dog_tracker.ino
//https://dweet.io/get/latest/dweet/for/869951031430170
#include <ArduinoJson.h>
#include "Adafruit_FONA.h" // https://github.com/botletics/SIM7000-LTE-Shield/tree/master/Code
#define SIMCOM_7000 // SIM7000A/C/E/G
#define FONA_PWRKEY 4
#define FONA_RST 25
#define FONA_TX 26 // ESP32 hardware serial RX2 (GPIO16)
#define FONA_RX 27 // ESP32 hardware serial TX2 (GPIO17)
#include <HardwareSerial.h>
HardwareSerial fonaSS(1);
Adafruit_FONA_LTE fona = Adafruit_FONA_LTE();
#define uS_TO_S_FACTOR 1000000ULL  /* Conversion factor for micro seconds to seconds */
#define TIME_TO_SLEEP  600        /* Time ESP32 will go to sleep (in seconds) */


uint8_t readline(char *buff, uint8_t maxbuff, uint16_t timeout = 0);
uint8_t type;
char replybuffer[255]; // this is a large buffer for replies
char imei[16] = {0}; // MUST use a 16 character buffer for IMEI!
char c [255];
float latitude, longitude, speed_kph, heading, altitude, second;
const char* found = "found";
const char* lost = "lost";
char latBuff[12], longBuff[12];

void setup() {
delay(1000);
  pinMode(FONA_RST, OUTPUT);
  digitalWrite(FONA_RST, HIGH); // Default state

  pinMode(FONA_PWRKEY, OUTPUT);

  powerOn(); // See function definition at the very end of the sketch

  Serial.begin(9600);
  Serial.println(F("ESP32 Basic Test"));
  Serial.println(F("Initializing....(May take several seconds)"));
  delay(2000);
  esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR);

  // Start at default SIM7000 shield baud rate
  fonaSS.begin(115200, SERIAL_8N1, FONA_TX, FONA_RX); // baud rate, protocol, ESP32 RX pin, ESP32 TX pin

  Serial.println(F("Configuring to 9600 baud"));
  fonaSS.println("AT+IPR=9600"); // Set baud rate
  delay(1000); // Short pause to let the command run
  fonaSS.begin(9600, SERIAL_8N1, FONA_TX, FONA_RX); // Switch to 9600
  if (! fona.begin(fonaSS)) {
    Serial.println(F("Couldn't find FONA"));
    fona.enableSleepMode(false);
    ESP.restart();
    while (1); // Don't proceed if it couldn't find the device
  }

  // Print module IMEI number.
  uint8_t imeiLen = fona.getIMEI(imei);
  if (imeiLen > 0) {
    Serial.print("Module IMEI: "); Serial.println(imei);
  }

  fona.setFunctionality(1); // AT+CFUN=1
  fona.setNetworkSettings(F("h2g2"), F("h2g2"));
  if (!fona.enableSleepMode(false)) {
    fona.enableSleepMode(false);
    ESP.restart();
  }

}




void loop() {
  fona.println("AT+SGPIO=0,4,1,1");
  delay(1000);
   fona.enableGPS(true);
  fona.enableGPRS(true); //enable data 
  delay(1000);
/*
  int8_t gpsstat = fona.GPSstatus();
 Serial.println("starting loop");
 uint8_t n = fona.getNetworkStatus();
        Serial.print(F("Network status "));
        Serial.print(n);
        if (n == 0) Serial.println(F("Not registered"));
        if (n == 1) Serial.println(F("Registered (home)"));
        if (n == 2) Serial.println(F("Not registered (searching)"));
        if (n == 3) Serial.println(F("Denied"));
        if (n == 4) Serial.println(F("Unknown"));
        if (n == 5) Serial.println(F("Registefona.getGPSred roaming"));
         delay(3000);
        // check GPS fix
        while (gpsstat < 0)
          Serial.println(gpsstat);          
        if (gpsstat == 0) Serial.println(F("GPS off"));
        if (gpsstat == 1) Serial.println(F("No fix"));
        if (gpsstat == 2) Serial.println(F("2D fix"));
        if (gpsstat == 3) Serial.println(F("3D fix"));
         delay(3000);
*/         
// read website URL
        uint16_t statuscode;
        int16_t length;
        char* url = "http://dweet.io/get/latest/dweet/for/869951031430170";
        char* URL = "http://";
        char replybuffer[254];
        uint16_t replyidx = 0;
        
