feat(logging): integrate spdlog for enhanced logging and debugging

- Added spdlog dependency to `CMakeLists.txt`.
- Implemented a centralized `Logger` with file rotation and console output support.
- Added detailed logging across server, client, and game modules for improved traceability.

CMakeLists.txt

@@ -8,6 +8,7 @@ find_package(nlohmann_json REQUIRED)
 find_package(asio REQUIRED)
 find_package(argparse REQUIRED)
 find_package(Slint REQUIRED)
+find_package(spdlog REQUIRED)
 
 # Uno Game Library
 add_library(uno-game-lib
@@ -15,6 +16,7 @@ add_library(uno-game-lib
         src/game/CardTile.cpp
         src/game/Player.cpp
         src/game/GameState.cpp
+        src/common/Logger.cpp
         src/common/Utils.cpp
         src/network/Message.cpp
         src/network/MessageSerializer.cpp
@@ -25,7 +27,8 @@ add_library(uno-game-lib
 target_link_libraries(uno-game-lib PUBLIC nlohmann_json::nlohmann_json)
 target_link_libraries(uno-game-lib PUBLIC asio::asio)
 target_link_libraries(uno-game-lib PUBLIC Slint::Slint)
-target_link_libraries(uno-game-lib PRIVATE argparse::argparse)
+target_link_libraries(uno-game-lib PUBLIC argparse::argparse)
+target_link_libraries(uno-game-lib PUBLIC spdlog::spdlog)
 
 slint_target_sources(uno-game-lib ui/MainWindow.slint)
 

src/client/UnoClient.cpp

@@ -10,11 +10,13 @@
 #include "../network/MessageSerializer.h"
 
 #include <memory>
+#include <spdlog/spdlog.h>
 #include <utility>
 
 namespace UNO::CLIENT {
     void UnoClient::handleNetworkConnected()
     {
+        SPDLOG_INFO("Connected to server, sending JOIN_GAME message");
         NETWORK::JoinGamePayload messagePayload = {this->clientGameState_->getPlayerName()};
         NETWORK::Message message                = {NETWORK::MessageStatus::OK, NETWORK::MessagePayloadType::JOIN_GAME, messagePayload};
         networkClient_->send(NETWORK::MessageSerializer::serialize(message));
@@ -25,11 +27,14 @@ namespace UNO::CLIENT {
 
     void UnoClient::handleNetworkInitGame(const NETWORK::InitGamePayload &payload)
     {
+        SPDLOG_INFO("Initializing game: player ID={}, {} players total", payload.playerId, payload.players.size());
         this->clientGameState_->init(payload.players, payload.discardPile, payload.handCard, payload.currentPlayerIndex, payload.playerId);
     }
 
     void UnoClient::handleNetworkPlayCard(const NETWORK::PlayCardPayload &payload)
     {
+        SPDLOG_DEBUG(
+            "Received PLAY_CARD: color={}, type={}", static_cast<int>(payload.card.getColor()), static_cast<int>(payload.card.getType()));
         if (clientGameState_->getClientGameStage() == GAME::ClientGameStage::ACTIVE) {
             clientGameState_->play(payload.card);
         }
@@ -38,6 +43,7 @@ namespace UNO::CLIENT {
 
     void UnoClient::handleNetworkDrawCard(const NETWORK::DrawCardPayload &payload)
     {
+        SPDLOG_DEBUG("Received DRAW_CARD: {} card(s)", payload.drawCount);
         if (clientGameState_->getClientGameStage() == GAME::ClientGameStage::ACTIVE) {
             clientGameState_->draw(payload.cards);
         }
@@ -46,12 +52,15 @@ namespace UNO::CLIENT {
 
     void UnoClient::handleNetworkEndGame(const NETWORK::EndGamePayload &payload)
     {
+        SPDLOG_INFO("Game ended");
         this->clientGameState_->endGame();
     }
 
