/**
 * The era on the daily card is derived, not authored: eraFor() puts the newest
 * design in the fight on MegaMek's era table. Every way that goes wrong is
 * quiet — an off-by-one at a boundary labels a Clan Invasion fight FedCom
 * Civil War, a name that is not a key of ERA_ICONS drops the symbol and shows
 * a bare word, and a row out of order makes eraFor() answer with whichever era
 * happens to come first.
 *
 * So this pins the table's shape, the boundaries against the chronology on
 * sarna.net, and the names against the icon map.
 *
 * Run with `npm test`.
 */
import { test } from "node:test";
import assert from "node:assert/strict";

const { ERAS, eraFor } = await import("../src/content/eras.ts");
const { ERA_ICONS } = await import("../src/content/trivia.ts");

test("the table is ordered, and only the last era is open-ended", () => {
  assert.equal(ERAS.length, 14, "eras.xml has fourteen eras");

  const codes = ERAS.map((era) => era.code);
  assert.equal(new Set(codes).size, codes.length, "two eras share a code");

  const open = ERAS.filter((era) => era.end === null);
  assert.equal(open.length, 1, "exactly one era has no end date");
  assert.equal(ERAS.at(-1), open[0], "the open-ended era is not last");

  let previous = 0;
  for (const era of ERAS.slice(0, -1)) {
    assert.ok(
      era.end > previous,
      `${era.code} ends in ${era.end}, at or before the era before it`,
    );
    previous = era.end;
  }
});

test("every era name has an icon the site ships", () => {
  for (const era of ERAS) {
    assert.ok(
      era.name in ERA_ICONS,
      `${era.code}: "${era.name}" is not a key of ERA_ICONS, so it has no symbol`,
    );
    assert.ok(
      ERA_ICONS[era.name] !== null,
      `${era.code}: "${era.name}" is mapped to no icon`,
    );
  }
});

test("a year lands in the era sarna puts it in, on both sides of every boundary", () => {
  // The chronology at https://www.sarna.net/wiki/BattleTech_eras, first and
  // last year of each era, walked in order. Both ends of every pair, because a
  // <= that should be a < is right on one side and wrong on the other.
  const canon = [
    [2005, "Age of War"],
    [2570, "Age of War"],
    [2571, "Star League"],
    [2780, "Star League"],
    [2781, "Early Succession War"],
    [2900, "Early Succession War"],
    [2901, "Late Succession War - LosTech"],
    [3019, "Late Succession War - LosTech"],
    [3020, "Late Succession War - Renaissance"],
    [3049, "Late Succession War - Renaissance"],
    [3050, "Clan Invasion"],
    [3061, "Clan Invasion"],
    [3062, "FedCom Civil War"],
    [3067, "FedCom Civil War"],
    [3068, "Jihad"],
    [3080, "Jihad"],
    [3081, "Republic Age"],
    [3130, "Republic Age"],
    [3131, "Dark Age"],
    [3150, "Dark Age"],
    [3151, "ilClan"],
  ];

  for (const [year, name] of canon) {
    assert.equal(eraFor(year)?.name, name, `${year} is not ${name}`);
  }

  // Open-ended, so a year past the table is still the last era rather than
  // nothing at all.
  assert.equal(eraFor(9999)?.name, "ilClan", "the last era stopped being open");
});

test("a year that is not a year has no era", () => {
  // mms index writes 0 when arena's report measured nothing, and the card
  // falls back to the year range on null rather than naming Pre-Star League.
  for (const year of [0, -1, Number.NaN, 3050.5]) {
    assert.equal(eraFor(year), null, `${year} was given an era`);
  }
});