From 0354ce776b715764383ade31137451f37d749f1d Mon Sep 17 00:00:00 2001
From: Persson-dev <sim16.prib@gmail.com>
Date: Sun, 13 Oct 2024 15:30:57 +0200
Subject: [PATCH] declare packets + commands

---
 include/td/common/DataBuffer.h                |  82 ++++-----
 include/td/common/VarInt.h                    |  58 +++++++
 include/td/misc/Format.h                      |  38 ++++
 include/td/misc/Log.h                         |  32 ++++
 include/td/protocol/ByteBuffer.h              |  94 ----------
 include/td/protocol/command/CommandData.h     |  18 +-
 include/td/protocol/command/CommandDeclare.h  |   9 +-
 .../td/protocol/command/CommandDispatcher.h   |   5 +-
 include/td/protocol/command/CommandHandler.h  |  33 ----
 include/td/protocol/command/Commands.h        |   3 +
 include/td/protocol/packet/PacketData.h       |  58 +++----
 include/td/protocol/packet/PacketDeclare.h    |  11 +-
 include/td/protocol/packet/PacketDispatcher.h |   5 +-
 include/td/protocol/packet/PacketHandler.h    |  33 ----
 src/main.cpp                                  |   4 +-
 src/td/common/DataBuffer.cpp                  | 162 ++++++++++++++++++
 src/td/common/VarInt.cpp                      |  52 ++++++
 src/td/misc/Log.cpp                           |  37 ++++
 18 files changed, 461 insertions(+), 273 deletions(-)
 create mode 100644 include/td/common/VarInt.h
 create mode 100644 include/td/misc/Format.h
 create mode 100644 include/td/misc/Log.h
 delete mode 100644 include/td/protocol/ByteBuffer.h
 delete mode 100644 include/td/protocol/command/CommandHandler.h
 delete mode 100644 include/td/protocol/packet/PacketHandler.h
 create mode 100644 src/td/common/DataBuffer.cpp
 create mode 100644 src/td/common/VarInt.cpp
 create mode 100644 src/td/misc/Log.cpp

diff --git a/include/td/common/DataBuffer.h b/include/td/common/DataBuffer.h
index b2fcc89..f471ca8 100644
--- a/include/td/common/DataBuffer.h
+++ b/include/td/common/DataBuffer.h
@@ -11,6 +11,7 @@
 #include <cstring>
 #include <string>
 #include <vector>
+#include <td/common/VarInt.h>
 
 namespace td {
 
@@ -65,19 +66,24 @@ class DataBuffer {
 	 * \warning Don't use it for binary data !
 	 * \param str The string to append
 	 */
-	DataBuffer& operator<<(const std::string& str) {
-		std::size_t strlen = str.length() + 1;	// including null character
-		Resize(GetSize() + strlen);
-		std::memcpy(m_Buffer.data() + GetSize() - strlen, str.data(), strlen);
-		return *this;
-	}
+	DataBuffer& operator<<(const std::string& str);
 
 	/**
 	 * \brief Append data to the buffer from another const buffer
 	 * \param data The buffer to append
 	 */
-	DataBuffer& operator<<(const DataBuffer& data) {
-		m_Buffer.insert(m_Buffer.end(), data.begin(), data.end());
+	DataBuffer& operator<<(const DataBuffer& data);
+
+	/**
+	 * \brief Append a vector to the buffer by first writing the size
+	 * \param data The buffer to append
+	 */
+	template <typename T>
+	DataBuffer& operator<<(const std::vector<T>& data) {
+		*this << VarInt {data.size()};
+		for (const auto& element : data) {
+			*this << element;
+		}
 		return *this;
 	}
 
@@ -96,25 +102,28 @@ class DataBuffer {
 	 * \brief Read some data from the buffer and assign to the new buffer
 	 * \param data The buffer to assign
 	 */
-	DataBuffer& operator>>(DataBuffer& data) {
-		data.Resize(GetSize() - m_ReadOffset);
-		std::copy(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset), m_Buffer.end(), data.begin());
-		m_ReadOffset = m_Buffer.size();
-		return *this;
-	}
+	DataBuffer& operator>>(DataBuffer& data);
 
