#include <WiFi.h>
#include <HTTPClient.h>

String payload;
int JSONLoop;
const int jsonPayloadSize = 50;
const int tmpdocSize = 8000 ; // 200 x jsonPayloadSize
const int MaxPIDs = 231; //Master

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");
    Serial.begin(9600);
  Serial.print("Connecting to WiFi");
  WiFi.begin("Wokwi-GUEST", "", 6);
  while (WiFi.status() != WL_CONNECTED) {
    delay(100);
    Serial.print(".");
  }
  Serial.println(" Connected!");

  httpPost();
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(10); // this speeds up the simulation
}


/* ======================================================================
Function: httpPost
Purpose : Do a http post
Input   : hostname
          port
          url
Output  : true if received 200 OK
Comments: -
====================================================================== */
//boolean httpPost(char * host, uint16_t port, char * url)
boolean httpPost()
{
  HTTPClient http;
  bool ret = false;

    if ((JSONLoop + jsonPayloadSize) > MaxPIDs) {
      JSONLoop=0;
  }
  else
  {
      JSONLoop = JSONLoop + jsonPayloadSize;
  }

  unsigned long start = millis();

  // configure target server and url
  //http.begin(host, port, url, port==443 ? true : false); 
  //http.begin("http://emoncms.org/input/post.json?node=20&apikey=apikey&json={PAPP:100}");

  String out = "https://api.tfgm.com/odata/Metrolinks?$top="  ;
//Serial.print("JSONLoop:");
//Serial.println(JSONLoop);
//Serial.print("jsonPayloadSize:");
//Serial.println(jsonPayloadSize);
//Serial.print("MaxPIDs:");
//Serial.println(MaxPIDs);
if((JSONLoop + jsonPayloadSize) > MaxPIDs)
{
  out += (MaxPIDs - JSONLoop);
} 
else
{
  out += jsonPayloadSize;
}

  
  
  out += "&$skip=";
  out += JSONLoop;
  out += "&$select=Wait0,PIDREF,Status0,Id,dest0";
  //Serial.println(out);
 
  http.begin(out); 
  //http.begin("https://api.tfgm.com/odata/Metrolinks?$filter=Line eq 'Trafford Park'&$top=10 HTTP/1.1"); doesn't work
  http.addHeader("Ocp-Apim-Subscription-Key", "012ac3b8b4f34600b75e90d9ed155872");
  http.addHeader("Host", "api.tfgm.com");

  //Debugf("http%s://%s:%d%s => ", port==443?"s":"", host, port, url);

  // start connection and send HTTP header
  //Serial.println("start GET");
  int httpCode = http.GET();
  //Serial.println("End GET");
  if(httpCode) {
      // HTTP header has been send and Server response header has been handled
      //Serial.println(httpCode);
      //Serial.println(" ");
      // file found at server
      if( httpCode > 199 && httpCode < 300 ) {
        //String payload = http.getString();
        payload = http.getString();
        Serial.println(payload);
       //                                             Parse();
        ret = true;
      }
  } else {
      Serial.println("failed!");
  }
  //Serial.println(" in %d ms\r\n",millis()-start);
  return ret;
}