//code sourced from [Bytes N Bits] & [Ahmad Logs]
#include <TinyGPSPlus.h>
#include <SoftwareSerial.h>

//GPS stuff
const byte gps_RX = 7, gps_TX = 6;// TXPin must be a PWM pin

TinyGPSPlus gps;
SoftwareSerial NEO6M(gps_RX, gps_TX);


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

//button stuff
const byte button_Vin = 9; 
const byte button_Vout = 11;

//pressure resistor stuff
const byte pressurePin_Vin = 8; 

//bluetooth stuff
const byte bt_Vin = 4;
const byte bt_gate = 2; //controls the dataflow of the Bluetooth




void setup() {
  
  Serial.begin(9600); //Bluetooth module now uses Serial pins 0 and 1
  NEO6M.begin(9600);
  
  //thermistor is connected to A0
  pinMode(motionPin, INPUT_PULLUP); //motion sensor
  pinMode(buzzPin, OUTPUT); //Buzzer

  pinMode(button_Vin, OUTPUT);
  pinMode(button_Vout, INPUT_PULLUP);

  pinMode(pressurePin_Vin, OUTPUT); //reads pressure with pin A1;

  pinMode(bt_Vin, OUTPUT);
  digitalWrite(bt_Vin, HIGH); //powers bluetooth
  
  pinMode(bt_gate, OUTPUT);
  digitalWrite(bt_gate, HIGH);

  Serial.print("The device is READY.\n");
  delay(1000);

}


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 pressure = analogRead(A1);
  static int buzzTime = 250; //buzzer rhythm
  static byte trackingMode = 0; //remembers if someone was in the backseat
  static int trackingTime = 0;
  static int alertTime = 50;
  //static uint16_t safeTIME;
  
  //static float safeLAT = 29.892, safeLNG = -95.430; //Qamar's Home
  //static float safeLAT = 29.722, safeLNG = -95.342; //Technology Annex
  static float safeLAT[3] = {29.892, 29.722, 0.000};
  static float safeLNG[3] = {-95.430, -95.342, 0.000};
  static float safeRange = 0.0072;
  
  static String msg_from_bt = "";
  static String atm = "";
  static byte dByte = 0;
  static byte alertMode = 0;
  static bool list = false;
  bool theft = true; //assumes theft occurs until verified

  
  while (NEO6M.available() > 0){
    if (gps.encode(NEO6M.read())) {} //reads GPS buffer without doing anything

    if (millis() > 5000 && gps.charsProcessed() < 10){
        Serial.println("No GPS detected: check wiring.");
        while(true);
    }
  }
  

  //button
  if (digitalRead(button_Vout) == 0 ) {
    Serial.print("\nButton Test Successful");
    
    displayInfo();
    tone(buzzPin,150,50);
    delay(buzzTime);
    tone(buzzPin,250,50);
  }

  //bt commands test
  if (msg_from_bt == "TEST") {
    theftInfo();
    tone(buzzPin,150,1250);
    delay(buzzTime);
    //tone(buzzPin,250,50);
  }

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

  //pressure sensor 
  
  if(list == true){
    Serial.print(pressure); 
    Serial.print("  ");
    //motion sensor
    Serial.print(motion);
    Serial.print("  ");
    //thermistor
    Serial.print(celsius);
    Serial.print("  ");
  }
  

  if (motion == 1 || pressure < 15){
    trackingMode = 1; //someone is in the backseat
    trackingTime = 10; //memory of someone in backseat
  }

  
  if (trackingMode == 1) {
    Serial.print("Passenger?");
    Serial.print("   \n");
  } else if(list == true){
    Serial.print(" \n");
  }

  

  //alert siren for heat stroke or hypothermia threat
  if (trackingMode == 1 && (celsius >= 37.8 || celsius <= 10)) {
    alertMode = 1;
    Serial.print("DANGER!");
    Serial.print("   ");
    tone(buzzPin,150,50);
    delay(buzzTime);
    tone(buzzPin,250,50);
    if (alertTime != 0) alertTime--;
  }
  else delay(buzzTime); //delay compensates for buzzer usage

  if (trackingMode == 1) trackingTime--; //passenger memory fades

  if (trackingTime == 0) trackingMode = 0;

  

  //phone -> bluetooth -> BG
  msg_from_bt = "";
  while(Serial.available() > 0){
    dByte = Serial.read();
    if (dByte >= 97 && dByte <= 122) dByte -= 32; //capitalizes message
    if (dByte > 31 && dByte < 127) msg_from_bt += (char)dByte; //only stores printing bytes
    Serial.print((char)dByte);
  }

  if (msg_from_bt == "LOC") {
    Serial.print("\n");
    Serial.print(gps.location.lat(), 6);
    Serial.print(", ");
    Serial.print(gps.location.lng(), 6);
    Serial.print("\n \n");
  }

  if (msg_from_bt == "LIST"){
    list = !list; //flip boolean
  }

  if (gps.date.isValid() && msg_from_bt == "SAFE"){
    readGPS();
    safeLAT[2] = gps.location.lat();
    safeLNG[2] = gps.location.lng();
    Serial.println("Your current location is marked as SAFE for now.");
  }

  /*
  if (gps.date.isValid()){
    readGPS();
    if ((safeRange < abs(safeLAT[0] - gps.location.lat())) || (safeRange < abs(safeLNG[0] - gps.location.lng()))){
      readGPS();
      if ((safeRange < abs(safeLAT[1] - gps.location.lat())) || (safeRange < abs(safeLNG[1] - gps.location.lng()))){
        readGPS();
        if ((safeRange < abs(safeLAT[2] - gps.location.lat())) || (safeRange < abs(safeLNG[2] - gps.location.lng()))){
          theftInfo();
        }
      }
    }
  }*/

  if (gps.date.isValid()){
    readGPS();
    for(int k = 0; k < 3; k++){
      if ((safeRange > abs(safeLAT[k] - gps.location.lat())) && (safeRange > abs(safeLNG[k] - gps.location.lng()))){
        theft = false;
      }
      readGPS();
    }
    if(theft == true) theftInfo();
  }
  

} 

//---------end of the main loop--------------

void displayInfo(){
  Serial.print("\nLocation: "); 
  if (gps.location.isValid())
  {
    Serial.print(gps.location.lat(), 6);
    Serial.print(", ");
    Serial.print(gps.location.lng(), 6);
  }
  else
  {
    Serial.print("N/A");
  }

  Serial.print("\nDate ");
  if (gps.date.isValid())
  {
    Serial.print(gps.date.month());
    Serial.print("/");
    Serial.print(gps.date.day());
    Serial.print("/");
    Serial.print(gps.date.year());
    Serial.print("\n");
  }
  else Serial.print("N/A \n");
  Serial.print("\n");

}

void readGPS(){
  while (NEO6M.available() > 0){
    if (gps.encode(NEO6M.read())) {} //reads GPS buffer without doing anything

    if (millis() > 5000 && gps.charsProcessed() < 10){
        Serial.println("No GPS detected: check wiring.");
        while(true);
    }
  }
}

void theftInfo(){
  readGPS();
  Serial.println("CAR STOLEN!");
  Serial.print(gps.location.lat(), 6);
  Serial.print(", ");
  Serial.println(gps.location.lng(), 6);
}