//Sample using LiquidCrystal library
#include <LiquidCrystal.h>

// select the pins used on the LCD panel
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

// define some values used by the panel and buttons
int lcd_key     = 0;
int adc_key_in  = 0;
#define btnRIGHT  0
#define btnUP     1
#define btnDOWN   2
#define btnLEFT   3
#define btnSELECT 4
#define btnNONE   5

int bst1 = 0;
const int buzzer = 2;
// read the buttons
int read_LCD_buttons()
{
adc_key_in = analogRead(0);      // read the value from the sensor

if (adc_key_in < 50)   return btnRIGHT;  
if (adc_key_in < 195)  return btnUP;
if (adc_key_in < 380)  return btnDOWN;
if (adc_key_in < 555)  return btnLEFT;
if (adc_key_in < 790)  return btnSELECT;  

return btnNONE;  // when all others fail, return this...
}

// data for timer 1. All notes for timer 1 is applicable for timer 2 which is denoted by number i.e. i1 and i2
int i1 = 0; // data for converted miliseconds to seconds
int m1 = 0; // data for converted seconds to minutes
int s1 = 0; // data to show current seconds of the minute
double a1 = millis(); // start point for timer
double c1; //current point for timer
int st1=0; // state change - 0-reset, 1-running, 2-stopped

// data for timer 2
int i2 = 0;
int m2 = 0;
int s2 = 0;
double a2 = millis();
double c2;
int st2=0;

void setup()
{
lcd.begin(16, 2);              // start the library
lcd.setCursor(0,0);
pinMode(3, OUTPUT);
pinMode(buzzer, OUTPUT);
}



void loop()
{
lcd_key = read_LCD_buttons();  // read the buttons
lcd.clear();

switch (lcd_key)               // depending on which button was pushed, we perform an action
{
  case btnRIGHT: // not in use
    {
      tone(buzzer, 1000); // Send 1KHz sound signal...
      delay(1000);        // ...for 1 sec
      noTone(buzzer);     // Stop sound...
    break;
    }
  case btnLEFT: // not in use
    {
   
    break;
    }
  case btnUP: // button to change timer 1 state
    {
      if (st1==0) // if state is reset (0) and button is pressed go to state 1 (running) and mark current time in a1
      {
       st1=1;
       a1=millis();
       delay(250);
       break;
      }
      else if (st1==1) // if state is running (1) and button is pressed go to state 2 (stopped)
      {
       st1=2;
       delay(250);
       break;
      }
      else if (st1==2) // start timer 2 // if state is stopped and button is pressed go to state 0 (reset)
      {
       st1=0;
       delay(250);
       break;
      }
      break;
    }
  case btnDOWN: // button to change timer 2 state
    {
      if (st2==0)
      {
       st2=1;
       a2=millis();
       delay(250);
       break;
      }
      else if (st2==1)
      {
       st2=2;
       delay(250);
       break;
      }
      else if (st2==2)
      {
       st2=0;
       delay(250);
       break;
      }
      break;
    }
  case btnSELECT: // stop both timers and reset by changing state to 0
    {
    st1=0;
    st2=0;
    break;
    }
    case btnNONE: // not in use
    {
   
    break;
    }
}

 if (st1==0) // if state is reset (0) park current and start timer point (a and c) as 0.
 {
    c1 = 0;
    a1 = 0;
    i1 = (c1 - a1) / 1000;
    m1 = i1 / 60;
    s1 = i1-(m1*60);
   
    lcd.setCursor(0,0);
    lcd.print ("T1:");
    lcd.setCursor(4,0);
    lcd.print(m1);
    lcd.setCursor(6,0);
    lcd.print("Min");
    lcd.setCursor (10,0);
    lcd.print(s1);
    lcd.setCursor(13,0);
    lcd.print("Sec");
    //lcd.setCursor(0,0);
    Serial.println(c1);
    Serial.println(a1);
    Serial.println(i1);
    Serial.println("......");
    //delay(250);
 };

