Index: sources/canbus/messagehandler.h
===================================================================
diff -u -rf623529d6ec25b555f3ac2248d71fc2b5e7063d6 -rd6c7d6c382fe56e19d132f6ba0bcbbc1e6b2060f
--- sources/canbus/messagehandler.h	(.../messagehandler.h)	(revision f623529d6ec25b555f3ac2248d71fc2b5e7063d6)
+++ sources/canbus/messagehandler.h	(.../messagehandler.h)	(revision d6c7d6c382fe56e19d132f6ba0bcbbc1e6b2060f)
@@ -20,6 +20,7 @@
 // Qt
 #include <QObject>
 #include <QCanBus>
+#include <QHash>
 
 // Project
 #include "main.h"
@@ -35,8 +36,27 @@
 using namespace Gui;
 namespace Can {
 
+#define CAN_FRAME_LENGTH            8
+#define MAX_PAYLOAD_IN_HEADER_FRAME 3
+
 /*!
- * \brief The MessageHandler class
+ *
+ * \brief   The MessageHandler class
+ * \details This class is handling the can message by building and striping it.
+ * // -- CAN MESSAGE STRUCTURE --
+ *   #1  #2  #3  #4  #5  #6  #7  #8
+ * +---+---+---+---+---+---+---+---+...........+
+ * | A5| MsgId |Len|  Payload  |CRC|..padding..|
+ * +---+---+---+---+---+---+---+---+...........+
+ *  Header Frame:
+ *  1 - CRC is last after payload
+ *  Ex1 - If Len=0 then CRC is #5
+ *  Ex2 - If Len=1 then CRC is #6 and payload is #5
+ *  2 - If CRC is not the last by in the frame
+ *  then there is padding 0x00 to make the frame 8 byte fix
+ *  Tail Frame:
+ *  3 - Partial frames only have Payload and CRC ( and padded)
+ *
  */
 class MessageHandler : public QObject
 {
@@ -45,33 +65,116 @@
     // friends
     friend class ::unittests;
 
+    struct Message {
+        quInt8          length;
+        GuiActionType   actionId;
+        QByteArray      data;
+        bool isFull() {
+            return length == data.length();
+        }
+    };
+
+    typedef QList<Message> MessageList;
+    QHash<Can_Id, MessageList> messages;
+
+    const QMap<GuiActions::GuiActionsType_Enum ,char> payloadLen {
+        {GuiActions::PowerOff, 0x01},
+        {GuiActions::Check_In, 0x00}
+    };
+
     // constants
-    enum payload_info {
-        ePayload_Sync = 0xA5,
+    enum Payload_Data   : quint8 {
+        ePayload_None   = 0x00,
+        ePayload_Sync   = 0xA5,
     };
 
-    enum can_id {
-        eChlid_HD = 0x020,
-        eChlid_UI = 0x100,
+    enum Frame_Data : quint8 {
+        eCanFrameLen    =   8,
+        eMaxHeaderData  =   3,
+
+        eLenSync        =   1,
+        eLenActionId    =   2,
+        eLenPayload     =   1,
+        eLenChecksum    =   1,
+
     };
 
+    enum Can_Id : quint16 {
+        // Broadcasts
+        //// Alarm
+        eChlid_HD_Alarm = 0x001, ///< HD alarm broadcast
+        eChlid_DG_Alarm = 0x002, ///< DG alarm broadcast
+        eChlid_UI_Alarm = 0x004, ///< UI alarm broadcast [Out]
+        //// Sync
+        eChlid_HD_Sync  = 0x040, ///< HD sync  broadcast
+        eChlid_DG_Sync  = 0x080, ///< DG sync  broadcast
+        eChlid_UI_Sync  = 0x200, ///< UI sync  broadcast [Out]
+
+        // UI not listening
+        eChlid_HD_DG    = 0x008, ///< HD => DG
+        eChlid_DG_HD    = 0x010, ///< DG => HD
+
+        // UI is  listening
+        eChlid_HD       = 0x020, ///< HD => UI
+        eChlid_UI       = 0x100, ///< UI => HD [Out]
+
+        // UI lessens occasionally
+        eChlid_DG_UI    = eChlid_DG_Alarm, ///< No direct channel has been defined between DG&UI, May be required for logging
+        eChlid_UI_DG    = eChlid_UI_Sync , ///< No direct channel has been defined between DG&UI, May be required for logging
+
+
+
+    };
+
     // Singleton
     SINGLETON_DECL(MessageHandler)
 public:
     void init();
 
 private:
     void connection();
+    void checked_in(); // TODO : needs to be renamed and called from the main timer to tell HD, UI is alive
 
+    // build message to be sent
+    QByteArray buildMessage (GuiActionType vAction  , GuiActionData vData  = GuiActionData::NoData);
+    void       addSyncByte  ( QByteArray  &vPayload );
+    void       addActionId  ( QByteArray  &vPayload , GuiActionType vAction);
+    void       addLegth     ( QByteArray  &vPayload , GuiActionType vAction);
+    void       addPayload   ( QByteArray  &vPayload , GuiActionData vData  = GuiActionData::NoData);
+    void       addChecksum  ( QByteArray  &vPayload );
+    void       addPadding   ( QByteArray  &vPayload );
+
+    quint8     checksum     ( QByteArray  &vBytes );
+
+    // strip message to its parts
+    QByteArray    stripMessage ( const QCanBusFrame &vFrame );
+    bool          hasSyncByte  ( QByteArray  &vPayload );
+    GuiActionType getActionId  ( QByteArray  &vPayload );
+    quint8        getLength    ( QByteArray  &vPayload );
+    QByteArray    getPayload   ( QByteArray  &vPayload );
+    bool          getChecksum  ( QByteArray  &vPayload );
+
+    // 0  - command definition
+    // 0.0- Can ID
+    // 0.1- command id
+    // 0.2- command payload length
+
+    // 1 - create, frame, schedule, send
+
+
+    // 2 - read, categorize, buffer, act
+
 private slots: // Should be private for thread safety and is connected internally.
     void onActionRequest (GuiActionType vAction);                      // UI => HD/DG
-    void onActionPerform (GuiActionType vAction, GuiActionInfo vInfo); // UI <= HD/DG
+    void onActionPerform (GuiActionType vAction, GuiActionData vData); // UI <= HD/DG
 
     void onRead          (const QCanBusFrame &vFrame);
 
+protected:
+    virtual void timerEvent(QTimerEvent *event) override;
 
 signals:
-    void didActionConfirm(GuiActionType vAction, GuiActionInfo vInfo); // UI <= HD/DG
+    void didActionConfirm(GuiActionType vAction, GuiActionData vData); // UI <= HD/DG
     void didActionCommand(GuiActionType vAction                     ); // UI <= HD/DG
 
     void didActionRequest(const QCanBusFrame &vFrame                ); // UI => HD/DG