const {
  dayKey,
  activeSessions,
  scheduleBounds,
  normalizeSessionsInput,
  sessionAcceptsCheckIn,
  currentSession,
  registrationClosesAt,
  lateInfo,
  latePrice,
  completionMet,
  normalizeReminders,
  normalizeCertificateConfig,
  scanSession,
  redeemedForSession,
  sessionLabel,
  isPickOption,
  expandPickLines,
  ticketScanSession,
  groupTickets,
  wholeCourseClosesAt,
  choosesSessions,
  lineSessions,
  mergeSessionIds,
  ticketDateText,
} = require('../src/utils/sessions');

// Africa/Johannesburg is UTC+2 all year, so 16:30Z is 18:30 local.
const wed = (day, h = 16, m = 30) => new Date(Date.UTC(2026, 10, day, h, m)); // November 2026
const session = (id, day, extra = {}) => ({ id, startsAt: wed(day), endsAt: wed(day, 18, 30), cancelledAt: null, ...extra });
// Five Wednesdays: 4, 11, 18, 25 Nov and 2 Dec (as day 32 → Date.UTC rolls over).
const COURSE = [session('s1', 4), session('s2', 11), session('s3', 18), session('s4', 25), session('s5', 32)];

describe('dayKey', () => {
  test('uses the church timezone, not UTC', () => {
    expect(dayKey(new Date('2026-11-04T23:30:00Z'))).toBe('2026-11-05'); // 01:30 local next day
    expect(dayKey(new Date('2026-11-04T21:59:00Z'))).toBe('2026-11-04');
  });
});

describe('activeSessions / scheduleBounds', () => {
  test('drops cancelled sessions and sorts by start', () => {
    const list = [session('b', 11), session('a', 4), session('c', 18, { cancelledAt: new Date() })];
    expect(activeSessions(list).map(s => s.id)).toEqual(['a', 'b']);
  });

  test('bounds run from the first start to the last end', () => {
    const b = scheduleBounds(COURSE);
    expect(b.startDate).toEqual(wed(4));
    expect(b.endDate).toEqual(wed(32, 18, 30));
  });

  test('a cancelled last session moves the end date back', () => {
    const list = [...COURSE.slice(0, 4), { ...COURSE[4], cancelledAt: new Date() }];
    expect(scheduleBounds(list).endDate).toEqual(wed(25, 18, 30));
  });

  test('no active sessions → null', () => {
    expect(scheduleBounds([session('a', 4, { cancelledAt: new Date() })])).toBeNull();
  });
});

describe('normalizeSessionsInput', () => {
  test('sorts sessions and trims labels', () => {
    const out = normalizeSessionsInput([
      { startsAt: wed(11), endsAt: wed(11, 18), label: '  Week 2 ' },
      { startsAt: wed(4), endsAt: wed(4, 18) },
    ]);
    expect(out.map(s => s.label)).toEqual([null, 'Week 2']);
  });

  test('rejects a session that ends before it starts', () => {
    expect(() => normalizeSessionsInput([{ startsAt: wed(4, 18), endsAt: wed(4, 16) }])).toThrow(/must end after/);
  });

  test('rejects missing dates', () => {
    expect(() => normalizeSessionsInput([{ startsAt: 'nope', endsAt: wed(4) }])).toThrow(/start and end/);
  });

  test('needs at least one session that is not cancelled', () => {
    expect(() => normalizeSessionsInput([{ startsAt: wed(4), endsAt: wed(4, 18), cancelled: true }])).toThrow(/at least one/);
    expect(() => normalizeSessionsInput([])).toThrow(/at least one/);
  });
});

describe('check-in window', () => {
  const s = session('s1', 4); // 18:30–20:30 local on 4 Nov

  test('whole day accepts any time on the session date (local)', () => {
    expect(sessionAcceptsCheckIn(s, new Date('2026-11-04T05:00:00Z'), 'whole_day')).toBe(true); // 07:00 local
    expect(sessionAcceptsCheckIn(s, new Date('2026-11-04T21:30:00Z'), 'whole_day')).toBe(true); // 23:30 local
    expect(sessionAcceptsCheckIn(s, new Date('2026-11-04T22:30:00Z'), 'whole_day')).toBe(false); // 00:30 next day
  });

