using System;
using System.Collections.Generic;
using SteamKit2.Internal;

namespace SteamKit2
{
    /// <summary>
    /// This handler is used for Steam networking sockets
    /// </summary>
    public sealed partial class SteamNetworking : ClientMsgHandler
    {
        private static CallbackMsg? GetCallback( IPacketMsg packetMsg ) => packetMsg.MsgType switch
        {
            EMsg.ClientNetworkingCertRequestResponse => new NetworkingCertificateCallback( packetMsg ),
            _ => null,
        };

        /// <summary>
        /// Request a signed networking certificate from Steam for your Ed25519 public key for the given app id.
        /// Results are returned in a <see cref="NetworkingCertificateCallback"/>.
        /// The returned <see cref="AsyncJob{T}"/> can also be awaited to retrieve the callback result.
        /// </summary>
        /// <param name="appId">The App ID the certificate will be generated for</param>
        /// <param name="publicKey">Your Ed25519 public key</param>
        /// <returns>The Job ID of the request. This can be used to find the appropriate <see cref="NetworkingCertificateCallback"/>.</returns>
        public AsyncJob<NetworkingCertificateCallback> RequestNetworkingCertificate( uint appId, byte[] publicKey )
        {
            ArgumentNullException.ThrowIfNull( publicKey );

            var msg = new ClientMsgProtobuf<CMsgClientNetworkingCertRequest>( EMsg.ClientNetworkingCertRequest );
            msg.SourceJobID = Client.GetNextJobID();

            msg.Body.app_id = appId;
            msg.Body.key_data = publicKey;

            Client.Send( msg );

            return new AsyncJob<NetworkingCertificateCallback>( this.Client, msg.SourceJobID );
        }

        /// <summary>
        /// Handles a client message. This should not be called directly.
        /// </summary>
        /// <param name="packetMsg">The packet message that contains the data.</param>
        public override void HandleMsg( IPacketMsg packetMsg )
        {
            var callback = GetCallback( packetMsg );

            if ( callback == null )
            {
                // ignore messages that we don't have a handler function for
                return;
            }

            this.Client.PostCallback( callback );
        }
    }
}
