#include <WiFi.h>
#include "ThingSpeak.h"
#define LED_BUILTIN 2
#define ECHO_PIN 18
#define TRIG_PIN 19
const int irPin = 5;       // IR sensor input
const int redLed = 4;      // Red LED output

const char* ssid = "Wokwi-GUEST";
const char* password = "";

WiFiClient client;

// ThingSpeak Settings
unsigned long channelID = 3016367;
const char* writeAPIKey = "3TJCHJTDN4X80XIL";

// Violation handling
unsigned long lastViolationTime = 0;
const unsigned long cooldownPeriod = 1000; // 1 second

void setup() {
  Serial.begin(115200);
  pinMode(irPin, INPUT);
  pinMode(redLed, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_BUILTIN, OUTPUT);  // Make sure it's defined

  // WiFi Connection
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nConnected to WiFi!");

  ThingSpeak.begin(client);
}

float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH, 30000); // 30ms timeout
  return duration * 0.034 / 2;
}

void loop() {
  // Reconnect WiFi if disconnected
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi disconnected. Reconnecting...");
    WiFi.begin(ssid, password);
    delay(1000);
    return;
  }

  int sensorValue = digitalRead(irPin);
  unsigned long currentTime = millis();
  digitalWrite(redLed, LOW);  // Default OFF

  float distance = readDistanceCM();
  bool isNearby = distance < 100;

  digitalWrite(LED_BUILTIN, isNearby ? HIGH : LOW);

  Serial.print("Measured distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // If IR detects and object is nearby and cooldown passed
  if (sensorValue == LOW && isNearby && (currentTime - lastViolationTime >= cooldownPeriod)) {
    Serial.println("Violation Detected!");
    digitalWrite(redLed, HIGH);
    delay(1000);
    digitalWrite(redLed, LOW);

    // Send data to ThingSpeak
    ThingSpeak.setField(1, "Violation");
    ThingSpeak.setField(2, String(currentTime));  // Send timestamp (ms since boot)

    int status = ThingSpeak.writeFields(channelID, writeAPIKey);
    if (status == 200) {
      Serial.println("Data sent to ThingSpeak!");
    } else {
      Serial.print("Error sending to ThingSpeak: ");
      Serial.println(status);
    }

    lastViolationTime = currentTime;
  }

  delay(100); // Small delay to avoid CPU overuse
}