#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 
#define SCREEN_HEIGHT 32 

// กำหนดขาต่อ I2C กับจอ OLED
#define OLED_RESET     -1 //ขา reset เป็น -1 ถ้าใช้ร่วมกับขา Arduino reset
Adafruit_SSD1306 OLED(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

enum PinAssignments {
  encoderPinA = 2, 
  encoderPinB = 3, 
  clearButton = 8
};

volatile unsigned int encoderPos = 0;  
unsigned int lastReportedPos = 1;   
static boolean rotating = false;  

boolean A_set = false;
boolean B_set = false;

int run = 0;

void setup() {
  Serial.begin(9600);

  if (!OLED.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
    Serial.println("SSD1306 allocation failed");
  } else {
    Serial.println("ArdinoAll OLED Start Work !!!");
  }

  pinMode(encoderPinA, INPUT_PULLUP); 
  pinMode(encoderPinB, INPUT_PULLUP);
  pinMode(clearButton, INPUT_PULLUP);
  attachInterrupt(0, doEncoderA, CHANGE); 
  attachInterrupt(1, doEncoderB, CHANGE);
}

void loop() {
  rotating = true;

  if (lastReportedPos != encoderPos) {
    Serial.print("Index:");
    Serial.println(encoderPos, DEC);
    lastReportedPos = encoderPos;
  }
  if (digitalRead(clearButton) == LOW )  {
    encoderPos = 0;
    Serial.println("Click:Reset Index");
    delay(200);
  }

  OLED.clearDisplay();
  OLED.setTextColor(WHITE, BLACK); 
  OLED.setCursor(0, 0); 
  OLED.setTextSize(2);

  OLED.drawRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, WHITE);


  //OLED.setCursor(DEC, SCREEN_HEIGHT/2-8);
  //OLED.println(encoderPos, DEC);
  OLED.setTextSize(1);
  OLED.setCursor(5,0);
  OLED.println("DESTINY DEVICE");

  OLED.display();
  delay(500);
}

// คำสั่งทำงานแบบ interrupt เมื่อมีการหมุน
void doEncoderA() {
  // debounce
  if ( rotating ) delay (1);  // หน่วงเวลาป้องกันสัญญาณบกวน debounce

  // เช็คว่ามีบิดสวิตช์
  if ( digitalRead(encoderPinA) != A_set ) { // debounce once more
    A_set = !A_set;
    // adjust counter + if A leads B
    if ( A_set && !B_set )
      encoderPos += 1;
    rotating = false;  // no more debouncing until loop() hits again
  }
}

// Interrupt on B changing state, same as A above
void doEncoderB() {
  if ( rotating ) delay (1);
  if ( digitalRead(encoderPinB) != B_set ) {
    B_set = !B_set;
    //  adjust counter - 1 if B leads A
    if ( B_set && !A_set )
      encoderPos -= 1;
    rotating = false;
  }
}