using System.Text;

namespace UnrealDemoScanner.Web.Infrastructure;

public static class FileNameSanitizer
{
    public static string Sanitize(string? input, string fallback = "demo.dem")
    {
        if (string.IsNullOrWhiteSpace(input))
        {
            return fallback;
        }

        var invalid = Path.GetInvalidFileNameChars();
        var builder = new StringBuilder(input.Length);
        foreach (var ch in input)
        {
            if (invalid.Contains(ch))
            {
                builder.Append('_');
                continue;
            }

            if (char.IsControl(ch))
            {
                builder.Append('_');
                continue;
            }

            builder.Append(ch);
        }

        var sanitized = builder.ToString().Trim();
        if (sanitized.Length == 0)
        {
            return fallback;
        }

        return sanitized;
    }
}