//oled
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
//encoder
#define ENC_A 2
#define ENC_B 3
#define encoder0Btn 4
const unsigned long eventInterval = 1000;
unsigned long previousTime = 0;
unsigned long _lastIncReadTime = micros(); 
unsigned long _lastDecReadTime = micros(); 
int _pauseLength = 25000;
int _fastIncrement = 10;
volatile int counter = 0;
int x=0;
//encoder
void setup(){
  Serial.begin(9600);
    if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
    }
     // Set encoder pins and attach interrupts
  pinMode(ENC_A, INPUT_PULLUP);
  pinMode(ENC_B, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(ENC_A), read_encoder, CHANGE);
  attachInterrupt(digitalPinToInterrupt(ENC_B), read_encoder, CHANGE);
pinMode(encoder0Btn, INPUT_PULLUP);


}
void loop(){
  
      unsigned long currentTime = millis();

  /* This is the event */
  if (currentTime - previousTime >= eventInterval) {
    /* Event code */
     int btn = digitalRead(encoder0Btn);
  
if(btn==1){
  Serial.println("button on ");
   Serial.println(x);

}
else{
  Serial.println("button off ");
  x=x+1;
  Serial.println(x);
  if(x>=4){
    x=0;
  }

}
  
    
   /* Update the timing for the next time around */
    previousTime = currentTime;
  }
  static int lastCounter = 0;

  // If count has changed print the new value to serial
  if(counter != lastCounter){
    display.clearDisplay();
         display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(0, 0);
     display.println("Encoder rotation  ");
  display.print(counter);
    lastCounter = counter;
     display.display();
  }

}
void read_encoder() {
  // Encoder interrupt routine for both pins. Updates counter
  // if they are valid and have rotated a full indent
 
  static uint8_t old_AB = 3;  // Lookup table index
  static int8_t encval = 0;   // Encoder value  
  static const int8_t enc_states[]  = {0,-1,1,0,1,0,0,-1,-1,0,0,1,0,1,-1,0}; // Lookup table

  old_AB <<=2;  // Remember previous state

  if (digitalRead(ENC_A)) old_AB |= 0x02; // Add current state of pin A
  if (digitalRead(ENC_B)) old_AB |= 0x01; // Add current state of pin B
  
  encval += enc_states[( old_AB & 0x0f )];

  // Update counter if encoder has rotated a full indent, that is at least 4 steps
  if( encval > 3 ) {        // Four steps forward
    int changevalue = 1;
    if((micros() - _lastIncReadTime) < _pauseLength) {
      changevalue = _fastIncrement * changevalue; 
    }
    _lastIncReadTime = micros();
    counter = counter + changevalue;              // Update counter
    encval = 0;
  }
  else if( encval < -3 ) {        // Four steps backward
    int changevalue = -1;
    if((micros() - _lastDecReadTime) < _pauseLength) {
      changevalue = _fastIncrement * changevalue; 
    }
    _lastDecReadTime = micros();
    counter = counter + changevalue;              // Update counter
    encval = 0;
  }
}