     void UnoClient::handleNetworkMessage(const std::string &message)
     {
         auto networkMessage = NETWORK::MessageSerializer::deserialize(message);
+        SPDLOG_DEBUG("Received network message, type: {}", static_cast<int>(networkMessage.getMessagePayloadType()));
+
         if (networkMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::INIT_GAME) {
             this->handleNetworkInitGame(std::get<NETWORK::InitGamePayload>(networkMessage.getMessagePayload()));
         }
@@ -68,6 +77,7 @@ namespace UNO::CLIENT {
         if (networkMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::EMPTY
             || networkMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::JOIN_GAME
             || networkMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::START_GAME) {
+            SPDLOG_ERROR("Invalid message type from server: {}", static_cast<int>(networkMessage.getMessagePayloadType()));
             throw std::invalid_argument("Invalid message type from server");
         }
 
@@ -76,6 +86,7 @@ namespace UNO::CLIENT {
 
     void UnoClient::handlePlayerAction(PlayerAction action)
     {
+        SPDLOG_DEBUG("Handling player action, type: {}", static_cast<int>(action.playerActionType));
         if (action.playerActionType == PlayerActionType::CONNECT) {
             this->handlePlayerConnect(std::get<PlayerConnectPayload>(action.payload));
         }
@@ -93,6 +104,7 @@ namespace UNO::CLIENT {
 
     void UnoClient::handlePlayerConnect(const PlayerConnectPayload &payload)
     {
+        SPDLOG_INFO("Player '{}' connecting to {}:{}", payload.playerName, payload.host, payload.port);
         clientGameState_->setPlayerName(payload.playerName);
         networkClient_->connect(payload.host, payload.port);
     }
@@ -100,6 +112,7 @@ namespace UNO::CLIENT {
 
     void UnoClient::handlePlayerStartGame(PlayerStartGamePayload payload)
     {
+        SPDLOG_INFO("Player requests to start game");
         NETWORK::StartGamePayload messagePayload = {};
         NETWORK::Message message                 = {NETWORK::MessageStatus::OK, NETWORK::MessagePayloadType::START_GAME, messagePayload};
         networkClient_->send(NETWORK::MessageSerializer::serialize(message));
@@ -115,9 +128,12 @@ namespace UNO::CLIENT {
 
         if ((card->getType() == GAME::CardType::WILD || card->getType() == GAME::CardType::WILDDRAWFOUR)
             && card->getColor() != GAME::CardColor::RED) {
+            SPDLOG_ERROR("Invalid wild card played by player: card doesn't have color set");
             throw std::invalid_argument("Invalid card played by player");
         }
 
+        SPDLOG_INFO("Player plays card: color={}, type={}", card->colorToString(), card->typeToString());
+
         NETWORK::PlayCardPayload messagePayload = {
             {(card->getType() != GAME::CardType::WILD && card->getType() != GAME::CardType::WILDDRAWFOUR) ? card->getColor()
                                                                                                           : payload.color,
@@ -128,6 +144,7 @@ namespace UNO::CLIENT {
 
     void UnoClient::handlePlayerDrawCard(PlayerDrawCardPayload payload)
     {
+        SPDLOG_INFO("Player requests to draw card");
         NETWORK::DrawCardPayload messagePayload = {};
         NETWORK::Message message                = {NETWORK::MessageStatus::OK, NETWORK::MessagePayloadType::DRAW_CARD, messagePayload};
         networkClient_->send(NETWORK::MessageSerializer::serialize(message));
@@ -135,6 +152,7 @@ namespace UNO::CLIENT {
 
     UnoClient::UnoClient()
     {
+        SPDLOG_DEBUG("UnoClient initialized");
         clientGameState_ = std::make_shared<GAME::ClientGameState>();
         networkClient_   = std::make_shared<NETWORK::NetworkClient>(
             [this]() { this->handleNetworkConnected(); }, [this](const std::string &message) { this->handleNetworkMessage(message); });
@@ -143,6 +161,7 @@ namespace UNO::CLIENT {
 
