#include <WiFi.h>
#include <PubSubClient.h>
#include <NTPClient.h>
#include <WiFiUdp.h>
#include <DHT.h>

// WiFi related
const char* ssid = "Wokwi-GUEST";
const char* password = "   ";

// MQTT related
WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
const unsigned long MSG_INTERVAL = 10000; // minimum interval between messages
//const unsigned long MSG_INTERVAL = 5000*60; // minimum interval between messages
const char* mqtt_server = "broker.mqtt-dashboard.com";
const int MQTT_PORT = 1883;
const char* MQTT_DEVICE_TOPIC = "cefet/biblioteca/esp32_03";
const char* MQTT_NODE_TOPIC = "cefet/biblioteca/esp32_03/dht22";
const char* MQTT_TIMESTAMP_TOPIC = "cefet/biblioteca/esp32_03/dht22/timestamp";
const char* MQTT_TEMPERATURE_TOPIC = "cefet/biblioteca/esp32_03/dht22/temperature";
const char* MQTT_HUMIDITY_TOPIC = "cefet/biblioteca/esp32_03 /dht22/humidity";
const boolean MQTT_RETAINED = true;
String mqtt_msg;

// NTP network time protocol related
const int UTC_OFFSET = -3*3600; // Brasilia UTC time offset
const long NTP_UPDATE_INTERVAL = 3600*1000;
WiFiUDP ntp_UDP;
NTPClient time_client(ntp_UDP, "south-america.pool.ntp.org", UTC_OFFSET, NTP_UPDATE_INTERVAL);
//String timestamp;

const int BUILTIN_LED = 2;

// DHT sensor related
const uint8_t DHT_PIN = 5;
//const uint8_t VCC_PIN = 18;
// const uint8_t GND_PIN = 19;

DHT dht(DHT_PIN, DHT22);
float temperature;
float humidity;

void setup_wifi() {

  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  randomSeed(micros());

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

String getTimestamp(unsigned long epoch_time) {
  //Get a time structure
  struct tm *ptm = gmtime ((time_t *)&epoch_time); 
  char string_buffer[20];

  //Print complete date:
  sprintf_P(string_buffer, PSTR("%4d-%02d-%02dT%d:%02d:%02d"), ptm->tm_year+1900, ptm->tm_mon+1, ptm->tm_mday, ptm->tm_hour, ptm->tm_min, ptm->tm_sec);
  String current_timestamp = String(string_buffer);
  return current_timestamp;
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Create a random client ID
    String clientId = "ESP8266Client-";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("connected");
      // Once connected, publish attributes
      // Device attributes
      client.publish((String(MQTT_DEVICE_TOPIC)+"/$homie").c_str(), (uint8_t *)"3.0.0", 5, MQTT_RETAINED);
      client.publish((String(MQTT_DEVICE_TOPIC)+"/$name").c_str(), (uint8_t *)"Casa", 14, MQTT_RETAINED);
      client.publish((String(MQTT_DEVICE_TOPIC)+"/$state").c_str(), (uint8_t *)"ready", 5, MQTT_RETAINED);
      client.publish((String(MQTT_DEVICE_TOPIC)+"/$nodes").c_str(), (uint8_t *)"dht22", 5, MQTT_RETAINED);
      client.publish((String(MQTT_DEVICE_TOPIC)+"/$implementation").c_str(), (uint8_t *)"esp32", 7, MQTT_RETAINED);

      // Node DHT22 attributes
      client.publish((String(MQTT_NODE_TOPIC)+"/$name").c_str(), (uint8_t *)"Temperature and Humidity sensor", 12, MQTT_RETAINED);
      mqtt_msg = "AM2302 DHT22";
      client.publish((String(MQTT_NODE_TOPIC)+"/$type").c_str(), (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
      mqtt_msg = "timestamp,temperature,humidity";
      client.publish((String(MQTT_NODE_TOPIC)+"/$properties").c_str(), (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
      
      // DHT22 properties attributes
      // Timestamp
      mqtt_msg = "Timestamp of sampled data";
      client.publish((String(MQTT_TIMESTAMP_TOPIC)+"/$name").c_str(), (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
      mqtt_msg = "DateTime";
      client.publish((String(MQTT_TIMESTAMP_TOPIC)+"/$datatype").c_str(), (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
      // Temperature
      mqtt_msg = "Ambient Temperature";
      client.publish((String(MQTT_TIMESTAMP_TOPIC)+"/$name").c_str(), (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
      mqtt_msg = "Float";
      client.publish((String(MQTT_TIMESTAMP_TOPIC)+"/$datatype").c_str(), (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
      mqtt_msg = "C";
      client.publish((String(MQTT_TIMESTAMP_TOPIC)+"/$unit").c_str(), (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
      // Humidity
      mqtt_msg = "Ambient Relative Humidity";
      client.publish((String(MQTT_TIMESTAMP_TOPIC)+"/$name").c_str(), (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
      mqtt_msg = "Percent";
      client.publish((String(MQTT_TIMESTAMP_TOPIC)+"/$datatype").c_str(), (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
      
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  pinMode(BUILTIN_LED, OUTPUT);     // Initialize the BUILTIN_LED pin as an output
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, MQTT_PORT);
  time_client.begin();

  // DHT22
  //pinMode(VCC_PIN, OUTPUT);
  //pinMode(GND_PIN, OUTPUT);
  //digitalWrite(VCC_PIN, HIGH);
  //digitalWrite(GND_PIN, LOW);
  pinMode(DHT_PIN, INPUT);
  dht.begin();
}

void loop() {

  if (!client.connected()) {
    reconnect();
  }
  client.loop();

  unsigned long now = millis();
  if (now - lastMsg > MSG_INTERVAL) {
    lastMsg = now;
    time_client.update();

    // Publish timestamp, temperature and humidity
    digitalWrite(BUILTIN_LED, HIGH);  // acende o LED
    mqtt_msg = getTimestamp(time_client.getEpochTime());
    client.publish(MQTT_TIMESTAMP_TOPIC, (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
    mqtt_msg = dht.readTemperature();
    client.publish(MQTT_TEMPERATURE_TOPIC, (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
    mqtt_msg = dht.readHumidity();
    client.publish(MQTT_HUMIDITY_TOPIC, (uint8_t *)mqtt_msg.c_str(), mqtt_msg.length(), MQTT_RETAINED);
    digitalWrite(BUILTIN_LED, LOW); // apaga o LED    
  }
}