#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

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 first
            screen_state = icon_number; //return back to last
          }
          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);
  
    // Show different things on display depending on the state
    if (button_active == 0 && screen_state == 1){ //Volume Active
      Serial.println("VolumeS Active");
    }

    else if (button_active == 0 && screen_state == 2){ //PS Active
      Serial.println("PS Active");
    }
 
    else if (button_active == 0 && screen_state == 3){ //AI Active
      Serial.println("AI Active");
    }

  }

  // 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);
  }
  //Serial.print("Button Active: ");
  //Serial.println(button_active);
  //Serial.print(" - screen_state: ");
  //Serial.println(screen_state);
  /*
  //### SCREEN DISPLAY ###
    // Show different things on display depending on the state
    if (button_active == 1 && screen_state == 1){ //Volume Active
      Serial.println("VolumeS Active");
    }

    else if (button_active == 1 && screen_state == 2){ //PS Active
      Serial.println("PS Active");
    }
 
    else if (button_active == 1 && screen_state == 3){ //AI Active
      Serial.println("AI Active");
    }
  */
}