//This combines the sensors and buzzer with the GSM
#include <SoftwareSerial.h> //used for GSM

SoftwareSerial mySerial(2, 3);
String cmd = "";

const float BETA = 3950; // should match the Beta Coefficient of the thermistor
const int motionPin = 13;
const int buzzPin = 12;

void setup() {
  Serial.begin(9600);// put your setup code here, to run once:
  //thermistor is connected to A0
  pinMode(motionPin, INPUT_PULLUP); //motion sensor
  pinMode(buzzPin, OUTPUT); //Buzzer
  
mySerial.begin(9600);
Serial.print("Initializing");

mySerial.println("AT");
updateSerial();
mySerial.println("AT+CMGF=1");
updateSerial();
mySerial.println("AT+CNMI=1,2,0,0,0");
updateSerial();

}


void loop() {

  int analogValue = analogRead(A0); //thermistor uses analog pins
  float celsius = 1 / (log(1 / (1023. / analogValue - 1)) / BETA + 1.0 / 298.15) - 273.15;
  
  int motion = digitalRead(motionPin);
  int buzzTime = 150; //buzzer rhythm
  static int trackingMode = 0; //remembers if someone was in the backseat

  static int trackingTime = 0;


  //---------------------

  updateSerial();

  Serial.print(motion);
  Serial.print("   ");
  Serial.print(celsius);
  Serial.print("   ");
  
  if (motion == 1){
    trackingMode = 1; //someone is in the backseat
    trackingTime = 200; //memory of someone in backseat
  }

if (trackingMode == 1) {
  Serial.print("Passenger?");
  Serial.print("   ");
}


//alert siren for heat stroke or hypothermia threat
if (trackingMode == 1 && (celsius >= 40 || celsius <= 0)) {
Serial.print("DANGER!");
  Serial.print("   ");
tone(buzzPin,150,50);
delay(buzzTime);
tone(buzzPin,250,50);
}
else delay(buzzTime); //delay compensates for buzzer usage

Serial.println();


if (trackingMode == 1) {
  trackingTime--; //passenger memory fades
  if (trackingTime == 0) {
    trackingMode = 0;
    alert_end();
  }
}


} //end of the main loop


void updateSerial(){
  delay(500);
  while (Serial.available()){
    cmd += (char)Serial.read();
    cmd.trim();
    if (cmd.equals("S") || cmd.equals("s")){
      testSMS();
    } else {
      mySerial.print(cmd);
      mySerial.println("");
    }
  }
}

void alert_end(){
  //Qamar's phone
  Serial.println("AT+CMGF=1");
  delay(500);
  Serial.println("AT+CMGS=\"+12816761164\"\r");
  delay(500);
  Serial.println("Danger Resolved.");
  delay(500);
  Serial.write(26);
  //Jesse's phone
  Serial.println("AT+CMGF=1");
  delay(500);
  Serial.println("AT+CMGS=\"+8327956864\"\r");
  delay(500);
  Serial.println("Danger Resolved.");
  delay(500);
  Serial.write(26);
  
}

void testSMS(){
  //Qamar's phone
  Serial.println("AT+CMGF=1");
  delay(500);
  Serial.println("AT+CMGS=\"+12816761164\"\r");
  delay(500);
  Serial.println("Test Successful.");
  delay(500);
  Serial.write(26);
  //Jesse's phone
  Serial.println("AT+CMGF=1");
  delay(500);
  Serial.println("AT+CMGS=\"+8327956864\"\r");
  delay(500);
  Serial.println("Test Successful.");
  delay(500);
  Serial.write(26);
  
}