#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
#include <DHTesp.h>
#include <PubSubClient.h>
#include <WiFi.h>

// Define the LCD screen
LiquidCrystal_I2C LCD = LiquidCrystal_I2C(0x27, 16, 2);

//definir Sensor Luz
const int LDR_PIN =2;
const float GAMMA = 0.7;
const float RL10 = 50;

// Define random ID
String ID_MQTT;
char *letters = "abcdefghijklmnopqrstuvwxyz0123456789";

// Define MQTT Topics
#define TOPIC_PUBLISH_TEMPERATURE "temperature"
#define TOPIC_PUBLISH_HUMIDITY "humidity"

// Update every 1 seconds
#define PUBLISH_DELAY 500
unsigned long publishUpdate;

// Wi-Fi settinges
const char *SSID = "Wokwi-GUEST";
const char *PASSWORD = "";

// Define MQTT Broker and PORT
const char *BROKER_MQTT = "broker.hivemq.com";
int BROKER_PORT = 1883;

// Defined ports
const int DHT_PIN = 15;

// Global variables
WiFiClient espClient;
PubSubClient MQTT(espClient); 
DHTesp dhtSensor;

// Declarations
void startWifi(void);
void initMQTT(void);
void callbackMQTT(char *topic, byte *payload, unsigned int length);
void reconnectMQTT(void);
void reconnectWiFi(void);
void checkWiFIAndMQTT(void);


// Starts the Wi-Fi
void startWifi(void) {
  reconnectWiFi();
}

// Starts everything from MQTT
void initMQTT(void) {
  MQTT.setServer(BROKER_MQTT, BROKER_PORT);
  MQTT.setCallback(callbackMQTT);
}

// Callback from Android 
// --- Get the messages here
void callbackMQTT(char *topic, byte *payload, unsigned int length) {
  String msg;

  // Convert payload to string
  for (int i = 0; i < length; i++) {
    char c = (char)payload[i];
    msg += c;
  }

  Serial.printf("Topic: %s\n", topic);
  Serial.printf("Message: %s\n", msg, topic);

}

// Connects to the Broker with a specific random ID
void reconnectMQTT(void) {
  while (!MQTT.connected()) {
    ID_MQTT = "";
    Serial.print("* Starting connection with broker: ");
    Serial.println(BROKER_MQTT);

    int i = 0;
    for (i = 0; i < 10; i++) {
      ID_MQTT = ID_MQTT + letters[random(0, 36)];
    }

    if (MQTT.connect(ID_MQTT.c_str())) {
      Serial.print("* Connected to broker successfully with ID: ");
      Serial.println(ID_MQTT);
    } else {
      Serial.println("* Failed to connected to broker. Trying again in 2 seconds.");
      delay(2000);
    }
  }
}

// Checks both Wi-Fi and MQTT state, and reconnects if something failed.
void checkWiFIAndMQTT(void) {
  if (!MQTT.connected())
    reconnectMQTT();
  reconnectWiFi();
}

void reconnectWiFi(void) {
  if (WiFi.status() == WL_CONNECTED)
    return;

  WiFi.begin(SSID, PASSWORD); // Conecta na rede WI-FI

  Serial.print("* Connecting to Wifi ");
  while (WiFi.status() != WL_CONNECTED) {
    delay(100);
    Serial.print(".");
  }

  Serial.println("");
  Serial.print("* Successfully connected to Wi-Fi, with local IP: ");
  Serial.println(WiFi.localIP());

  LCD.clear();
  LCD.setCursor(0, 0);
  LCD.print("Finished!");
  LCD.setCursor(0, 1);
  LCD.print("-- ");
  LCD.print(WiFi.localIP());
}


void setup()
{
  Wire.begin(23, 22);
  Serial.begin(115200);
  pinMode(LDR_PIN, INPUT);
  LCD.init();
  LCD.backlight();
  LCD.setCursor(0, 0);
  LCD.print("Initializing...");
  LCD.setCursor(0, 1);
  LCD.print("Please wait...");

  dhtSensor.setup(DHT_PIN, DHTesp::DHT22);

  startWifi();
  initMQTT();
}

void loop()
{
  int16_t i = analogRead(34);
  String msg = i < 2165 ? "WET" : i > 3135 ? "DRY" : "OK";
  LCD.clear();
  LCD.setCursor(0, 0);
  LCD.print("Soil: ");
  LCD.print(msg);

  int analogValue = analogRead(LDR_PIN);
  float voltage = analogValue / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));
  
  LCD.setCursor(0, 1);
  LCD.print("Lux: ");
  LCD.print(lux);
  LCD.print("          ");

  delay(500); 
}