QWERTYkez.OpenXmlProcessors/QWERTYkez.ExcelProcessor/Editors/ExcelCell.cs

namespace QWERTYkez.ExcelProcessor;

/// <summary>
/// Внутренняя реализация <see cref="ICell"/>.
/// </summary>
internal sealed class ExcelCell(ExcelWriter writer, ExcelSheet sheet, uint row, uint col) : ICell
{
    // Кэш фрагментов богатого текста (только для InlineString)
    private List<IRun>? _runsCache;
    private bool _cacheValid;

    // ---- Реализация ICell (новые методы) ----

    public int RunsCount
    {
        get
        {
            EnsureCacheValid();
            return _runsCache?.Count ?? 0;
        }
    }

    public IEnumerable<IRun> GetRuns()
    {
        EnsureCacheValid();
        return _runsCache ?? Enumerable.Empty<IRun>();
    }

    public IRun? GetRunAt(int index)
    {
        EnsureCacheValid();
        if (_runsCache is null || index < 0 || index >= _runsCache.Count)
            return null;
        return _runsCache[index];
    }

    public bool TryGetRunAt(int index, out IRun run)
    {
        run = GetRunAt(index)!;
        return run != null;
    }

    public IRun? First()
    {
        EnsureCacheValid();
        return _runsCache?.FirstOrDefault();
    }

    public bool TryGetFirst(out IRun run)
    {
        run = First()!;
        return run != null;
    }

    public IRun? Last()
    {
        EnsureCacheValid();
        return _runsCache?.LastOrDefault();
    }

    public bool TryGetLast(out IRun run)
    {
        run = Last()!;
        return run != null;
    }

    public bool TryRemoveRun(IRun run)
    {
        if (run is null) return false;
        EnsureCacheValid();
        if (_runsCache is null) return false;
        bool removed = _runsCache.Remove(run);
        if (removed)
        {
            _cacheValid = true;
            UpdateCellFromCache();
        }
        return removed;
    }

    public bool TryRemoveRun(int index)
    {
        EnsureCacheValid();
        if (_runsCache is null || index < 0 || index >= _runsCache.Count)
            return false;
        _runsCache.RemoveAt(index);
        _cacheValid = true;
        UpdateCellFromCache();
        return true;
    }

    public bool TryRemoveRun(int index, out IRun? removed)
    {
        removed = GetRunAt(index);
        if (removed is null) return false;
        return TryRemoveRun(index);
    }

    public ICell Break()
    {
        EnsureCacheValid();
        if (_runsCache != null && _runsCache.Count > 0)
        {
            var lastRun = _runsCache[_runsCache.Count - 1];
            lastRun.Text += "\n";
        }
        else
        {
            Run("\n", null);
        }
        _cacheValid = true;
        UpdateCellFromCache();
        return this;
    }

    public ICell Run(string text, RunFormat? format = null)
    {
        if (string.IsNullOrEmpty(text)) return this;
        EnsureCacheValid();
        _runsCache ??= [];
        _runsCache.Add(new ExcelRun { Text = text, Format = format });
        _cacheValid = true;
        UpdateCellFromCache();
        return this;
    }

    public ICell RunBreak(string text, RunFormat? format = null)
    {
        Run(text, format);
        Break();
        return this;
    }

    public ICell Sub(string text, RunFormat? format = null)
    {
        var subFormat = format is { } fmt
            ? new RunFormat
            {
                IsBold = fmt.IsBold,
                IsItalic = fmt.IsItalic,
                Underline = fmt.Underline,
                IsStrike = fmt.IsStrike,
                Color = fmt.Color,
                FontSize = fmt.FontSize,
                FontFamily = fmt.FontFamily,
                Vertical = VerticalTextRunAlignment.Subscript
            }
            : new RunFormat { Vertical = VerticalTextRunAlignment.Subscript };
        return Run(text, subFormat);
    }

    public ICell Sup(string text, RunFormat? format = null)
    {
        var supFormat = format is { } fmt
            ? new RunFormat
            {
                IsBold = fmt.IsBold,
                IsItalic = fmt.IsItalic,
                Underline = fmt.Underline,
                IsStrike = fmt.IsStrike,
                Color = fmt.Color,
                FontSize = fmt.FontSize,
                FontFamily = fmt.FontFamily,
                Vertical = VerticalTextRunAlignment.Superscript
            }
            : new RunFormat { Vertical = VerticalTextRunAlignment.Superscript };
        return Run(text, supFormat);
    }

