#include <Arduino.h>

// Hardware setup:
// Attach a rotary encoder with output pins to A2 and A3.
// The common contact should be attached to ground.

#include <RotaryEncoder.h>
#include <U8g2lib.h>

//#define UPPER_LIMIT 100
#define UPPER_LIMIT 255
#if(UPPER_LIMIT == 255)
  #define USE_PWM_MULTIPLIER 0
#else
  #define USE_PWM_MULTIPLIER 1
#endif

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif

// Setup a RoraryEncoder for pins A2 and A3:
RotaryEncoder encoder(A3, A2);
U8G2_SH1106_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);

int pwmpin = 3;
uint8_t buttonpin = 2;
uint8_t ledpin = 7;
uint32_t frequency = 50000;
bool running = true;
uint8_t newButton = HIGH;
uint8_t oldButton = HIGH;

void UpdateDisplay(long newPos, long pos);

void setup()
{
  // You may have to modify the next 2 lines if using other pins than A2 and A3
  PCICR |= (1 << PCIE1);    // This enables Pin Change Interrupt 1 that covers the Analog input pins or Port C.
  PCMSK1 |= (1 << PCINT10) | (1 << PCINT11);  // This enables the interrupt for pin 2 and 3 of Port C.
  pinMode(buttonpin, INPUT_PULLUP);
  pinMode(ledpin, OUTPUT);
  digitalWrite(ledpin, running);
#if 0
  InitTimersSafe(frequency - 10);
   
  bool success = SetPinFrequencySafe(pwmpin, frequency);
  if(success)
  {
    pinMode(pwmpin, OUTPUT);
    digitalWrite(pwmpin, LOW);
  }
#endif

  u8g2.begin();
  u8g2.enableUTF8Print();
  u8g2.setFontMode(0);
  u8g2.setDrawColor(1);

  u8g2.firstPage();
  do
  {
    u8g2.setFont(u8g2_font_logisoso32_tn);
    uint8_t wid = u8g2.getStrWidth("0");
    u8g2.setCursor(64 - wid/2, 63); //bottom, centered
    u8g2.print(0);
    u8g2.drawFrame(12, 2, 104, 19);
  } while (u8g2.nextPage() );
}

/* The Interrupt Service Routine for Pin Change Interrupt 1
 This routine will only be called on any signal change on A2 and A3: exactly where we need to check. */
ISR(PCINT1_vect)
{
  encoder.tick(); // just call tick() to check the state.
}

// Read the current position of the encoder and print out when changed.
void loop()
{
  static long pos = 0;
  static RotaryEncoder::Direction direction = RotaryEncoder::Direction::NOROTATION;
  unsigned char pwmvalue = 0;

  newButton = digitalRead(buttonpin);
  if(newButton != oldButton)
  {
    oldButton = newButton;
    if(newButton == LOW)
    {
      running = !running;
    }
  }

  digitalWrite(ledpin, running);
  long newPos = encoder.getPosition();

  direction = encoder.getDirection();

  if(pos != newPos)
  {
    if(newPos < 0)
    {
      newPos = 0;
      encoder.setPosition(newPos);
    }
	  if(newPos > UPPER_LIMIT)
	  {
      newPos = UPPER_LIMIT;
      encoder.setPosition(newPos);
	  }
    pos = newPos;
    
    #if 0
      #if(USE_PWM_MULTIPLIER == 1)
        pwmvalue = map(newPos, 0, UPPER_LIMIT, 0, 255);
      #else
        pwmvalue = newPos;
      #endif
      if(newPos == 0)
      {
        digitalWrite(pwmpin, LOW);
      }
      else if(newPos == UPPER_LIMIT)
      {
        digitalWrite(pwmpin, HIGH);
      }
      else
      {
        pwmWrite(pwmpin, pwmvalue);
      }
    #endif
  }
  UpdateDisplay(newPos, pos);

}


void UpdateDisplay(long newPos, long pos)
{
    char theStr[10];

    memset(theStr, 0, sizeof(theStr));

    u8g2.firstPage();
    do
    {
      u8g2.setFont(u8g2_font_logisoso32_tn);
      uint8_t wid = u8g2.getStrWidth(itoa(newPos, theStr, 10));
      u8g2.setCursor(64 - wid/2, 63 ); // bottom, centered
      u8g2.setDrawColor(1);
      u8g2.print(newPos);
      u8g2.drawFrame(12, 2, 104, 19);
      u8g2.setDrawColor(0);
      u8g2.drawBox(13, 3, 102, 17);
      u8g2.setDrawColor(1);
      u8g2.drawBox(14, 4, pos, 15);

      u8g2.setFont(u8g2_font_7x13B_tf);
      u8g2.setCursor(0,63);
      if(!running)
      {
        u8g2.print("OFF");
      }
      else
      {
        u8g2.setDrawColor(0);
        u8g2.drawBox(0,63,20,56);
      }
    } while(u8g2.nextPage());

}