FirstFloor.ModernUI.Windows.Controls.HistoricalTextBox.AddText C# (CSharp) Method

        private void AddText() {
            var value = Text;
            if (string.IsNullOrWhiteSpace(value)) return;

            var previous = _filtersHistory.TakeWhile(x => !string.Equals(x, value, StringComparison.OrdinalIgnoreCase)).Count();
            if (previous < _filtersHistory.Count) {
                _filtersHistory.Move(previous, 0);
            } else if (DateTime.Now - _lastChanged > TimeSpan.FromSeconds(4) || _filtersHistory.Count == 0) {
                if (_filtersHistory.Count > MaxSize) {
                    _filtersHistory.RemoveAt(_filtersHistory.Count - 1);
                }

                _filtersHistory.Insert(0, value);
            } else {
                _filtersHistory[0] = value;
            }

            _lastChanged = DateTime.Now;

            var saveKey = SaveKey;
            if (saveKey != null) {
                ValuesStorage.Set(saveKey, _filtersHistory);
            }
        }