 	/**
 	 * \brief Read a string from the buffer
 	 * \param str The string to assign in the new buffer
 	 * \warning Don't use it for binary data !
 	 */
-	DataBuffer& operator>>(std::string& str) {
-		std::size_t stringSize =
-			strlen(reinterpret_cast<const char*>(m_Buffer.data()) + m_ReadOffset) + 1;	// including null character
-		str.resize(stringSize);
-		std::copy(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset),
-			m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset + stringSize), str.begin());
-		m_ReadOffset += stringSize;
+	DataBuffer& operator>>(std::string& str);
+
+	/**
+	 * \brief Read a vector (size + data) from the buffer 
+	 * \pre The vector is assumed to be empty
+	 */
+	template <typename T>
+	DataBuffer& operator>>(std::vector<T>& data) {
+		VarInt arraySize;
+		*this >> arraySize;
+		for (std::size_t i = 0; i < arraySize.GetValue(); i++) {
+			T newElement;
+			*this >> newElement;
+			data.push_back(newElement);
+		}
 		return *this;
 	}
 
@@ -123,56 +132,35 @@ class DataBuffer {
 	 * \param buffer The buffer to write
 	 * \param amount The amount of data to write
 	 */
-	void WriteSome(const char* buffer, std::size_t amount) {
-		std::size_t end_pos = m_Buffer.size();
-		m_Buffer.resize(m_Buffer.size() + amount);
-		std::memcpy(m_Buffer.data() + end_pos, buffer, amount);
-	}
+	void WriteSome(const char* buffer, std::size_t amount);
 
 	/**
 	 * \brief Write some data to the buffer
 	 * \param buffer The buffer to write
 	 * \param amount The amount of data to write
 	 */
-	void WriteSome(const std::uint8_t* buffer, std::size_t amount) {
-		std::size_t end_pos = m_Buffer.size();
-		m_Buffer.resize(m_Buffer.size() + amount);
-		std::memcpy(m_Buffer.data() + end_pos, buffer, amount);
-	}
+	void WriteSome(const std::uint8_t* buffer, std::size_t amount);
 
 	/**
 	 * \brief Read some data from the buffer
 	 * \param buffer The buffer to Read
 	 * \param amount The amount of data from the buffer
 	 */
-	void ReadSome(char* buffer, std::size_t amount) {
-		assert(m_ReadOffset + amount <= GetSize());
-		std::copy_n(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset), amount, buffer);
-		m_ReadOffset += amount;
-	}
+	void ReadSome(char* buffer, std::size_t amount);
 
 	/**
 	 * \brief Read some data from the buffer
 	 * \param buffer The buffer to Read
 	 * \param amount The amount of data from the buffer
 	 */
-	void ReadSome(std::uint8_t* buffer, std::size_t amount) {
-		assert(m_ReadOffset + amount <= GetSize());
-		std::copy_n(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset), amount, buffer);
-		m_ReadOffset += amount;
-	}
+	void ReadSome(std::uint8_t* buffer, std::size_t amount);
 
 	/**
 	 * \brief Read some data from the buffer
 	 * \param buffer The buffer to Read
 	 * \param amount The amount of data from the buffer
 	 */
-	void ReadSome(DataBuffer& buffer, std::size_t amount) {
-		assert(m_ReadOffset + amount <= GetSize());
-		buffer.Resize(amount);
-		std::copy_n(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset), amount, buffer.begin());
-		m_ReadOffset += amount;
-	}
+	void ReadSome(DataBuffer& buffer, std::size_t amount);
 
