import {
  datetimeMessage,
  deriveEventState,
  endAfterStartValidator,
  isoDatetimeValidator,
  normalizePageTitle,
  pageTitleError,
  pageTitleMessage,
  toDatetimeLocal,
  toIsoUtc,
} from '../../frontend/src/app/features/admin/general.pure';

describe('deriveEventState', () => {
  const start = '2026-01-01T00:00:00Z';
  const end = '2026-01-02T00:00:00Z';

  it('returns "unconfigured" when start or end is missing', () => {
    expect(deriveEventState('', '')).toBe('unconfigured');
    expect(deriveEventState(start, '')).toBe('unconfigured');
    expect(deriveEventState('', end)).toBe('unconfigured');
  });

  it('returns "unconfigured" when dates cannot be parsed', () => {
    expect(deriveEventState('not-a-date', end)).toBe('unconfigured');
  });

  it('returns "countdown" when now is before start', () => {
    const s = new Date(Date.now() + 60_000).toISOString();
    const e = new Date(Date.now() + 120_000).toISOString();
    expect(deriveEventState(s, e)).toBe('countdown');
  });

  it('returns "running" when now is between start and end', () => {
    const s = new Date(Date.now() - 60_000).toISOString();
    const e = new Date(Date.now() + 60_000).toISOString();
    expect(deriveEventState(s, e)).toBe('running');
  });

  it('returns "stopped" when now is after end', () => {
    const s = new Date(Date.now() - 120_000).toISOString();
    const e = new Date(Date.now() - 60_000).toISOString();
    expect(deriveEventState(s, e)).toBe('stopped');
  });
});

describe('endAfterStartValidator', () => {
  const ctrl = (start: string, end: string) => ({
    get: (k: string) =>
      k === 'eventStartUtc'
        ? { value: start }
        : k === 'eventEndUtc'
        ? { value: end }
        : { value: '' },
  });

  it('returns null when either field is empty', () => {
    expect(endAfterStartValidator(ctrl('', '2026-01-01T00:00:00Z'))).toBeNull();
    expect(endAfterStartValidator(ctrl('2026-01-01T00:00:00Z', ''))).toBeNull();
  });

  it('returns null when end is strictly after start', () => {
    expect(endAfterStartValidator(ctrl('2026-01-01T00:00:00Z', '2026-01-02T00:00:00Z'))).toBeNull();
  });

  it('returns { endBeforeStart: true } when end equals start', () => {
    expect(endAfterStartValidator(ctrl('2026-01-01T00:00:00Z', '2026-01-01T00:00:00Z'))).toEqual({ endBeforeStart: true });
  });

  it('returns { endBeforeStart: true } when end is before start', () => {
    expect(endAfterStartValidator(ctrl('2026-01-02T00:00:00Z', '2026-01-01T00:00:00Z'))).toEqual({ endBeforeStart: true });
  });
});

describe('datetime helpers', () => {
  it('toDatetimeLocal formats an ISO timestamp with UTC components', () => {
    expect(toDatetimeLocal('2026-01-02T03:04:00Z')).toBe('2026-01-02T03:04');
  });

  it('toDatetimeLocal returns empty string for invalid input', () => {
    expect(toDatetimeLocal('')).toBe('');
    expect(toDatetimeLocal('garbage')).toBe('');
  });

  it('toIsoUtc converts a local datetime back to UTC ISO', () => {
    const iso = toIsoUtc('2026-01-02T03:04');
    expect(iso).toMatch(/^2026-01-02T03:04:00\.000Z$/);
  });

  it('toIsoUtc returns input verbatim when empty', () => {
    expect(toIsoUtc('')).toBe('');
  });
});

describe('pageTitleError', () => {
  it('returns "required" for empty input', () => {
    expect(pageTitleError('')).toBe('required');
    expect(pageTitleError(null)).toBe('required');
    expect(pageTitleError(undefined)).toBe('required');
  });

  it('returns "required" for whitespace-only input', () => {
    expect(pageTitleError('   ')).toBe('required');
    expect(pageTitleError('\t\n ')).toBe('required');
  });

  it('returns null for a valid title', () => {
    expect(pageTitleError('OpenVelo')).toBeNull();
  });