  test('session only accepts from 2 h before start until the end', () => {
    expect(sessionAcceptsCheckIn(s, new Date('2026-11-04T14:29:00Z'), 'session_only')).toBe(false);
    expect(sessionAcceptsCheckIn(s, new Date('2026-11-04T14:30:00Z'), 'session_only')).toBe(true);
    expect(sessionAcceptsCheckIn(s, new Date('2026-11-04T18:30:00Z'), 'session_only')).toBe(true);
    expect(sessionAcceptsCheckIn(s, new Date('2026-11-04T18:31:00Z'), 'session_only')).toBe(false);
  });

  test('cancelled sessions never accept check-ins', () => {
    expect(sessionAcceptsCheckIn({ ...s, cancelledAt: new Date() }, wed(4), 'whole_day')).toBe(false);
  });
});

describe('currentSession', () => {
  test('finds today\'s session', () => {
    expect(currentSession(COURSE, new Date('2026-11-11T08:00:00Z')).id).toBe('s2');
  });

  test('null on a day without a session', () => {
    expect(currentSession(COURSE, new Date('2026-11-12T08:00:00Z'))).toBeNull();
  });

  test('with two sessions in a day, picks the running one, else the next, else the last', () => {
    const day = [
      { id: 'am', startsAt: new Date('2026-11-07T07:00:00Z'), endsAt: new Date('2026-11-07T10:00:00Z'), cancelledAt: null },
      { id: 'pm', startsAt: new Date('2026-11-07T14:00:00Z'), endsAt: new Date('2026-11-07T17:00:00Z'), cancelledAt: null },
    ];
    expect(currentSession(day, new Date('2026-11-07T08:00:00Z')).id).toBe('am');
    expect(currentSession(day, new Date('2026-11-07T11:00:00Z')).id).toBe('pm'); // between: next one
    expect(currentSession(day, new Date('2026-11-07T13:00:00Z')).id).toBe('pm'); // within 2 h of pm
    expect(currentSession(day, new Date('2026-11-07T19:00:00Z')).id).toBe('pm'); // after both: last
    expect(currentSession(day, new Date('2026-11-07T04:00:00Z')).id).toBe('am'); // before both: next
  });
});

describe('registrationClosesAt', () => {
  const base = { scheduleType: 'sessions', endDate: wed(32, 18, 30), registrationDeadline: null, lateJoinEnabled: false, lateJoinUntilSessionId: null };

  test('single-date events close at the end date', () => {
    expect(registrationClosesAt({ ...base, scheduleType: 'single' }, [])).toEqual(wed(32, 18, 30));
  });

  test('without late joining, closes when the first session starts', () => {
    expect(registrationClosesAt(base, COURSE)).toEqual(wed(4));
  });

  test('with late joining, closes when the chosen session starts', () => {
    expect(registrationClosesAt({ ...base, lateJoinEnabled: true, lateJoinUntilSessionId: 's3' }, COURSE)).toEqual(wed(18));
  });

  test('an earlier registration deadline wins', () => {
    const deadline = new Date('2026-11-01T00:00:00Z');
    expect(registrationClosesAt({ ...base, lateJoinEnabled: true, lateJoinUntilSessionId: 's3', registrationDeadline: deadline }, COURSE)).toEqual(deadline);
  });

  test('a cancelled "until" session falls back to the first session', () => {
    const list = COURSE.map(s => (s.id === 's3' ? { ...s, cancelledAt: new Date() } : s));
    expect(registrationClosesAt({ ...base, lateJoinEnabled: true, lateJoinUntilSessionId: 's3' }, list)).toEqual(wed(4));
  });
});

describe('late pricing', () => {
  const event = { scheduleType: 'sessions', lateJoinEnabled: true, latePricing: 'prorata', lateFixedPrice: null };

  test('not active before the first session starts', () => {
    expect(lateInfo(event, COURSE, wed(3)).active).toBe(false);
  });

  test('pro-rata on sessions not yet started, rounded to the nearest R10', () => {
    const info = lateInfo(event, COURSE, wed(5)); // session 1 done → 4 of 5 left
    expect(info).toMatchObject({ active: true, sessionsLeft: 4, totalSessions: 5 });
    expect(latePrice(300, info)).toBe(240);
    expect(latePrice(229, info)).toBe(180); // 183.2 → 180
    expect(latePrice(232, info)).toBe(190); // 185.6 → 190
  });

