#include <Keypad.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,20,4);

//declare buttons and led pins
const int buttonPin1 = 18;  
const int buttonPin2 = 19;  
const int ledPins[] = {2,3,4,5,6,7}; 

int pattern = 0;      // variable to store LED pattern
int frequency = 200;  // variable to store LED blinking frequency (in milliseconds)

int pot;
int num;

unsigned long holdingTime;
long previousHoldingTime;
unsigned long firstButtonPressTime;
byte buttonState;
byte previousButtonState = HIGH;
bool AdcFlag = false;

//define constants for the number of rows and columns on the keypad
const byte rows=4;
const byte columns=4; 
char password[] = "1234";
String input;
static int pos=0; //initialize position counter. static is a storage class specifier, which means that it modifies the storage duration of the variable
char key;

//declare a 2-dimensional keymap array keys[rows][columns] that contains characters to be printed when a specific keypad button is pressed.
char keys[rows][columns]={ 
  {'1','2','3','A'},
  {'4','5','6','B'},
  {'7','8','9','C'},
  {'*','0','#','D'}
};

//specify the arduino connections to the keypad using two arrays. One for rows and one for columns
byte rowPins[rows]={25,27,29,31};
byte columnPins[columns]={33,35,37,39};

//create a keypad object that accepts 5 arguments
Keypad keypad = Keypad( makeKeymap(keys), rowPins, columnPins, rows, columns); //makeKeymap(keys) initializes internal keymap to be equal to the user defined keymap

void setup() {
  lcd.begin(20,4);
  lcd.init();
  lcd.backlight();

  Serial.begin(9600);
  lcd.setCursor(0,0);//Set cursor to character 0 on line 0
  lcd.print("Enter Password ");
  lcd.setCursor(5,3); //Set cursor to character 0 on line 3
  lcd.print("# - Delete");

  for (int i = 0; i < 7; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
  pinMode(buttonPin1, INPUT_PULLUP);
  pinMode(buttonPin2, INPUT_PULLUP);


  Serial.begin(9600);
  
  attachInterrupt(digitalPinToInterrupt(buttonPin1), checkButton1, CHANGE);

  attachInterrupt(digitalPinToInterrupt(buttonPin2), checkButton2, CHANGE);
}

void checkKeypad(){

  char key = keypad.getKey(); 
  lcd.setCursor(0,1); //cursor is on character 0, line 1
  lcd.print(key);

  if (key == '#') { 
    if (input.length() > 0) { 
      input.remove(input.length() - 1); // Remove the last digit from the input string
      lcd.setCursor(0,1);
      lcd.print("    "); // Clear the display on the LCD
      lcd.setCursor(0,1);
      lcd.print(input); // Display the updated input string on the LCD
    }
  }
    else{ // If any other key is pressed
     static char input[6]; //initialize input string
    // input += key; // Add the pressed digit to the input string
    if (key != NO_KEY && pos < 5) { //if a key was pressed and input is not full
       input[pos++] = key; 
       lcd.setCursor(pos, 1); 
       lcd.print("*"); 
    }
  
    else if (pos == 4) { //if input is complete
      if (strcmp(input, password) == 0) { //if password is correct. The string compare strcmp() function is a standard C library function that is used to compare two strings. 
         lcd.clear();
         lcd.print("Successful Login");
         delay(500); 
      }
      else { //if password is incorrect
       lcd.clear(); //clear LCD
       lcd.print("Wrong password!"); //display error message on LCD
       delay(2000); //wait 2 seconds
       lcd.clear(); //clear LCD
       lcd.print("Enter password:"); //display prompt on LCD
       pos = 0; //reset position counter
     }
   }
 }
}

void checkButton1(){
    buttonState = digitalRead(buttonPin1);

    if (buttonState == LOW && previousButtonState == HIGH) 
    {
      firstButtonPressTime = millis();
    }
    holdingTime = (millis() - firstButtonPressTime);

    if (holdingTime > 50) 
    {
    
      if (buttonState == HIGH && previousButtonState == LOW) 
      {
          Serial.println("Button 1 pressed pattern changer");
          pattern = (pattern + 1) % 5;  // change pattern
          frequency = 200; //reset frequency on pattern change
      }
    }
  
  previousButtonState = buttonState;