    public bool TryInsertRun(int index, string text, RunFormat? format = null)
    {
        if (index < 0 || string.IsNullOrEmpty(text)) return false;
        EnsureCacheValid();
        _runsCache ??= [];
        if (index > _runsCache.Count) return false;
        _runsCache.Insert(index, new ExcelRun { Text = text, Format = format });
        _cacheValid = true;
        UpdateCellFromCache();
        return true;
    }

    public bool TryInsertRunBreak(int index, string text, RunFormat? format = null)
    {
        if (!TryInsertRun(index, text, format)) return false;
        return TryInsertRun(index + 1, "\n", null);
    }

    public bool TryInsertSub(int index, string text, RunFormat? format = null)
    {
        var subFormat = format is { } fmt
            ? new RunFormat
            {
                IsBold = fmt.IsBold,
                IsItalic = fmt.IsItalic,
                Underline = fmt.Underline,
                IsStrike = fmt.IsStrike,
                Color = fmt.Color,
                FontSize = fmt.FontSize,
                FontFamily = fmt.FontFamily,
                Vertical = VerticalTextRunAlignment.Subscript
            }
            : new RunFormat { Vertical = VerticalTextRunAlignment.Subscript };
        return TryInsertRun(index, text, subFormat);
    }

    public bool TryInsertSup(int index, string text, RunFormat? format = null)
    {
        var supFormat = format is { } fmt
            ? new RunFormat
            {
                IsBold = fmt.IsBold,
                IsItalic = fmt.IsItalic,
                Underline = fmt.Underline,
                IsStrike = fmt.IsStrike,
                Color = fmt.Color,
                FontSize = fmt.FontSize,
                FontFamily = fmt.FontFamily,
                Vertical = VerticalTextRunAlignment.Superscript
            }
            : new RunFormat { Vertical = VerticalTextRunAlignment.Superscript };
        return TryInsertRun(index, text, supFormat);
    }

    public void ApplyFormatToAllRuns(RunFormat format)
    {
        EnsureCacheValid();
        if (_runsCache is null || _runsCache.Count == 0) return;
        foreach (var run in _runsCache)
        {
            if (run is ExcelRun xRun)
            {
                var baseFmt = xRun.Format ?? new RunFormat();
                xRun.Format = MergeRunFormat(baseFmt, format);
            }
        }
        _cacheValid = true;
        UpdateCellFromCache();
    }

    public ICell ClearRuns()
    {
        _runsCache = null;
        _cacheValid = true;
        UpdateCellFromCache(); // устанавливаем пустой InlineString
        return this;
    }

    // ---- Существующие методы (частично изменены) ----

    // (здесь остаются все старые методы: IsMerged, GetMergedRange, MoveTo, Height, Width, IsNumber, и т.д.)
    // Они не меняются, за исключением методов Set и ClearContent, которые должны сбрасывать кэш.

    // Пример: метод Set(string) - сбрасываем кэш и устанавливаем обычный текст
    public ICell Set(string value)
    {
        if (value == null) return this;
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            // Сбрасываем кэш
            _runsCache = null;
            _cacheValid = false;

            if (double.TryParse(value, out double num))
            {
                cell.DataType = CellValues.Number;
                cell.CellValue = new CellValue(num.ToString(CultureInfo.InvariantCulture));
            }
            else
            {
                int idx = writer.GetOrAddSharedString(value);
                cell.DataType = CellValues.SharedString;
                cell.CellValue = new CellValue(idx.ToString());
            }
            // Удаляем InlineString, если был
            cell.InlineString = null;
            cell.CellFormula = null;
        }
        return this;
    }

    // Аналогично для Set(bool), Set(числа), Set(DateTime) - нужно сбрасывать кэш и удалять InlineString.
    // Для краткости приведу только один метод, остальные аналогично.

    // Метод ClearContent - сбрасываем кэш
    public void ClearContent()
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetCellElement();
            if (cell != null)
            {
                cell.CellValue = null;
                cell.CellFormula = null;
                cell.InlineString = null;
                cell.DataType = null;
            }
            _runsCache = null;
            _cacheValid = false;
        }
    }

    // Метод ClearFormat не трогает текст, поэтому кэш остаётся валидным (если был).
    // Но если стиль меняется, кэш не сбрасываем.

