#include <WiFi.h>
#include <PubSubClient.h>
#include <ArduinoJson.h>
#include <ESP32Servo.h>

// parameters for Wi-Fi connection
const char* WIFI_SSID = "Wokwi-GUEST";
const char* PASSWORD = "";

// parameters for MQTT-server
const char* MQTT_CLIENT_ID = "ESPLab3";
const char* MQTT_BROKER_IP = "broker.mqttdashboard.com";
const int MQTT_BROKER_PORT = 1883;
const char* MQTT_USER = "";
const char* MQTT_PASSWORD = "";
const char* MQTT_TOPIC = "ESP32_photoresistor_HC-ST04";

WiFiClient wifiClient;
PubSubClient client(wifiClient);
Servo servo;
Servo servo1;

// limit values
const int MAX_LIGHT = 1200; // max lightning value for 12-bit ADC
const int MIN_DISTANCE = 200; // min distance in cm

// sensors pins
const int LIGHT_SENSOR_PIN = 34;
const int TRIG_PIN = 4;
const int ECHO_PIN = 2;
const int LED_PIN = 5;
const int SERVO_PIN = 12;

// ESP32 work permission
bool deviceEnabled = true;

bool objectDetected = false;
bool lightDetected = false;

void setup() {
  Serial.begin(115200);
  
  pinMode(LED_PIN, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  
  servo.attach(SERVO_PIN);
  servo1.attach(18);


  // Wi-Fi connection
  WiFi.begin(WIFI_SSID, PASSWORD);
  Serial.print("Attempting to connect to Wi-Fi -> ");
  Serial.print(WIFI_SSID);
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(100);
  }
  Serial.println("Connected to Wi-Fi successfully!");

  // MQTT-server configuration
  client.setServer(MQTT_BROKER_IP, MQTT_BROKER_PORT);
  client.setCallback(callback);
  
  // Connection to MQTT-server
  if (client.connect(MQTT_CLIENT_ID, MQTT_USER, MQTT_PASSWORD)) {
    Serial.println("Connected to MQTT-server successfully!");
  } else {
    Serial.println("Failed to connect to MQTT-server :(");
  }

  // Topic subscription
  client.subscribe(MQTT_TOPIC);
}

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

void reconnect() {
  while (!client.connected()) {
    Serial.println("Attempting to connect to MQTT-server");
    if (client.connect(MQTT_CLIENT_ID, MQTT_USER, MQTT_PASSWORD)) {
      Serial.println("Connected to MQTT-server successfully!");
      client.subscribe(MQTT_TOPIC);
    } else {
      Serial.print("Failed to connect to MQTT-server :(");
      Serial.print(client.state());
      Serial.println("Retrying in 3 seconds");
      delay(3000);
    }
  }
}

void callback(char* MQTT_TOPIC, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(MQTT_TOPIC);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();

  DynamicJsonDocument doc(1024);
  deserializeJson(doc, payload, length);
  String command = doc["command"].as<String>();

  if (command == "on") {
    deviceEnabled = true;
    Serial.println("Device enabled");
  } else if (command == "off") {
    deviceEnabled = false;
    digitalWrite(LED_PIN, LOW);
    Serial.println("Device disabled");
  }
}

void checkSensors() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  long duration = pulseIn(ECHO_PIN, HIGH);
  int distance = duration / 58;

  if (distance > MIN_DISTANCE) {
    if (!objectDetected) {
      client.publish(MQTT_TOPIC, "{\"alert\":\"object gone\"}");
      objectDetected = true;
    }
  } else {
    if (objectDetected) {
      client.publish(MQTT_TOPIC, "{\"alert\":\"object detected\"}");
      objectDetected = false;
    }
    servo.write(90);
    delay(500);
    servo.write(0);
  }
    if (distance > 300) {
    if (!objectDetected) {
      client.publish(MQTT_TOPIC, "{\"alert\":\"object gone\"}");
      objectDetected = true;
    }
  } else {
    if (objectDetected) {
      client.publish(MQTT_TOPIC, "{\"alert\":\"object detected\"}");
      objectDetected = false;
    }
    servo1.write(90);
    delay(500);
    servo1.write(0);
  }
}