  test('pro-rata never goes below R10 or above the normal price', () => {
    const info = lateInfo(event, COURSE, wed(26)); // 1 of 5 left
    expect(latePrice(15, info)).toBe(10); // 3 → 0 → at least R10
    expect(latePrice(8, info)).toBe(8); // under R10 already: unchanged
    expect(latePrice(0, info)).toBe(0);
  });

  test('a session in progress counts as started', () => {
    const info = lateInfo(event, COURSE, new Date(wed(11).getTime() + 60_000));
    expect(info.sessionsLeft).toBe(3);
  });

  test('fixed late price only ever lowers the price', () => {
    const info = lateInfo({ ...event, latePricing: 'fixed', lateFixedPrice: 150 }, COURSE, wed(12));
    expect(latePrice(300, info)).toBe(150);
    expect(latePrice(100, info)).toBe(100);
  });

  test('full price, late joining off, or a fixed price without an amount → no change', () => {
    expect(lateInfo({ ...event, latePricing: 'full' }, COURSE, wed(12)).active).toBe(false);
    expect(lateInfo({ ...event, lateJoinEnabled: false }, COURSE, wed(12)).active).toBe(false);
    expect(lateInfo({ ...event, latePricing: 'fixed', lateFixedPrice: null }, COURSE, wed(12)).active).toBe(false);
    expect(latePrice(300, { active: false })).toBe(300);
  });
});

describe('completionMet', () => {
  test('all sessions (default)', () => {
    expect(completionMet(undefined, 5, 5)).toBe(true);
    expect(completionMet({ type: 'all' }, 4, 5)).toBe(false);
  });

  test('at least N sessions, capped at the total', () => {
    expect(completionMet({ type: 'count', value: 4 }, 4, 5)).toBe(true);
    expect(completionMet({ type: 'count', value: 4 }, 3, 5)).toBe(false);
    expect(completionMet({ type: 'count', value: 10 }, 3, 3)).toBe(true);
  });

  test('at least N percent', () => {
    expect(completionMet({ type: 'percent', value: 80 }, 4, 5)).toBe(true);
    expect(completionMet({ type: 'percent', value: 80 }, 3, 5)).toBe(false);
    expect(completionMet({ type: 'percent', value: 66 }, 2, 3)).toBe(true);
  });

  test('nobody completes without attending', () => {
    expect(completionMet({ type: 'count', value: 1 }, 0, 5)).toBe(false);
    expect(completionMet(undefined, 0, 0)).toBe(false);
  });
});

describe('settings cleaning', () => {
  test('reminders: off unless an offset and a channel are chosen', () => {
    expect(normalizeReminders(null)).toBeNull();
    expect(normalizeReminders({ offsets: [180], channels: [] })).toBeNull();
    expect(normalizeReminders({ offsets: [180, 999, 1440], channels: ['email', 'sms'] })).toEqual({ offsets: [1440, 180], channels: ['email'] });
  });

  test('certificates: unknown template falls back to classic, rule is tidied', () => {
    const c = normalizeCertificateConfig({ template: 'fancy', rule: { type: 'count', value: '3' } });
    expect(c.template).toBe('classic');
    expect(c.rule).toEqual({ type: 'count', value: 3 });
    expect(c.title).toBe('Certificate of Completion');
    expect(normalizeCertificateConfig({ rule: { type: 'all', value: 4 } }).rule).toEqual({ type: 'all', value: null });
  });
});

describe('scanSession', () => {
  const event = { checkInWindow: 'whole_day' };

  test("defaults to today's session", () => {
    expect(scanSession(event, COURSE, null, new Date('2026-11-18T09:00:00Z')).session.id).toBe('s3');
  });

  test('no session today: says when the next one is', () => {
    const r = scanSession(event, COURSE, null, new Date('2026-11-12T09:00:00Z'));
    expect(r.session).toBeNull();
    expect(r.error).toMatch(/next one is Session 3 on 2026-11-18/);
  });

  test('after the last session: all over', () => {
    expect(scanSession(event, COURSE, null, new Date('2026-12-10T09:00:00Z')).error).toMatch(/over/);
  });