     UnoClient::~UnoClient()
     {
+        SPDLOG_DEBUG("UnoClient shutting down");
         networkClient_->stop();
         if (networkThread_.joinable()) {
             networkThread_.join();
@@ -151,6 +170,7 @@ namespace UNO::CLIENT {
 
     void UnoClient::run()
     {
+        SPDLOG_INFO("UnoClient starting");
         networkThread_ = std::thread([this]() { this->networkClient_->run(); });
         gameUI_->run();
     }

src/client/main.cpp

@@ -1,11 +1,18 @@
 #include "UnoClient.h"
 
+#include "../common/Logger.h"
+#include <spdlog/spdlog.h>
 #include <windows.h>
 
 int main()
 {
+    UNO::COMMON::Logger::init("uno-client");
+    SPDLOG_INFO("Starting uno-client application");
+
     UNO::CLIENT::UnoClient client;
     client.run();
+
+    SPDLOG_INFO("uno-client exited");
     return 0;
 }
 

src/common/Logger.cpp

@@ -0,0 +1,42 @@
+/**
+ * @file Logger.cpp
+ */
+#include "Logger.h"
+
+#include <filesystem>
+#include <memory>
+
+#include <spdlog/sinks/rotating_file_sink.h>
+#include <spdlog/sinks/stdout_color_sinks.h>
+#include <spdlog/spdlog.h>
+
+namespace fs = std::filesystem;
+
+namespace UNO::COMMON {
+    void Logger::init(const std::string &app_name, const std::string &log_dir)
+    {
+        fs::path dir{log_dir};
+        if (!fs::exists(dir)) {
+            fs::create_directories(dir);
+        }
+
+        auto logfile = (dir / (app_name + ".log")).string();
+
+        constexpr std::size_t max_file_size = 5 * 1024 * 1024;
+        constexpr std::size_t max_files     = 3;
+
+        auto rotating_sink = std::make_shared<spdlog::sinks::rotating_file_sink_mt>(logfile, max_file_size, max_files);
+        auto console_sink  = std::make_shared<spdlog::sinks::stdout_color_sink_mt>();
+
+        rotating_sink->set_level(spdlog::level::debug);
+        console_sink->set_level(spdlog::level::info);
+
+        std::vector<spdlog::sink_ptr> sinks{rotating_sink, console_sink};
+        auto logger = std::make_shared<spdlog::logger>(app_name, sinks.begin(), sinks.end());
+
+        logger->set_pattern("[%Y-%m-%d %H:%M:%S.%e] [%^%l%$] [%s:%#] [%!] %v");
+
+        spdlog::register_logger(logger);
+        spdlog::set_default_logger(logger);
+    }
+}   // namespace UNO::COMMON

src/common/Logger.h

@@ -0,0 +1,14 @@
+/**
+ * @file Logger.h
+ */
+#pragma once
+
+#include <string>
+
+namespace UNO::COMMON {
+    struct Logger {
+        // Initialize global logging. Safe to call multiple times.
+        // Default log directory aligns with CMake runtime output: <build>/bin/log
+        static void init(const std::string &app_name, const std::string &log_dir = "log");
+    };
+}   // namespace UNO::COMMON

src/game/GameState.cpp

@@ -7,6 +7,7 @@
 #include "GameState.h"
 
 #include <ranges>
+#include <spdlog/spdlog.h>
 #include <stdexcept>
 #include <utility>
 
@@ -141,9 +142,11 @@ namespace UNO::GAME {
         this->self_          = this->players_.begin() + static_cast<int>(selfIndex);
         if (this->self_ == this->currentPlayer_) {
             this->clientGameStage_ = ClientGameStage::ACTIVE;
+            SPDLOG_INFO("Client game initialized: {} players, self index: {}, it's our turn", players.size(), selfIndex);
         }
         else {
             this->clientGameStage_ = ClientGameStage::IDLE;
+            SPDLOG_INFO("Client game initialized: {} players, self index: {}, waiting for turn", players.size(), selfIndex);
         }
     }
 
