import assert from 'node:assert/strict'
import { test } from 'node:test'
import { buildIcs, parseIntervals } from '../dist/ics.js'

const build = (raw, name = 'Belegt (Exchange)') => {
  const { intervals } = parseIntervals(raw)
  return buildIcs({ syncedAt: '2026-08-19T12:04:11.000Z', intervals }, name)
}

test('rechnet Ortszeit mit Offset korrekt nach UTC', () => {
  const { intervals } = parseIntervals('2026-08-19T14:00:00+02:00|2026-08-19T15:30:00+02:00')
  assert.equal(intervals.length, 1)
  assert.equal(intervals[0].start, '2026-08-19T12:00:00.000Z')
  assert.equal(intervals[0].end, '2026-08-19T13:30:00.000Z')
})

test('normalisiert Offset ohne Doppelpunkt (+0200)', () => {
  const { intervals } = parseIntervals('2026-08-19T14:00:00+0200|2026-08-19T15:00:00+0200')
  assert.equal(intervals[0].start, '2026-08-19T12:00:00.000Z')
})

test('behandelt Winterzeit und Sommerzeit unterschiedlich', () => {
  const winter = parseIntervals('2026-01-15T14:00:00+01:00|2026-01-15T15:00:00+01:00').intervals[0]
  const sommer = parseIntervals('2026-07-15T14:00:00+02:00|2026-07-15T15:00:00+02:00').intervals[0]
  assert.equal(winter.start, '2026-01-15T13:00:00.000Z')
  assert.equal(sommer.start, '2026-07-15T12:00:00.000Z')
})

test('ganztaegiger Termin deckt den vollen lokalen Tag ab', () => {
  const { intervals } = parseIntervals('2026-08-19T00:00:00+02:00|2026-08-20T00:00:00+02:00')
  assert.equal(intervals[0].start, '2026-08-18T22:00:00.000Z')
  assert.equal(intervals[0].end, '2026-08-19T22:00:00.000Z')
})

test('ueberspringt kaputte und sinnlose Zeilen, meldet sie zurueck', () => {
  const { intervals, skipped } = parseIntervals(
    [
      '2026-08-19T14:00:00+02:00|2026-08-19T15:00:00+02:00',
      'voelliger unsinn',
      '2026-08-19T14:00:00+02:00',
      '2026-08-19T15:00:00+02:00|2026-08-19T14:00:00+02:00',
      '',
    ].join('\n'),
  )
  assert.equal(intervals.length, 1)
  assert.deepEqual(skipped, [
    'voelliger unsinn',
    '2026-08-19T14:00:00+02:00',
    '2026-08-19T15:00:00+02:00|2026-08-19T14:00:00+02:00',
  ])
})

test('erzeugt niemals TZID - das ist der Cal.com-Bug', () => {
  const ics = build('2026-08-19T14:00:00+02:00|2026-08-19T15:00:00+02:00')
  assert.ok(!ics.includes('TZID'), 'ICS darf kein TZID enthalten')
  assert.ok(!ics.includes('BEGIN:VTIMEZONE'), 'ICS darf keine VTIMEZONE enthalten')
})

test('schreibt alle Zeitstempel als UTC mit Z', () => {
  const ics = build('2026-08-19T14:00:00+02:00|2026-08-19T15:00:00+02:00')
  const stamps = ics.match(/^(DTSTART|DTEND|DTSTAMP):.*$/gm)
  assert.equal(stamps.length, 3)
  for (const stamp of stamps) {
    assert.match(stamp, /:\d{8}T\d{6}Z$/, `nicht UTC: ${stamp}`)
  }
  assert.ok(ics.includes('DTSTART:20260819T120000Z'))
  assert.ok(ics.includes('DTEND:20260819T130000Z'))
})

test('erzeugt kein RRULE', () => {
  const ics = build('2026-08-19T14:00:00+02:00|2026-08-19T15:00:00+02:00')
  assert.ok(!ics.includes('RRULE'))
})

test('gibt ausschliesslich Belegt als Titel aus', () => {
  const ics = build('2026-08-19T14:00:00+02:00|2026-08-19T15:00:00+02:00')
  const summaries = ics.match(/^SUMMARY:.*$/gm)
  assert.deepEqual(summaries, ['SUMMARY:Belegt'])
})

test('UID ist deterministisch ueber mehrere Laeufe', () => {
  const raw = '2026-08-19T14:00:00+02:00|2026-08-19T15:00:00+02:00'
  const first = build(raw).match(/^UID:.*$/m)[0]
  const second = build(raw).match(/^UID:.*$/m)[0]
  assert.equal(first, second)
})

test('verwendet CRLF als Zeilenende', () => {
  const ics = build('2026-08-19T14:00:00+02:00|2026-08-19T15:00:00+02:00')
  assert.ok(ics.startsWith('BEGIN:VCALENDAR\r\n'))
  assert.ok(ics.endsWith('END:VCALENDAR\r\n'))
  assert.ok(!/[^\r]\n/.test(ics), 'jedes LF muss ein CR vorangehen')
})

test('escaped Sonderzeichen im Kalendernamen', () => {
  const ics = build('', 'Belegt, extern; intern')
  const bs = String.fromCharCode(92)
  assert.ok(ics.includes(`X-WR-CALNAME:Belegt${bs}, extern${bs}; intern`))
})

test('faltet Zeilen laenger als 75 Oktette', () => {
  const ics = build('', 'A'.repeat(200))
  for (const line of ics.split('\r\n')) {
    assert.ok(Buffer.byteLength(line, 'utf8') <= 75, `zu lang: ${line.length}`)
  }
})

test('leerer Snapshot ergibt gueltigen, leeren Kalender', () => {
  const ics = buildIcs(null, 'Belegt (Exchange)')
  assert.ok(ics.includes('X-WR-CALDESC:Noch kein Sync empfangen'))
  assert.ok(!ics.includes('BEGIN:VEVENT'))
  assert.ok(ics.includes('END:VCALENDAR'))
})

test('meldet den Sync-Zeitpunkt im CALDESC', () => {
  const ics = build('2026-08-19T14:00:00+02:00|2026-08-19T15:00:00+02:00')
  assert.ok(ics.includes('X-WR-CALDESC:Letzter Sync 2026-08-19T12:04:11.000Z'))
})