#include <Wire.h>
#include <U8g2lib.h>

#define SCREEN_ADDRESS 0x3C

// Rev 2+ Config
#define ENC_BTN_PIN 14
#define ENC_D1_PIN 17
#define ENC_D2_PIN 4
#define START_STOP_BTN_PIN 5
#define SHIFT_BTN_PIN 12
#define EXT_INPUT_PIN 2  //needs to be an interrupt pin
#define ANALOGUE_INPUT_1_PIN A7
#define ANALOGUE_INPUT_2_PIN A6
const byte outsPins[6] = { 7, 8, 10, 6, 9, 11 };
const byte clockOutPin = 3;
bool rotateScreen = false;
bool reverseEnc = false;
//

/* Rev 1 Config
#define ENC_BTN_PIN 14
#define ENC_D1_PIN 17
#define ENC_D2_PIN 4
#define START_STOP_BTN_PIN 5
#define SHIFT_BTN_PIN 100

#define EXT_INPUT_PIN 2 //needs to be an interrupt pin
#define ANALOGUE_INPUT_1_PIN A2
#define ANALOGUE_INPUT_2_PIN A1

const byte clockOutPin = 13;
const byte outsPins[6] = {6, 11, 7, 10, 8, 9};
bool rotateScreen = true;
*/

U8G2_SSD1306_128X64_NONAME_2_HW_I2C u8g2(U8G2_R2, SCL, SDA, U8X8_PIN_NONE); 

int16_t counter = 0;

void setup() {

  pinMode(clockOutPin, OUTPUT);

  pinMode(ENC_D1_PIN, INPUT_PULLUP);
  pinMode(ENC_D2_PIN, INPUT_PULLUP);

  //Enabling PinChange Interrupts for the encoder 
  //pins 17 (PC3/PCINT11) and 4 (PD4/PCINT20), ports C and D
  PCICR |= 0b00000110;
  PCMSK1 |= 0b00001000;
  PCMSK2 |= 0b00010000;

  u8g2.begin();
  updateScreen();
}

void loop() {
  checkInputs();
}

//Encoder interrupts
ISR (PCINT1_vect) {
  checkEncoderStatus();
}
ISR (PCINT2_vect) {
  checkEncoderStatus();
}

uint8_t encoderStatus;
uint32_t encoderCheckTime = 0;
uint32_t encoderTimeBetweenPulses = 0;
bool encoderDirectionOld; //0 = -, 1 = +, Old because current direction can be determined by encoderChange
int8_t encoderChange = 0;
//uint8_t encoderBurstCount = 0;

void checkEncoderStatus() {
  //noInterrupts();
  uint8_t newStatus = (digitalRead(ENC_D1_PIN) << 1) | digitalRead(ENC_D2_PIN);
  switch(encoderStatus) {
    case 0b00:
      if (newStatus == 0b01) {
        encoderChange++;
      } else if (newStatus == 0b10) {
        encoderChange--;
      }
      break;
    case 0b01:
      if (newStatus == 0b11) {
        encoderChange++;
      } else if (newStatus == 0b00) {
        encoderChange--;
      }
      break;
    case 0b11:
      if (newStatus == 0b10) {
        encoderChange++;
      } else if (newStatus == 0b01) {
        encoderChange--;
      }
      break;
    case 0b10:
      if (newStatus == 0b00) {
        encoderChange++;
      } else if (newStatus == 0b11) {
        encoderChange--;
      }
      break;
  }
  encoderStatus = newStatus;

  uint32_t currentTime = millis();
  encoderTimeBetweenPulses = currentTime - encoderCheckTime;
  encoderCheckTime = currentTime;
  //interrupts();
}