#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include <Wire.h> 
#include <time.h>
#include <string.h>

#define ledPin 12
#define soundPin 13
#define detonationTime 40

// set up keypad
const byte KEYPAD_ROWS = 4;
const byte KEYPAD_COLS = 4;
byte rowPins[KEYPAD_ROWS] = {2,3,4,5};
byte colPins[KEYPAD_COLS] = {6,7,8,9};
char keys[KEYPAD_ROWS][KEYPAD_COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, KEYPAD_ROWS, KEYPAD_COLS);

// set up display
LiquidCrystal_I2C lcd(0X27,16,2); //SCL A5 SDA A4

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  lcd.init();       //allow arduino to use screen
  lcd.backlight();   //turn on back light
  pinMode(ledPin, OUTPUT); // set led pin as output
  pinMode(soundPin, OUTPUT); // set sound pin as output
}

void loop() {
  // put your main code here, to run repeatedly:
  // countDownTimer(40);
  char inputPassword[7];
  do{
  memcpy(inputPassword,displayInputPasswordScreen(),7);
  } while (!checkPassword(inputPassword));
  countDownTimer(detonationTime);
}

void countDownTimer (int seconds){
  int hours = floor(seconds/3600);
  int minutes;
  int second;
  int ledInterval = 1000;
  int oneSecond;
  while (seconds >= 0){
    oneSecond = 0;
    hours = floor(seconds/3600);
    minutes = floor((seconds % 3600)/60);
    second = seconds%60;
    lcd.setCursor(0,0);
    lcd.print(hours);
    lcd.print(":");
    lcd.print(minutes);
    lcd.print(":");
    if(second < 10){
      lcd.setCursor(4,0);
      lcd.print("0");
    }
    lcd.print(second);
    switch(second){
      case 30:
        ledInterval = 750;
        break;
      case 20:
        ledInterval = 500;
        break;
      case 10:
        ledInterval = 200;
        break;
      case 5:
        ledInterval = 100;
        break;
    }
    while (oneSecond < 750){
      digitalWrite(12, HIGH);
      digitalWrite(13, HIGH);
      delay(100);
      digitalWrite(12, LOW);
      digitalWrite(13, LOW);
      delay(ledInterval);
      oneSecond = oneSecond + ledInterval;
    }
    seconds--;
  }
  lcd.clear();
}

boolean checkPassword(char* inputPass){
  char password[7] = {'7','3','5','5','6','0','8'};
  boolean lul = true;
  for (int i=0;i<7;i++){
    if (inputPass[i] != password[i]){
      lul = false;
    }
  }
  if (lul){
    lcd.clear();
    return lul;
  }
  else {
    lcd.setCursor(0,1);
    lcd.print("invalid");
    return lul;}
}

char* displayInputPasswordScreen(){
  char *password = malloc(7*sizeof(char));
  memcpy(password,"*******",7);
  lcd.setCursor(9,0);
  lcd.print(password);
  while(password[0] == '*'){
    char key = keypad.getKey();
    if (key >= '0' && key <= '9') {
      for(int i=0; i < 6; i++){
        password[i] = password[i+1];
      }
      password[6] = key;
    }
    if (key == '#'){
      for(int i=0; i<7; i++){
        password[i] = '*';
      }
    }
    lcd.setCursor(9,0);
    lcd.print(password);
  }
  return password;
}