#include <WiFi.h>
#include <WiFiClient.h>
#include <PubSubClient.h>

unsigned long previousMillis = 0;
const int interval = 2000;
int redLedState = LOW;

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.hivemq.com";
const int   mqtt_port = 1883;
const char* mqtt_topic = "3091637K/y_led";

WiFiClient espClient;
PubSubClient client(espClient);
const char* espClientName = "3091637K";

// Pin configuration (updated for your diagram)
const int RED_LED_PIN    = 5;   // red LED connected to GPIO5
const int YELLOW_LED_PIN = 17;  // yellow LED connected to GPIO17
const int POT_PIN        = 36;  // VP pin (ADC1_0) corresponds to GPIO36

bool voltageExceeded85 = false;
bool voltageDroppedBelow83 = false;

void setup_wifi() {
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected.");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
}

void callback(const char* topic, byte* payload, unsigned int length) {
  Serial.print("Message received in topic: ");
  Serial.println(topic);
  Serial.print("Data: ");

  String message = "";
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
    message += (char)payload[i];
  }
  Serial.println();

  if (String(topic) == mqtt_topic) {
    if (message.equalsIgnoreCase("on")) {
      digitalWrite(YELLOW_LED_PIN, HIGH);
    } else if (message.equalsIgnoreCase("off")) {
      digitalWrite(YELLOW_LED_PIN, LOW);
    }
  }
}

void MQTTSubscribe() {
  client.subscribe(mqtt_topic);
  Serial.println("Subscribed to topic: " + String(mqtt_topic));
}

void setup_MQTT() {
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
}

void connectMQTT() {
  while (!client.connected()) {
    Serial.print("Connecting to MQTT broker...");
    if (client.connect(espClientName)) {
      Serial.println("connected.");
      MQTTSubscribe();
    } else {
      Serial.print("failed with state ");
      Serial.print(client.state());
      delay(2000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(RED_LED_PIN, OUTPUT);
  pinMode(YELLOW_LED_PIN, OUTPUT);
  pinMode(POT_PIN, INPUT);
  setup_wifi();
  setup_MQTT();
}

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

  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;

    redLedState = !redLedState;
    digitalWrite(RED_LED_PIN, redLedState);

    int adcValue = analogRead(POT_PIN);
    float voltage = (adcValue / 4095.0) * 3.3;

    char voltageStr[10];
    dtostrf(voltage, 1, 2, voltageStr);
    client.publish("3091637K/voltage", voltageStr);

    float maxVoltage = 5.0;
    float threshold85 = 0.85 * maxVoltage;
    float threshold83 = 0.83 * maxVoltage;

    if (voltage > threshold85 && !voltageExceeded85) {
      client.publish("3091637K/alert", "Voltage exceeded 85%");
      voltageExceeded85 = true;
      voltageDroppedBelow83 = false;
    } else if (voltage < threshold83 && !voltageDroppedBelow83) {
      client.publish("3091637K/alert", "Voltage dropped below 83%");
      voltageDroppedBelow83 = true;
      voltageExceeded85 = false;
    }
  }
}