/*!
 *
 * Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
 * copyright

 *          THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM,

 *          IN PART OR IN WHOLE,

 *          WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.

 *
 * file    messagehandler.h
 * date    10/26/2019
 * author  Behrouz NematiPour
 *
 */
#pragma once

// Qt
#include <QObject>
#include <QCanBus>
#include <QHash>

// Project
#include "main.h"
#include "guiactions.h"

// Define
#define _MessageHandler MessageHandler::I()

// forward declarations
class unittests;

// namespace
using namespace Gui;
namespace Can {

#define CAN_FRAME_LENGTH            8
#define MAX_PAYLOAD_IN_HEADER_FRAME 3

/*!
 *
 * \brief   The MessageHandler class
 * \details This class is handling the can message by building and striping it.
 *
 * // -- CAN PAYLOAD STRUCTURE --
 *   #0  #1  #2  #3  #4  #5  #6  #7
 * +---+---+---+---+---+---+---+---+--.......--+
 * | A5| MsgId |Len|   Data    |CRC|..padding..|
 * +---+---+---+---+---+---+---+---+--.......--+
 *
 *  Header Frame:
 *  1 - CRC is last after payload
 *  Ex1 - If Len=0 then CRC is #4
 *  Ex2 - If Len=1 then CRC is #5 and payload is #4
 *  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
{
    Q_OBJECT

    // friends
    friend class ::unittests;

    const QHash<GuiActionType ,char> payloadLen {
        {GuiActionType::PowerOff, 0x01},
        {GuiActionType::Check_In, 0x00}
    };

    // constants
    enum Payload_Data   : quint8 {
        ePayload_None   = 0x00,
        ePayload_Sync   = 0xA5,
    };

    enum Frame_Data : quint8 {
        eLenCanFrame        =   8,
        eLenMaxHeaderData   =   3,

        eLenSyncByte        =   1,
        eLenActionId        =   2,
        eLenLength          =   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

    };

    struct Message { // Private Data Class
        quint8        length;
        GuiActionType actionId;
        QByteArray    data;

        bool isComplete() { return data.length() == length; }
        bool isEmpty   () { return data.length() == 0     ; }
    };
    typedef QList<Message> MessageList;
    QHash<Can_Id, MessageList> messages;

    // Singleton
    SINGLETON_DECL(MessageHandler)
public:
        void init();

private:
    void initConnections();
    void checked_in();

    void transmitFrame(MessageHandler::Can_Id vCan_Id, GuiActionType vAction, GuiActionData vData = GuiActionData::NoData);

    bool ignoreChannel(const QCanBusFrame &vFrame);

    // build message to be sent
    QByteArray    buildMessage (GuiActionType vAction , GuiActionData vData);
    void          addSyncByte  (QByteArray   &vPayload);
    void          addActionId  (QByteArray   &vPayload, GuiActionType vAction);
    void          addLegth     (QByteArray   &vPayload, GuiActionType vAction);
    void          addData      (QByteArray   &vPayload, GuiActionData vData);
    void          addCRC       (QByteArray   &vPayload);
    void          addPadding   (QByteArray   &vPayload);

    // CRC tools
    quint8        calcCRC      (const QByteArray &vData);
    bool          checkCRC     (const QByteArray &vData, quint8 vCRC);

    // strip message to its parts
    bool          stripMessage(const QCanBusFrame &vFrame, Message &vMessage);
    bool          hasSyncByte  (QByteArray   &vPayload);
    GuiActionType getActionId  (QByteArray   &vPayload);
    quint8        getLength    (QByteArray   &vPayload);
    QByteArray    getData      (QByteArray   &vPayload, quint8 vLen, bool *ok = nullptr);

    // interpret the data into GUI understandable Actions/Data
    bool          interpretData(const Message &vMessage, GuiActionType &vActionId, GuiActionData &vData);

private slots: // Should be private for thread safety and is connected internally.
    void  onActionTransmit(GuiActionType vAction, GuiActionData vData); // UI => HD/DG
    void  onFrameReceive  (const QCanBusFrame &vFrame                ); // UI <= HD/DG

    void onMainTimerTimeout();

signals:
    void didActionReceive (GuiActionType vAction, GuiActionData vData); // UI <= HD/DG
    void didFrameTransmit (const QCanBusFrame &vFrame                ); // UI => HD/DG
};
}