}

void checkButton2(){

  buttonState = digitalRead(buttonPin2);

  if (buttonState == LOW && previousButtonState == HIGH && (millis() - firstButtonPressTime) > 200) 
  {
    firstButtonPressTime = millis();
  }
  holdingTime = (millis() - firstButtonPressTime);

  if (holdingTime > 100) 
  {
   
    if (buttonState == HIGH && previousButtonState == LOW) 
    {
      if (holdingTime <= 700)
      {
        Serial.println("short button press");      
        frequency += 100; 
      }
      if (holdingTime > 700) 
      {
        if(AdcFlag == true){
          Serial.println("long button press");
          AdcFlag = false; //long press to get out of ADC mode back to the patterns
        }else{
          Serial.println("long button press");
          AdcFlag = true;  //long press makes flag true so that void loop can enter adc isr   
        }
         
        
      }
    }
  }
   previousButtonState = buttonState;
   previousHoldingTime = holdingTime;

}



void loop() {
    checkKeypad(); // Call the checkKeypad() function for all other keys

    if (AdcFlag == true){
  longPress();
}else if (AdcFlag == false){
  switch (pattern) {
    case 0:  // pattern 1
        Serial.println("Patt 1");

        for (int i = 0; i < 7; i++) {
          
          digitalWrite(ledPins[i], HIGH);
          delay(frequency);
          digitalWrite(ledPins[i], LOW);
          delay(frequency);
        }
      
      break;

    case 1:  // pattern 2
        Serial.println("Patt 2");          

        for (int i = 6; i >= 0; i--) {
          digitalWrite(ledPins[i], HIGH);
          delay(frequency);
          digitalWrite(ledPins[i], LOW);
          delay(frequency);
        }
      
      break;

      case 2:  // pattern 3
        Serial.println("Patt 3");          

        for (int i = 0; i < 7; i++) {
          digitalWrite(ledPins[i], HIGH);
          digitalWrite(ledPins[i+1], HIGH);
          delay(frequency);
          digitalWrite(ledPins[i], LOW);
          digitalWrite(ledPins[i+1], LOW);

          delay(frequency);
        }
      
      break;

      case 3:  // pattern 4
        Serial.println("Patt 4");          

        for (int i = 6; i >= 0; i--) {
          digitalWrite(ledPins[i], HIGH);
          digitalWrite(ledPins[i-2], HIGH);
          delay(frequency);
          digitalWrite(ledPins[i], LOW);
          digitalWrite(ledPins[i-2], LOW);

          delay(frequency);
        }
      
      break;

      case 4:  // pattern 5
        Serial.println("Patt 5");          

        pot = analogRead(A0);
        num = map(pot, 0, 1023, 0, 255);

        for(int i=2; i<10; i++){
          analogWrite(i, num); 
        }
            
      break;
  }
 }
  }

void longPress(){
  pot = analogRead(A0);
  num = map(pot, 0, 1023, 0, 7);

  switch(num){
    case 0: //all OFF
    for (int i = 0; i < 6; i++) {
      digitalWrite(ledPins[i], LOW);
    }
    break;

    case 1: //led 1
    digitalWrite(ledPins[0], HIGH);
    off();
        break;

    case 2: //led <2
    for (int i = 0; i < 2; i++) {
      digitalWrite(ledPins[i], HIGH);
    }
    off();
    break;

    case 3: //led <3
    for (int i = 0; i < 3; i++) {
      digitalWrite(ledPins[i], HIGH);
    }
    off();
    break;

    case 4: //led <4
    for (int i = 0; i < 4; i++) {
      digitalWrite(ledPins[i], HIGH);
    }
    off();
    break;

    case 5: //led <5
    for (int i = 0; i < 5; i++) {
      digitalWrite(ledPins[i], HIGH);
    }
    off();
    break;

    case 6: //led <6
    for (int i = 0; i < 6; i++) {
      digitalWrite(ledPins[i], HIGH);
    }
    off();
    break;

    case 7: //all ON
    for (int i = 0; i < 7; i++) {
      digitalWrite(ledPins[i], HIGH);
    }
    off();
    break;

  }
}

void off(){//TURN OFF LEDs BETWEEN CASES
    digitalWrite(ledPins[0], LOW);
    digitalWrite(ledPins[1], LOW);
    digitalWrite(ledPins[2], LOW);
    digitalWrite(ledPins[3], LOW);
    digitalWrite(ledPins[4], LOW);
    digitalWrite(ledPins[5], LOW);
    digitalWrite(ledPins[6], LOW);
}