#include <Arduino.h>
#include <WiFi.h>
#include <PubSubClient.h>
#include <ArduinoJson.h>
#include <LiquidCrystal_I2C.h>

const String SSID = "Wokwi-GUEST";
const String PW = "";

const String BROKER = "mqtt.beebotte.com";
const uint16_t PORT = 1883;
const String CHANNEL = "";
const String TOKEN = "";

const String TEMP_FIELD = "Temperature";
const String HUMIDITY_FIELD = "Humidity";
const String DISTANCE_FIELD = "Distance";
const String LED_FIELD = "Led";

const uint16_t LED_PIN = 32;
const uint16_t TRIG_PIN = 14;
const uint16_t ECHO_PIN = 35;

// Automatically generated from other variables
const String USERNAME = "token:" + TOKEN;
const String TEMP_TOPIC = CHANNEL + "/" + TEMP_FIELD;
const String HUMIDITY_TOPIC = CHANNEL + "/" + HUMIDITY_FIELD;
const String DISTANCE_TOPIC = CHANNEL + "/" + DISTANCE_FIELD;
const String LED_TOPIC = CHANNEL + "/" + LED_FIELD;

WiFiClient wifi;
PubSubClient mqtt;
LiquidCrystal_I2C lcd = LiquidCrystal_I2C(0x27, 20, 4);

StaticJsonDocument<64> receiveDoc;
StaticJsonDocument<128> sendDoc;

float measureDistance() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  long duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}

void callback(const char* topic, byte* payload, unsigned int length) {
  Serial.println();

  char termPayload[length + 1];
  strncpy(termPayload, (char*)payload, length);
  termPayload[length] = '\0';

  Serial.println("Received " + String(termPayload) + " on topic " + String(topic) + ".");

  if (deserializeJson(receiveDoc, termPayload) != DeserializationError::Ok) {
    Serial.println("Error parsing JSON.");
  } else if (String(topic) == TEMP_TOPIC) {
    float data = receiveDoc["data"];
    lcd.setCursor(13, 0);
    lcd.print(data);
  } else if (String(topic) == HUMIDITY_TOPIC) {
    float data = receiveDoc["data"];
    lcd.setCursor(10, 1);
    lcd.print(data);
  } else if (String(topic) == LED_TOPIC) {
    boolean data = receiveDoc["data"];
    digitalWrite(LED_PIN, data ? HIGH : LOW);
    publish();
  } else {
    Serial.println("Unrecognized topic " + String(topic));
  }
}

void publish() {
  float distance = measureDistance();
  lcd.setCursor(10, 2);
  lcd.print(distance);
  sendDoc["data"] = distance;
  String payload;
  serializeJson(sendDoc, payload);

  Serial.println("Publishing  " + payload + " to " + DISTANCE_TOPIC);

  if (mqtt.publish(DISTANCE_TOPIC.c_str(), payload.c_str())) {
    Serial.println("Distance published.");
  } else {
    Serial.println("Error publishing distance.");
  }
}

void setup() {
  Serial.begin(115200);
  while (!Serial) continue;
  Serial.println();
  Serial.print("Started.\nConnecting to wifi \"" + SSID + "\" with password \"" + PW + "\" ...");

  WiFi.begin(SSID.c_str(), PW.c_str());
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(500);
  }

  Serial.print(" Connected to Wifi. \nFinishing setup... ");

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);

  lcd.init();
  lcd.setCursor(0, 0);
  lcd.print("Temperature:       C");
  lcd.setCursor(0, 1);
  lcd.print("Humidity:       %");
  lcd.setCursor(0, 2);
  lcd.print("Distance:        cm");

  sendDoc["channel"] = CHANNEL;
  sendDoc["write"] = false;
  sendDoc["resource"] = DISTANCE_FIELD;

  mqtt.setServer(BROKER.c_str(), PORT);
  mqtt.setClient(wifi);
  mqtt.setCallback(callback);

  Serial.println("Ready.");
}

void loop() {
  if (!mqtt.connected()) {
    Serial.println("\nMQTT not connected. Connecting to broker " + BROKER + " on port " + String(PORT) + " with username=\"" + USERNAME + "\" and no password.");

    if (!mqtt.connect(String(random(4294967295)).c_str(), USERNAME.c_str(), NULL)) {
      return;
    }

    Serial.println("Connected to broker. Subbing.");
    if (mqtt.subscribe(TEMP_TOPIC.c_str())) {
      Serial.println("Subbed to " + TEMP_TOPIC + ".");
    }
    if (mqtt.subscribe(HUMIDITY_TOPIC.c_str())) {
      Serial.println("Subbed to " + HUMIDITY_TOPIC + ".");
    }
    if (mqtt.subscribe(LED_TOPIC.c_str())) {
      Serial.println("Subbed to " + LED_TOPIC + ".");
    }
    return;
  }

  mqtt.loop();
  delay(200);
}