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

// WiFi credentials
const char* ssid = "Wokwi-GUEST"; // Change this to your WiFi network name
const char* password = "";        // Change this to your WiFi network password

// MQTT Broker details
const char* mqtt_server = "broker.hivemq.com";
const int mqtt_port = 1883;
const char* mqtt_topic = "worker_temperature01";

// LCD I2C address and dimensions
LiquidCrystal_I2C lcd(0x27, 16, 2); // Change 0x27 to your LCD's I2C address

// LED Pin
const int ledPin = 2;

WiFiClient espClient;
PubSubClient client(espClient);

void setup_wifi() {
    Serial.println("Connecting to WiFi...");
    WiFi.begin(ssid, password);

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

    Serial.println("WiFi Connected.");
}

void flashLED(int pin, int times, int delayTime) {
    for (int i = 0; i < times; i++) {
        digitalWrite(pin, HIGH);
        delay(delayTime);
        digitalWrite(pin, LOW);
        delay(delayTime);
    }
}

void mqtt_callback(char* topic, byte* payload, unsigned int length) {
    Serial.print("Message arrived [");
    Serial.print(topic);
    Serial.print("] ");
    char msg[length + 1];
    for (unsigned int i = 0; i < length; i++) {
        msg[i] = (char)payload[i];
    }
    msg[length] = '\0';
    Serial.println(msg);

    // Display on LCD
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Temp: ");
    lcd.print(msg);
    lcd.print(" C");

    // Check temperature and flash LED if higher than 40 degrees
    float temperature = atof(msg);
    if (temperature > 40.0) {
        flashLED(ledPin, 5, 500); // Flash 5 times with 500ms interval
    }
}

void reconnect() {
    while (!client.connected()) {
        Serial.print("Attempting MQTT connection...");
        if (client.connect("ESP32_LCD_Display")) {
            Serial.println("connected");
            client.subscribe(mqtt_topic);
        } else {
            Serial.print("failed, rc=");
            Serial.print(client.state());
            Serial.println(" try again in 5 seconds");
            delay(5000);
        }
    }
}

void setup() {
    Serial.begin(115200);
    setup_wifi();
    client.setServer(mqtt_server, mqtt_port);
    client.setCallback(mqtt_callback);

    lcd.init(); // initialize the lcd
    lcd.backlight();

    pinMode(ledPin, OUTPUT); // Initialize the LED pin as an output
}

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