 	/**
 	 * \brief Resize the buffer
diff --git a/include/td/common/VarInt.h b/include/td/common/VarInt.h
new file mode 100644
index 0000000..02c33d5
--- /dev/null
+++ b/include/td/common/VarInt.h
@@ -0,0 +1,58 @@
+#pragma once
+
+/**
+ * \file VarInt.h
+ * \brief File containing the blitz::VarInt class
+ */
+
+#include <cstddef>
+#include <cstdint>
+
+namespace td {
+
+class DataBuffer;
+
+/**
+ * \class VarInt
+ * \brief Variable-length format such that smaller numbers use fewer bytes.
+ */
+class VarInt {
+  private:
+	std::uint64_t m_Value;
+
+  public:
+	VarInt() : m_Value(0) {}
+	/**
+	 * \brief Construct a variable integer from a value
+	 * \param value The value of the variable integer
+	 */
+	VarInt(std::uint64_t value) : m_Value(value) {}
+
+	/**
+	 * \brief Get the value of the variable integer
+	 */
+	std::uint64_t GetValue() const {
+		return m_Value;
+	}
+
+	/**
+	 * \brief Get the length of the serialized variable integer
+	 */
+	std::size_t GetSerializedLength() const;
+
+	/**
+	 * \brief Serialize the variable integer
+	 * \param out The buffer to write the serialized variable integer to
+	 * \param var The variable integer to serialize
+	 */
+	friend DataBuffer& operator<<(DataBuffer& out, const VarInt& var);
+
+	/**
+	 * \brief Deserialize the variable integer
+	 * \param in The buffer to read the serialized variable integer from
+	 * \param var The variable integer to deserialize
+	 */
+	friend DataBuffer& operator>>(DataBuffer& in, VarInt& var);
+};
+
+}  // namespace td
diff --git a/include/td/misc/Format.h b/include/td/misc/Format.h
new file mode 100644
index 0000000..b407a38
--- /dev/null
+++ b/include/td/misc/Format.h
@@ -0,0 +1,38 @@
+#pragma once
+
+/**
+ * \file Format.h
+ * \brief This file contains the definition of the `Format` function.
+ */
+
+#include <memory>
+#include <stdexcept>
+#include <string>
+
+namespace td {
+namespace utils {
+
+/**
+ * \brief Formats a string using a format string and variadic arguments.
+ *
+ * This function takes a format string and a variable number of arguments and returns a formatted string.
+ * The format string can contain placeholders that will be replaced by the corresponding arguments.
+ *
+ * \param format The format string.
+ * \param args The variadic arguments to be formatted.
+ * \return The formatted string.
+ * \throws std::runtime_error if an error occurs during formatting.
+ */
+template <typename... Args>
+std::string Format(const std::string& format, Args... args) {
+	int size = snprintf(nullptr, 0, format.c_str(), args...) + 1;  // Extra space for '\0'
+	if (size <= 0) {
+		throw std::runtime_error("Error during formatting.");
+	}
+	std::unique_ptr<char[]> buf(new char[size]);
+	snprintf(buf.get(), static_cast<std::size_t>(size), format.c_str(), args...);
+	return std::string(buf.get(), buf.get() + size - 1);  // We don't want the '\0' inside
+}
+
+}  // namespace utils
+}  // namespace td
diff --git a/include/td/misc/Log.h b/include/td/misc/Log.h
new file mode 100644
index 0000000..042aa80
--- /dev/null
+++ b/include/td/misc/Log.h
@@ -0,0 +1,32 @@
+#pragma once
+
+/**
+ * \file Log.h
+ * \brief File defining log functions
+ */
+
+#include <string>
+
+namespace td {
+namespace utils {
+
+/**
+ * \brief Logs a normal message.
+ * \param msg The message to be logged.
+ */
+void LOG(const std::string& msg);
+
+/**
+ * \brief Logs a normal message in debug mode.
+ * \param msg The message to be logged.
+ */
+void LOGD(const std::string& msg);
+
+/**
+ * \brief Logs an error message.
+ * \param err The error message to be logged.
+ */
+void LOGE(const std::string& err);
+
+}  // namespace utils
+}  // namespace td
diff --git a/include/td/protocol/ByteBuffer.h b/include/td/protocol/ByteBuffer.h
deleted file mode 100644
index 076843c..0000000
--- a/include/td/protocol/ByteBuffer.h
+++ /dev/null
@@ -1,94 +0,0 @@
-#pragma once
-
-#include <godot_cpp/variant/packed_byte_array.hpp>
-#include <godot_cpp/variant/string.hpp>
-#include <stdexcept>
-#include <vector>
-
-namespace td {
-namespace protocol {
-
-class PlayerInfo;
-
-class ByteBuffer {
-  private:
-	godot::PackedByteArray m_Buffer;
-	std::size_t m_ReadOffset;
-
-  public:
-	class ReadError : public std::runtime_error {
-	  public:
-		ReadError(const std::string& msg) : std::runtime_error(msg) {}
-	};
-
-	ByteBuffer(godot::PackedByteArray&& a_Buffer) : m_Buffer(std::move(a_Buffer)), m_ReadOffset(0) {}
-	ByteBuffer() : m_ReadOffset(0) {
-		m_Buffer.resize(0);
-	}
-
-	const godot::PackedByteArray& GetByteArray() const {
-		return m_Buffer;
-	}
-
-	godot::PackedByteArray& GetByteArray() {
-		return m_Buffer;
-	}
-
-	// Integers
-	ByteBuffer& operator<<(int8_t a_Data);
-	ByteBuffer& operator>>(int8_t& a_Data);
-	ByteBuffer& operator<<(uint8_t a_Data);
-	ByteBuffer& operator>>(uint8_t& a_Data);
-
-	ByteBuffer& operator<<(int16_t a_Data);
-	ByteBuffer& operator>>(int16_t& a_Data);
-	ByteBuffer& operator<<(uint16_t a_Data);
-	ByteBuffer& operator>>(uint16_t& a_Data);
-
-	ByteBuffer& operator<<(int32_t a_Data);
-	ByteBuffer& operator>>(int32_t& a_Data);
-	ByteBuffer& operator<<(uint32_t a_Data);
-	ByteBuffer& operator>>(uint32_t& a_Data);
-
-	ByteBuffer& operator<<(int64_t a_Data);
-	ByteBuffer& operator>>(int64_t& a_Data);
-	ByteBuffer& operator<<(uint64_t a_Data);
-	ByteBuffer& operator>>(uint64_t& a_Data);
-
-	ByteBuffer& operator<<(float a_Data);
-	ByteBuffer& operator>>(float& a_Data);
-	ByteBuffer& operator<<(double a_Data);
-	ByteBuffer& operator>>(double& a_Data);
-
-	ByteBuffer& operator<<(const godot::String& a_Data);
-	ByteBuffer& operator>>(godot::String& a_Data);
-
-	ByteBuffer& operator<<(const godot::Vector3& a_Data);
-	ByteBuffer& operator>>(godot::Vector3& a_Data);
-
-	template <typename T>
-	ByteBuffer& operator<<(const std::vector<T>& a_Data) {
-		*this << static_cast<std::uint32_t>(a_Data.size());
-		for (const T& data : a_Data) {
-			*this << data;
-		}
-		return *this;
-	}
-
-	template <typename T>
-	ByteBuffer& operator>>(std::vector<T>& a_Data) {
-		std::uint32_t arraySize;
-		*this >> arraySize;
-		a_Data.resize(arraySize);
-		for (std::uint32_t i = 0; i < arraySize; i++) {
-			*this >> a_Data[i];
-		}
-		return *this;
-	}
-
-	ByteBuffer& operator<<(const PlayerInfo& a_Data);
-	ByteBuffer& operator>>(PlayerInfo& a_Data);
-};
-
-}  // namespace protocol
-}  // namespace td
diff --git a/include/td/protocol/command/CommandData.h b/include/td/protocol/command/CommandData.h
index f385112..d7c7689 100644
--- a/include/td/protocol/command/CommandData.h
+++ b/include/td/protocol/command/CommandData.h
@@ -2,25 +2,11 @@
 