@@ -179,6 +182,7 @@ namespace UNO::GAME {
 
     void ClientGameState::endGame()
     {
+        SPDLOG_INFO("Client game ended");
         this->clientGameStage_ = ClientGameStage::AFTER_GAME;
         this->player_.clear();
     }
@@ -190,19 +194,25 @@ namespace UNO::GAME {
         long long currentPlayerIndex = this->currentPlayer_ - this->players_.begin();
         this->players_.push_back(std::move(playerState));
         this->currentPlayer_ = this->players_.begin() + currentPlayerIndex;
+        SPDLOG_DEBUG("Player '{}' added to game state, total players: {}", playerState.getName(), this->players_.size());
     }
 
     void ServerGameState::init()
     {
+        SPDLOG_INFO("Initializing server game state");
         while (discardPile_.isEmpty() || discardPile_.getFront().getType() > CardType::NUM9) {
             discardPile_.add(deck_.draw());
         }
+        SPDLOG_DEBUG("Initial discard pile card: color={}, type={}",
+                     discardPile_.getFront().colorToString(),
+                     discardPile_.getFront().typeToString());
 
         for (size_t i = 0; i < 7; i++) {
             for (auto &player : this->players_) {
                 player.draw(1, this->deck_.draw(1));
             }
         }
+        SPDLOG_INFO("Dealt 7 cards to each of {} players", this->players_.size());
 
         this->serverGameStage_ = ServerGameStage::IN_GAME;
     }
@@ -212,6 +222,7 @@ namespace UNO::GAME {
         if (this->drawCount_ == 0) {
             this->drawCount_ = 1;
         }
+        SPDLOG_DEBUG("Player '{}' drawing {} card(s)", this->currentPlayer_->getName(), this->drawCount_);
         auto cards = deck_.draw(this->drawCount_);
         this->currentPlayer_->draw(this->drawCount_, cards);
         this->drawCount_ = 0;
@@ -226,6 +237,7 @@ namespace UNO::GAME {
 
     void ServerGameState::endGame()
     {
+        SPDLOG_INFO("Ending server game, returning to pre-game state");
         this->serverGameStage_ = ServerGameStage::PRE_GAME;
         deck_.clear();
 

src/network/NetworkClient.cpp

@@ -9,47 +9,63 @@
 #include <asio/connect.hpp>
 #include <iostream>
 #include <memory>
+#include <spdlog/spdlog.h>
 #include <utility>
 
 namespace UNO::NETWORK {
     NetworkClient::NetworkClient(std::function<void()> onConnect, std::function<void(std::string)> callback) :
         onConnected_(std::move(onConnect)), callback_(std::move(callback)), workGuard_(asio::make_work_guard(io_context_))
     {
+        SPDLOG_DEBUG("NetworkClient initialized");
     }
 
     void NetworkClient::connect(const std::string &host, uint16_t port)
     {
+        SPDLOG_INFO("Connecting to {}:{}", host, port);
         auto socket   = std::make_shared<asio::ip::tcp::socket>(io_context_);
         auto resolver = std::make_shared<asio::ip::tcp::resolver>(io_context_);
-        resolver->async_resolve(host,
+        resolver->async_resolve(
-                                std::to_string(port),
+            host,
-                                [this, resolver, socket](const asio::error_code &ec, const asio::ip::tcp::resolver::results_type &results) {
+            std::to_string(port),
-                                    if (!ec) {
+            [this, resolver, socket, host, port](const asio::error_code &ec, const asio::ip::tcp::resolver::results_type &results) {
-                                        asio::async_connect(
+                if (!ec) {
-                                            *socket, results, [this, socket](const asio::error_code &ec, const asio::ip::tcp::endpoint &) {
+                    SPDLOG_DEBUG("Resolved host {}:{}", host, port);
-                                                if (!ec) {
+                    asio::async_connect(
-                                                    this->session_ = std::make_shared<Session>(std::move(*socket));
+                        *socket, results, [this, socket, host, port](const asio::error_code &ec, const asio::ip::tcp::endpoint &) {
-                                                    this->session_->start(callback_);
+                            if (!ec) {
-                                                    this->onConnected_();
+                                SPDLOG_INFO("Successfully connected to {}:{}", host, port);
-                                                }
+                                this->session_ = std::make_shared<Session>(std::move(*socket));
-                                            });
+                                this->session_->start(callback_);
-                                    }
+                                this->onConnected_();
-                                });
+                            }
+                            else {
+                                SPDLOG_ERROR("Failed to connect to {}:{}: {}", host, port, ec.message());
+                            }
+                        });
+                }
+                else {
+                    SPDLOG_ERROR("Failed to resolve host {}:{}: {}", host, port, ec.message());
+                }
+            });
     }
 
