#define ENCODER_CLK_PIN 34 // CLK-Pin des Rotary Encoders
#define ENCODER_DT_PIN 35  // DT-Pin des Rotary Encoders
#define BUTTON_PIN 32      // Externer Button Pin
#define OLED_RESET -1     // OLED Reset Pin

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

Adafruit_SSD1306 display(128, 64, &Wire, OLED_RESET);

int menuIndex = 0;
int submenuIndex = 0;
int value1 = 200;
int value2 = 300;
bool maindisplayActive = true;
bool submenuActive = false;
volatile int encoderPos = 0;
//volatile int lastEncoded = 0;
int lastClk = HIGH;

//For ESP32 we can use all GPIO pins for external interrupt except for GPIO6, GPIO7, GPIO8, GPIO9, GPIO10, and GPIO11.
//This pins are connected to the integrated SPI flas integrated on ESP-WROOM-32 and are not recommended for other use
void IRAM_ATTR updateEncoder(); //It is recommended to add the flag IRAM_ATTR so that the function code is stored in RAM (and not in Flash) so that the function runs faster.

void setup() {
  Serial.begin(9600);
  pinMode(ENCODER_CLK_PIN, INPUT_PULLUP);
  pinMode(ENCODER_DT_PIN, INPUT_PULLUP);
  pinMode(BUTTON_PIN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(ENCODER_CLK_PIN), updateEncoder, CHANGE);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.display();
  delay(2000);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE); 
  display.setCursor(0, 10);
  display.print("Main Display");
  display.display();


}

void loop() {
  if (maindisplayActive){
    handleMainDisplay();
  }else {
    if (!submenuActive) {
      displayMainMenu();
      if (digitalRead(BUTTON_PIN) == LOW) {
        handleMainMenuSelection();
      }
    } else {
      displaySubMenu(); 
      if (digitalRead(BUTTON_PIN) == LOW) {
        if (menuIndex == 3){
          submenuActive = false;
          menuIndex = 0;
        }
        handleSubMenuSelection();
      }
    }
  }
}

void IRAM_ATTR updateEncoder() {
  Serial.println("updateEncoder");
  int newClk = digitalRead(ENCODER_CLK_PIN);
  if (newClk != lastClk) {
    // There was a change on the CLK pin
    Serial.println("There was a change on the CLK pin");
    lastClk = newClk;
    int dtValue = digitalRead(ENCODER_DT_PIN);
    if (newClk == LOW && dtValue == HIGH) {
      Serial.println("Rotated clockwise ⏩");
      if (!submenuActive && !maindisplayActive && encoderPos < 3){
        encoderPos++;
      }else if (submenuActive && encoderPos < 3) {
        encoderPos++;
      }else{
        encoderPos = 0;
      }
      
      Serial.println(encoderPos);
    }
    if (newClk == LOW && dtValue == LOW) {
      Serial.println("Rotated counterclockwise ⏪");
      if (!submenuActive && !maindisplayActive && encoderPos > 0){
        encoderPos--;
      }else if (submenuActive && encoderPos > 0) {
        encoderPos--;
      }else{
        encoderPos = 0;
      }
      Serial.println(encoderPos);
    }
    menuIndex = encoderPos;
  }
}
void handleMainDisplay() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 10);
  display.print("Main Display");
  display.display();
  if (digitalRead(BUTTON_PIN) == LOW) {
    maindisplayActive = false;
  }
 }

void displayMainMenu() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 10);
  for (int i = 0; i < 4; i++) {
    if (i == menuIndex) {
      display.print(">");
    }
    if (i < 3) {
      display.print("Menu");
      display.println(i + 1); 
    } else {
      display.println("Exit");
    }

  }
  //display.println("Exit");
  display.display();
}

void handleMainMenuSelection() {
  if (menuIndex == 3) {
    submenuActive = false;
    maindisplayActive = true;
    menuIndex = 0;
    return;
  }
  submenuActive = true;
}

void displaySubMenu() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(0, 10);
  switch (menuIndex) {
    case 0:
      display.println("SubMenu1:");
      display.print("Value1: ");
      display.println(value1);
      display.print("Value2: ");
      display.println(value2);
      break;
    case 1:
      display.println("SubMenu2:");
      break;
    case 2:
      display.println("SubMenu3:");
      break;
    case 3:
      display.println("Back");
      break;    
  }
  display.display();
}

void handleSubMenuSelection() {
  if (menuIndex == 0) {
    // Submenu 1
    submenu1Selection();
  }
  // Weitere Fälle für andere Untermenüs...
}

void submenu1Selection() {
  // Navigation und Wertänderung mit dem Encoder
  if (digitalRead(BUTTON_PIN) == LOW) {
    // Externer Button gedrückt, Wert ändern
    switch (submenuIndex) {
      case 0:
        // Wert 1 ausgewählt
        // Hier kannst du den Wert ändern, z.B. durch Inkrementierung/ Dekrementierung
        value1++;
        break;
      case 1:
        // Wert 2 ausgewählt
        // Hier kannst du den Wert ändern, z.B. durch Inkrementierung/ Dekrementierung
        value2++;
        break;
    }
    // Hier kannst du die Änderungen auf dem Display anzeigen
  }
}