// Checks the JS engine port against spec/test-vectors.json (generated from the Odoo engine).
// Run: node engine/tests/run-vectors.mjs (also part of npm test)
import { readFileSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';
import { applyOffers, allocateByLine, largestRemainderCents, toUnits } from '../engine.js';

const here = dirname(fileURLToPath(import.meta.url));
const { vectors } = JSON.parse(readFileSync(join(here, '..', '..', 'spec', 'test-vectors.json'), 'utf8'));

const scope = (s) => ({ variantIds: new Set(s.variant_ids || []), productIds: new Set(s.product_ids || []),
                        collectionIds: new Set(s.collection_ids || []) });
const toOffer = (o) => ({
  id: o.id, type: o.type, maxUses: o.max_uses || 0, discountType: o.discount_type, value: o.value,
  lines: (o.lines || []).map((l) => ({ variantId: l.variant_id, productId: l.product_id, quantity: l.quantity })),
  qty: o.qty, scope: o.scope && scope(o.scope),
  buyQty: o.buy_qty, getQty: o.get_qty, getPercent: o.get_percent,
  buyScope: o.buy_scope && scope(o.buy_scope), getScope: o.get_scope && scope(o.get_scope),
});
const close = (a, b) => Math.abs(a - b) < 1e-6;

let failed = 0;
for (const v of vectors) {
  const lines = v.cart.lines.map((l) => ({ id: l.id, variantId: l.variant_id, productId: l.product_id,
                                          collectionIds: l.collection_ids, unitPrice: l.unit_price, quantity: l.quantity }));
  const apps = applyOffers(toUnits(lines), v.offers.map(toOffer));
  const totals = allocateByLine(apps);
  const allocations = [];
  for (const o of v.offers) {
    const items = lines.map((l) => [l.id, totals.get(o.id + '\u0000' + l.id)]).filter(([, a]) => a !== undefined);
    const rounded = largestRemainderCents(items.map(([, a]) => a));
    items.forEach(([lineId, a], i) => allocations.push({ offer_id: o.id, line_id: lineId, amount_exact: a, amount: rounded[i] }));
  }
  const exp = v.expected;
  const errors = [];
  if (apps.length !== exp.applications.length) errors.push(`applications ${apps.length} != ${exp.applications.length}`);
  apps.forEach((a, i) => {
    const e = exp.applications[i]; if (!e) return;
    if (a.offerId !== e.offer_id || !close(a.discount, e.discount)) errors.push(`app ${i}: ${a.offerId}/${a.discount} != ${e.offer_id}/${e.discount}`);
    const used = a.units.map((u) => u.lineId);
    if (JSON.stringify(used) !== JSON.stringify(e.line_ids_used)) errors.push(`app ${i} units ${used} != ${e.line_ids_used}`);
  });
  if (allocations.length !== exp.allocations.length) errors.push(`allocations ${allocations.length} != ${exp.allocations.length}`);
  allocations.forEach((a, i) => {
    const e = exp.allocations[i]; if (!e) return;
    if (a.offer_id !== e.offer_id || a.line_id !== e.line_id || !close(a.amount_exact, e.amount_exact) || !close(a.amount, e.amount))
      errors.push(`alloc ${i}: ${JSON.stringify(a)} != ${JSON.stringify(e)}`);
  });
  if (errors.length) { failed += 1; console.log(`FAIL ${v.name}\n  ` + errors.join('\n  ')); }
  else console.log(`ok   ${v.name}`);
}
console.log(failed ? `\n${failed} of ${vectors.length} failed` : `\nall ${vectors.length} vectors pass`);
process.exit(failed ? 1 : 0);