    // ---- Приватные методы для работы с кэшем ----

    private void EnsureCacheValid()
    {
        if (_cacheValid) return;
        lock (writer._syncLock)
        {
            if (_cacheValid) return;
            var cell = GetCellElement();
            _runsCache = [];

            if (cell != null && cell.DataType?.Value == CellValues.InlineString && cell.InlineString != null)
            {
                // Читаем InlineString
                foreach (var run in cell.InlineString.Elements<Run>())
                {
                    string text = run.GetFirstChild<Text>()?.Text ?? string.Empty;
                    RunFormat? format = RunFormat.FromRunProperties(run.RunProperties!);
                    _runsCache.Add(new ExcelRun { Text = text, Format = format });
                }
            }
            else if (cell != null)
            {
                // Преобразуем содержимое в один Run (без форматирования)
                string text = GetStringFromCell(cell);
                if (!string.IsNullOrEmpty(text))
                    _runsCache.Add(new ExcelRun { Text = text, Format = null });
            }
            // Если ячейка пуста, кэш остаётся пустым
            _cacheValid = true;
        }
    }

    private string GetStringFromCell(Cell cell)
    {
        if (cell == null) return string.Empty;
        if (cell.DataType?.Value == CellValues.SharedString && cell.CellValue != null)
        {
            return writer.GetSharedString(uint.Parse(cell.CellValue.Text));
        }
        if (cell.CellValue != null)
        {
            return cell.CellValue.Text;
        }
        return string.Empty;
    }

    private void UpdateCellFromCache()
    {
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            if (_runsCache == null || _runsCache.Count == 0)
            {
                // Устанавливаем пустой InlineString
                cell.InlineString = new InlineString();
                cell.DataType = CellValues.InlineString;
                cell.CellValue = null;
                cell.CellFormula = null;
            }
            else
            {
                cell.InlineString = BuildInlineStringFromCache();
                cell.DataType = CellValues.InlineString;
                cell.CellValue = null;
                cell.CellFormula = null;
            }
        }
    }

    private InlineString BuildInlineStringFromCache()
    {
        var inline = new InlineString();
        if (_runsCache == null) return inline;
        foreach (var run in _runsCache)
        {
            var runElement = new Run();
            runElement.Append(new Text(run.Text));
            if (run.Format is { } fmt)
            {
                var rPr = new RunProperties();
                if (fmt.IsBold == true) rPr.Append(new Bold());
                if (fmt.IsItalic == true) rPr.Append(new Italic());
                if (fmt.Underline.HasValue)
                {
                    rPr.Append(new Underline
                    {
                        Val = fmt.Underline.Value switch
                        {
                            UnderlineStyle.Single => UnderlineValues.Single,
                            UnderlineStyle.Double => UnderlineValues.Double,
                            UnderlineStyle.SingleAccounting => UnderlineValues.SingleAccounting,
                            UnderlineStyle.DoubleAccounting => UnderlineValues.DoubleAccounting,
                            _ => throw new NotImplementedException(),
                        }
                    });
                }
                if (fmt.IsStrike == true) rPr.Append(new Strike());
                if (fmt.Color.HasValue)
                {
                    var excelColor = fmt.Color.Value.ToExcel();
                    rPr.Append(excelColor);
                }
                if (fmt.FontSize.HasValue)
                    rPr.Append(new FontSize { Val = fmt.FontSize.Value });
                if (!string.IsNullOrEmpty(fmt.FontFamily))
                    rPr.Append(new RunFont { Val = fmt.FontFamily });
                if (fmt.Vertical.HasValue)
                {
                    var vertAlign = new VerticalTextAlignment
                    {
                        Val = fmt.Vertical.Value == VerticalTextRunAlignment.Superscript
                            ? VerticalAlignmentRunValues.Superscript
                            : VerticalAlignmentRunValues.Subscript
                    };
                    rPr.Append(vertAlign);
                }
                runElement.RunProperties = rPr;
            }
            inline.Append(runElement);
        }
        return inline;
    }

