using System.Buffers.Binary;

namespace AcDream.Core.Net.Messages;

/// <summary>
/// Outbound <c>0x00C8 IdentifyObject / Appraise</c> GameAction.
///
/// <para>
/// Wire shape (inside the <c>0xF7B1</c> envelope):
/// <code>
///   u32 0xF7B1                   // GameMessage opcode (GameAction envelope)
///   u32 gameActionSequence       // client-tracked sequence
///   u32 0x00C8                   // GameAction sub-opcode
///   u32 targetGuid               // whose appraisal we're requesting
/// </code>
/// </para>
///
/// <para>
/// Server replies with a <c>0xF7B0 / 0x00C9 IdentifyObjectResponse</c>
/// containing the full <c>AppraiseInfo</c> property bundle. See
/// <c>GameEvents.cs</c> for the matching parser (once wired).
/// </para>
/// </summary>
public static class AppraiseRequest
{
    public const uint GameActionEnvelope = 0xF7B1u;
    public const uint SubOpcode = 0x00C8u;

    /// <summary>
    /// Pack an AppraiseRequest body (with envelope) ready to be handed
    /// to <c>WorldSession.SendGameAction</c>.
    /// </summary>
    public static byte[] Build(uint gameActionSequence, uint targetGuid)
    {
        byte[] body = new byte[16];
        BinaryPrimitives.WriteUInt32LittleEndian(body,            GameActionEnvelope);
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(4),  gameActionSequence);
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(8),  SubOpcode);
        BinaryPrimitives.WriteUInt32LittleEndian(body.AsSpan(12), targetGuid);
        return body;
    }
}