/**
 * Outage detection tests for the ride detail page's Today chart.
 *
 * Pure unit tests against lib/outage.ts — no DOM, no Recharts.
 *
 * Run with: npm test
 */

import { test } from "node:test";
import assert from "node:assert/strict";
import { computeOutages, formatOutageDuration, outageLookup } from "../lib/outage";
import type { OutageSample } from "../lib/outage";

/** Build a sample at the given UTC time (just a convenience). */
function s(t: string, isOpen: boolean): OutageSample {
  return { recordedAt: `2026-05-30T${t}:00Z`, isOpen };
}

// ── computeOutages ───────────────────────────────────────────────────────────

test("no outages when every sample is open", () => {
  const out = computeOutages([s("12:00", true), s("12:05", true), s("12:10", true)]);
  assert.deepEqual(out, []);
});

test("single outage in the middle of the day → #1, duration matches", () => {
  // closed at 13:00, 13:05, 13:10; reopens at 13:15
  const out = computeOutages([
    s("12:55", true),
    s("13:00", false),
    s("13:05", false),
    s("13:10", false),
    s("13:15", true),
    s("13:20", true),
  ]);
  assert.equal(out.length, 1);
  assert.equal(out[0].n, 1);
  assert.equal(out[0].durationMin, 15);
  assert.equal(out[0].startISO, "2026-05-30T13:00:00Z");
  assert.equal(out[0].endISO, "2026-05-30T13:15:00Z");
});

test("two separate outages → numbered 1 then 2 in chronological order", () => {
  const out = computeOutages([
    s("12:00", true),
    s("12:05", false), s("12:10", false),
    s("12:15", true),
    s("14:00", false), s("14:05", false), s("14:10", false),
    s("14:15", true),
  ]);
  assert.equal(out.length, 2);
  assert.equal(out[0].n, 1);
  assert.equal(out[0].durationMin, 10);
  assert.equal(out[1].n, 2);
  assert.equal(out[1].durationMin, 15);
});

test("outage at start of day is still #1", () => {
  const out = computeOutages([
    s("10:00", false), s("10:05", false),
    s("10:10", true),
  ]);
  assert.equal(out.length, 1);
  assert.equal(out[0].n, 1);
  assert.equal(out[0].durationMin, 10);
});

test("outage that never reopens uses the last sample as the end", () => {
  const out = computeOutages([
    s("16:00", true),
    s("16:05", false), s("16:10", false), s("16:15", false),
  ]);
  assert.equal(out.length, 1);
  assert.equal(out[0].n, 1);
  // start 16:05 → end 16:15 → 10 min (in-progress at end of day)
  assert.equal(out[0].durationMin, 10);
  assert.equal(out[0].endISO, "2026-05-30T16:15:00Z");
});

test("empty sample array → no outages", () => {
  assert.deepEqual(computeOutages([]), []);
});

test("single closed sample → 0-minute outage, still numbered #1", () => {
  const out = computeOutages([s("12:00", true), s("12:05", false), s("12:10", true)]);
  assert.equal(out.length, 1);
  assert.equal(out[0].n, 1);
  assert.equal(out[0].durationMin, 5);
});

// ── outageLookup ─────────────────────────────────────────────────────────────

test("outageLookup tags each closed sample's time label with its outage", () => {
  const samples = [
    s("12:00", true),
    s("12:05", false), s("12:10", false),
    s("12:15", true),
    s("14:00", false), s("14:05", false),
    s("14:10", true),
  ];
  const outages = computeOutages(samples);
  const lookup = outageLookup(samples, outages);

  // 12:05 and 12:10 belong to outage #1; 14:00 and 14:05 belong to #2.
  // The exact HH:MM labels depend on the runner's local timezone, so we
  // assert membership using the same TIME_FMT that outage.ts uses.
  const TIME_FMT = new Intl.DateTimeFormat([], {
    hour: "2-digit",
    minute: "2-digit",
    hour12: false,
  });
  const fmt = (iso: string) => TIME_FMT.format(new Date(iso));

  assert.equal(lookup.get(fmt("2026-05-30T12:05:00Z"))?.n, 1);
  assert.equal(lookup.get(fmt("2026-05-30T12:10:00Z"))?.n, 1);
  assert.equal(lookup.get(fmt("2026-05-30T14:00:00Z"))?.n, 2);
  assert.equal(lookup.get(fmt("2026-05-30T14:05:00Z"))?.n, 2);
  // Open samples are not in the lookup.
  assert.equal(lookup.get(fmt("2026-05-30T12:00:00Z")), undefined);
  assert.equal(lookup.get(fmt("2026-05-30T14:10:00Z")), undefined);
});

// ── formatOutageDuration ─────────────────────────────────────────────────────

test("formatOutageDuration renders minutes-only under 1 hour", () => {
  assert.equal(formatOutageDuration(0), "0m");
  assert.equal(formatOutageDuration(1), "1m");
  assert.equal(formatOutageDuration(47), "47m");
  assert.equal(formatOutageDuration(59), "59m");
});

test("formatOutageDuration renders exact hours as 'Xh'", () => {
  assert.equal(formatOutageDuration(60), "1h");
  assert.equal(formatOutageDuration(120), "2h");
});

test("formatOutageDuration renders hours + minutes", () => {
  assert.equal(formatOutageDuration(88), "1h 28m");
  assert.equal(formatOutageDuration(150), "2h 30m");
});