use only one backend and adapt to the new communication structure

avoid empty messages

include/aman/com/Backend.h

@@ -0,0 +1,76 @@
+/*
+ * @brief Defines the backend module to communicate with the backend
+ * @file aman/com/Backend.h
+ * @author Sven Czarnian <devel@svcz.de>
+ * @copyright Copyright 2021 Sven Czarnian
+ * @license This project is published under the GNU General Public License v3 (GPLv3)
+ */
+
+#pragma once
+
+#include <zmq.hpp>
+
+#include <aman/types/Communication.h>
+
+#pragma warning(push, 0)
+#include <protobuf/Communication.pb.h>
+#pragma warning(pop)
+
+namespace aman {
+    /**
+     * @brief Defines the bakcend class which sends and receives aircraft information to and from the backend
+     * @ingroup com
+     */
+    class Backend {
+    private:
+        std::unique_ptr<zmq::socket_t> m_socket;
+
+        Backend() noexcept;
+
+        template <typename T>
+        bool setSocketKey(const std::string& key, T entry) {
+            try {
+                this->m_socket->set(entry, key);
+                return true;
+            }
+            catch (std::exception&) {
+                return false;
+            }
+        }
+
+        std::shared_ptr<aman::AircraftSequence> receiveSequence();
+
+    public:
+        Backend(const Backend&) = delete;
+        Backend(Backend&&) = delete;
+        Backend& operator=(const Backend&) = delete;
+        Backend& operator=(Backend&&) = delete;
+
+        /**
+         * @brief Initializes the aircraft reporter
+         * @param[in] configuration The current AMAM communication configuration
+         * @return True if the initialization is done, else false
+         */
+        bool initialize(const Communication& configuration);
+        /**
+         * @brief Terminates the reporter connection
+         */
+        bool deinitialize();
+        /**
+         * @brief Checks if the reporter is initialized
+         * @return True if it is initialized, else false
+         */
+        bool initialized() const noexcept;
+        /**
+         * @brief Sends a new message to the backend
+         * @param[in] report The new aircraft update
+         * @return Receives the current sequence of the airport
+         */
+        std::shared_ptr<aman::AircraftSequence> update(aman::AircraftUpdate& report);
+        /**
+         * @brief Returns the reporter instance
+         * @return The system-wide instance
+         */
+        static Backend& instance() noexcept;
+    };
+}