Packet.h

#pragma once
 
#include <memory>
#include <string>
 
#include "ll/api/base/Macro.h"
#include "ll/api/network/packet/PacketRegistrar.h"
#include "ll/api/reflection/TypeName.h"
#include "mc/common/SubClientId.h"
#include "mc/deps/raknet/PacketPriority.h"
#include "mc/network/Compressibility.h"
#include "mc/network/NetworkPeer.h"
#include "mc/platform/Result.h"
 
class BinaryStream;
class IPacketHandlerDispatcher;
class ReadOnlyBinaryStream;
class NetworkIdentifier;
class NetEventCallback;
class UserEntityIdentifierComponent;
struct NetworkIdentifierWithSubId;
 
namespace ll::network {
 
class IPacketHandler;
class PacketRegistrar;
 
class Packet {
public:
    PacketPriority           mPriority;
    NetworkPeer::Reliability mReliability;
    SubClientId              mSenderSubId;
    Compressibility          mCompressible;
 
    [[nodiscard]] constexpr explicit Packet(
        PacketPriority           priority    = PacketPriority::MediumPriority,
        NetworkPeer::Reliability reliability = NetworkPeer::Reliability::ReliableOrdered,
        SubClientId              clientSubId = SubClientId::PrimaryClient,
        bool                     compress    = true
    )
    : mPriority(priority),
      mReliability(reliability),
      mSenderSubId(clientSubId),
      mCompressible(compress ? Compressibility::Compressible : Compressibility::Incompressible) {}
 
    virtual ~Packet() = default;
 
    virtual void                                  write(::BinaryStream&) const  = 0;
    [[nodiscard]] virtual ::Bedrock::Result<void> read(::ReadOnlyBinaryStream&) = 0;
    [[nodiscard]] virtual ::std::string_view      getName() const               = 0;
 
    [[nodiscard]] virtual PacketRuntimeId getRuntimeId() const;
 
    LLAPI void sendToServer() const;
    LLAPI void sendToClient(::NetworkIdentifier const& identifier, ::SubClientId clientId) const;
    LLAPI void sendToClient(::UserEntityIdentifierComponent const*);
    LLAPI void sendToClients(::std::vector<::NetworkIdentifierWithSubId> const&);
    LLAPI void sendBroadcast();
    LLAPI void sendBroadcast(::NetworkIdentifier const&, ::SubClientId);
};
 
class IPacketHandler {
public:
    virtual ~IPacketHandler() = default;
    virtual void
    handle(const NetworkIdentifier& netId, NetEventCallback& callback, const ll::network::Packet& packet) const = 0;
};
 
namespace detail {
template <bool&>
struct StaticRegistrationAnchor {};
 
template <class Derived>
inline bool packetRegistration = [] {
    PacketRegistrar::getInstance().registerPacket(
        reflection::type_unprefix_name_v<Derived>,
        ll::hash_utils::doHash(reflection::type_unprefix_name_v<Derived>),
        []() -> std::unique_ptr<Packet> { return std::make_unique<Derived>(); }
    );
    return true;
}();
 
template <class Derived, class PacketType>
inline bool packetHandlerRegistration = [] {
    static Derived instance;
    PacketRegistrar::getInstance().registerHandler(
        reflection::type_unprefix_name_v<PacketType>,
        ll::hash_utils::doHash(reflection::type_unprefix_name_v<PacketType>),
        instance
    );
    return true;
}();
} // namespace detail
 
template <class Derived>
class PacketBase
: public Packet,
  private detail::StaticRegistrationAnchor<detail::packetRegistration<Derived>> {
    static bool ensureRegistered() {
        return detail::packetRegistration<Derived>;
    }
 
protected:
    using Packet::Packet;
 
public:
    [[nodiscard]] ::std::string_view getName() const override {
        return reflection::type_unprefix_name_v<Derived>;
    }
    [[nodiscard]] PacketRuntimeId getRuntimeId() const override {
        constexpr PacketRuntimeId runtimeId = ll::hash_utils::doHash(reflection::type_unprefix_name_v<Derived>);
        return runtimeId;
    }
 
    inline static bool sRegistered = ensureRegistered();
};
 
template <class Derived, class PacketType>
class PacketHandlerBase
: public IPacketHandler,
  private detail::StaticRegistrationAnchor<detail::packetHandlerRegistration<Derived, PacketType>> {
    static bool ensureRegistered() {
        return detail::packetHandlerRegistration<Derived, PacketType>;
    }
 
    inline static bool sRegistered = ensureRegistered();
 
public:
    void handle(const NetworkIdentifier& netId, NetEventCallback& callback, const Packet& packet) const final {
        static_cast<const Derived*>(this)->handlePacket(netId, callback, static_cast<const PacketType&>(packet));
    }
};
 
} // namespace ll::network