#ifndef ModbusRTUMaster_h
#define ModbusRTUMaster_h

#define MODBUS_RTU_MASTER_BUF_SIZE 256
#define NO_DE_PIN 255

#include "Arduino.h"
//#ifdef __AVR__
//#include <SoftwareSerial.h>
//#endif

class ModbusRTUMaster {
  public:
    ModbusRTUMaster(HardwareSerial& serial, uint8_t dePin = NO_DE_PIN);
//    #ifdef __AVR__
//    ModbusRTUMaster(SoftwareSerial& serial, uint8_t dePin = NO_DE_PIN);
//    #endif
    #ifdef HAVE_CDCSERIAL
    ModbusRTUMaster(Serial_& serial, uint8_t dePin = NO_DE_PIN);
    #endif
    void setTimeout(unsigned long timeout);
    #ifdef ESP32
    void begin(unsigned long baud, uint32_t config = SERIAL_8N1, int8_t rxPin = -1, int8_t txPin = -1, bool invert = false);
    #else
    void begin(unsigned long baud, uint32_t config = SERIAL_8N1);
    #endif
    bool readCoils(uint8_t id, uint16_t startAddress, bool *buf, uint16_t quantity);
    bool readDiscreteInputs(uint8_t id, uint16_t startAddress, bool *buf, uint16_t quantity);

    bool readHoldingRegisters(uint8_t id, uint16_t startAddress, uint16_t *buf, uint16_t quantity);
    void begin_readHoldingRegisters(uint8_t id, uint16_t startAddress, uint16_t quantity);
    bool readHoldingRegisters_end(uint8_t id, uint16_t *buf, uint16_t quantity);

    bool readInputRegisters(uint8_t id, uint16_t startAddress, uint16_t *buf, uint16_t quantity);
    bool writeSingleCoil(uint8_t id, uint16_t address, bool value);
    bool writeSingleHoldingRegister(uint8_t id, uint16_t address, uint16_t value);
    bool writeMultipleCoils(uint8_t id, uint16_t startAddress, bool *buf, uint16_t quantity);
    bool writeMultipleHoldingRegisters(uint8_t id, uint16_t startAddress, uint16_t *buf, uint16_t quantity);
    bool getTimeoutFlag();
    void clearTimeoutFlag();
    uint8_t getExceptionResponse();
    void clearExceptionResponse();

  private:
    HardwareSerial *_hardwareSerial;
//    #ifdef __AVR__
//    SoftwareSerial *_softwareSerial;
//    #endif
    #ifdef HAVE_CDCSERIAL
    Serial_ *_usbSerial;
    #endif
    Stream *_serial;
    uint8_t _dePin;
    uint8_t _buf[MODBUS_RTU_MASTER_BUF_SIZE];
    unsigned long _charTimeout;
    unsigned long _frameTimeout;
    unsigned long _responseTimeout = 100;
    bool _timeoutFlag = false;
    uint8_t _exceptionResponse = 0;
    
    void _writeRequest(uint8_t len);
    uint16_t _readResponse(uint8_t id, uint8_t function);
    void _clearRxBuffer();

    void _calculateTimeouts(unsigned long baud, uint32_t config);
    uint16_t _crc(uint8_t len);
    uint16_t _div8RndUp(uint16_t value);
    uint16_t _bytesToWord(uint8_t high, uint8_t low);
};

#endif