#include <WiFi.h>
#include <ThingSpeak.h>

// Pin configuration
const int trigPin = 5;
const int echoPin = 18;
const int ledPin = 15;

// Wi-Fi credentials
const char* ssid = "Wokwi-GUEST";        // <- Set this to your hotspot name
const char* pass = "";           // <- Set this to your hotspot password

// ThingSpeak settings
WiFiClient client;
unsigned long myChannelNumber = 3038309;
const char* myWriteAPIKey = "7OGOA0K820DZPV2R";

float distance = 0.0;

void connectToWiFi() {
  Serial.print("Connecting to Wi-Fi");
    WiFi.begin(ssid, pass);
      int attempts = 0;

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

                        if (WiFi.status() == WL_CONNECTED) {
                            Serial.println("\n✅ Wi-Fi Connected");
                                Serial.print("IP Address: ");
                                    Serial.println(WiFi.localIP());
                                      } else {
                                          Serial.println("\n❌ Wi-Fi Connection Failed. Restarting...");
                                              delay(3000);
                                                  ESP.restart();
                                                    }
                                                    }

                                                    void setup() {
                                                      Serial.begin(115200);
                                                        pinMode(trigPin, OUTPUT);
                                                          pinMode(echoPin, INPUT);
                                                            pinMode(ledPin, OUTPUT);

                                                              WiFi.mode(WIFI_STA);
                                                                connectToWiFi();

                                                                  ThingSpeak.begin(client);
                                                                  }

                                                                  void loop() {
                                                                    // Measure distance
                                                                      digitalWrite(trigPin, LOW);
                                                                        delayMicroseconds(2);
                                                                          digitalWrite(trigPin, HIGH);
                                                                            delayMicroseconds(10);
                                                                              digitalWrite(trigPin, LOW);

                                                                                long duration = pulseIn(echoPin, HIGH);
                                                                                  distance = duration * 0.034 / 2;

                                                                                    Serial.print("📏 Distance: ");
                                                                                      Serial.print(distance);
                                                                                        Serial.println(" cm");

                                                                                          // Control LED
                                                                                            if (distance < 100) {
                                                                                                digitalWrite(ledPin, HIGH);
                                                                                                  } else {
                                                                                                      digitalWrite(ledPin, LOW);
                                                                                                        }

                                                                                                          // Upload to ThingSpeak
                                                                                                            if (WiFi.status() == WL_CONNECTED) {
                                                                                                                ThingSpeak.setField(1, distance);
                                                                                                                    int statusCode = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
                                                                                                                        if (statusCode == 200) {
                                                                                                                              Serial.println("✅ ThingSpeak Update Successful");
                                                                                                                                  } else {
                                                                                                                                        Serial.print("⚠️ ThingSpeak Update Failed. Code: ");
                                                                                                                                              Serial.println(statusCode);
                                                                                                                                                  }
                                                                                                                                                    } else {
                                                                                                                                                        Serial.println("⚠️ Wi-Fi not connected. Skipping ThingSpeak update.");
                                                                                                                                                          }

                                                                                                                                                            delay(20000);
                                                                                                                                                            }