 
     void NetworkClient::send(const std::string &message)
     {
+        SPDLOG_DEBUG("Queueing message to send, size: {} bytes", message.size());
         asio::post(io_context_, [session = this->session_, message]() { session->send(message); });
     }
 
     void NetworkClient::run()
     {
+        SPDLOG_INFO("NetworkClient starting io_context loop");
         this->io_context_.run();
+        SPDLOG_INFO("NetworkClient io_context loop stopped");
     }
 
     void NetworkClient::stop()
     {
+        SPDLOG_INFO("NetworkClient stopping");
         this->workGuard_.reset();
         this->io_context_.stop();
     }

src/network/NetworkServer.cpp

@@ -6,6 +6,7 @@
  */
 #include "NetworkServer.h"
 
+#include <spdlog/spdlog.h>
 #include <utility>
 
 namespace UNO::NETWORK {
@@ -13,15 +14,20 @@ namespace UNO::NETWORK {
     {
         this->acceptor_.async_accept([this](const asio::error_code &ec, asio::ip::tcp::socket socket) {
             if (!ec) {
+                SPDLOG_INFO("Accepted new connection from {}", socket.remote_endpoint().address().to_string());
                 this->addPlayer(std::move(socket));
                 accept();
             }
+            else {
+                SPDLOG_ERROR("Accept error: {}", ec.message());
+            }
         });
     }
 
     NetworkServer::NetworkServer(uint16_t port, std::function<void(size_t, std::string)> callback) :
         acceptor_(io_context_, asio::ip::tcp::endpoint(asio::ip::tcp::v4(), port)), playerCount(0), callback_(std::move(callback))
     {
+        SPDLOG_INFO("NetworkServer initialized on port {}", port);
         accept();
     }
 
@@ -32,24 +38,30 @@ namespace UNO::NETWORK {
         this->sessions_[playerId] = std::make_shared<Session>(std::move(socket));
         this->sessions_[playerId]->start([this, playerId](std::string message) { this->callback_(playerId, std::move(message)); });
         this->playerCount++;
+        SPDLOG_INFO("Player {} added, total players: {}", playerId, this->playerCount);
     }
 
     void NetworkServer::send(size_t id, const std::string &message)
     {
         std::lock_guard<std::mutex> lock(this->mutex_);
         if (this->sessions_.contains(id) == false) {
+            SPDLOG_ERROR("Failed to send message: Player session {} not found", id);
             throw std::invalid_argument("Player session not found");
         }
+        SPDLOG_DEBUG("Sending message to player {}, size: {} bytes", id, message.size());
         this->sessions_[id]->send(message);
     }
 
     void NetworkServer::run()
     {
+        SPDLOG_INFO("NetworkServer starting io_context loop");
         this->io_context_.run();
+        SPDLOG_INFO("NetworkServer io_context loop stopped");
     }
 
     void NetworkServer::stop()
     {
+        SPDLOG_INFO("NetworkServer stopping");
         this->acceptor_.close();
         this->io_context_.stop();
     }

src/network/Session.cpp

@@ -6,11 +6,17 @@
  */
 #include "Session.h"
 
