// From https://randomnerdtutorials.com/esp32-mqtt-publish-subscribe-arduino-ide

#include <WiFi.h>
#include "PubSubClient.h"
#include <ArduinoJson.h>

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqttServer = "broker.hivemq.com";
int port = 1883;
String stMac;
char mac[50];
char clientId[50];

WiFiClient espClient;
PubSubClient client(espClient);

const int ledPin = 2;

void setup() {
  Serial.begin(115200);
  randomSeed(analogRead(0));

  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  wifiConnect();

  Serial.println("");
  Serial.println("WiFi connected");
  
  client.setServer(mqttServer, port);
  client.setCallback(callback);
  pinMode(ledPin, OUTPUT);
}

void wifiConnect() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
}

void mqttReconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    long r = random(1000);
    sprintf(clientId, "clientId-%ld", r);
    if (client.connect(clientId)) {
      Serial.print(clientId);
      Serial.println(" connected");
      client.subscribe("order");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  
  StaticJsonDocument<200> doc;
  DeserializationError error = deserializeJson(doc, payload, length);
  
  if (error) {
    Serial.println("ORDER CONFIRMED");
    return;
  }

  int chips = doc["c1"];
  int biriyani = doc["c2"];
  int coke = doc["c3"];
  int puffs = doc["c4"];
  int sides = doc["c5"];
  int id = doc["id"];
  
  Serial.print("Customer ID: "); Serial.println(id);
  Serial.print("Chips :"); Serial.println(chips);
  Serial.print("Biriyani :"); Serial.println(biriyani);
  Serial.print("Coke :"); Serial.println(coke);
  Serial.print("Egg puffs :"); Serial.println(puffs);
  Serial.print("Chicken 65 :"); Serial.println(sides);
}

void loop() {
  delay(10);
  if (!client.connected()) {
    mqttReconnect();
  }
  client.loop();
}