 #include <string>
 #include <td/Types.h>
+#include <array>
 
 namespace td {
 namespace protocol {
 
-#define LOCKSTEP_BUFFER_SIZE 10
-
-struct LockStepCommand {};
-
-struct LockStep {
-	std::uint8_t m_CommandNumber;
-	std::vector<LockStepCommand> m_Commands;
-};
-
-struct LockSteps {
-	std::uint16_t m_FirstFrameNumber;
-	std::array<LockStep, LOCKSTEP_BUFFER_SIZE> m_LockSteps;
-};
-
-
 namespace cdata {
 
 
@@ -58,6 +44,8 @@ struct PlayerJoin {
 	std::string m_Name;
 };
 
+struct End {};
+
 }  // namespace cdata
 
 
diff --git a/include/td/protocol/command/CommandDeclare.h b/include/td/protocol/command/CommandDeclare.h
index 4cf6fde..76013d7 100644
--- a/include/td/protocol/command/CommandDeclare.h
+++ b/include/td/protocol/command/CommandDeclare.h
@@ -6,15 +6,16 @@ namespace protocol {
 
 /**
  * \def DeclareAllPacket
- * \brief Avoids repetitive operations on packets
+ * \brief Avoids repetitive operations on commands
  */
 #define DeclareAllCommand() \
+	DeclareCommand(End) \
 	DeclareCommand(PlaceTower) \
-	DeclareCommand(UpgradeTower) \
+	DeclareCommand(PlayerJoin) \
 	DeclareCommand(SpawnTroop) \
-	DeclareCommand(UseItem) \
 	DeclareCommand(TeamChange) \
-	DeclareCommand(PlayerJoin)
+	DeclareCommand(UpgradeTower) \
+	DeclareCommand(UseItem)
 
 
 }  // namespace protocol
diff --git a/include/td/protocol/command/CommandDispatcher.h b/include/td/protocol/command/CommandDispatcher.h
index ca3534f..0dc3ef9 100644
--- a/include/td/protocol/command/CommandDispatcher.h
+++ b/include/td/protocol/command/CommandDispatcher.h
@@ -6,13 +6,12 @@
  */
 
 #include <td/protocol/Dispatcher.h>
+#include <td/protocol/command/Commands.h>
 
 namespace td {
 namespace protocol {
 
-class CommandHandler;
-
-using CommandDispatcher = Dispatcher<CommandType, CommandHandler, Command>;
+using CommandDispatcher = Dispatcher<CommandType, CommandVisitor, Command>;
 
