#ifndef PI_HAL_H
#define PI_HAL_H

// include RadioLib
#include <RadioLib/RadioLib.h>

// include the library for Raspberry GPIO pins
#include "pigpio.h"

// create a new Raspberry Pi hardware abstraction layer
// using the pigpio library
// the HAL must inherit from the base RadioLibHal class
// and implement all of its virtual methods
class PiHal : public RadioLibHal {
  public:
    // default constructor - initializes the base HAL and any needed private members
    PiHal(uint8_t spiChannel, uint32_t spiSpeed = 2000000)
      : RadioLibHal(PI_INPUT, PI_OUTPUT, PI_LOW, PI_HIGH, RISING_EDGE, FALLING_EDGE), 
      _spiChannel(spiChannel),
      _spiSpeed(spiSpeed) {
    }

    void init() override {
      // first initialise pigpio library
      gpioInitialise();

      // now the SPI
      spiBegin();

      // Waveshare LoRaWAN Hat also needs pin 18 to be pulled high to enable the radio
      gpioSetMode(18, PI_OUTPUT);
      gpioWrite(18, PI_HIGH);
    }

    void term() override {
      // stop the SPI
      spiEnd();

      // pull the enable pin low
      gpioSetMode(18, PI_OUTPUT);
      gpioWrite(18, PI_LOW);

      // finally, stop the pigpio library
      gpioTerminate();
    }

    // GPIO-related methods (pinMode, digitalWrite etc.) should check
    // RADIOLIB_NC as an alias for non-connected pins
    void pinMode(uint32_t pin, uint32_t mode) override {
      if(pin == RADIOLIB_NC) {
        return;
      }

      gpioSetMode(pin, mode);
    }

    void digitalWrite(uint32_t pin, uint32_t value) override {
      if(pin == RADIOLIB_NC) {
        return;
      }

      gpioWrite(pin, value);
    }

    uint32_t digitalRead(uint32_t pin) override {
      if(pin == RADIOLIB_NC) {
        return(0);
      }

      return(gpioRead(pin));
    }

    void attachInterrupt(uint32_t interruptNum, void (*interruptCb)(void), uint32_t mode) override {
      if(interruptNum == RADIOLIB_NC) {
        return;
      }

      gpioSetISRFunc(interruptNum, mode, 0, (gpioISRFunc_t)interruptCb);
    }

    void detachInterrupt(uint32_t interruptNum) override {
      if(interruptNum == RADIOLIB_NC) {
        return;
      }

      gpioSetISRFunc(interruptNum, 0, 0, NULL);
    }

    void delay(RadioLibTime_t ms) override {
      gpioDelay(ms * 1000);
    }

    void delayMicroseconds(RadioLibTime_t us) override {
      gpioDelay(us);
    }

    RadioLibTime_t millis() override {
      return(gpioTick() / 1000);
    }

    RadioLibTime_t micros() override {
      return(gpioTick());
    }

    long pulseIn(uint32_t pin, uint32_t state, RadioLibTime_t timeout) override {
      if(pin == RADIOLIB_NC) {
        return(0);
      }

      this->pinMode(pin, PI_INPUT);
      RadioLibTime_t start = this->micros();
      RadioLibTime_t curtick = this->micros();

      while(this->digitalRead(pin) == state) {
        if((this->micros() - curtick) > timeout) {
          return(0);
        }
      }

      return(this->micros() - start);
    }

   void spiBegin() {
      if(_spiHandle < 0) {
        _spiHandle = spiOpen(_spiChannel, _spiSpeed, 0);
      }
    }

    void spiBeginTransaction() {}
    
    void spiTransfer(uint8_t* out, size_t len, uint8_t* in) {
      spiXfer(_spiHandle, (char*)out, (char*)in, len);
    }

    void spiEndTransaction() {}

    void spiEnd() {
      if(_spiHandle >= 0) {
        spiClose(_spiHandle);
        _spiHandle = -1;
      }
    }

  private:
    // the HAL can contain any additional private members
    const unsigned int _spiSpeed;
    const uint8_t _spiChannel;
    int _spiHandle = -1;
};

#endif
