd.vg_pct == pytest.approx(66.0)
    # mL
    assert bd.nic_ml == pytest.approx(7.2)  # 6% of 120
    assert bd.pg_ml == pytest.approx(19.2)  # 16% of 120
    assert bd.vg_ml == pytest.approx(79.2)  # 66% of 120
    assert {f.name for f in bd.flavors} == {"Vanilla", "Strawberry"}