/*!
 * @file TinyLoRa.h
 *
 * This is part of Adafruit's TinyLoRa library for the Arduino platform. It is
 * designed specifically to work with the Adafruit Feather 32u4 RFM95 LoRa:
 * https://www.adafruit.com/product/3078
 *
 * This library uses SPI to communicate, 4 pins (SCL, SDA, IRQ, SS)
 * are required to interface with the HopeRF RFM95/96 breakout.
 *
 * Adafruit invests time and resources providing this open source code,
 * please support Adafruit and open-source hardware by purchasing
 * products from Adafruit!
 *
 * Copyright 2015, 2016 Ideetron B.V.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * Modified by Brent Rubell for Adafruit Industries.
 *
 * LGPL license, all text here must be included in any redistribution.
 *
 */

#ifndef TINY_LORA_H
#define TINY_LORA_H

#include <Arduino.h>
#include <avr/pgmspace.h>

// uncomment for debug output
// #define DEBUG

/** RFM channel options */
typedef enum rfm_channels
{
  CH0,
  CH1,
  CH2,
  CH3,
  CH4,
  CH5,
  CH6,
  CH7,
  MULTI,
} rfm_channels_t;

/** RFM fixed datarate, dependent on region */
typedef enum rfm_datarates
{
  SF7BW125,
  SF7BW250,
  SF8BW125,
  SF9BW125,
  SF10BW125,
  SF11BW125,
  SF12BW125,
} rfm_datarates_t;

/** Region configuration*/
//#define US902 ///< Used in USA, Canada and South America
#define EU863 ///< Used in Europe
//#define AU915 ///< Used in Australia
//#define AS920 ///< Used in Asia

/* RFM Modes */
#define MODE_SLEEP  0x00  ///<low-power mode
#define MODE_LORA   0x80  ///<LoRa operating mode
#define MODE_STDBY  0x01  ///<Osc. and baseband disabled
#define MODE_TX     0x83  ///<Configures and transmits packet

/* RFM Registers */
#define REG_PA_CONFIG              0x09 ///<PA selection and Output Power control
#define REG_PREAMBLE_MSB           0x20 ///<Preamble Length, MSB
#define REG_PREAMBLE_LSB           0x21 ///<Preamble Length, LSB
#define REG_FRF_MSB                0x06 ///<RF Carrier Frequency MSB
#define REG_FRF_MID                0x07 ///<RF Carrier Frequency Intermediate
#define REG_FRF_LSB                0x08 ///<RF Carrier Frequency LSB
#define REG_FEI_LSB                0x1E ///<Info from Prev. Header
#define REG_FEI_MSB                0x1D ///<Number of received bytes
#define REG_MODEM_CONFIG           0x26 ///<Modem configuration register

/**************************************************************************/
/*! 
    @brief  TinyLoRa Class
*/
/**************************************************************************/
class TinyLoRa
{
	public:
		uint8_t txrandomNum;  ///<random number for AES
		uint16_t frameCounter;  ///<frame counter
    void setChannel(rfm_channels_t channel);
    void setDatarate(rfm_datarates_t datarate);
    TinyLoRa(int8_t rfm_dio0, int8_t rfm_nss);
		bool begin(void);
		void sendData(unsigned char *Data, unsigned char Data_Length, unsigned char Port, unsigned int Frame_Counter_Tx);

	private:
		uint8_t randomNum;
		int8_t _cs, _irq;
    bool _isMultiChan;
    unsigned char _rfmMSB, _rfmMID, _rfmLSB, _sf, _bw, _modemcfg;
    static const unsigned char LoRa_Frequency[8][3];
		static const unsigned char S_Table[16][16];
		void RFM_Send_Package(unsigned char *RFM_Tx_Package, unsigned char Package_Length);
		void RFM_Write(unsigned char RFM_Address, unsigned char RFM_Data);
    uint8_t RFM_Read(uint8_t RFM_Address);
		void Encrypt_Payload(unsigned char *Data, unsigned char Data_Length, unsigned int Frame_Counter, unsigned char Direction);
		void Calculate_MIC(unsigned char *Data, unsigned char *Final_MIC, unsigned char Data_Length, unsigned int Frame_Counter, unsigned char Direction);
		void Generate_Keys(unsigned char *K1, unsigned char *K2);
		void Shift_Left(unsigned char *Data);
		void XOR(unsigned char *New_Data, unsigned char *Old_Data);
		void AES_Encrypt(unsigned char *Data, unsigned char *Key);
		void AES_Add_Round_Key(unsigned char *Round_Key, unsigned char(*State)[4]);
		unsigned char AES_Sub_Byte(unsigned char Byte);
		void AES_Shift_Rows(unsigned char(*State)[4]);
		void AES_Mix_Collums(unsigned char(*State)[4]);
		void AES_Calculate_Round_Key(unsigned char Round, unsigned char *Round_Key);

};

#endif