using AcDream.Core.Net.Packets;

namespace AcDream.Core.Net.Messages;

/// <summary>
/// Outbound reply to the server's <c>DddInterrogation</c> game message
/// (0xF7E5). Sent during the post-EnterWorld handshake; without it the
/// server keeps the client in a transitional state and other clients
/// see the character as a stationary purple loading haze.
///
/// <para>
/// Wire layout (see
/// <c>references/holtburger/crates/holtburger-protocol/src/messages/misc/types.rs::DddInterrogationResponseData</c>):
/// </para>
/// <list type="bullet">
///   <item>u32 game-message opcode = 0xF7E6 (<c>DddInterrogationResponse</c>)</item>
///   <item>u32 language = 1 (English)</item>
///   <item>u32 count = 0 (no tagged iteration lists; we acknowledge the
///         interrogation without claiming any dat-list versions). The
///         loop body is then empty.</item>
/// </list>
///
/// <para>
/// Total payload: 12 bytes. Should be sent automatically by
/// <c>WorldSession</c> in response to receiving 0xF7E5.
/// </para>
/// </summary>
public static class DddInterrogationResponse
{
    public const uint Opcode = 0xF7E6u;
    public const uint EnglishLanguage = 1u;

    public static byte[] Build()
    {
        var w = new PacketWriter(16);
        w.WriteUInt32(Opcode);
        w.WriteUInt32(EnglishLanguage);
        w.WriteUInt32(0u);  // empty TaggedIterationList vec
        return w.ToArray();
    }
}