 }  // namespace protocol
 }  // namespace td
diff --git a/include/td/protocol/command/CommandHandler.h b/include/td/protocol/command/CommandHandler.h
deleted file mode 100644
index 8d8e09d..0000000
--- a/include/td/protocol/command/CommandHandler.h
+++ /dev/null
@@ -1,33 +0,0 @@
-#pragma once
-
-/**
- * \file CommandHandler.h
- * \brief File containing the td::protocol::CommandHandler class
- */
-
-#include <td/protocol/command/CommandVisitor.h>
-#include <td/protocol/command/Commands.h>
-
-namespace td {
-namespace protocol {
-
-#define DeclareCommand(CommandName, ...)                                                                                              \
-	virtual void Visit(const commands::CommandName&);                                                                                 \
-	virtual void HandleCommand(const commands::CommandName&) {}
-
-/**
- * \class CommandHandler
- * \brief Class used to handle packets
- */
-class CommandHandler : public CommandVisitor {
-  public:
-	CommandHandler() {}
-	~CommandHandler() {}
-
-	DeclareAllCommand()
-};
-
-#undef DeclareCommand
-
-}  // namespace protocol
-}  // namespace td
\ No newline at end of file
diff --git a/include/td/protocol/command/Commands.h b/include/td/protocol/command/Commands.h
index 65495d2..4444d21 100644
--- a/include/td/protocol/command/Commands.h
+++ b/include/td/protocol/command/Commands.h
@@ -9,6 +9,7 @@
 #include <td/common/NonCopyable.h>
 #include <td/protocol/command/CommandData.h>
 #include <td/protocol/command/CommandDeclare.h>
+#include <memory>
 
 namespace td {
 namespace protocol {
@@ -104,5 +105,7 @@ DeclareAllCommand()
 
 }  // namespace commands
 
+using LockStep = std::vector<std::shared_ptr<protocol::Command>>;
+
 }  // namespace protocol
 }  // namespace td
diff --git a/include/td/protocol/packet/PacketData.h b/include/td/protocol/packet/PacketData.h
index 8f86352..fdcfb62 100644
--- a/include/td/protocol/packet/PacketData.h
+++ b/include/td/protocol/packet/PacketData.h
@@ -2,6 +2,10 @@
 
 #include <td/Types.h>
 #include <vector>
+#include <td/protocol/command/Commands.h>
+
+// Make it dynamic ?
+#define LOCKSTEP_BUFFER_SIZE 10
 
 namespace td {
 namespace protocol {
@@ -11,64 +15,60 @@ struct PlayerInfo {
 	std::string m_PlayerName;
 };
 
+struct MapData {
+
+};
+
 namespace pdata {
 
+/** Client attempts to login (very basic) */
 struct PlayerLogin {
 	std::string m_PlayerName;
 };
 
-struct UpdateHealth {
-	float m_NewHealth;
-};
-
+/** Server indicates success */
 struct LoggingSuccess {
 	PlayerID m_PlayerId;
 };
 
-struct PlayerDeath {};
-
+/** Player joins the lobby */
 struct PlayerJoin {
 	PlayerInfo m_Player;
 };
 
+/** Player leaves the lobby */
 struct PlayerLeave {
 	PlayerID m_PlayerId;
 };
 
-struct PlayerStats {};
-
-struct PlayerList {
-	std::vector<PlayerInfo> m_Players;
-};
-
-struct ServerConfig {};
-
-struct ServerTps {};
-
-struct UpdateGameState {};
-
+/** Keep alive */
 struct KeepAlive {
 	std::uint64_t m_KeepAliveId;
 };
 
-struct Disconnect {};
+/** Can be used by both client and server */
+struct Disconnect {
+	std::string m_Reason;
+};
 
+/** Chat message */
 struct ChatMessage {
 	std::string m_Text;
 };
 
-struct PlayerPositionAndRotation {
-	PlayerID m_Player;
-	// godot::Vector3 m_Position;
-	// godot::Vector3 m_Rotation;
-	// godot::Vector3 m_Velocity;
+// TODO: handle players joining in the first second
+
+struct BeginGame {
+	MapData m_Map;
+	std::vector<PlayerInfo> m_BlueTeam;
+	std::vector<PlayerInfo> m_RedTeam;
+	// optional, used for players joining mid game
+	std::vector<LockStep> m_FirstLocksteps;
 };
 
-struct PlayerShoot {
-	PlayerID m_Sender;
-	// godot::Vector3 m_Position;
-	// godot::Vector3 m_Rotation;
-	// godot::Vector3 m_Velocity;
+struct LockSteps {
+	std::uint16_t m_FirstFrameNumber;
+	std::array<LockStep, LOCKSTEP_BUFFER_SIZE> m_LockSteps;
 };
 