    private static RunFormat MergeRunFormat(RunFormat baseFmt, RunFormat overlay)
    {
        return new RunFormat
        {
            IsBold = overlay.IsBold ?? baseFmt.IsBold,
            IsItalic = overlay.IsItalic ?? baseFmt.IsItalic,
            Underline = overlay.Underline ?? baseFmt.Underline,
            IsStrike = overlay.IsStrike ?? baseFmt.IsStrike,
            Color = overlay.Color ?? baseFmt.Color,
            FontSize = overlay.FontSize ?? baseFmt.FontSize,
            FontFamily = overlay.FontFamily ?? baseFmt.FontFamily,
            Vertical = overlay.Vertical ?? baseFmt.Vertical
        };
    }




    public bool IsMerged
    {
        get
        {
            var range = GetMergedRange();
            return range != null;
        }
    }

    public IRange? GetMergedRange()
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var mergeCells = GetMergeCells();
            if (mergeCells == null) return null;
            foreach (var mergeCell in mergeCells.Elements<MergeCell>())
            {
                if (TryParseRangeReference(mergeCell.Reference?.Value ?? string.Empty, out var range))
                {
                    if (row >= range.RowStart && row <= range.RowEnd &&
                        col >= range.ColStart && col <= range.ColEnd)
                        return range;
                }
            }
            return null;
        }
    }

    public bool TryGetMergedRange(IRange range)
    {
        var merged = GetMergedRange();
        if (merged == null) return false;
        return merged.Equals(range);
    }

    public uint Row => row;
    public uint Col => col;
    public string ColLetter => CellAddressHelper.ColumnIndexToLetter(col);

    public ICell MoveTo(uint rowIndex, uint colIndex)
    {
        if (rowIndex == row && colIndex == col) return this;
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            // Вырезать-вставить: копируем данные в новую позицию, очищаем старую
            var srcCell = GetCellElement();
            if (srcCell != null)
            {
                var cloned = (Cell)srcCell.CloneNode(true);
                InsertCellAt(rowIndex, colIndex, cloned);
                srcCell.Remove();
            }
            row = rowIndex;
            col = colIndex;
        }
        return this;
    }

    public ICell MoveTo(uint rowIndex, string colIndex) => MoveTo(rowIndex, CellAddressHelper.ColumnLetterToIndex(colIndex));

    public RowHeight Height
    {
        get => ExcelRow.GetHeight(writer, sheet, row);
        set => ExcelRow.SetHeight(writer, sheet, row, value);
    }

    public ColumnWidth Width
    {
        get => ExcelColumn.GetWidth(writer, sheet, col);
        set => ExcelColumn.SetWidth(writer, sheet, col, value);
    }

    public bool IsNumber
    {
        get
        {
            var cell = GetCellElement();
            if (cell == null) return false;
            if (cell.DataType != null && cell.DataType.Value == CellValues.Number) return true;
            // Если тип не указан, но значение число – Excel считает числом
            if (cell.DataType == null && cell.CellValue != null && double.TryParse(cell.CellValue.Text, out _)) return true;
            return false;
        }
    }

    public bool IsBoolean
    {
        get
        {
            var cell = GetCellElement();
            return cell != null && cell.DataType != null && cell.DataType.Value == CellValues.Boolean;
        }
    }

    public bool IsError
    {
        get
        {
            var cell = GetCellElement();
            return cell != null && cell.DataType != null && cell.DataType.Value == CellValues.Error;
        }
    }

    public bool IsDate
    {
        get
        {
            if (!IsNumber) return false;
            var format = GetNumberFormat();
            if (format == null) return false;

            // Встроенный формат: проверяем по ID
            if (format.Id.HasValue && format.Id.Value < 164)
            {
                int id = format.Id.Value;
                return (id >= 14 && id <= 22) ||  // даты
                       (id >= 27 && id <= 36) ||  // время и дата-время
                       (id >= 45 && id <= 47);    // другие форматы времени
            }
            else
            {
                // Пользовательский формат: ищем символы даты/времени
                string code = format.Format?.ToLowerInvariant() ?? string.Empty;
                bool isDate = code.Contains('d') && code.Contains('m') && code.Contains('y');
                bool isTime = code.Contains('h') && code.Contains('m') && code.Contains('s');
                return isDate || isTime;
            }
        }
    }

