using ProtoBuf;
using Serilog;

namespace ClientTester.Packet
{
    // 패킷 헤더 크기 4(패킷 타입, 패킷 길이)

    public static class PacketSerializer
    {
        // 직렬화: 객체 → byte[] (size는 payload 크기로 자동 계산)
        public static byte[] Serialize<T>(ushort type, T packet)
        {
            using MemoryStream payloadMs = new MemoryStream();
            Serializer.Serialize(payloadMs, packet);
            byte[] payload = payloadMs.ToArray();
            ushort size = (ushort)payload.Length;

            byte[] result = new byte[4 + payload.Length];
            result[0] = (byte)(type & 0xFF);
            result[1] = (byte)(type >> 8);
            result[2] = (byte)(size & 0xFF);
            result[3] = (byte)(size >> 8);
            Buffer.BlockCopy(payload, 0, result, 4, payload.Length);
            return result;
        }

        // 역직렬화: byte[] → (PacketType, payload bytes)
        public static (ushort type, ushort size, byte[] payload) Deserialize(byte[] data)
        {
            if (data.Length < 4)
            {
                Log.Warning("[PacketHeader]의 길이가 4이하입니다.");
                return (0, 0, null)!;
            }

            ushort type = (ushort)(data[0] | (data[1] << 8));
            ushort size = (ushort)(data[2] | (data[3] << 8));

            int actualPayloadLen = data.Length - 4;
            if (size > actualPayloadLen)
            {
                Log.Warning("[PacketSerializer] 페이로드 크기 불일치 HeaderSize={Size} ActualSize={Actual}", size, actualPayloadLen);
                return (0, 0, null)!;
            }

            byte[] payload = new byte[size];
            Buffer.BlockCopy(data, 4, payload, 0, size);
            return (type, size, payload);
        }

        // 페이로드 → 특정 타입으로 역직렬화
        public static T DeserializePayload<T>(byte[] payload)
        {
            using MemoryStream ms = new MemoryStream(payload);
            return Serializer.Deserialize<T>(ms);
        }
    }
}