 }  // namespace pdata
diff --git a/include/td/protocol/packet/PacketDeclare.h b/include/td/protocol/packet/PacketDeclare.h
index 35adbe4..1354d6d 100644
--- a/include/td/protocol/packet/PacketDeclare.h
+++ b/include/td/protocol/packet/PacketDeclare.h
@@ -34,21 +34,14 @@ enum class PacketSendType {
  */
 #define DeclareAllPacket() \
 	DeclarePacket(ChatMessage, Reliable, Both) \
+	DeclarePacket(BeginGame, Reliable, Server) \
 	DeclarePacket(Disconnect, Reliable, Both) \
 	DeclarePacket(KeepAlive, Reliable, Both)  \
+	DeclarePacket(LockSteps, Unreliable, Both)  \
 	DeclarePacket(LoggingSuccess, Reliable, Server) \
-	DeclarePacket(PlayerDeath, Reliable, Server) \
 	DeclarePacket(PlayerJoin, Reliable, Server) \
 	DeclarePacket(PlayerLeave, Reliable, Server) \
-	DeclarePacket(PlayerList, Reliable, Server) \
 	DeclarePacket(PlayerLogin, Reliable, Client) \
-	DeclarePacket(PlayerPositionAndRotation, Unreliable, Both) \
-	DeclarePacket(PlayerShoot, Reliable, Both) \
-	DeclarePacket(PlayerStats, Reliable, Server) \
-	DeclarePacket(ServerConfig, Reliable, Server) \
-	DeclarePacket(ServerTps, Reliable, Server) \
-	DeclarePacket(UpdateGameState, Reliable, Server) \
-	DeclarePacket(UpdateHealth, Reliable, Client)
 
 
 }  // namespace protocol
diff --git a/include/td/protocol/packet/PacketDispatcher.h b/include/td/protocol/packet/PacketDispatcher.h
index 627e8f4..d0a5d21 100644
--- a/include/td/protocol/packet/PacketDispatcher.h
+++ b/include/td/protocol/packet/PacketDispatcher.h
@@ -6,13 +6,12 @@
  */
 
 #include <td/protocol/Dispatcher.h>
+#include <td/protocol/packet/Packets.h>
 
 namespace td {
 namespace protocol {
 
-class PacketHandler;
-
-using PacketDispatcher = Dispatcher<PacketType, PacketHandler, Packet>;
+using PacketDispatcher = Dispatcher<PacketType, PacketVisitor, Packet>;
 
 }  // namespace protocol
 }  // namespace td
diff --git a/include/td/protocol/packet/PacketHandler.h b/include/td/protocol/packet/PacketHandler.h
deleted file mode 100644
index 8c3b671..0000000
--- a/include/td/protocol/packet/PacketHandler.h
+++ /dev/null
@@ -1,33 +0,0 @@
-#pragma once
-
-/**
- * \file PacketHandler.h
- * \brief File containing the td::protocol::PacketHandler class
- */
-
-#include <td/protocol/packet/PacketVisitor.h>
-#include <td/protocol/packet/Packets.h>
-
-namespace td {
-namespace protocol {
-
-#define DeclarePacket(PacketName, ...)                                                                                                \
-	virtual void Visit(const packets::PacketName&);                                                                                   \
-	virtual void HandlePacket(const packets::PacketName&) {}
-
-/**
- * \class PacketHandler
- * \brief Class used to handle packets
- */
-class PacketHandler : public PacketVisitor {
-  public:
-	PacketHandler() {}
-	~PacketHandler() {}
-
-	DeclareAllPacket()
-};
-
-#undef DeclarePacket
-
-}  // namespace protocol
-}  // namespace td
\ No newline at end of file
diff --git a/src/main.cpp b/src/main.cpp
index c27958c..75637d9 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2,14 +2,12 @@
 // #include <td/protocol/packet/PacketVisitor.h>
 #include <td/protocol/command/CommandDispatcher.h>
 #include <td/protocol/command/CommandFactory.h>
-#include <td/protocol/command/CommandHandler.h>
 #include <td/protocol/command/CommandSerializer.h>
 #include <td/protocol/command/CommandVisitor.h>
+#include <td/game/GameHistory.h>
 
 class Test : public td::protocol::CommandVisitor {};
 