+#include <spdlog/spdlog.h>
+
 namespace UNO::NETWORK {
-    Session::Session(asio::ip::tcp::socket socket) : socket_(std::move(socket)) {}
+    Session::Session(asio::ip::tcp::socket socket) : socket_(std::move(socket))
+    {
+        SPDLOG_DEBUG("Session created");
+    }
 
     void Session::start(std::function<void(std::string)> callback)
     {
+        SPDLOG_DEBUG("Session started");
         this->callback_ = std::move(callback);
         this->doRead();
     }
@@ -19,6 +25,7 @@ namespace UNO::NETWORK {
     {
         bool writeInProgress = !this->messages_.empty();
         messages_.push(message);
+        SPDLOG_DEBUG("Message queued for sending, size: {} bytes, queue size: {}", message.size(), messages_.size());
         if (writeInProgress == false) {
             this->doWrite();
         }
@@ -31,13 +38,18 @@ namespace UNO::NETWORK {
                          asio::buffer(messageLength.get(), sizeof(size_t)),
                          [this, self = shared_from_this(), messageLength](const asio::error_code &ec, size_t length) {
                              if (!ec) {
+                                 SPDLOG_TRACE("Read message header, length: {} bytes", *messageLength);
                                  if (*messageLength <= 10 * 1024 * 1024) {
                                      this->doReadBody(*messageLength);
                                  }
                                  else {
+                                     SPDLOG_WARN("Message length {} exceeds limit, skipping", *messageLength);
                                      doRead();
                                  }
                              }
+                             else {
+                                 SPDLOG_DEBUG("Session read error: {}", ec.message());
+                             }
                          });
     }
 
@@ -45,12 +57,16 @@ namespace UNO::NETWORK {
     {
         auto buffer = std::make_shared<std::vector<char>>(length);
         asio::async_read(
-            socket_, asio::buffer(*buffer), [this, self = shared_from_this(), buffer](const asio::error_code &ec, size_t length) {
+            socket_, asio::buffer(*buffer), [this, self = shared_from_this(), buffer, length](const asio::error_code &ec, size_t) {
                 if (!ec) {
                     std::string message = {buffer->begin(), buffer->end()};
+                    SPDLOG_TRACE("Received message body, size: {} bytes", length);
                     this->callback_(message);
                     doRead();
                 }
+                else {
+                    SPDLOG_DEBUG("Session read body error: {}", ec.message());
+                }
             });
     }
 
@@ -62,10 +78,17 @@ namespace UNO::NETWORK {
         auto length = std::make_shared<size_t>(message.size());
         auto msg    = std::make_shared<std::string>(message);
 
+        SPDLOG_TRACE("Sending message, size: {} bytes", *length);
         std::array<asio::const_buffer, 2> buffers = {asio::buffer(length.get(), sizeof(size_t)), asio::buffer(*msg)};
         asio::async_write(socket_, buffers, [this, self = shared_from_this(), length, msg](const asio::error_code &ec, size_t) {
-            if (!ec && this->messages_.empty() == false) {
+            if (!ec) {
-                this->doWrite();
+                SPDLOG_TRACE("Message sent successfully, size: {} bytes", *length);
+                if (this->messages_.empty() == false) {
+                    this->doWrite();
+                }
+            }
+            else {
+                SPDLOG_ERROR("Session write error: {}", ec.message());
             }
         });
     }

src/server/UnoServer.cpp

@@ -7,12 +7,14 @@
 #include "UnoServer.h"
 
 #include "../network/MessageSerializer.h"
+#include <spdlog/spdlog.h>
 
 namespace UNO::SERVER {
     UnoServer::UnoServer(uint16_t port) :
         networkServer_(port, [this](size_t playerId, const std::string &message) { this->handlePlayerMessage(playerId, message); }),
         playerCount(0)
     {
+        SPDLOG_INFO("UnoServer initialized on port {}", port);
     }
 
     void UnoServer::handlePlayerMessage(size_t playerId, const std::string &message)
@@ -20,6 +22,8 @@ namespace UNO::SERVER {
         auto playerMessage = NETWORK::MessageSerializer::deserialize(message);
 
         if (playerMessage.getMessageStatus() == NETWORK::MessageStatus::OK) {
+            SPDLOG_DEBUG("Processing message from player {}, type: {}", playerId, static_cast<int>(playerMessage.getMessagePayloadType()));
+
             if (playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::JOIN_GAME) {
                 auto playerName = std::get<NETWORK::JoinGamePayload>(playerMessage.getMessagePayload()).playerName;
 
