private static Style?Parse(string text, out string?error)
{
var effectiveDecoration = (Decoration?)null;
var effectiveForeground = (Color?)null;
var effectiveBackground = (Color?)null;
var effectiveLink = (string?)null;
var parts = text.Split(new[] { ' ' });
var foreground = true;
foreach (var part in parts)
{
if (part.Equals("default", StringComparison.OrdinalIgnoreCase))
{
continue;
}
if (part.Equals("on", StringComparison.OrdinalIgnoreCase))
{
foreground = false;
continue;
}
if (part.StartsWith("link=", StringComparison.OrdinalIgnoreCase))
{
if (effectiveLink != null)
{
error = "A link has already been set.";
return(null);
}
effectiveLink = part.Substring(5);
continue;
}
else if (part.StartsWith("link", StringComparison.OrdinalIgnoreCase))
{
effectiveLink = Constants.EmptyLink;
continue;
}
var decoration = DecorationTable.GetDecoration(part);
if (decoration != null)
{
effectiveDecoration ??= Decoration.None;
effectiveDecoration |= decoration.Value;
}
else
{
var color = ColorTable.GetColor(part);
if (color == null)
{
if (part.StartsWith("#", StringComparison.OrdinalIgnoreCase))
{
color = ParseHexColor(part, out error);
if (!string.IsNullOrWhiteSpace(error))
{
return(null);
}
}
else if (part.StartsWith("rgb", StringComparison.OrdinalIgnoreCase))
{
color = ParseRgbColor(part, out error);
if (!string.IsNullOrWhiteSpace(error))
{
return(null);
}
}
else if (int.TryParse(part, out var number))
{
if (number < 0)
{
error = $"Color number must be greater than or equal to 0 (was {number})";
return(null);
}
else if (number > 255)
{
error = $"Color number must be less than or equal to 255 (was {number})";
return(null);
}
color = number;
}
else
{
error = !foreground
? $"Could not find color '{part}'."
: $"Could not find color or style '{part}'.";
return(null);
}
}
if (foreground)
{
if (effectiveForeground != null)
{
error = "A foreground color has already been set.";
return(null);
}
effectiveForeground = color;
}
else
{
if (effectiveBackground != null)
{
error = "A background color has already been set.";
return(null);
}
effectiveBackground = color;
}
}
}
error = null;
return(new Style(
effectiveForeground,
effectiveBackground,
effectiveDecoration,
effectiveLink));
}