-class Test2 : public td::protocol::CommandHandler {};
-
 int main(int argc, char** argv) {
 	// Test visitor;
 	// td::protocol::packets::ChatMessage chat{{"coucou"}};
diff --git a/src/td/common/DataBuffer.cpp b/src/td/common/DataBuffer.cpp
new file mode 100644
index 0000000..f3e45e3
--- /dev/null
+++ b/src/td/common/DataBuffer.cpp
@@ -0,0 +1,162 @@
+#include <td/common/DataBuffer.h>
+
+#include <fstream>
+#include <iomanip>
+#include <sstream>
+
+#include <td/misc/Format.h>
+#include <td/misc/Log.h>
+
+namespace td {
+
+DataBuffer::DataBuffer() : m_ReadOffset(0) {}
+
+DataBuffer::DataBuffer(const DataBuffer& other) : m_Buffer(other.m_Buffer), m_ReadOffset(other.m_ReadOffset) {}
+
+DataBuffer::DataBuffer(DataBuffer&& other) : m_Buffer(std::move(other.m_Buffer)), m_ReadOffset(std::move(other.m_ReadOffset)) {}
+
+DataBuffer::DataBuffer(const std::string& str) : m_Buffer(str.begin(), str.end()), m_ReadOffset(0) {}
+
+DataBuffer::DataBuffer(const DataBuffer& other, Data::difference_type offset) : m_ReadOffset(0) {
+	m_Buffer.reserve(other.GetSize() - static_cast<std::size_t>(offset));
+	std::copy(other.m_Buffer.begin() + offset, other.m_Buffer.end(), std::back_inserter(m_Buffer));
+}
+
+DataBuffer& DataBuffer::operator<<(const std::string& str) {
+	std::size_t strlen = str.length() + 1;	// including null character
+	Resize(GetSize() + strlen);
+	std::memcpy(m_Buffer.data() + GetSize() - strlen, str.data(), strlen);
+	return *this;
+}
+
+DataBuffer& DataBuffer::operator<<(const DataBuffer& data) {
+	m_Buffer.insert(m_Buffer.end(), data.begin(), data.end());
+	return *this;
+}
+
+DataBuffer& DataBuffer::operator>>(std::string& str) {
+	std::size_t stringSize = strlen(reinterpret_cast<const char*>(m_Buffer.data()) + m_ReadOffset) + 1;	 // including null character
+	str.resize(stringSize);
+	std::copy(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset),
+		m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset + stringSize), str.begin());
+	m_ReadOffset += stringSize;
+	return *this;
+}
+
+DataBuffer& DataBuffer::operator>>(DataBuffer& data) {
+	data.Resize(GetSize() - m_ReadOffset);
+	std::copy(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset), m_Buffer.end(), data.begin());
+	m_ReadOffset = m_Buffer.size();
+	return *this;
+}
+
+void DataBuffer::WriteSome(const char* buffer, std::size_t amount) {
+	std::size_t end_pos = m_Buffer.size();
+	m_Buffer.resize(m_Buffer.size() + amount);
+	std::memcpy(m_Buffer.data() + end_pos, buffer, amount);
+}
+
+void DataBuffer::WriteSome(const std::uint8_t* buffer, std::size_t amount) {
+	std::size_t end_pos = m_Buffer.size();
+	m_Buffer.resize(m_Buffer.size() + amount);
+	std::memcpy(m_Buffer.data() + end_pos, buffer, amount);
+}
+
+void DataBuffer::ReadSome(char* buffer, std::size_t amount) {
+	assert(m_ReadOffset + amount <= GetSize());
+	std::copy_n(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset), amount, buffer);
+	m_ReadOffset += amount;
+}
+
+
+void DataBuffer::ReadSome(std::uint8_t* buffer, std::size_t amount) {
+	assert(m_ReadOffset + amount <= GetSize());
+	std::copy_n(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset), amount, buffer);
+	m_ReadOffset += amount;
+}
+
+
+void DataBuffer::ReadSome(DataBuffer& buffer, std::size_t amount) {
+	assert(m_ReadOffset + amount <= GetSize());
+	buffer.Resize(amount);
+	std::copy_n(m_Buffer.begin() + static_cast<difference_type>(m_ReadOffset), amount, buffer.begin());
+	m_ReadOffset += amount;
+}
+
+
+DataBuffer& DataBuffer::operator=(const DataBuffer& other) {
+	m_Buffer = other.m_Buffer;
+	m_ReadOffset = other.m_ReadOffset;
+	return *this;
+}
+
+DataBuffer& DataBuffer::operator=(DataBuffer&& other) {
+	m_Buffer = std::move(other.m_Buffer);
+	m_ReadOffset = std::move(other.m_ReadOffset);
+	return *this;
+}
+
+void DataBuffer::SetReadOffset(std::size_t pos) {