@@ -27,12 +31,15 @@ namespace UNO::SERVER {
                 this->gameIdToNetworkId[this->playerCount] = playerId;
                 this->playerCount++;
                 this->serverGameState_.addPlayer(GAME::ServerPlayerState{playerName, 0, false});
+                SPDLOG_INFO("Player {} joined with name '{}', game ID: {}", playerId, playerName, this->playerCount - 1);
             }
-            if (playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::START_GAME) {
+            else if (playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::START_GAME) {
                 this->isReadyToStart[networkIdToGameId[playerId]] = true;
+                SPDLOG_INFO("Player {} (game ID: {}) is ready to start", playerId, networkIdToGameId[playerId]);
 
                 for (size_t i = 0; i <= this->playerCount; i++) {
                     if (i == this->playerCount) {
+                        SPDLOG_INFO("All {} players ready, starting game", this->playerCount);
                         this->handleStartGame();
                         break;
                     }
@@ -41,25 +48,41 @@ namespace UNO::SERVER {
                     }
                 }
             }
-            if (playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::INIT_GAME
+            else if (playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::INIT_GAME
-                || playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::END_GAME) {
+                     || playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::END_GAME) {
+                SPDLOG_ERROR(
+                    "Invalid message payload type from client {}: {}", playerId, static_cast<int>(playerMessage.getMessagePayloadType()));
                 throw std::invalid_argument("Invalid message payload type from client");
             }
-            if (this->serverGameState_.getServerGameStage() == GAME::ServerGameStage::IN_GAME
+            else if (this->serverGameState_.getServerGameStage() == GAME::ServerGameStage::IN_GAME
-                && this->networkIdToGameId.at(playerId) != this->serverGameState_.getCurrentPlayerId()) {
+                     && this->networkIdToGameId.at(playerId) != this->serverGameState_.getCurrentPlayerId()) {
+                SPDLOG_WARN("Player {} sent message but it's not their turn (current: {})",
+                            this->networkIdToGameId.at(playerId),
+                            this->serverGameState_.getCurrentPlayerId());
                 throw std::invalid_argument("Invalid player message: not this player's turn");
             }
-            if (playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::DRAW_CARD) {
+            else if (playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::DRAW_CARD) {
+                SPDLOG_INFO("Player {} (game ID: {}) draws card", playerId, this->networkIdToGameId.at(playerId));
                 this->handleDrawCard(playerId);
             }
-            if (playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::PLAY_CARD) {
+            else if (playerMessage.getMessagePayloadType() == NETWORK::MessagePayloadType::PLAY_CARD) {
-                this->handlePlayCard(playerId, std::get<NETWORK::PlayCardPayload>(playerMessage.getMessagePayload()).card);
+                auto card = std::get<NETWORK::PlayCardPayload>(playerMessage.getMessagePayload()).card;
+                SPDLOG_INFO("Player {} (game ID: {}) plays card: color={}, type={}",
+                            playerId,
+                            this->networkIdToGameId.at(playerId),
+                            card.colorToString(),
+                            card.typeToString());
+                this->handlePlayCard(playerId, card);
             }
         }
+        else {
+            SPDLOG_ERROR("Received message with error status from player {}", playerId);
+        }
     }
 
