using System.Text;

namespace Sonex.Data.Database;

public sealed class DbClientSessionInfo
{
    public string ApplicationName { get; set; } = string.Empty;
    public string ApplicationVersion { get; set; } = string.Empty;
    public string InstanceId { get; set; } = string.Empty;
    public string? OsVersion { get; set; }
    public string? OsVersionNumber { get; set; }
    public string? OsProductName { get; set; }
    public string? OsDisplayVersion { get; set; }

    public string BuildDatabaseApplicationName()
    {
        var parts = new List<string>(4);

        AddPart(parts, ApplicationName, 20);
        AddPart(parts, ApplicationVersion, 18);
        AddPart(parts, InstanceId, 12);
        AddPart(parts, OsVersion, 18);

        var value = string.Join('|', parts);
        return value.Length <= 63
            ? value
            : value[..63];
    }

    private static void AddPart(List<string> parts, string? value, int maxLength)
    {
        var normalized = Normalize(value, maxLength);
        if (!string.IsNullOrWhiteSpace(normalized))
            parts.Add(normalized);
    }

    private static string Normalize(string? value, int maxLength)
    {
        if (string.IsNullOrWhiteSpace(value))
            return string.Empty;

        var builder = new StringBuilder(value.Length);
        foreach (var ch in value)
        {
            if (ch < 32 || ch > 126 || ch == '|')
                continue;

            builder.Append(ch == ' ' ? '-' : ch);
        }

        var result = builder.ToString();
        return result.Length <= maxLength
            ? result
            : result[..maxLength];
    }
}