Variant Correlation

1'use strict';
2
3// Stores V3 reads a variant choice back as optionChoiceIds even when it was written by
4// optionChoiceNames; the product's own option/choice dictionary turns the ids back into names.
5function choiceNames(choice, target) {
6  if (choice.optionChoiceNames) return choice.optionChoiceNames;
7  const options = (target.options || []).filter(o => o.id === choice.optionChoiceIds?.optionId);
8  if (options.length !== 1) throw new Error('Target option identity is missing or ambiguous');
9  const values = (options[0].choicesSettings?.choices || []).filter(v => v.choiceId === choice.optionChoiceIds.choiceId);
10  if (values.length !== 1) throw new Error('Target choice identity is missing or ambiguous');
11  return { optionName: options[0].name, choiceName: values[0].name, renderType: options[0].optionRenderType };
12}
13
14// Shared deterministic one-to-one comparison; response order is never an identity.
15function resolveInventoryRows(canonical, target) {
16  if (!target || !target.id || !Array.isArray(target.variantsInfo?.variants)) throw new Error('Target product omitted variant identities');
17  // Stores V3 may re-case option and choice names on write ("ALTERNATIV" reads back
18  // "Alternativ", "10m" reads back "10M"; LIVE-VERIFIED 2026-10-15), so names match
19  // case-insensitively. A case-only collision still fails below as an ambiguous match.
20  const key = (choices) => JSON.stringify(choices.map(c => [String(c.optionName).toLowerCase(), String(c.choiceName).toLowerCase()]).sort((a, b) => JSON.stringify(a).localeCompare(JSON.stringify(b))));
21  const targetByChoices = new Map();
22  for (const variant of target.variantsInfo.variants) {
23    if (!variant.id) throw new Error('Target variant omitted identity');
24    const identity = key((variant.choices || []).map(c => choiceNames(c, target)));
25    if (targetByChoices.has(identity)) throw new Error('Ambiguous target variant choices');
26    targetByChoices.set(identity, variant.id);
27  }
28  const matched = new Set();
29  return canonical.variants.map(variant => {
30    const variantId = targetByChoices.get(key(variant.choices));
31    if (!variantId || matched.has(variantId)) throw new Error('Source variant has no unique target match');
32    matched.add(variantId);
33    return { productId: target.id, variantId, inventory: { inStock: variant.inStock } };
34  });
35}
36
37module.exports = { choiceNames, resolveInventoryRows };