#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include <Servo.h>
#include "pitches.h"

#define SPEAKER_PIN 11
#define SERVO_PIN 2
#define SERVO_LOCKED_POS   0 // position of the servo motor when in locked status
#define SERVO_UNLOCKED_POS 90 // position of the servo motor when in unlocked status
Servo lockServo;

LiquidCrystal_I2C lcd(0x27,20,4);

const int ROW_NUM = 4;
const int COLUMN_NUM = 3;
byte pin_rows[ROW_NUM] = {9, 8, 7, 6};
byte pin_column[COLUMN_NUM] = {5, 4, 3};
char keys[ROW_NUM][COLUMN_NUM] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'},
  {'*','0','#'}
};

int currTry;
int leftTry;
int maxTry = 3;
int ledRed = 12;
int ledGreen = 13;
char key;
boolean statusLocked = true;
boolean instance = false;
boolean isSuccessful = false;
String storePassword;

Keypad keypad = Keypad( makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM );

void startScreen() { // displays the initial screen
  while(statusLocked){
    lockServo.write(SERVO_LOCKED_POS);
    lcd.setCursor(4, 0);
    lcd.print("LOCKED!");
    lcd.setCursor(1, 1);
    lcd.print("'#' to Unlock");
    ledStatus();
    key = keypad.getKey();

    if (key){
      if (checkKeyLocked(key) && instance == false){ // true when used on the first run
        createPass();
      }
      if (checkKeyLocked(key) && instance == true){ // true when used on the consecutive runs
        locked();
      } 
    }
  }
}

// create new one time password when used for the first time
void createPass(){
  while(statusLocked){ // while door lock is still in locked status
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Enter new pass:");
    String newPass = passwordInpt();

    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Confirm new pass");
    String confirmPass = passwordInpt(); 

    if (newPass.equals(confirmPass)) { // confirm if confirmPass and newPass is equal/same
      instance = true;
      storePassword = newPass;
      lcd.clear();
      success();
      startScreen();
    } 
    else {
      lcd.clear();
      lcd.setCursor(4, 0);
      lcd.print("Password");
      lcd.setCursor(4, 1);
      lcd.print("Mismatch!");
      invalid();
      delay(2000);
      lcd.clear();
      startScreen();
    }
  }
}

void locked(){
  while(statusLocked){ // while door lock is still in locked status
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Enter password:");
    String tempPass = passwordInpt(); // store input to tempPass

    if (tempPass == storePassword) { 
      lcd.clear();
      success();
      unlocked();
    } 
    else {
      lcd.clear();
      lcd.setCursor(4, 0);
      lcd.print("Password");
      lcd.setCursor(3, 1);
      lcd.print("Incorrect!");
      invalid();
      check_first();
      currTry +=1;
      leftTry = maxTry - currTry;
      delay(500);
      lcd.clear();
      lcd.setCursor(1, 0);
      lcd.print("Attempt/s left:");
      lcd.setCursor(7, 1);
      lcd.print(leftTry);
      check_second();
      delay(500);
      lcd.clear();
      startScreen();
    }
  }
}

void unlocked() {
  isSuccessful = true;
  statusLocked = false; // change statusLocked flag into false
  lcd.clear();
  lcd.setCursor(4, 0);
  lcd.print("UNLOCKED!");
  lockServo.write(SERVO_UNLOCKED_POS); // re-position servo motor
  ledStatus();
  delay(3000); // automatically locks after 3 seconds
  statusLocked = true; // change back again to true
  lcd.clear();
  startScreen();
}

void ledStatus() { // change LED values depending statusLocked flag
  if (statusLocked == true){
    digitalWrite(ledRed, HIGH);
    digitalWrite(ledGreen, LOW);
  }
  else{
    digitalWrite(ledGreen, HIGH);
    digitalWrite(ledRed, LOW);
  }
}

void invalid() { // performs a combination of tone when invalid
  tone(SPEAKER_PIN,NOTE_G4);
  delay(100);
  tone(SPEAKER_PIN,NOTE_C4);
  delay(100);
  noTone(SPEAKER_PIN);
}

void success() { // performs a combination of tone when successful
  tone(SPEAKER_PIN, 650, 750);
  delay(100);
  tone(SPEAKER_PIN, 900, 1000);
  delay(100);
  tone(SPEAKER_PIN, 650, 750);
  delay(100);
  tone(SPEAKER_PIN, 900, 1000);
  noTone(SPEAKER_PIN);
}

void check_first() { // first part of checking
  if (isSuccessful) {
    currTry = 0;
  }
  isSuccessful = false;
}

void check_second() { // second part of checking
  if (leftTry == 0){
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Intruder Alert!!");
    warning();
  }
}

void warning() { // when max attempt is used
  while(true){
    digitalWrite(ledGreen, HIGH);
    digitalWrite(ledRed, HIGH);
    invalid();
    key = keypad.getKey();
    if (key == '*'){
      currTry = 0; // resets the value of current try
      break; // stop the alarm
    }
  }
}

String passwordInpt() { // prompts the user to input 4-digit password
  lcd.setCursor(5, 1);
  lcd.print("[____]");
  lcd.setCursor(6, 1);
  String result = "";
  while (result.length() < 4) {
    char key = keypad.getKey();
    if (key >= '0' && key <= '9') {
      lcd.print('*');
      result += key;
    }
  }
  return result;
}

boolean checkKeyLocked(char input){ // checks if key == '#'
  if(input != '#'){
    return false;
  }
  else{
    return true;
  }
}

void setup() {
  lcd.init();                 
  lcd.backlight();             
  lcd.home();
  lockServo.attach(SERVO_PIN);
  pinMode(SPEAKER_PIN, OUTPUT);
  pinMode(ledRed, OUTPUT); 
  pinMode(ledGreen, OUTPUT);  
  Serial.begin(9600);
  statusLocked = true; // statusLocked is set true on default
}

void loop() {
  startScreen();
}