#include <ArduinoJson.h>
#include <TimeLib.h>

// Root document for JSON
// Variable name is stored at the root level. Cannot start with underscore (_).
// `data` subfield stores the actual data
// `ri` subfield stores the refresh interval
// `lr` subfield stores the last refresh timestamp if refresh interval is set
// `d` subfield indicates whether the data is dirty and needs to be flushed
DynamicJsonDocument  root(128);

// Add a variable to root ot type int.
// @var: the name of the variable (document)
// @key: the key / name
// @val: the initial value
// @refresh_interval: the frequency, in sec, to force update the value even if value is unchanged
void addValueInt(const String& var, const String& key, const int val, const long refresh_interval = 0) {
  JsonObject doc = root.createNestedObject(var);
  JsonObject data = doc.createNestedObject("data");
  data[key] = val;
  doc["ri"] = refresh_interval;
  if(refresh_interval) {
    doc["lr"] = now();
  }
  doc["d"] = 1;
}

void updateValueInt(const String& var, const String& key, const int val) {
  Serial.println("2.1");
  Serial.flush();
  JsonObject doc = root[var];
  Serial.println("2.2");
  JsonObject data = doc["data"];
  Serial.println("2.3");
  // long t = now();
  if(data[key] != val) {
    // data["ts"] = t;
    Serial.println("2.4");
    data[key] = val;
    if(doc["ri"]) {
      doc["lr"] = now();
    }
    doc["d"] = 1;
  }
  Serial.println("2.5");
  /* else {
    long refresh_interval = doc["ri"];
    if (refresh_interval && t >= (long)data["ts"] + refresh_interval) {
      data["ts"] = t;
      data[key] = val;
      doc["d"] = 1;
    }
  }*/
}

String serializeVar(const String& var, bool add_timestamp = false, bool mark_flushed = false) {
  String s;
  if(add_timestamp) {
    JsonObject data = root[var]["data"];
    DynamicJsonDocument d(data.memoryUsage() + 8);  // Timestamp occupies 8 spaces.
    d = data;
    d["ts"] = now();
    serializeJson(d, s);
  } else {
    serializeJson(root[var]["data"], s);
  }
  if(mark_flushed) {
    root[var]["d"] = 0;
  }
  return s;
}

String poll() {
  JsonObject root_ = root.as<JsonObject>();  // Iterator is only defined for JsonObject & Array.
  for (JsonPair kv : root_) {
    String key = String(kv.key().c_str());
    JsonObject doc = root[key];
    // Check if refresh is due.
    bool update = false;
    if(doc["d"]) {
      update = true;
    } else if (doc["ri"] && (now() >= (long) doc["ri"] + (long) doc["lr"])) {
      update = true;
      doc["lr"] = now();
    }
    if(update) {
      Serial.println("Send " + key + "=" + serializeVar(key, true, true));
    }
  }
}

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  while(!Serial);

  long t = 1678528333;  // Epoch for Mar 11 3:52AM CT
  // May be optional depending on WifiNINA implementation.
  setTime(t);
  Serial.println(now());
  // Serial.println(year());
  // Serial.println(month());
  // Serial.println(day());
  // Serial.println(hour());
  // Serial.println(minute());

  Serial.println(root.memoryUsage());

  addValueInt("ktc1", "temp", 1234, 2);

  Serial.println(root.memoryUsage());

  // serializeJson(root, Serial);
  // Serial.println();
  poll();
  // String data;
  // serializeJson(doc, data);
  // Serial.println(data); 
  delay(3000);
  updateValueInt("ktc1", "temp", 2345);

  // serializeJson(root, Serial);
  // Serial.println();
  poll();

  delay(3000);
  Serial.println("1");
  // serializeJson(root, Serial);
  // Serial.println();
  Serial.println("2");
  updateValueInt("ktc1", "temp", 2345);
  Serial.println("3");
  serializeJson(root, Serial);
  Serial.println();
  Serial.println("4");
  poll();
  serializeJson(root, Serial);
  Serial.println();
  Serial.println("5");
  /*
  JsonObject root_ = root.as<JsonObject>();  // Iterator is only defined for JsonObject & Array.
  for (JsonPair kv : root_) {
    String key = String(kv.key().c_str());
    Serial.println(key + "=" + serializeVar(key, false, true));
  }

  serializeJson(root, Serial);
  Serial.println();

  Serial.println(root.memoryUsage());
  */
}


void loop() {
  // put your main code here, to run repeatedly:

}