#include <ezButton.h>  // the library to use for SW pin
#include <Arduino.h>
#include <U8g2lib.h>
#include <Wire.h> // library requires for IIC communication

//## ENCODER FUNCTIONS ###
    #define CLK_PIN 25 // ESP32 pin GPIO25 connected to the rotary encoder's CLK pin
    #define DT_PIN  26 // ESP32 pin GPIO26 connected to the rotary encoder's DT pin
    #define SW_PIN  27 // ESP32 pin GPIO27 connected to the rotary encoder's SW pin

    #define DIRECTION_CW  0   // clockwise direction
    #define DIRECTION_CCW 1  // counter-clockwise direction

    int counter = 0;
    int direction = DIRECTION_CW;
    int CLK_state;
    int prev_CLK_state;
    int button_active = 0;
    int screen_state = 1; // 1: volume, 2: PS, 3 AI
    int icon_number = 3; // number of total icons
    ezButton button(SW_PIN);  // create ezButton object that attach to pin 7;

//### OLED SCREEN FUNCTIONS
    //OLED Setup
      U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE); // initialization for the used OLED display
    // Icons for OLED
      static const unsigned char image_AI_bits[] U8X8_PROGMEM = {0x03,0x00,0x0f,0x00,0x7f,0x00,0xff,0x03,0xf8,0x0f,0xf8,0x3f,0x38,0x7e,0x38,0x78,0x38,0x7e,0xf8,0x3f,0xf8,0x0f,0xfe,0x03,0xff,0x00,0x1f,0x00,0x07,0x00,0x00,0x00,0x00,0x00,0xff,0x31,0xff,0x79,0xff,0x31};
      static const unsigned char image_Frame_bits[] U8X8_PROGMEM = {0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0x07,0x00,0x00,0x00,0x38,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f,0xff,0xff,0xff,0xff,0x3f};
      static const unsigned char image_Arrow_bits[] U8X8_PROGMEM = {0xff,0x1f,0xfe,0x0f,0xfc,0x07,0xf8,0x03,0xf0,0x01,0xe0,0x00,0x40,0x00};
      static const unsigned char image_PS_bits[] U8X8_PROGMEM = {0xff,0x7f,0xff,0xff,0xff,0xff,0xf0,0xf0,0x70,0xe0,0x70,0xe0,0xe0,0x70,0xe0,0x79,0xc0,0x3f,0x80,0x1f,0x00,0x00,0x00,0x00,0xc6,0x03,0xc7,0x07,0xe7,0x0f,0x67,0x0e,0x7f,0x0e,0x7e,0x0e,0x3c,0x06};
      static const unsigned char image_Volume_bits[] U8X8_PROGMEM = {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xfc,0x03,0x00,0x00,0xfc,0x03,0x00,0x00,0xfc,0x03,0x00,0x00,0xfc,0x03,0x00,0x00,0xfc,0x03,0x00,0x00,0xfc,0x03,0x00,0x00,0xfe,0x07,0x00,0x00,0xff,0x0f,0x00,0x80,0xff,0x1f,0x00,0xc0,0xff,0x3f,0x00,0xe0,0xff,0x7f,0x00,0xf0,0xff,0xff,0x00,0xf8,0xff,0xff,0x01,0xf8,0xff,0xff,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x03,0x0c,0x00,0x00,0x07,0x0e,0x00,0x00,0xfe,0x07,0x00,0x00,0xfc,0x03,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};

void setup() {
    Serial.begin(9600);
  //## ENCODER FUNCTIONS ###
    // configure encoder pins as inputs
      pinMode(CLK_PIN, INPUT);
      pinMode(DT_PIN, INPUT);
      button.setDebounceTime(50);  // set debounce time to 50 milliseconds

    // read the initial state of the rotary encoder's CLK pin
      prev_CLK_state = digitalRead(CLK_PIN);