  it('returns "maxlength" when the raw string exceeds 120 characters', () => {
    expect(pageTitleError('a'.repeat(121))).toBe('maxlength');
  });

  it('returns null when surrounding whitespace keeps the trimmed length within bounds', () => {
    expect(pageTitleError('  OpenVelo  ')).toBeNull();
  });
});

describe('normalizePageTitle', () => {
  it('returns an empty string for empty input', () => {
    expect(normalizePageTitle('')).toBe('');
  });

  it('returns an empty string for whitespace-only input', () => {
    expect(normalizePageTitle('   ')).toBe('');
  });

  it('trims surrounding whitespace from a valid title', () => {
    expect(normalizePageTitle('  OpenVelo  ')).toBe('OpenVelo');
  });
});

describe('pageTitleMessage', () => {
  const requiredMsg = 'Page title is required and cannot contain only whitespace.';
  const maxLengthMsg = 'Page title must be 120 characters or fewer.';

  it('returns the required message for empty input', () => {
    expect(pageTitleMessage('', null)).toBe(requiredMsg);
  });

  it('returns the required message for whitespace-only input', () => {
    expect(pageTitleMessage('   ', null)).toBe(requiredMsg);
    expect(pageTitleMessage('\t\n ', null)).toBe(requiredMsg);
  });

  it('returns null for a valid title', () => {
    expect(pageTitleMessage('OpenVelo', null)).toBeNull();
  });

  it('returns the maxlength message when the raw string exceeds 120 characters', () => {
    expect(pageTitleMessage('a'.repeat(121), null)).toBe(maxLengthMsg);
  });

  it('surfaces the whitespace validator error when control errors are provided', () => {
    expect(pageTitleMessage('   ', { whitespace: true })).toBe(requiredMsg);
  });

  it('surfaces the required control error', () => {
    expect(pageTitleMessage('', { required: true })).toBe(requiredMsg);
  });

  it('surfaces the maxlength control error', () => {
    expect(pageTitleMessage('a'.repeat(121), { maxlength: { requiredLength: 120 } })).toBe(maxLengthMsg);
  });
});

describe('isoDatetimeValidator', () => {
  it('returns { invalidDatetime: true } for an empty value (empty string no longer accepted)', () => {
    expect(isoDatetimeValidator({ value: '' })).toEqual({ invalidDatetime: true });
    expect(isoDatetimeValidator({ value: null })).toEqual({ invalidDatetime: true });
    expect(isoDatetimeValidator({ value: undefined })).toEqual({ invalidDatetime: true });
  });

  it('returns null for a valid ISO-8601 datetime', () => {
    expect(isoDatetimeValidator({ value: '2026-08-15T10:30:00.000Z' })).toBeNull();
  });

  it('returns { invalidDatetime: true } for a non-datetime string', () => {
    expect(isoDatetimeValidator({ value: 'not-a-date' })).toEqual({ invalidDatetime: true });
    expect(isoDatetimeValidator({ value: 'also-not-a-date' })).toEqual({ invalidDatetime: true });
  });
});

describe('datetimeMessage', () => {
  it('returns the per-field error when controlErrors carries invalidDatetime', () => {
    expect(datetimeMessage('Event start', 'not-a-date', { invalidDatetime: true }))
      .toBe('Event start must be a valid ISO-8601 datetime.');
    expect(datetimeMessage('Event end', 'garbage', { invalidDatetime: true }))
      .toBe('Event end must be a valid ISO-8601 datetime.');
  });

  it('falls back to detecting an unparseable value when controlErrors are absent', () => {
    expect(datetimeMessage('Event start', 'not-a-date', null))
      .toBe('Event start must be a valid ISO-8601 datetime.');
  });

  it('returns the per-field error for an empty value (empty is now invalid)', () => {
    expect(datetimeMessage('Event start', '', null)).toBe('Event start must be a valid ISO-8601 datetime.');
    expect(datetimeMessage('Event end', '', { invalidDatetime: true })).toBe('Event end must be a valid ISO-8601 datetime.');
  });

  it('returns null for a valid ISO-8601 datetime', () => {
    expect(datetimeMessage('Event start', '2026-08-15T10:30:00.000Z', null)).toBeNull();
  });
});