#include <WiFi.h>
#include <HTTPClient.h>

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

// -------- ThingSpeak --------
String apiKey = "YOUR_API_KEY";   // Paste your Write API Key
const char* server = "http://api.thingspeak.com/update";

// -------- Pin Definitions --------
#define TRIG_PIN 5
#define ECHO_PIN 18
#define LED_PIN  2
#define GAS_PIN  34
#define PIR_PIN  27
#define LDR_PIN  35

// -------- Settings --------
const int binHeight = 30;     // cm
int gasThreshold = 2000;
int ldrThreshold = 1500;     // adjust in Wokwi

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

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(GAS_PIN, INPUT);
  pinMode(PIR_PIN, INPUT);
  pinMode(LDR_PIN, INPUT);

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

void loop() {
  // -------- Ultrasonic --------
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.034 / 2;
  float wasteLevel = ((binHeight - distance) / binHeight) * 100;
  wasteLevel = constrain(wasteLevel, 0, 100); 
  
  // -------- LDR --------
  int lightValue = analogRead(LDR_PIN);
  bool isDark = lightValue < ldrThreshold;

  // -------- Serial --------
  Serial.println("---- SENSOR DATA ----");
  Serial.print("Waste Level: "); Serial.print(wasteLevel); Serial.println(" %");
  Serial.print("Gas Value: "); Serial.println(gasValue);
  Serial.print("Motion: "); Serial.println(motionDetected ? "Detected" : "No");
  Serial.print("Light Value: "); Serial.println(lightValue);
  Serial.println(isDark ? "Night / Low Light" : "Day / Bright");

  // -------- Alert Logic --------
  if (wasteLevel >= 80 || gasValue > gasThreshold || motionDetected == HIGH || isDark) {
    digitalWrite(LED_PIN, HIGH);
    Serial.println("⚠ ALERT CONDITION!");
  } else {
    digitalWrite(LED_PIN, LOW);
  }

  // -------- ThingSpeak --------
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;
    String url = server + String("?api_key=") + apiKey +
                 "&field1=" + String(wasteLevel) +
                 "&field2=" + String(gasValue) +
                 "&field3=" + String(motionDetected) +
                 "&field4=" + String(lightValue);

    http.begin(url);
    http.GET();
    http.end();
  }

  delay(15000);
}