  test('a picked session must be open now', () => {
    expect(scanSession(event, COURSE, 's3', new Date('2026-11-18T09:00:00Z')).session.id).toBe('s3');
    expect(scanSession(event, COURSE, 's4', new Date('2026-11-18T09:00:00Z')).error).toMatch(/only open on the day/);
    expect(scanSession({ checkInWindow: 'session_only' }, COURSE, 's3', new Date('2026-11-18T09:00:00Z')).error).toMatch(/2 hours before/);
  });

  test('a cancelled or unknown session is refused', () => {
    const list = COURSE.map(s => (s.id === 's3' ? { ...s, cancelledAt: new Date() } : s));
    expect(scanSession(event, list, 's3', new Date('2026-11-18T09:00:00Z')).error).toMatch(/cancelled/);
    expect(scanSession(event, COURSE, 'nope').error).toMatch(/isn't part/);
  });
});

describe('redeemedForSession / sessionLabel', () => {
  test("counts only that session's check-ins", () => {
    const usages = [{ sessionId: 's1', quantityRedeemed: 2 }, { sessionId: 's2', quantityRedeemed: 1 }, { sessionId: 's1' }];
    expect(redeemedForSession(usages, 's1')).toBe(3);
    expect(redeemedForSession(usages, 's3')).toBe(0);
  });

  test('uses the label, else the position among active sessions', () => {
    expect(sessionLabel({ id: 'x', label: 'Opening night' }, COURSE)).toBe('Opening night');
    expect(sessionLabel(COURSE[2], COURSE)).toBe('Session 3');
    const list = [{ ...COURSE[0], cancelledAt: new Date() }, ...COURSE.slice(1)];
    expect(sessionLabel(list[2], list)).toBe('Session 2');
  });
});

describe('pick sessions', () => {
  const pickEvent = {
    scheduleType: 'sessions', attendanceMode: 'pick', endDate: wed(32, 18, 30), registrationDeadline: null,
    lateJoinEnabled: false, sessions: COURSE,
    eventOptions: [{ id: 'drop', name: 'Drop-in', sessionMode: 'pick' }, { id: 'full', name: 'Full course', sessionMode: 'all' }],
  };

  test('choosesSessions: pick-mode multi-day events only', () => {
    expect(choosesSessions(pickEvent)).toBe(true);
    expect(choosesSessions({ ...pickEvent, attendanceMode: 'whole' })).toBe(false);
    expect(choosesSessions({ ...pickEvent, scheduleType: 'single' })).toBe(false);
  });

  test('lineSessions / mergeSessionIds', () => {
    expect(lineSessions({ sessionId: 's2', sessionIds: [] })).toEqual(['s2']);
    expect(lineSessions({ sessionId: null, sessionIds: ['s1', 's3'] })).toEqual(['s1', 's3']);
    expect(lineSessions({ sessionId: null, sessionIds: [] })).toBeNull();
    expect(mergeSessionIds(['s1'], ['s3', 's1'])).toEqual(['s1', 's3']);
    expect(mergeSessionIds(['s1'], [])).toEqual([]);
  });

  test('an all-sessions ticket with sessions ticked only scans on those', () => {
    const ev = { checkInWindow: 'whole_day' };
    const onDay2 = new Date(wed(11).getTime() + 30 * 60000);
    expect(ticketScanSession(ev, COURSE, null, null, onDay2, ['s2', 's4']).session.id).toBe('s2');
    expect(ticketScanSession(ev, COURSE, null, null, onDay2, ['s1', 's4']).error).toMatch(/isn't booked for Session 2/);
    expect(ticketScanSession(ev, COURSE, null, null, onDay2, []).session.id).toBe('s2');
  });

  test('ticket dates list the ticked sessions', () => {
    const ev = { ...pickEvent, sessions: COURSE };
    expect(ticketDateText(ev, 'short', null, null, ['s2', 's4'])).toBe('2 sessions · 11 Nov, 25 Nov');
    expect(ticketDateText(ev, 'long', null, null, ['s2'])).toBe('Wednesday, 11 November 2026 (Session 2)');
  });