+	assert(pos <= GetSize());
+	m_ReadOffset = pos;
+}
+
+std::size_t DataBuffer::GetSize() const {
+	return m_Buffer.size();
+}
+
+std::size_t DataBuffer::GetRemaining() const {
+	return m_Buffer.size() - m_ReadOffset;
+}
+
+DataBuffer::iterator DataBuffer::begin() {
+	return m_Buffer.begin();
+}
+
+DataBuffer::iterator DataBuffer::end() {
+	return m_Buffer.end();
+}
+
+DataBuffer::const_iterator DataBuffer::begin() const {
+	return m_Buffer.begin();
+}
+
+DataBuffer::const_iterator DataBuffer::end() const {
+	return m_Buffer.end();
+}
+
+std::ostream& operator<<(std::ostream& os, const DataBuffer& buffer) {
+	for (unsigned char u : buffer)
+		os << std::hex << std::setfill('0') << std::setw(2) << static_cast<int>(u) << " ";
+	os << std::dec;
+	return os;
+}
+
+bool DataBuffer::ReadFile(const std::string& fileName) {
+	try {
+		std::ifstream file(fileName, std::istream::binary);
+		std::ostringstream ss;
+		ss << file.rdbuf();
+		const std::string& s = ss.str();
+		m_Buffer = DataBuffer::Data(s.begin(), s.end());
+		m_ReadOffset = 0;
+	} catch (std::exception& e) {
+		utils::LOGE(utils::Format("[IO] Failed to read file %s ! reason : %s", fileName.c_str(), e.what()));
+		return false;
+	}
+	return m_Buffer.size() > 0;
+}
+
+bool DataBuffer::WriteFile(const std::string& fileName) const {
+	try {
+		std::ofstream file(fileName, std::ostream::binary);
+		file.write(reinterpret_cast<const char*>(m_Buffer.data()), static_cast<std::streamsize>(m_Buffer.size()));
+		file.flush();
+	} catch (std::exception& e) {
+		utils::LOGE(utils::Format("[IO] Failed to read file %s ! reason : %s", fileName.c_str(), e.what()));
+		return false;
+	}
+	return true;
+}
+
+}  // namespace td
diff --git a/src/td/common/VarInt.cpp b/src/td/common/VarInt.cpp
new file mode 100644
index 0000000..b47bb88
--- /dev/null
+++ b/src/td/common/VarInt.cpp
@@ -0,0 +1,52 @@
+#include <td/common/VarInt.h>
+
+#include <td/common/DataBuffer.h>
+#include <stdexcept>
+
+namespace td {
+
+static constexpr int SEGMENT_BITS = 0x7F;
+static constexpr int CONTINUE_BIT = 0x80;
+
+std::size_t VarInt::GetSerializedLength() const {
+	DataBuffer buffer;
+	buffer << *this;
+	return buffer.GetSize();
+}
+
+DataBuffer& operator<<(DataBuffer& out, const VarInt& var) {
+	std::uint64_t value = var.m_Value;
+	while (true) {
+		if ((value & ~static_cast<std::uint64_t>(SEGMENT_BITS)) == 0) {
+			out << static_cast<std::uint8_t>(value);
+			return out;
+		}
+
+		out << static_cast<std::uint8_t>((value & SEGMENT_BITS) | CONTINUE_BIT);
+
+		value >>= 7;
+	}
+}
+
+DataBuffer& operator>>(DataBuffer& in, VarInt& var) {
+	var.m_Value = 0;
+	unsigned int position = 0;
+	std::uint8_t currentByte;
+
+	while (true) {
+		in.ReadSome(&currentByte, 1);
+		var.m_Value |= static_cast<std::uint64_t>(currentByte & SEGMENT_BITS) << position;
+
+		if ((currentByte & CONTINUE_BIT) == 0)
+			break;
+
+		position += 7;
+
+		if (position >= 8 * sizeof(var.m_Value))
+			throw std::runtime_error("VarInt is too big");
+	}
+
+	return in;
+}
+
+}  // namespace td
diff --git a/src/td/misc/Log.cpp b/src/td/misc/Log.cpp
new file mode 100644
index 0000000..db143a4
--- /dev/null
+++ b/src/td/misc/Log.cpp
@@ -0,0 +1,37 @@
+#include <td/misc/Log.h>
+
+
+
+#ifdef TD_ANDROID_LOGGING
+#include <android/log.h>
+#else
+#include <iostream>
+#endif
+
+namespace td {
+namespace utils {
+
+void LOG(const std::string& msg) {
+#ifdef TD_ANDROID_LOGGING
+	__android_log_print(ANDROID_LOG_INFO, "TRACKERS", "%s", msg.c_str());
+#else
+	std::cout << msg << "\n";
+#endif
+}
+
+void LOGD(const std::string& msg) {
+#if !defined(NDEBUG)
+	LOG(msg);
+#endif
+}
+
+void LOGE(const std::string& err) {
+#ifdef TD_ANDROID_LOGGING
+	__android_log_print(ANDROID_LOG_ERROR, "TRACKERS", "%s", err.c_str());
+#else
+	std::cerr << err << "\n";
+#endif
+}
+
+}  // namespace utils
+}  // namespace td