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

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.emqx.io";
const int mqtt_port = 1883;
const char* mqtt_client_id = "esp32_iluminacao";

WiFiClient espClient;
PubSubClient client(espClient);

#define TRIG 5
#define ECHO 18
#define LDR 34
#define LED 2

long duration;
float distance;
int ldrValue;

float lastDistance = 0;
int lastLdrValue = 0;
const float DISTANCE_THRESHOLD = 10.0;
const int LDR_THRESHOLD = 500;
unsigned long lastPublishTime = 0;
const unsigned long PUBLISH_INTERVAL = 2000;

String lastPresenca = "";
String lastLuminosidade = "";

void setup_wifi() {
  delay(10);
  Serial.println("\n\n=== INICIANDO CONEXAO WiFi ===");
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 20) {
    delay(500);
    Serial.print(".");
    attempts++;
  }

  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("\n[WiFi] Conectado com sucesso!");
    Serial.print("[WiFi] IP: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println("\n[WiFi] Falha ao conectar!");
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("[MQTT] Mensagem recebida em: ");
  Serial.println(topic);
}

void reconnect() {
  if (client.connected()) {
    return;
  }

  int attempts = 0;
  while (!client.connected() && attempts < 3) {
    Serial.print("[MQTT] Tentativa ");
    Serial.print(attempts + 1);
    Serial.print("/3...");
    
    if (client.connect(mqtt_client_id)) {
      Serial.println(" OK!");
      return;
    } else {
      Serial.print(" ERRO (");
      Serial.print(client.state());
      Serial.println(")");
      delay(2000);
      attempts++;
    }
  }
}

void setup() {
  Serial.begin(115200);
  delay(2000);

  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(LED, OUTPUT);
  digitalWrite(LED, LOW);

  Serial.println("\n========================================");
  Serial.println("SISTEMA IoT - ILUMINACAO INTELIGENTE");
  Serial.println("HC-SR04 + LDR + MQTT + Node-RED");
  Serial.println("========================================\n");

  setup_wifi();
  
  Serial.println("[MQTT] Configurando broker...");
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
  
  delay(3000);
  reconnect();
  
  Serial.println("[Sistema] Setup concluido!\n");
}

void loop() {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("[WiFi] Desconectado! Reconectando...");
    setup_wifi();
  }

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

  client.loop();

  if (millis() - lastPublishTime >= PUBLISH_INTERVAL) {
    lastPublishTime = millis();

    // ============ HC-SR04 ============
    digitalWrite(TRIG, LOW);
    delayMicroseconds(2);
    digitalWrite(TRIG, HIGH);
    delayMicroseconds(10);
    digitalWrite(TRIG, LOW);

    duration = pulseIn(ECHO, HIGH, 30000);
    distance = duration * 0.034 / 2;

    if (distance > 400 || distance == 0) {
      distance = 400;
    }

    // ============ LDR ============
    ldrValue = analogRead(LDR);

    // ============ PROCESSAMENTO ============
    String presenca;
    String luminosidade;

    if (distance < 100) {
      presenca = "detectado";
    } else {
      presenca = "sem_presenca";
    }

    if (ldrValue < 2000) {
      luminosidade = "escuro";
    } else {
      luminosidade = "claro";
    }

    // ============ PUBLICAR MQTT - VALORES NUMERICOS ============
    if (client.connected()) {
      // Publica a distancia em cm (numero)
      char distStr[8];
      dtostrf(distance, 1, 2, distStr);
      if (abs(distance - lastDistance) > DISTANCE_THRESHOLD) {
        client.publish("esp32/sensor/distancia", distStr);
        lastDistance = distance;
      }
      
      // Publica o LDR em ADC (numero)
      char ldrStr[5];
      snprintf(ldrStr, sizeof(ldrStr), "%d", ldrValue);
      if (abs(ldrValue - lastLdrValue) > LDR_THRESHOLD) {
        client.publish("esp32/sensor/ldr", ldrStr);
        lastLdrValue = ldrValue;
      }
      
      // Publica o status (texto)
      if (presenca != lastPresenca) {
        client.publish("esp32/sensor/presenca", presenca.c_str());
        lastPresenca = presenca;
      }
      
      if (luminosidade != lastLuminosidade) {
        client.publish("esp32/sensor/luminosidade", luminosidade.c_str());
        lastLuminosidade = luminosidade;
      }
      
      Serial.print("[MQTT] Distancia: ");
      Serial.print(distance);
      Serial.print(" cm | LDR: ");
      Serial.println(ldrValue);
    }

    // ============ LOGICA DO LED ============
    if (presenca == "detectado" && luminosidade == "escuro") {
      digitalWrite(LED, HIGH);
    } else {
      digitalWrite(LED, LOW);
    }

    Serial.print("[Sensores] ");
    Serial.print(distance);
    Serial.print("cm | ");
    Serial.print(ldrValue);
    Serial.print(" | ");
    Serial.print(presenca);
    Serial.print(" | ");
    Serial.println(luminosidade);
  }
}