 
 if (st1==1) //if state is running (1) current timer point is constantly updated with timer. difference between current running time and start timer point gives time since state change
 {
    c1 = millis(); //updates current time since state change
    i1 = (c1 - a1) / 1000; //calculate time since state change
    m1 = i1 / 60; //calculate time in minutes that has ecliped
    s1 = i1-(m1*60); //calculates time in seconds since last minute has ecliped
   
    lcd.setCursor(0,0);
    lcd.print ("T1:");
    lcd.setCursor(4,0);
    lcd.print(m1);
    lcd.setCursor(6,0);
    lcd.print("Min");
    lcd.setCursor (10,0);
    lcd.print(s1);
    lcd.setCursor(13,0);
    lcd.print("Sec");
    //lcd.setCursor(0,0);
    Serial.println(c1);
    Serial.println(a1);
    Serial.println(i1);
    Serial.println("......");
    //delay(250);
 };

   if (st1==2) // if state is stopped (2) current timer point (c) is no longer updated but calculation to show time difference between current and start timer points continues (c1 - a1)
 {
    //c1 = millis();
    i1 = (c1 - a1) / 1000;
    m1 = i1 / 60;
    s1 = i1-(m1*60);
   
    lcd.setCursor(0,0);
    lcd.print ("T1:");
    lcd.setCursor(4,0);
    lcd.print(m1);
    lcd.setCursor(6,0);
    lcd.print("Min");
    lcd.setCursor (10,0);
    lcd.print(s1);
    lcd.setCursor(13,0);
    lcd.print("Sec");
    //lcd.setCursor(0,0);
    Serial.println(c1);
    Serial.println(a1);
    Serial.println(i1);
    Serial.println("......");
    //delay(250);
 };



   if (st2==0)
 {
    c2 = 0;
    a2 = 0;
    i2 = (c2 - a2) / 1000;
    m2 = i2 / 60;
    s2 = i2-(m2*60);
   
    lcd.setCursor(0,1);
    lcd.print ("T2:");
    lcd.setCursor(4,1);
    lcd.print(m2);
    lcd.setCursor(6,1);
    lcd.print("Min");
    lcd.setCursor (10,1);
    lcd.print(s2);
    lcd.setCursor(13,1);
    lcd.print("Sec");
    lcd.setCursor(0,1);
    Serial.println(c2);
    Serial.println(a2);
    Serial.println(i2);
    Serial.println("......");
    //delay(250);
 };

 
 if (st2==1)
 {
    c2 = millis();
    i2 = (c2 - a2) / 1000;
    m2 = i2 / 60;
    s2 = i2-(m2*60);
   
    lcd.setCursor(0,1);
    lcd.print ("T2:");
    lcd.setCursor(4,1);
    lcd.print(m2);
    lcd.setCursor(6,1);
    lcd.print("Min");
    lcd.setCursor (10,1);
    lcd.print(s2);
    lcd.setCursor(13,1);
    lcd.print("Sec");
    lcd.setCursor(0,1);
    Serial.println(c2);
    Serial.println(a2);
    Serial.println(i2);
    Serial.println("......");
    //delay(250);
 };

   if (st2==2)
 {
    //c1 = millis();
    i2 = (c2 - a2) / 1000;
    m2 = i2 / 60;
    s2 = i2-(m2*60);
   
    lcd.setCursor(0,1);
    lcd.print ("T2:");
    lcd.setCursor(4,1);
    lcd.print(m2);
    lcd.setCursor(6,1);
    lcd.print("Min");
    lcd.setCursor (10,1);
    lcd.print(s2);
    lcd.setCursor(13,1);
    lcd.print("Sec");
    lcd.setCursor(0,1);
    Serial.println(c2);
    Serial.println(a2);
    Serial.println(i2);
    Serial.println("......");
    //delay(250);
 };

 if ((st1==1 && s1==0) || (st2==1 && s2==0) || (st1==1 && s1==50) || (st2==1 && s2==50))
  {
    tone(buzzer, 2500); // Send 2.5KHz sound signal...
  }
 delay(250);
 if ((s1>0 && s1<10) || (s2>0 &&s2<10) || (s1>50 && s1<59) || (s2>50 &&s2<59))
  {
   noTone(buzzer);     // Stop sound...
  }

 
}