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

// OLED display TWI/I2C address (usually 0x3C or 0x3D)
#define OLED_ADDR   0x3C

// OLED display width and height, in pixels
#define SCREEN_WIDTH  128
#define SCREEN_HEIGHT 64

// LED OUTPUT SHIFT REGISTER SETUP
// Define the connections to the shift register
const int dataPin = 23;  // SER (Serial Input)
const int latchPin = 19; // RCLK (Register Clock)
const int clockPin = 18; // SRCLK (Shift Register Clock)

// Declaration for an SSD1306 display connected to I2C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire);

// Encoder Pin Definitions
const int encoderClk = 25;
const int encoderDt = 33;

// Variables to hold the encoder state
volatile int encoderPos = 0;
int lastEncoded = 0;

bool encoderUpdated = false;

void setup() {
    Serial.begin(115200);
  // initialize with the I2C addr 0x3C (for the 128x64)
  if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Don't proceed, loop forever
  }

   // Encoder setup
  pinMode(encoderClk, INPUT);
  pinMode(encoderDt, INPUT);
  attachInterrupt(digitalPinToInterrupt(encoderClk), updateEncoder, CHANGE);
  attachInterrupt(digitalPinToInterrupt(encoderDt), updateEncoder, CHANGE);

  // Clear the buffer
  display.clearDisplay();

  // Set text size, color, and position
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 0);

  // Display static text
  display.println(F("Hello, ESP32!"));
  display.println(F("SSD1306 OLED Test"));

  // Update the display with all of the above graphics
  display.display();


  // LED SHIFT REGISTER
    // Set pins to output
  pinMode(dataPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  Serial.println("hello bitch");
}

void updateEncoder() {
  int MSB = digitalRead(encoderClk); //MSB = most significant bit
  int LSB = digitalRead(encoderDt); //LSB = least significant bit

  int encoded = (MSB << 1) | LSB; //converting the 2 pin value to single number
  int sum = (lastEncoded << 2) | encoded; //adding it to the previous encoded value

  if (sum == 0b1101 || sum == 0b0100 || sum == 0b0010 || sum == 0b1011) encoderPos++;
  if (sum == 0b1110 || sum == 0b0111 || sum == 0b0001 || sum == 0b1000) encoderPos--;

  lastEncoded = encoded; //store this value for next time

    // Indicate that the encoder position has been updated
  encoderUpdated = true;
}

void updateShiftRegister(byte data) {
  // Take the latchPin low so the LEDs don't change while sending in bits
  digitalWrite(latchPin, LOW);

  // Shift out the bits
  shiftOut(dataPin, clockPin, MSBFIRST, data);

  // Take the latchPin high so the LEDs will light up
  digitalWrite(latchPin, HIGH);
}

void loop() {
    if(encoderUpdated) {
      // Update the display
      display.clearDisplay();
      display.setCursor(0, 0);
      display.print("Encoder Pos: ");
      display.println(encoderPos);
      display.display();

      // Reset the flag
      encoderUpdated = false;
  }

  // LED SHIFT REGISTER
   // Turn all LEDs on
  updateShiftRegister(B11111111);
  delay(1000); // Wait for 1 second

  // Turn all LEDs off
  updateShiftRegister(B00000000);
  delay(1000); // Wait for 1 second
}