     void UnoServer::handleStartGame()
     {
+        SPDLOG_INFO("Initializing game state");
         serverGameState_.init();
         std::vector<GAME::ClientPlayerState> players;
         players.reserve(serverGameState_.getPlayers().size());
@@ -67,18 +90,23 @@ namespace UNO::SERVER {
             players.emplace_back(player.getName(), player.getRemainingCardCount(), player.getIsUno());
         }
         size_t currentPlayerIndex = serverGameState_.getCurrentPlayerId();
+        SPDLOG_INFO("Game started, current player index: {}", currentPlayerIndex);
+
         for (size_t i = 0; i < playerCount; i++) {
             NETWORK::InitGamePayload payload = {
                 i, players, serverGameState_.getDiscardPile(), serverGameState_.getPlayers()[i].getCards(), currentPlayerIndex};
             this->networkServer_.send(
                 gameIdToNetworkId.at(i),
                 NETWORK::MessageSerializer::serialize({NETWORK::MessageStatus::OK, NETWORK::MessagePayloadType::INIT_GAME, payload}));
+            SPDLOG_DEBUG("Sent INIT_GAME to player {}", i);
         }
     }
 
     void UnoServer::handleDrawCard(size_t playerId)
     {
         auto cards = this->serverGameState_.updateStateByDraw();
+        SPDLOG_INFO("Player {} drew {} card(s)", this->networkIdToGameId.at(playerId), cards.size());
+
         for (size_t i = 0; i < playerCount; i++) {
             auto networkId = gameIdToNetworkId.at(i);
             NETWORK::DrawCardPayload payload;
@@ -103,6 +131,7 @@ namespace UNO::SERVER {
         for (const auto &player : this->serverGameState_.getPlayers()) {
             if (player.isEmpty()) {
                 gameEnded = true;
+                SPDLOG_INFO("Player '{}' wins the game!", player.getName());
                 break;
             }
         }
@@ -120,6 +149,7 @@ namespace UNO::SERVER {
 
     void UnoServer::handleEndGame()
     {
+        SPDLOG_INFO("Game ended, resetting to pre-game state");
         this->serverGameState_.endGame();
 
         NETWORK::EndGamePayload payload{};
@@ -136,6 +166,7 @@ namespace UNO::SERVER {
 
     void UnoServer::run()
     {
+        SPDLOG_INFO("UnoServer starting");
         this->networkServer_.run();
     }
 

src/server/main.cpp

@@ -4,11 +4,16 @@
  * @author Yuzhe Guo
  * @date 2025.12.01
  */
+#include "../common/Logger.h"
 #include <argparse/argparse.hpp>
+#include <spdlog/spdlog.h>
 
 #include "UnoServer.h"
 int main(int argc, char *argv[])
 {
+    UNO::COMMON::Logger::init("uno-server");
+    SPDLOG_INFO("Starting uno-server");
+
     argparse::ArgumentParser parser("Uno Server", "0.1.0");
 
     parser.add_argument("-p", "--port").help("server port").default_value(static_cast<uint16_t>(10001)).scan<'i', uint16_t>();
@@ -17,17 +22,18 @@ int main(int argc, char *argv[])
         parser.parse_args(argc, argv);
     }
     catch (const std::exception &e) {
-        std::cerr << e.what() << std::endl;
+        SPDLOG_ERROR("Argument parsing failed: {}", e.what());
-        std::cerr << parser;
         return 1;
     }
 
     try {
-        UNO::SERVER::UnoServer uno_server(parser.get<uint16_t>("--port"));
+        auto port = parser.get<uint16_t>("--port");
+        SPDLOG_INFO("Launching server on port {}", port);
+        UNO::SERVER::UnoServer uno_server(port);
         uno_server.run();
     }
     catch (const std::exception &e) {
-        std::cerr << e.what() << std::endl;
+        SPDLOG_ERROR("Server crashed with exception: {}", e.what());
         return 1;
     }
 

src/ui/GameUI.cpp

@@ -49,7 +49,7 @@ namespace UNO::UI {
         for (auto color : GAME::AllColors) {
             for (auto type : GAME::AllTypes) {
                 this->images_[{color, type}] =
-                    slint::Image::load_from_path(std::format("../assets/cards/{}.svg", GAME::Card{color, type}.toString()).data());
+                    slint::Image::load_from_path(std::format("assets/cards/{}.svg", GAME::Card{color, type}.toString()).data());
             }
         }
     }