// ESP32 Temperature Monitor with WiFi + LCD + ThingSpeak
// WiFi Simulated like Wokwi method

#include <WiFi.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <HTTPClient.h>

// LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);

// DS18B20 setup
#define ONE_WIRE_BUS 4
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

// GPIOs
#define GREEN_LED 14
#define RED_LED 12
#define BUZZER 5

// WiFi & ThingSpeak config
const char* ssid = "Wokwi-GUEST"; // Use "Wokwi-GUEST" for simulation
const char* password = "";        // Empty password for Wokwi
const char* server = "http://api.thingspeak.com/update";
String apiKey = "AIZL2CMKJWPU8O0P"; // Your ThingSpeak Write API Key

void spinner() {
  static int8_t counter = 0;
  const char* glyphs = "\xa1\xa5\xdb";
  lcd.setCursor(15, 1);
  lcd.print(glyphs[counter++]);
  if (counter == strlen(glyphs)) counter = 0;
}

void setup() {
  Serial.begin(115200);

  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Connecting to ");
  lcd.setCursor(0, 1);
  lcd.print("WiFi ");

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(250);
    spinner();
  }

  Serial.println("\nWiFi connected");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("WiFi Connected");
  delay(1000);

  sensors.begin();
  pinMode(GREEN_LED, OUTPUT);
  pinMode(RED_LED, OUTPUT);
  pinMode(BUZZER, OUTPUT);
}

void loop() {
  sensors.requestTemperatures();
  float tempC = sensors.getTempCByIndex(0);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(tempC, 1);
  lcd.print(" C");

  lcd.setCursor(0, 1);
  if (tempC == -127.00 || tempC == 85.00) {
    lcd.print("SENSOR ERROR!");
    digitalWrite(RED_LED, HIGH);
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(BUZZER, HIGH);
  } else if (tempC >= 38.0) {
    lcd.print("Fever!");
    digitalWrite(RED_LED, HIGH);
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(BUZZER, HIGH);
  } else if (tempC < 20.0) {
    lcd.print("FEVER!");
    digitalWrite(RED_LED, HIGH);
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(BUZZER, HIGH);
  } else {
    lcd.print("Normal");
    digitalWrite(RED_LED, LOW);
    digitalWrite(GREEN_LED, HIGH);
    digitalWrite(BUZZER, LOW);
  }

  // Send to ThingSpeak
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    String url = String(server) + "?api_key=" + apiKey + "&field1=" + String(tempC);
    http.begin(url);
    int httpCode = http.GET();
    if (httpCode > 0) {
      Serial.println("Sent to ThingSpeak");
    } else {
      Serial.println("ThingSpeak Send Failed");
    }
    http.end();
  }

  delay(20000); // Wait 20 seconds
}