#include <TinyGPS++.h> // Library TinyGPS++
#include <SoftwareSerial.h> // Library SoftwareSerial

// Define pins for GPS
int GPS_RXPin = 8; // Connect to TX of GPS
int GPS_TXPin = 9; // Connect to RX of GPS
int GPSBaud = 9600; // Default baud rate for GPS

// Create TinyGPS++ object
TinyGPSPlus gps;

// Create SoftwareSerial object for GPS
SoftwareSerial gpsSerial(GPS_RXPin, GPS_TXPin);

// Define pins for SIM800L
#define SIM800L_RX 3
#define SIM800L_TX 2
SoftwareSerial sim800L(SIM800L_RX, SIM800L_TX);

// URL to send data to server
String serverURL = "http://tesgpslakatan.000webhostapp.com";

void setup() {
  Serial.begin(9600); // Start serial communication at 9600 baud rate
  gpsSerial.begin(GPSBaud); // Start serial communication with GPS
  sim800L.begin(9600); // Start serial communication with SIM800L

  Serial.println("Initializing SIM800L...");
  delay(10000); // Wait for SIM800L to be ready

  if (sendATcommand("AT", "OK", 2000)) {
    Serial.println("SIM800L is ready");
  } else {
    Serial.println("Failed to communicate with SIM800L");
    while (true); // Halt execution if SIM800L fails
  }
}

void loop() {
  while (gpsSerial.available() > 0) {
    gps.encode(gpsSerial.read());
  }

  if (gps.location.isValid()) {
    String lat = String(gps.location.lat(), 6);
    String lng = String(gps.location.lng(), 6);
    String altitude = String(gps.altitude.meters());
    String date = String(gps.date.value());
    String time = String(gps.time.value());

    Serial.println("GPS signal acquired");
    Serial.print("Latitude: "); Serial.println(lat);
    Serial.print("Longitude: "); Serial.println(lng);
    Serial.print("Altitude: "); Serial.println(altitude);
    Serial.print("Date: "); Serial.println(date);
    Serial.print("Time: "); Serial.println(time);

    sendGpsToServer(lat, lng, altitude, date, time);
    delay(60000); // Wait 60 seconds before sending data again
  } else {
    Serial.println("Waiting for GPS signal...");
    delay(1000); // Wait 1 second before checking again
  }
}

void sendGpsToServer(String lat, String lng, String altitude, String date, String time) {
  String data = "lat=" + lat + "&lng=" + lng + "&alt=" + altitude + "&date=" + date + "&time=" + time;

  if (sendATcommand("AT+CGATT=1", "OK", 2000) &&
      sendATcommand("AT+SAPBR=3,1,\"Contype\",\"GPRS\"", "OK", 2000) &&
      sendATcommand("AT+SAPBR=3,1,\"APN\",\"internet\"", "OK", 2000) &&
      sendATcommand("AT+SAPBR=1,1", "OK", 2000)) {

    sendATcommand("AT+HTTPINIT", "OK", 2000);
    sendATcommand("AT+HTTPPARA=\"CID\",1", "OK", 2000);
    sim800L.print("AT+HTTPPARA=\"URL\",\"");
    sim800L.print(serverURL);
    sim800L.println("\"");
    sendATcommand("", "OK", 2000);

    sendATcommand("AT+HTTPPARA=\"CONTENT\",\"application/x-www-form-urlencoded\"", "OK", 2000);
    sim800L.print("AT+HTTPDATA=");
    sim800L.print(data.length());
    sim800L.println(",10000");
    delay(100);
    sim800L.println(data);
    delay(10000);
    sendATcommand("AT+HTTPACTION=1", "200", 30000);
    sendATcommand("AT+HTTPTERM", "OK", 2000);
  } else {
    Serial.println("Failed to configure GPRS connection");
  }
}

bool sendATcommand(const char* ATcommand, const char* expected_response, unsigned int timeout) {
  sim800L.println(ATcommand);
  unsigned long startTime = millis();
  String response = "";

  while (millis() - startTime < timeout) {
    if (sim800L.available()) {
      response += sim800L.readStringUntil('\n');
      if (response.indexOf(expected_response) != -1) {
        return true;
      }
    }
  }

  Serial.print("Timeout waiting for response: ");
  Serial.println(response);
  return false;
}