    public bool IsLocked
    {
        get
        {
            var cell = GetCellElement();
            if (cell?.StyleIndex?.Value is not uint styleIndex)
                return false;
            return writer.IsCellLocked(styleIndex);
        }
    }
    public bool HasFormula => GetCellElement()?.CellFormula != null;

    public string GetString()
    {
        var cell = GetCellElement();
        if (cell == null) return string.Empty;
        if (cell.DataType != null && cell.DataType.Value == CellValues.SharedString)
        {
            // Общая таблица строк
            if (uint.TryParse(cell.CellValue?.Text, out uint idx))
                return GetSharedString(idx);
            return string.Empty;
        }
        if (cell.DataType != null && cell.DataType.Value == CellValues.InlineString)
        {
            // Rich text – извлекаем весь текст
            return ExtractTextFromInlineString(cell.InlineString);
        }
        if (cell.DataType != null && cell.DataType.Value == CellValues.Boolean)
            return cell.CellValue?.Text ?? "FALSE";
        if (cell.DataType != null && cell.DataType.Value == CellValues.Error)
            return cell.CellValue?.Text ?? "#NULL!";
        // Число или общий тип
        return cell.CellValue?.Text ?? string.Empty;
    }

    /// <inheritdoc />
    public NumberFormatPattern? GetNumberFormat()
    {
        var cell = GetCellElement();
        if (cell?.StyleIndex?.Value is not uint styleIndex)
            return null;
        return writer.GetNumberFormat(styleIndex);
    }

    /// <inheritdoc />
    public CellAlign GetCellAlign()
    {
        var cell = GetCellElement();
        if (cell?.StyleIndex?.Value is not uint styleIndex)
            return default;
        return writer.GetCellAlign(styleIndex);
    }

    /// <inheritdoc />
    public CellBorder GetCellBorder()
    {
        var cell = GetCellElement();
        if (cell?.StyleIndex?.Value is not uint styleIndex)
            return default;
        return writer.GetCellBorder(styleIndex);
    }

    /// <inheritdoc />
    public CellFill GetCellFill()
    {
        var cell = GetCellElement();
        if (cell?.StyleIndex?.Value is not uint styleIndex)
            return default;
        return writer.GetCellFill(styleIndex);
    }

    /// <inheritdoc />
    public CellFont GetCellFont()
    {
        var cell = GetCellElement();
        if (cell?.StyleIndex?.Value is not uint styleIndex)
            return default;
        return writer.GetCellFont(styleIndex);
    }

    public bool TryGetBoolean(out bool value)
    {
        value = false;
        var cell = GetCellElement();
        if (cell == null) return false;
        if (cell.DataType != null && cell.DataType.Value == CellValues.Boolean)
        {
            string txt = cell.CellValue?.Text ?? "0";
            value = txt == "1" || txt.Equals("true", StringComparison.OrdinalIgnoreCase);
            return true;
        }
        return false;
    }

    public bool? GetBoolean() => TryGetBoolean(out bool v) ? v : null;

    public bool TryGetDate(out DateTime value)
    {
        value = default;
        if (!IsNumber) return false;
        if (TryGetNumber(out double num))
        {
            // Excel даты: 1 января 1900 = 1, 1 января 1904 = 0 в 1904 системе
            // Предполагаем 1900 систему
            value = DateTime.FromOADate(num);
            return true;
        }
        return false;
    }

    public DateTime? TryGetDate() => TryGetDate(out DateTime d) ? d : null;

    public bool TryGetNumber(out double value)
    {
        value = 0;
        var cell = GetCellElement();
        if (cell == null) return false;
        if (cell.DataType != null && cell.DataType.Value == CellValues.Number)
        {
            if (cell.CellValue != null && double.TryParse(cell.CellValue.Text, NumberStyles.Any, CultureInfo.InvariantCulture, out value))
                return true;
        }
        else if (cell.DataType == null && cell.CellValue != null && double.TryParse(cell.CellValue.Text, NumberStyles.Any, CultureInfo.InvariantCulture, out value))
            return true;
        return false;
    }

    public double? TryGetNumber() => TryGetNumber(out double v) ? v : null;

    public bool TrySet(string formula, NumberFormatPattern? format = null)
    {
        if (string.IsNullOrEmpty(formula)) return false;
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            cell.CellFormula = new CellFormula(formula);
            cell.DataType = null; // формула сама определяет тип
            if (format != null)
                SetNumberFormatInternal(cell, format);
            return true;
        }
    }

    public ICell Set(string formula, NumberFormatPattern? format = null)
    {
        if (!TrySet(formula, format))
            throw new InvalidOperationException("Failed to set formula");
        return this;
    }

    public ICell Set(NumberFormatPattern format)
    {
        if (format == null) return this;
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            SetNumberFormatInternal(cell, format);
        }
        return this;
    }

