namespace QWERTYkez.ExcelProcessor;

/// <summary>
/// Определяет заливку (фон) ячейки.
/// </summary>
public readonly struct CellFill : IEquatable<CellFill>
{
    /// <summary>Цвет фона.</summary>
    public System.Drawing.Color? BackgroundColor { get; init; }

    /// <summary>Создаёт элемент Fill для Open XML.</summary>
    public Fill? ToFill()
    {
        if (BackgroundColor is not { } c) return null;

        var fill = new Fill
        {
            PatternFill = new PatternFill
            {
                PatternType = PatternValues.Solid,
                ForegroundColor = new ForegroundColor { Rgb = $"{c.R:X2}{c.G:X2}{c.B:X2}" }
            }
        };
        return fill;
    }

    /// <summary>Создаёт CellFill из элемента Fill Open XML.</summary>
    public static CellFill FromFill(Fill? fill)
    {
        if (fill?.PatternFill?.ForegroundColor?.Rgb?.Value is not string rgb || rgb.Length < 6)
            return default;

        var color = System.Drawing.Color.FromArgb(
            Convert.ToByte(rgb.Substring(0, 2), 16),
            Convert.ToByte(rgb.Substring(2, 2), 16),
            Convert.ToByte(rgb.Substring(4, 2), 16)
        );
        return new CellFill { BackgroundColor = color };
    }

    public override bool Equals(object? obj) => obj is CellFill other && Equals(other);
    public bool Equals(CellFill other) => this == other;

    public static bool operator ==(CellFill left, CellFill right) =>
        Equals(left.BackgroundColor, right.BackgroundColor);

    public static bool operator !=(CellFill left, CellFill right) => !(left == right);

    public override int GetHashCode() =>
        BackgroundColor?.GetHashCode() ?? 0;
}