#include <Nextion.h>

#define trigPin A0
#define echoPin A1

String d1_str, d2_str, diff_str;
float d1, d2, diff;
long duration;
int distance;

//Declare your Nextion objects , pageid, component id., component name
NexButton b0 = NexButton(0, 2, "b0");
NexButton b1 = NexButton(0, 5, "b1");
NexButton b2 = NexButton(0, 13, "b2");
NexText t3 = NexText(0, 7, "t3");
NexText t4 = NexText(0, 8, "t4");
NexText t5 = NexText(0, 9, "t5");

//Register a button object to the touch event list

NexTouch *nex_listen_list[] = {
  &b0,
  &b1,
  &b2,
  NULL
};

void b0PopCallback(void *ptr) {
  d1 = read_Ultrasonic_Sensor();
  d1_str = String(d1);
  const char* d1CharArray = d1_str.c_str();
  t3.setText (d1CharArray);
  //t3.setText ("0.02");
}
void b1PopCallback(void *ptr) {
  d1 = d1;
  d2 = read_Ultrasonic_Sensor();
  diff = abs(d1 - d2);
  d2_str    = String(d2);
  diff_str  = String(diff);
  const char* d2CharArray   = d2_str.c_str();
  const char* diffCharArray = diff_str.c_str();
  t4.setText (d2CharArray);
  t5.setText (diffCharArray);
}
void b2PopCallback(void *ptr) {
  d1    = 0;
  d2    = 0;
  diff  = 0;
  t3.setText ("0.00");
  t4.setText ("0.00");
  t5.setText ("0.00");
}
void setup(void) {
  Serial.begin(9600);
  init_Sensors();
  nexInit();
  //Register the pop event callback function of the components
  b0.attachPop(b0PopCallback, &b0);
  b1.attachPop(b1PopCallback, &b1);
  b2.attachPop(b2PopCallback, &b2);

}

void loop() {
  nexLoop(nex_listen_list);
}



void init_Sensors() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

float read_Ultrasonic_Sensor() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  //Serial.print("Distance: ");
  //Serial.println(distance);
  return distance;
}