namespace Supercell.Laser.Server.Networking
{
    using System;
    using System.IO;
    using System.Text;

    // Opt-in packet capture for comparing the C# wire format with the Zig
    // implementation. Enable with BS_WIRE_DUMP=1.
    internal static class WireDump
    {
        private static readonly object Sync = new object();
        private static readonly string Path = Environment.GetEnvironmentVariable("BS_WIRE_DUMP_PATH")
            ?? "/tmp/bsav36-csharp-wire.log";

        public static void Write(string direction, byte[] data, int offset, int length)
        {
            if (Environment.GetEnvironmentVariable("BS_WIRE_DUMP") != "1") return;
            if (data == null || offset < 0 || length < 0 || offset + length > data.Length) return;
            var hex = new StringBuilder(length * 2);
            for (int i = offset; i < offset + length; i++) hex.Append(data[i].ToString("X2"));
            lock (Sync)
            {
                File.AppendAllText(Path,
                    $"{DateTime.UtcNow:O} {direction} len={length} hex={hex}\n",
                    Encoding.ASCII);
            }
        }
    }
}