        //flushSerial();
        Serial.println(F("URL to read (e.g. dweet.io/get/latest/dweet/for/869951031430170):"));
        //Serial.print(F("http://")); readline(url, 79);
        Serial.println(url);
        Serial.println(F("****"));
        if (!fona.HTTP_GET_start(url, &statuscode, (uint16_t *)&length)) {
          Serial.println("Failed!");

        }
        while (length > 0) {
          while (fona.available()) {
            char c = fona.read();
            replybuffer[replyidx] = c;
            replyidx++;
            // Serial.write is too slow, we'll write directly to Serial register!
            Serial.write(c);   
            length--;
            if (! length) break;
          }
        }
        Serial.println(F("\n****"));
        fona.HTTP_GET_end();
        Serial.println(replybuffer);
        
        const size_t capacity = JSON_OBJECT_SIZE(1) + 2*JSON_OBJECT_SIZE(4) + 310;
        DynamicJsonDocument doc(capacity);
        const char* json = replybuffer;
        deserializeJson(doc, json);

        const char* by = doc["by"]; // "getting"
        const char* the = doc["the"]; // "dweets"

        JsonObject with_0 = doc["with"][0];
        const char* with_0_thing = with_0["thing"]; // "869951031430170"
        const char* with_0_created = with_0["created"]; // "2020-11-18T07:20:23.410Z"

        const char* with_0_content_state = with_0["content"]["state"]; // "found"
        Serial.println(with_0_content_state);
        if (strcmp(with_0_content_state, lost) == 0){
          Serial.println("lost");
          //float latitude, longitude, speed_kph, heading, altitude, second;
          uint16_t year;
          uint8_t month, day, hour, minute;
          char URL[150];

          // Use the top line if you want to parse UTC time data as well, the line below it if you don't care
          //        if (fona.getGPS(&latitude, &longitude, &speed_kph, &heading, &altitude, &year, &month, &day, &hour, &minute, &second)) {
          if (fona.getGPS(&latitude, &longitude, &speed_kph, &heading, &altitude)) { // Use this line instead if you don't want UTC time
            Serial.println(F("---------------------"));
            Serial.print(F("Latitude: ")); Serial.println(latitude, 6);
            Serial.print(F("Longitude: ")); Serial.println(longitude, 6);
//          Serial.print(F("Speed: ")); Serial.println(speed_kph);
//          Serial.print(F("Heading: ")); Serial.println(heading);
//          Serial.print(F("Altitude: ")); Serial.println(altitude);
            dtostrf(latitude, 1, 6, latBuff);
            dtostrf(longitude, 1, 6, longBuff);

            sprintf(URL, "dweet.io/dweet/for/%s1?lat=%s&long=%s", imei, latBuff, longBuff);

          if (!fona.postData("GET", URL))
          Serial.println(F("Failed to complete HTTP GET..."));
          
        }

        }
        Serial.println("sleeping");
        fona.enableSleepMode(true);
        esp_deep_sleep_start();
}

void flushSerial() {
  Serial.println("flushing serial");
  while (! Serial.available() ) {
    if (fona.available()) {
      Serial.write(fona.read());
    }
  }
}

  

// Power on the module
void powerOn() {
  digitalWrite(FONA_PWRKEY, LOW);
  // See spec sheets for your particular module
#if defined(SIMCOM_2G)
  delay(1050);
#elif defined(SIMCOM_3G)
  delay(180); // For SIM5320
#elif defined(SIMCOM_7000)
  delay(100); // For SIM7000
#elif defined(SIMCOM_7500)
  delay(500); // For SIM7500
#endif
  digitalWrite(FONA_PWRKEY, HIGH);
}