// Tests for the pricing picker's pure helpers.  node home/test/fx.test.mjs
import assert from "node:assert/strict";
import { BANDS, bandName, bandsOffered, tierForBand, regionCurrency, approxLocal, capNote } from "../web/static/fx.js";

let failures = 0;
async function test(name, fn) {
  try {
    await fn();
    console.log("PASS  " + name);
  } catch (e) {
    console.log("FAIL  " + name + "  —  " + (e && e.message));
    failures++;
  }
}

const tiers = [
  { key: "family", name: "Family", label: "€5/year", eur: 5 },
  { key: "friends", name: "Friends", label: "€4/month", eur: 4,
    bands: { reduced: { label: "€2/month", eur: 2 }, supporter: { label: "€5.50/month", eur: 5.5 } } },
];

await test("band vocabulary is the doc's four, in display order", () => {
  assert.deepEqual(BANDS.map((b) => b.key), ["supporter", "base", "reduced", "solidarity"]);
  assert.equal(bandName("base"), "Standard");
  // The messaging rules: aggregate cross-subsidy only, never "discount"/"eligible".
  for (const b of BANDS) {
    assert.ok(!/discount|eligible/i.test(b.line), b.key + " line breaks the messaging rules");
  }
});

await test("bandsOffered: base always; others once any tier defines them", () => {
  assert.deepEqual(bandsOffered([tiers[0]]), ["base"]);
  assert.deepEqual(bandsOffered(tiers), ["supporter", "base", "reduced"]);
  assert.deepEqual(bandsOffered([]), ["base"]);
});

await test("tierForBand: band label when offered, base flagged when not", () => {
  assert.deepEqual(tierForBand(tiers[1], "reduced"), { label: "€2/month", eur: 2, band: "reduced", offered: true });
  assert.deepEqual(tierForBand(tiers[1], "base"), { label: "€4/month", eur: 4, band: "base", offered: true });
  // family has no bands: a reduced selection falls back to base, UNOFFERED —
  // the UI says "standard price" instead of implying a reduction.
  assert.deepEqual(tierForBand(tiers[0], "reduced"), { label: "€5/year", eur: 5, band: "base", offered: false });
});

await test("regionCurrency: locale region → ECB currency; euro area and unknown → none", () => {
  assert.equal(regionCurrency("en-US"), "USD");
  assert.equal(regionCurrency("en-GB"), "GBP");
  assert.equal(regionCurrency("ja"), "JPY"); // maximize() infers the region
  assert.equal(regionCurrency("de-DE"), ""); // euro area: billed in EUR already
  assert.equal(regionCurrency("fr"), "");
  assert.equal(regionCurrency(""), "");
  assert.equal(regionCurrency("not a locale"), "");
});

await test("approxLocal: converts and formats; silent when it can't be honest", () => {
  const rates = { USD: 1.1, JPY: 170 };
  assert.equal(approxLocal(5, "USD", rates, "en"), "≈ $5.50");
  // Larger amounts drop the cents (an estimate pretending precision reads wrong).
  assert.equal(approxLocal(999, "USD", rates, "en"), "≈ $1,099");
  // Unknown currency / missing rate / zero amount → no figure at all.
  assert.equal(approxLocal(5, "CHF", rates, "en"), "");
  assert.equal(approxLocal(0, "USD", rates, "en"), "");
  assert.equal(approxLocal(5, "", rates, "en"), "");
  assert.equal(approxLocal(5, "USD", null, "en"), "");
});

await test("capNote: the 15% promise in euros, not percent", () => {
  assert.equal(capNote(5, "en"), "never more than €0.75 more at renewal without your say-so");
  assert.equal(capNote(0, "en"), "");
});

console.log(failures === 0 ? "\nALL PASSED" : `\n${failures} FAILED`);
process.exit(failures === 0 ? 0 : 1);