//<< ===================== 1) LIBRARIES =======================================
  #include <Wire.h>
  #include <Adafruit_GFX.h>
  #include <Adafruit_SSD1306.h>
  #include <RTClib.h>

  //<< ===================== 2) CONSTANTS + GLOBAL VARIABLES =====================
  //<< --- OLED setup ---
  #define WIDTH  128
  #define HEIGHT 64
  #define RESET  -1
  Adafruit_SSD1306 display(WIDTH, HEIGHT, &Wire, RESET);

  RTC_DS3231 clock;

  #define PREV 4
  #define NEXT 3
  #define SELECT  2

  int counter = 0;  // variable to hold current state

  //<< --- status options array ---
  const char* status[] = {
    "Eat",
    "Sleep",
    "Study",
    "Relax",
  };
  int totalStatus = 4;
  int currentStatus = 0;

  //<< ---------- MAIN MENU ----------
  String mainMenu[] = { //main menu array
    "Status",
    "Clock",
  };
  int totalNum = 2; //total number of main menu options
  int mainCurrent = 0; //tracks the current selected main menu option
  int counterIndex = 0;
  int statusTotal = 4;
 

  //<< ===================== 3) SETUP (RUNS ONCE) ===============================

  void setup() {
    Wire.begin();
    display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
    display.clearDisplay();         // to clear display
    
    //<< set the modes for the buttons you are using 
    pinMode(PREV, INPUT_PULLUP);
    pinMode(NEXT, INPUT_PULLUP);
    pinMode(SELECT,  INPUT_PULLUP);

    showWelcome();  // show welcome message
    delay(2000);
    mainmenu();
    clock.begin(); //Intialize Clock
  }

  //<< ===================== 4) LOOP (RUNS FOREVER) ============================
  void loop() {
  if (counter == 0){
    mainmenu(); //go to main menu screen
  }
  if (counter == 1){ //if the screen mode is 1
    showStatusMenu(); //go to that screen display
  }
  if (counter == 2){ //if the screen mode is 2
    Clock(); //go to that screen display
  }
}

    //<< Your main code will go here
    //<< Forever detect button presses
    //<< Navigate through the main menu, status menu, and other screens from the button presses
  

  //<< ===================== 5) FUNCTIONS (OUTSIDE setup/loop) =================
  //<< Function to show welcome message on screen
  void showWelcome() {
  display.setTextColor(SSD1306_WHITE);
  display.setTextSize(1);
  display.println("Welcome to the ");
  display.print("Display!");
  display.display();
}

  //<< Function to show chosen status on screen
  

  //<< Function to show status menu on screen
  void showStatusMenu() {
    display.clearDisplay();           // clear display
    display.setTextSize(1);                   // set text size to 1
    display.setTextColor(SSD1306_WHITE);                   // set color to white
    display.setCursor(0,0);            // set cursor location to (0,0)
    display.println("statusMenu");            // print your header
    display.println("-------------------");       // feel free to change what this looks like 
    int i = 0;
    while (i < totalStatus) {
      if (i == currentStatus) {
        display.print("> ");     // highlight the current status
      } else {
        display.print(" ");     // keep spacing for non-selected
      }
      display.println(status[i]);    // print the status text
      i = i + 1;                     // move to the next item
    }
    display.display();                // push everything to the screen

  
    
    //<< --- Place the button logic blocks here in the correct order ---
    if (buttonHelper(PREV)) {    // If the PREV button is pressed.
      counter = 0; // Back to main menu
      delay(200); // short delay
    }

    else if (buttonHelper(NEXT)) {        // If the NEXT button is pressed.
      counterIndex = counterIndex + 1; // Increase the status index by 1
      if (counterIndex > statusTotal - 1) { // If the status index is "greater than" the last index (total statuses - 1)
        counterIndex = counterIndex - 1;
      }
    delay(200); // short delay
    }

    else if (buttonHelper(SELECT)) {      // If the SELECT button is pressed
      counter = 3;  // Update the screen variable number to show confirmed status screen
      delay(200); // short delay
    }
  }
    
  //<< Function to show main menu on screen
  void mainmenu() {
    display.clearDisplay();                 // clear display
    display.setTextSize(1);                 // set text size to 1
    display.setTextColor(SSD1306_WHITE);                 // set text color to white
    display.setCursor(0,0);                 // set cursor to (0,0)
    display.println("mainMenu");                 // print header 
    display.println("----------------");

    int i = 0;
    while (i < totalNum) { // loop through all main menu options
      if (i == mainCurrent) { // check if this is the selected option using the counter variable
        display.print(">");     // highlight the current main menu option
      } else {
        display.print(" ");       // keep spacing for non-selected
      }
      display.println(mainMenu[i]);     // print the main menu option text
      i = i + 1;       // move to the next item
    }
  //display.display();           // push everything to the screen
  
    display.setCursor(0, 56);
    display.println("SEL: Select");
    display.display();
  
    // buttons
    if (buttonHelper(PREV)) {
      mainCurrent = mainCurrent - 1;
      if (mainCurrent < 0) mainCurrent= totalNum - 1;
      delay(200);
    }

  if (buttonHelper(NEXT)) {
    mainCurrent = mainCurrent + 1;
    if (mainCurrent> totalNum - 1) {
      mainCurrent = 0;
    }
    delay(200);
  }

  if (buttonHelper(SELECT)) {
    if (mainCurrent== 0) {
      counter=  1; // Status -> goes to Status Menu function
    } else if (mainCurrent == 1) {
      counter = 2; // Clock
    }
    delay(200);
  }
  }        



  //<< Example of how this function can be used in the void loop() 
  

  //<< Button Helper Function
  bool buttonHelper(int buttonPin) { //boolean function because it returns true or false. Not a void type. 
    if (digitalRead(buttonPin)==LOW) { //if high or low
      delay(50); //create a short delay
      if (digitalRead(buttonPin)==LOW) {//if hight or low
        return true; //if the button is still pressed after a delay, return (true/false)
      }
      return false; //if not, return (true/false)
    }
      return false;
  }
static void Time() {
  DateTime now = clock.now();

  int hour = now.hour();
  int min= now.minute();
   int sec = now.second();

   if( hour < 10) {
    display.print("0");
   }
   display.print(hour);
   display.print(":");
   if(min<10){
    display.print("0");
   }
   display.print(min);
   display.print(":");

   if(sec < 10) {
    display.print("0");
   }
   display.print(sec);
}
//Clock Function
void Clock() {
  display.clearDisplay();
  display.setTextColor(WHITE);

display.setTextSize(1);
display.setCursor(0,0);
display.println("Clock");

display.setTextSize(2);
display.setCursor(0,20);
Time();

display.setTextSize(1);
display.setCursor(0,56);
display.println("PREV: Menu");

display.display();

if(buttonHelper(PREV)){
  counter = 0;
  delay(150);
}
}