import { test } from 'node:test';
import assert from 'node:assert/strict';
import { channels, programme, guide, SLOT_MS } from './schedule.ts';
test('join in progress returns the broadcast offset', () => {
  const start = SLOT_MS * 100;
  assert.equal(programme(channels[0], start + 18 * 60000).offsetMs, 18 * 60000);
});
test('exact boundary switches programmes with no gap', () => {
  const a = programme(channels[0], SLOT_MS - 1), b = programme(channels[0], SLOT_MS);
  assert.equal(a.end, b.start); assert.equal(b.offsetMs, 0); assert.notEqual(a.title, b.title);
});
test('schedule is deterministic and contiguous across midnight', () => {
  const at = Date.UTC(2026, 9, 31, 23, 59);
  assert.deepEqual(guide(at), guide(at));
  for (const channel of guide(at, 48)) channel.programmes.slice(1).forEach((show, i) => assert.equal(channel.programmes[i].end, show.start));
});
test('invalid input is rejected and negative epochs work', () => {
  for (const count of [0, -1, 49, 1.5, NaN]) assert.throws(() => guide(0, count));
  for (const at of [NaN, Infinity, 8.1e15]) assert.throws(() => guide(at));
  assert.equal(programme(channels[0], -1).start, -SLOT_MS);
});

test('future guide entries start at zero rather than inheriting current offset', () => {
  const programmes = guide(18 * 60000)[0].programmes;
  assert.equal(programmes[0].offsetMs, 18 * 60000);
  assert.ok(programmes.slice(1).every(show => show.offsetMs === 0));
});