/*
 * SerialCommand.hpp
 *
 * Copyright 2020 Kevin Krüger <kkevin@gmx.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 *
 *
 */

#ifndef _SERIALCOMMAND_H_INCLUDED_
#define _SERIALCOMMAND_H_INCLUDED_

#include <cstdint>
#include <vector>
#include <chrono>
#include <cmath>
#include <ctime>
#include <libnova/julian_day.h>
#include "config.h"

#define MESSAGE_FRAME_SIZE (13)

namespace SerialDeviceControl
{
//After determining the message frame size and structure,
//these commands where found to affect the telescope controller (Handbox + Motors).
//If an invalid command is issued the telescope controller stops reporting its status,
//until another valid command is issued.
//Command IDs which did not stop the report messages are considered effective and are listed below:
enum SerialCommandID
{
    //a null command message.
    NULL_COMMAND_ID = (uint8_t) 0x00,

    //these command IDs move the telescope in certain direction while tracking:
    //move the telescope "east".
    MOVE_EAST_COMMAND_ID  = (uint8_t)0x01,

    //move the telescope "west".
    MOVE_WEST_COMMAND_ID  = (uint8_t)0x02,

    //move the telescope "north".
    MOVE_NORTH_COMMAND_ID = (uint8_t)0x04,

    //move the telescope "south".
    MOVE_SOUTH_COMMAND_ID = (uint8_t)0x08,

    //immediatly stops slewing the telescope.
    STOP_MOTION_COMMAND_ID = (uint8_t)0x1D,

    //slews the telescope back into the park/initial position.
    PARK_COMMAND_ID = (uint8_t)0x1E,

    //Requests the site location geodesic coordinates from the controller.
    GET_SITE_LOCATION_COMMAND_ID = (uint8_t)0x1f,

    //Tell the mount to gracefully disconnect the driver from the serial protocol. Stops the mount from sending status reports.
    DISCONNET_COMMAND_ID = (uint8_t) 0x22,

    //Slews the telescope to the equatorial coordinates provided.
    GOTO_COMMAND_ID = (uint8_t)0x23,

    //Tell the controller to match/align to the delivered coordinates. This updates the scope alignment.
    SYNC_COMMAND_ID = (uint8_t)0x24,

    //sets the site location on the telescope controller.
    SET_SITE_LOCATION_COMMAND_ID = (uint8_t)0x25,

    //sets time and date on the telescope controller.
    SET_DATE_TIME_COMMAND_ID = (uint8_t)0x26,

    //If the GET_SITE_LOCATION message was sent, the controller responds with this message, along side the Geo-Coordinates.
    TELESCOPE_SITE_LOCATION_REPORT_COMMAND_ID = (uint8_t)0xfe,
    
    //This id is used when the telescope is in an untracked state. Found in the C# implementation but apparently not used.
    TELESCOPE_POSITION_REPORT_UNTRACKED_COMMAND_ID = (uint8_t)0xf0,

    //This id is used by the telescope controller to announce its pointing coordinates.
    TELESCOPE_POSITION_REPORT_COMMAND_ID = (uint8_t)0xff
};

//Simple data structure for a coordinate pair.
struct EquatorialCoordinates
{
    //The time stamp when this coordinates where received.
    std::chrono::time_point<std::chrono::system_clock> TimeStamp;

    //decimal value of the right ascension.
    float RightAscension;

    //decimal value of the declination.
    float Declination;

    static EquatorialCoordinates Delta(EquatorialCoordinates &first, EquatorialCoordinates &second)
    {
        EquatorialCoordinates result;

        result.RightAscension = first.RightAscension - second.RightAscension;
        result.Declination = first.RightAscension - second.RightAscension;

        return result;
    }

    static float Absolute(EquatorialCoordinates &deltaCoordinates)
    {
        float a = deltaCoordinates.RightAscension;
        float b = deltaCoordinates.Declination;

        float abs = std::fabs(a * a + b * b);

        return abs;
    }
};

//Enum with month names for easy legibility.
enum DateMonths
{
    January = 1,
    February = 2,
    March = 3,
    April = 4,
    May = 5,
    June = 6,
    July = 7,
    August = 8,
    September = 9,
    October = 10,
    November = 11,
    December = 12,
};

//helper union to read out float bytes without the hazzle with pointers
union FloatByteConverter
{
    uint8_t bytes[4];
    float decimal_number;
};

//Simple static class providing the message generation mechanisms.
//The message frame size is 13 bytes, a 4 byte header/preamble,
//a one byte command followed by 2 to 6 arguments,
//distributed over the 8 remaining bytes.
//see the Get...Message() implementations for details.
//Since the serial protocol is faily simple, a lot of the error handling is on the client side to avoid the controller to go haywire.
class SerialCommand
{
    private:


        //helper function pushing a number of bytes into the buffer, for padding.
        static void push_bytes(std::vector<uint8_t> &buffer, uint8_t byte, size_t count);

        //simple constant containing the message header as of firmware V2.3.
        static uint8_t MessageHeader[4];

        //helper function to push the float values into the buffer
        static void push_float_bytes(std::vector<uint8_t> &buffer, FloatByteConverter &values);

    public:
        //Gracefully disconnect from the GoTo Controller.
        //returns false if an error occurs.
        static bool GetDisconnectCommandMessage(std::vector<uint8_t> &buffer);

        //put the stop message into the buffer provided.
        //returns false if an error occurs.
        static bool GetStopMotionCommandMessage(std::vector<uint8_t> &buffer);

        //put the park message into the buffer provided.
        //returns false if an error occurs.
        static bool GetParkCommandMessage(std::vector<uint8_t> &buffer);

        //put the get site location message into the buffer provided.
        //returns false if an error occurs.
        static bool GetGetSiteLocationCommandMessage(std::vector<uint8_t> &buffer);

        //put the goto message corresponding to the coordinates provided into the buffer provided.
        //returns false if an error occurs.
        static bool GetGotoCommandMessage(std::vector<uint8_t> &buffer, float decimal_right_ascension, float decimal_declination);

        //put the sync message corresponding to the coordinates provided into the buffer provided.
        //This function is used when plate solving.
        //returns false if an error occurs.
        static bool GetSyncCommandMessage(std::vector<uint8_t> &buffer, float decimal_right_ascension, float decimal_declination);

        //put the set site location message corresponding the coordinates provided into the buffer provided
        //returns false if an error occurs.
        static bool GetSetSiteLocationCommandMessage(std::vector<uint8_t> &buffer, float decimal_latitude, float decimal_longitude);

        //put the date time message corresponding to the time/date provided into the buffer provided.
        //returns false if an error occurs.
        static bool GetSetDateTimeCommandMessage(std::vector<uint8_t> &buffer, uint16_t year, uint8_t month, uint8_t day,
                uint8_t hour, uint8_t minute, uint8_t second, int8_t utc_offset);

        //move the telescope in a certain direction. Use the first 4 command IDs for a particular direction.
        static bool GetMoveWhileTrackingCommandMessage(std::vector<uint8_t> &buffer, SerialCommandID direction);

        //helper function pushing the header into the buffer.
        static void PushHeader(std::vector<uint8_t> &buffer);


};
}

#endif