import { describe, it, expect } from 'vitest';
import { scaleIngredients, roundQuantity } from '../../src/lib/recipes/scaler';
import type { Ingredient } from '../../src/lib/types';

const mk = (q: number | null, unit: string | null, name: string): Ingredient => ({
  position: 0,
  quantity: q,
  unit,
  name,
  note: null,
  raw_text: '',
  section_heading: null
});

describe('roundQuantity', () => {
  it.each([
    [0.333333, 0.33],
    [12.345, 12],
    [1.55, 1.6],
    [100.49, 100],
    [0.5, 0.5]
  ] as const)('rounds %f to %f', (input, expected) => {
    expect(roundQuantity(input)).toBe(expected);
  });
});

describe('scaleIngredients', () => {
  it('scales parsed quantities', () => {
    const scaled = scaleIngredients([mk(200, 'g', 'Mehl'), mk(3, null, 'Eier')], 2);
    expect(scaled[0].quantity).toBe(400);
    expect(scaled[1].quantity).toBe(6);
  });

  it('leaves null quantities alone', () => {
    const scaled = scaleIngredients([mk(null, null, 'etwas Salz')], 2);
    expect(scaled[0].quantity).toBeNull();
    expect(scaled[0].name).toBe('etwas Salz');
  });

  it('rounds sensibly', () => {
    const scaled = scaleIngredients([mk(100, 'g', 'Butter')], 1 / 3);
    expect(scaled[0].quantity).toBe(33);
  });

  it('preserves section_heading through scaling', () => {
    const input: Ingredient[] = [
      { position: 1, quantity: 200, unit: 'g', name: 'Mehl', note: null, raw_text: '200 g Mehl', section_heading: 'Teig' },
      { position: 2, quantity: null, unit: null, name: 'Ei', note: null, raw_text: 'Ei', section_heading: null }
    ];
    const scaled = scaleIngredients(input, 2);
    expect(scaled[0].section_heading).toBe('Teig');
    expect(scaled[1].section_heading).toBeNull();
    expect(scaled[0].quantity).toBe(400);
  });
});