namespace QWERTYkez.ExcelProcessor;

/// <summary>
/// Неизменяемый набор всех параметров оформления ячейки.
/// </summary>
public sealed record CellStyle
{
    public CellAlign? Align { get; init; }
    public CellFont? Font { get; init; }
    public CellFill? Fill { get; init; }
    public CellBorder? Border { get; init; }
    public NumberFormatPattern? NumberFormat { get; init; }

    public bool IsEmpty() =>
        Align == null && Font == null && Fill == null && Border == null && NumberFormat == null;

    internal bool TryMerge(NumberFormatPattern format, out CellStyle result)
    {
        result = this;
        if (format is not null)
        {
            if (!Equals(NumberFormat, format))
            {
                result = result with { NumberFormat = format };
                return true;
            }
        }
        return false;
    }

    internal bool TryMerge(CellAlign align, out CellStyle result)
    {
        result = this;
        var current = Align ?? new CellAlign();
        if (current.TryMerge(align, out align))
        {
            result = result with { Align = align };
            return true;
        }
        return false;
    }

    internal bool TryMerge(CellBorder border, out CellStyle result)
    {
        result = this;
        var current = Border ?? new CellBorder();
        if (current.TryMerge(border, out border))
        {
            result = result with { Border = border };
            return true;
        }
        return false;
    }

    internal bool TryMerge(CellFill fill, out CellStyle result)
    {
        result = this;
        var current = Fill ?? new CellFill();
        if (!current.Equals(fill))
        {
            result = result with { Fill = fill };
            return true;
        }
        return false;
    }

    internal bool TryMerge(CellFont font, out CellStyle result)
    {
        result = this;
        var current = Font ?? new CellFont();
        if (!current.Equals(font))
        {
            result = result with { Font = font };
            return true;
        }
        return false;
    }

    internal CellStyle Merge(CellStyle other)
    {
        if (other == null) return this;
        return new CellStyle
        {
            Align = other.Align ?? Align,
            Font = other.Font ?? Font,
            Fill = other.Fill ?? Fill,
            Border = other.Border ?? Border,
            NumberFormat = other.NumberFormat ?? NumberFormat
        };
    }

    internal bool TryMerge(CellStyle other, out CellStyle result)
    {
        result = this;

        bool changed = false;

        // Объединяем Align, если есть
        if (other.Align is not null)
        {
            var currentAlign = Align ?? new CellAlign();
            if (currentAlign.TryMerge(other.Align.Value, out var newAlign))
            {
                result = result with { Align = newAlign };
                changed = true;
            }
        }

        // Аналогично для Font
        if (other.Font is not null)
        {
            var currentFont = Font ?? new CellFont();
            if (currentFont.TryMerge(other.Font.Value, out var newFont))
            {
                result = result with { Font = newFont };
                changed = true;
            }
        }

        // Для Fill просто заменяем, если он задан (нет nullable-полей)
        if (other.Fill is not null)
        {
            if (!Fill.Equals(other.Fill))
            {
                result = result with { Fill = other.Fill };
                changed = true;
            }
        }

        // Border
        if (other.Border is not null)
        {
            var currentBorder = Border ?? new CellBorder();
            if (currentBorder.TryMerge(other.Border.Value, out var newBorder))
            {
                result = result with { Border = newBorder };
                changed = true;
            }
        }

        // NumberFormat
        if (other.NumberFormat is not null)
        {
            if (!Equals(NumberFormat, other.NumberFormat))
            {
                result = result with { NumberFormat = other.NumberFormat };
                changed = true;
            }
        }

        return changed;
    }
}