  test('isPickOption needs a pick-mode multi-day event and a pick option', () => {
    expect(isPickOption(pickEvent, pickEvent.eventOptions[0])).toBe(true);
    expect(isPickOption(pickEvent, pickEvent.eventOptions[1])).toBe(false);
    expect(isPickOption({ ...pickEvent, attendanceMode: 'whole' }, pickEvent.eventOptions[0])).toBe(false);
  });

  test('a pick line becomes one line per session; an all-sessions line keeps its ticked sessions', () => {
    const out = expandPickLines(pickEvent, [
      { eventOptionId: 'drop', quantity: 2, sessionIds: ['s3', 's4', 's3'] },
      { eventOptionId: 'full', quantity: 1 },
      { eventOptionId: 'full', quantity: 1, sessionIds: ['s2', 's5'] },
    ], { now: wed(5) });
    expect(out).toEqual([
      { eventOptionId: 'drop', quantity: 2, sessionId: 's3' },
      { eventOptionId: 'drop', quantity: 2, sessionId: 's4' },
      { eventOptionId: 'full', quantity: 1, sessionId: null, sessionIds: [] },
      { eventOptionId: 'full', quantity: 1, sessionId: null, sessionIds: ['s2', 's5'] },
    ]);
  });

  test('sessions must be chosen, upcoming, and only on events where people choose them', () => {
    expect(() => expandPickLines(pickEvent, [{ eventOptionId: 'drop', quantity: 1 }])).toThrow(/Choose the sessions/);
    expect(() => expandPickLines(pickEvent, [{ eventOptionId: 'drop', quantity: 1, sessionIds: ['s1'] }], { now: wed(5) })).toThrow(/already started/);
    expect(() => expandPickLines(pickEvent, [{ eventOptionId: 'full', quantity: 1, sessionIds: ['s1'] }], { now: wed(5) })).toThrow(/already started/);
    expect(() => expandPickLines({ ...pickEvent, attendanceMode: 'whole' }, [{ eventOptionId: 'full', quantity: 1, sessionIds: ['s3'] }])).toThrow(/covers every session/);
    expect(() => expandPickLines({ ...pickEvent, requiresParentalConsent: true }, [{ eventOptionId: 'drop', quantity: 1, sessionIds: ['s3'] }], { now: wed(5) })).toThrow(/youth/);
  });

  test('staff can still book a session that is in progress', () => {
    const during = new Date(wed(4).getTime() + 30 * 60000);
    expect(expandPickLines(pickEvent, [{ eventOptionId: 'drop', quantity: 1, sessionIds: ['s1'] }], { now: during, staff: true })).toHaveLength(1);
  });

  test('registration stays open until the last session; whole-course tickets close at the first', () => {
    expect(registrationClosesAt(pickEvent, COURSE)).toEqual(wed(32));
    expect(wholeCourseClosesAt(pickEvent, COURSE)).toEqual(wed(4));
  });

  test('a picked ticket only checks in on its own session', () => {
    const event = { checkInWindow: 'whole_day' };
    expect(ticketScanSession(event, COURSE, 's3', null, new Date('2026-11-18T09:00:00Z')).session.id).toBe('s3');
    expect(ticketScanSession(event, COURSE, 's3', null, new Date('2026-11-11T09:00:00Z')).error).toMatch(/This ticket is for Session 3 \(2026-11-18\)/);
    expect(ticketScanSession(event, COURSE, 's3', 's2', new Date('2026-11-18T09:00:00Z')).error).toMatch(/only for Session 3/);
    expect(ticketScanSession(event, COURSE, null, null, new Date('2026-11-11T09:00:00Z')).session.id).toBe('s2');
  });

  test('groupTickets puts one booking\'s picked tickets together', () => {
    const t = (id, sessionId, registrationId = 'r1', eventOptionId = 'drop') => ({ id, registrationOption: { registrationId, eventOptionId, variantId: null, sessionId } });
    const groups = groupTickets([t('a', 's1'), t('b', null, 'r1', 'full'), t('c', 's2'), t('d', 's1', 'r2')]);
    expect(groups.map(g => g.tickets.map(x => x.id))).toEqual([['a', 'c'], ['b'], ['d']]);
    expect(groups[0].sessionIds).toEqual(['s1', 's2']);
    expect(groups[1].sessionIds).toBeNull();
  });
});