  //### OLED SCREEN FUNCTIONS
    // start the u8g2library for the screen
      u8g2.begin(); 
}

void loop() {
  button.loop();  // MUST call the loop() function first

  // read the current state of the rotary encoder's CLK pin
  CLK_state = digitalRead(CLK_PIN);

  // If the state of CLK is changed, then pulse occurred
  // React to only the rising edge (from LOW to HIGH) to avoid double count
  if (CLK_state != prev_CLK_state && CLK_state == HIGH) {
    // if the DT state is HIGH
    // the encoder is rotating in counter-clockwise direction => decrease the counter
    if (digitalRead(DT_PIN) == HIGH) {
      counter--;
      direction = DIRECTION_CCW;
      // Check if the button is active 
        if (button_active == 0){ // if the button is not active
          if (screen_state == 1){ // check if last icon
            screen_state = icon_number; //return back to beginning
          }
          else{
            screen_state--; // scroll back
          }
        }
    } 
    else {
      // the encoder is rotating in clockwise direction => increase the counter
      counter++;
      direction = DIRECTION_CW;
      // Check if the button is active 
        if (button_active == 0){ // if the button is not active
          if (screen_state == icon_number){ // check if last icon
            screen_state = 1; //return back to beginning
          }
          else{
            screen_state++; // scroll to next
          }
        }
    }

    Serial.print("Rotary Encoder:: direction: ");
    if (direction == DIRECTION_CW)
      Serial.print("Clockwise");
    else
      Serial.print("Counter-clockwise");

    Serial.print(" - count: ");
    Serial.println(counter);
    Serial.print(" - screen_state: ");
    Serial.println(screen_state);
    
    
    //### SCREEN DISPLAY ###
    // Show different things on display depending on the state
    if (button_active == 0 && screen_state == 1){ //Volume Active
      Serial.println("VolumeS Active");
      u8g2.clearBuffer(); // clear the internal memory
      u8g2.setFontMode(1);
      u8g2.setBitmapMode(1);  
      u8g2.drawXBMP(98, 20, 15, 20, image_AI_bits);
      u8g2.drawXBMP(45, 13, 38, 38, image_Frame_bits);
      u8g2.drawXBMP(58, 4, 13, 7, image_Arrow_bits);
      u8g2.drawXBMP(14, 23, 16, 19, image_PS_bits);
      u8g2.drawXBMP(50, 18, 27, 28, image_Volume_bits);
      u8g2.sendBuffer();
    }

    else if (button_active == 0 && screen_state == 2){ //PS Active
      Serial.println("PS Active");
      u8g2.clearBuffer(); // clear the internal memory
      u8g2.setFontMode(1);
      u8g2.setBitmapMode(1);  
      u8g2.drawXBMP(15, 21, 15, 20, image_AI_bits);
      u8g2.drawXBMP(45, 13, 38, 38, image_Frame_bits);
      u8g2.drawXBMP(58, 4, 13, 7, image_Arrow_bits);
      u8g2.drawXBMP(56, 23, 16, 19, image_PS_bits);
      u8g2.drawXBMP(92, 18, 27, 28, image_Volume_bits);
      u8g2.sendBuffer();
    }
 
     else if (button_active == 0 && screen_state == 3){ //AI Active
      Serial.println("AI Active");
      u8g2.clearBuffer(); // clear the internal memory
      u8g2.setFontMode(1);
      u8g2.setBitmapMode(1);  
      u8g2.drawXBMP(56, 21, 15, 20, image_AI_bits);
      u8g2.drawXBMP(45, 13, 38, 38, image_Frame_bits);
      u8g2.drawXBMP(58, 4, 13, 7, image_Arrow_bits);
      u8g2.drawXBMP(98, 23, 16, 19, image_PS_bits);
      u8g2.drawXBMP(8, 19, 27, 28, image_Volume_bits);
      u8g2.sendBuffer();
    }
    
  }

  // save last CLK state
  prev_CLK_state = CLK_state;

  if (button.isPressed()) {
    // Toggle button_active state
    button_active = !button_active;

    Serial.print("Button Active: ");
    Serial.println(button_active);
  }

}