#include <LiquidCrystal_I2C.h>
#include <Wire.h> 

LiquidCrystal_I2C lcd(0x27,  16, 2);

const int led1Pin = 2;
const int led2Pin = 3;
const int led3Pin = 4;
const int led4Pin = 5;
const int button1Pin = 14;
const int button2Pin = 15;
const int yellowbtn = 11;

unsigned long lastBlink1 = 0;  // millis timestamp for LED1 blink
unsigned long lastDebounce1 = 0; // debounce timestamp for button1 hold
unsigned long lastBlink2 = 0;  // millis timestamp for LED3 blink
unsigned long task3StartTime = 0; // timestamp for Task3 start

unsigned long interval_debouncebnt1 = 50; 
unsigned long interval_debouncebnt2 = 50; 
unsigned long interval_debounceyellowbtn = 50; 
unsigned long interval_purpleLed = 500;
unsigned long prevTime_debouncebnt1 = 0;
unsigned long prevTime_debouncebnt2 = 0;
unsigned long prevTime_debounceyellowbtn = 0;
unsigned long prevTime_purpleLed = 0;

int counter = 10;
bool done_flag = false;


//flags
bool button1flag = false;
bool button1Held = false;
bool button2Pressed = false;



int buttonState;

bool lastButtonState = LOW; // the previous reading from the input pin
bool ledState = LOW; 

bool last_ylwButtonState = LOW; // the previous reading from the input pin
bool ledgreenState = LOW; 
bool sendPulse_flag = false;

void setup() {
  pinMode(led1Pin, OUTPUT);
  pinMode(led2Pin, OUTPUT);
  pinMode(led3Pin, OUTPUT);
  pinMode(led4Pin, OUTPUT);
  pinMode(button1Pin, INPUT);
  pinMode(button2Pin, INPUT);
  pinMode(yellowbtn, INPUT);

  Serial.begin(9600);

  lcd.init();
// turn on the backlight
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("hello");
}

void Task_1(unsigned long CT) {
  buttonState = digitalRead(button1Pin);
  if(CT - prevTime_debouncebnt1 > interval_debouncebnt1) {
    prevTime_debouncebnt1 = CT;
    if(buttonState == HIGH && button1flag == false){
      digitalWrite(led2Pin, !digitalRead(led2Pin)); // Toggle LED state
      button1flag = true;
    }
    if(buttonState == LOW){
      button1flag = false;
    }
    // delay(50);
  }  
}

void loop() {
  unsigned long currentTime = millis();


  Task_1(currentTime);

  if(currentTime - prevTime_debouncebnt2 > interval_debouncebnt2) {
    bool currentButtonState = digitalRead(button2Pin);
    prevTime_debouncebnt2 = currentTime;
    // if state change detected
    if (currentButtonState != lastButtonState) {
      if (currentButtonState == HIGH) {
        ledState = !ledState; // Toggle the LED state
      }
      // Delay a little bit to avoid bouncing
      // delay(50);
    }

    lastButtonState = currentButtonState;
    digitalWrite(led1Pin, ledState);
  }

  if(currentTime - prevTime_debounceyellowbtn > interval_debounceyellowbtn) {
    bool currentButtonState = digitalRead(yellowbtn);
    prevTime_debounceyellowbtn = currentTime;
    // if state change detected
    if (currentButtonState != last_ylwButtonState) {
      if (currentButtonState == HIGH) {
        ledgreenState = !ledgreenState; // Toggle the LED state
        sendPulse_flag = !sendPulse_flag;  //Toggle Flag
        lcd.clear();
        lcd.print(" SP flag: " + String(sendPulse_flag));
      }
      // Delay a little bit to avoid bouncing
      // delay(50);
    }

    last_ylwButtonState = currentButtonState;
    digitalWrite(led3Pin, ledgreenState);
  }

  if (sendPulse_flag && digitalRead(led2Pin) && ledState && !done_flag){
    if (currentTime - prevTime_purpleLed > interval_purpleLed ){
      prevTime_purpleLed = currentTime;
      lcd.clear();
      lcd.setCursor(0,0);
      lcd.print("sending pulse...");
      digitalWrite(led4Pin, !digitalRead(led4Pin));
      if(counter > 0) {
        counter--;
        lcd.setCursor(0,1);
        lcd.print("counter: " + String(counter));
      }
      if(counter == 0 && !done_flag) {
        done_flag = true;
        lcd.clear();
        lcd.print("DONE Sending pulse");
      }
    }
  }
}