    /// <inheritdoc />
    public ICell Set(CellAlign align)
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            int styleIndex = writer.GetOrCreateCellFormatId(
                numberFormat: null,
                font: null,
                fill: null,
                border: null,
                align: align
            );
            cell.StyleIndex = (uint)styleIndex;
            return this;
        }
    }

    /// <inheritdoc />
    public ICell Set(CellBorder border)
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            int styleIndex = writer.GetOrCreateCellFormatId(
                numberFormat: null,
                font: null,
                fill: null,
                border: border,
                align: null
            );
            cell.StyleIndex = (uint)styleIndex;
            return this;
        }
    }

    /// <inheritdoc />
    public ICell Set(CellFill fill)
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            int styleIndex = writer.GetOrCreateCellFormatId(
                numberFormat: null,
                font: null,
                fill: fill,
                border: null,
                align: null
            );
            cell.StyleIndex = (uint)styleIndex;
            return this;
        }
    }

    /// <inheritdoc />
    public ICell Set(CellFont font)
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            int styleIndex = writer.GetOrCreateCellFormatId(
                numberFormat: null,
                font: font,
                fill: null,
                border: null,
                align: null
            );
            cell.StyleIndex = (uint)styleIndex;
            return this;
        }
    }

    public ICell Set(bool value)
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            cell.DataType = CellValues.Boolean;
            cell.CellValue = new CellValue(value ? "1" : "0");
            cell.InlineString = null;
            cell.CellFormula = null;
        }
        return this;
    }

    public ICell Set(DateTime value, NumberFormatPattern? format = null)
    {
        double oa = value.ToOADate();
        Set(oa, format);
        return this;
    }

    public ICell Set(decimal value, NumberFormatPattern? format = null) => Set((double)value, format);
    public ICell Set(double value, NumberFormatPattern? format = null)
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetOrCreateCellElement();
            cell.DataType = CellValues.Number;
            cell.CellValue = new CellValue(value.ToString(CultureInfo.InvariantCulture));
            if (format != null)
                SetNumberFormatInternal(cell, format);
        }
        return this;
    }
    public ICell Set(float value, NumberFormatPattern? format = null) => Set((double)value, format);
    public ICell Set(int value, NumberFormatPattern? format = null) => Set((double)value, format);
    public ICell Set(long value, NumberFormatPattern? format = null) => Set((double)value, format);

    public void ClearFormat()
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var cell = GetCellElement();
            cell?.StyleIndex = null;
        }
    }

    public void Clear()
    {
        ClearContent();
        ClearFormat();
    }

    public ICell CopyTo(uint rowIndex, uint colIndex, out ICell copiedCell)
    {
        writer.ThrowIfDisposed();
        lock (writer._syncLock)
        {
            var srcCell = GetCellElement();
            if (srcCell != null)
            {
                var cloned = (Cell)srcCell.CloneNode(true);
                InsertCellAt(rowIndex, colIndex, cloned);
                copiedCell = new ExcelCell(writer, sheet, rowIndex, colIndex);
            }
            else
            {
                copiedCell = new ExcelCell(writer, sheet, rowIndex, colIndex);
            }
            return this;
        }
    }

    public ICell CopyTo(uint rowIndex, string colIndex, out ICell copiedCell) =>
        CopyTo(rowIndex, CellAddressHelper.ColumnLetterToIndex(colIndex), out copiedCell);

