Add initial project structure with CMake configuration, source files, and README documentation for Unitree GO2 Custom Controller

include/mqtt.hpp

@@ -0,0 +1,97 @@
+#pragma once
+
+#include <string>
+#include <functional>
+#include <memory>
+#include <thread>
+#include <atomic>
+#include <queue>
+#include <mutex>
+#include <condition_variable>
+#include <nlohmann/json.hpp>
+#include <mqtt/async_client.h>
+
+namespace custom {
+
+class MqttClient {
+public:
+    using MessageCallback = std::function<void(const std::string& topic, const std::string& payload)>;
+    using ConnectionCallback = std::function<void(bool connected)>;
+
+    MqttClient(const std::string& broker, int port, const std::string& clientId);
+    ~MqttClient();
+
+    bool connect(const std::string& username = "", const std::string& password = "");
+    void disconnect();
+    bool isConnected() const;
+
+    bool subscribe(const std::string& topic, int qos = 1);
+    bool unsubscribe(const std::string& topic);
+    
+    bool publish(const std::string& topic, const std::string& payload, int qos = 1, bool retain = false);
+    bool publishJson(const std::string& topic, const nlohmann::json& json, int qos = 1, bool retain = false);
+
+    void setMessageCallback(MessageCallback callback);
+    void setConnectionCallback(ConnectionCallback callback);
+
+    // Message queue for async processing
+    void startMessageProcessor();
+    void stopMessageProcessor();
+
+private:
+    class Callback : public virtual mqtt::callback,
+                     public virtual mqtt::iaction_listener {
+    public:
+        Callback(MqttClient* client) : client_(client) {}
+
+        void connected(const std::string& cause) override;
+        void connection_lost(const std::string& cause) override;
+        void message_arrived(mqtt::const_message_ptr msg) override;
+        void delivery_complete(mqtt::delivery_token_ptr token) override;
+
+        void on_failure(const mqtt::token& tok) override;
+        void on_success(const mqtt::token& tok) override;
+
+    private:
+        MqttClient* client_;
+    };
+
+    struct QueuedMessage {
+        std::string topic;
+        std::string payload;
+    };
+
+    void processMessageQueue();
+    void handleConnectionLost();
+    void handleConnectionEstablished();
+
+    std::unique_ptr<mqtt::async_client> client_;
+    std::unique_ptr<Callback> callback_;
+    
+    MessageCallback messageCallback_;
+    ConnectionCallback connectionCallback_;
+    
+    std::atomic<bool> connected_;
+    std::atomic<bool> reconnecting_;
+    
+    // Message processing
+    std::queue<QueuedMessage> messageQueue_;
+    std::mutex queueMutex_;
+    std::condition_variable queueCondition_;
+    std::thread messageProcessor_;
+    std::atomic<bool> processorRunning_;
+    
+    // Connection parameters
+    std::string broker_;
+    int port_;
+    std::string clientId_;
+    std::string username_;
+    std::string password_;
+    
+    // Reconnection
+    std::thread reconnectThread_;
+    std::atomic<bool> shouldReconnect_;
+    int reconnectDelay_ = 5; // seconds
+};
+
+} // namespace custom