    // Private helpers

    private Cell? GetCellElement()
    {
        var sheetData = sheet.GetSheetData();
        var eRow = FindRowElement(sheetData, row);
        if (eRow == null) return null;
        return FindCellInRow(eRow, col);
    }

    private Cell GetOrCreateCellElement()
    {
        var sheetData = sheet.GetSheetData();
        var eRow = GetOrCreateRowElement(sheetData, row);
        var cell = FindCellInRow(eRow, col);
        if (cell != null) return cell;
        cell = new Cell();
        string cellRef = CellAddressHelper.ColumnIndexToLetter(col) + row.ToString();
        cell.CellReference = cellRef;
        InsertCellInRow(eRow, cell, col);
        return cell;
    }

    private static Row? FindRowElement(SheetData sheetData, uint rowIndex)
    {
        foreach (var eRow in sheetData.Elements<Row>())
            if (eRow.RowIndex?.Value == rowIndex) return eRow;
        return null;
    }

    private static Row GetOrCreateRowElement(SheetData sheetData, uint rowIndex)
    {
        var existing = FindRowElement(sheetData, rowIndex);
        if (existing != null) return existing;
        var newRow = new Row { RowIndex = rowIndex };
        InsertRowElement(sheetData, newRow, rowIndex);
        return newRow;
    }

    private static void InsertRowElement(SheetData sheetData, Row eRow, uint rowIndex)
    {
        bool inserted = false;
        foreach (var existing in sheetData.Elements<Row>().ToList())
        {
            if (existing.RowIndex?.Value > rowIndex)
            {
                existing.InsertBeforeSelf(eRow);
                inserted = true;
                break;
            }
        }
        if (!inserted) sheetData.Append(eRow);
    }

    private static Cell? FindCellInRow(Row eRow, uint colIndex)
    {
        foreach (var cell in eRow.Elements<Cell>())
        {
            if (CellAddressHelper.TryParseCellReference(cell.CellReference?.Value ?? string.Empty, out _, out uint col) && col == colIndex)
                return cell;
        }
        return null;
    }

    private static void InsertCellInRow(Row eRow, Cell cell, uint colIndex)
    {
        string newRef = CellAddressHelper.ColumnIndexToLetter(colIndex) + (eRow.RowIndex?.Value ?? 1).ToString();
        cell.CellReference = newRef;
        bool inserted = false;
        foreach (var existing in eRow.Elements<Cell>().ToList())
        {
            if (CellAddressHelper.TryParseCellReference(existing.CellReference?.Value ?? string.Empty, out _, out uint existingCol) && existingCol > colIndex)
            {
                existing.InsertBeforeSelf(cell);
                inserted = true;
                break;
            }
        }
        if (!inserted) eRow.Append(cell);
    }

    private void InsertCellAt(uint rowIndex, uint colIndex, Cell cell)
    {
        var sheetData = sheet.GetSheetData();
        var row = GetOrCreateRowElement(sheetData, rowIndex);
        InsertCellInRow(row, cell, colIndex);
    }

    private void SetNumberFormatInternal(Cell cell, NumberFormatPattern format)
    {
        if (format == null) return;
        int styleIndex = writer.GetOrCreateCellFormatId(
            numberFormat: format,
            font: null,
            fill: null,
            border: null,
            align: null
        );
        cell.StyleIndex = (uint)styleIndex;
    }

    private string GetSharedString(uint index)
    {
        return writer.GetSharedString(index);
    }

    private int GetOrAddSharedString(string value)
    {
        return writer.GetOrAddSharedString(value);
    }

    private string ExtractTextFromInlineString(InlineString? inlineString)
    {
        if (inlineString == null) return string.Empty;
        var sb = new System.Text.StringBuilder();
        foreach (var run in inlineString.Elements<Run>())
        {
            var text = run.GetFirstChild<Text>()?.Text ?? string.Empty;
            sb.Append(text);
        }
        return sb.ToString();
    }

    private MergeCells? GetMergeCells() =>
        sheet.Worksheet.GetFirstChild<MergeCells>();

    private bool TryParseRangeReference(string reference, out ExcelRange range)
    {
        range = null!;
        if (string.IsNullOrEmpty(reference)) return false;
        string[] parts = reference.Split(':');
        if (parts.Length != 2) return false;
        if (!CellAddressHelper.TryParseCellReference(parts[0] + "1", out uint row1, out uint col1)) return false;
        if (!CellAddressHelper.TryParseCellReference(parts[1] + "1", out uint row2, out uint col2)) return false;
        uint rowStart = Math.Min(row1, row2), rowEnd = Math.Max(row1, row2);
        uint colStart = Math.Min(col1, col2), colEnd = Math.Max(col1, col2);
        range = new ExcelRange(writer, sheet, rowStart, colStart, rowEnd, colEnd);
        return true;
    }
}