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

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

// ================= TELEGRAM =================
String botToken = "8593534577:AAFaeFrGxeubqWcEK-P6fO_04xK0x0B7A5s";
String chatID   = "1238392831";

// ================= PINS =================
// Metal
const int trigMetal = 5;
const int echoMetal = 18;

// Paper
const int trigPaper = 17;
const int echoPaper = 16;

// Plastic
const int trigPlastic = 27;
const int echoPlastic = 26;

// ================= THRESHOLD =================
const float fullThreshold = 4.0;
const float resetThreshold = 9.0;

// ================= FLAGS =================
bool metalSent = false;
bool paperSent = false;
bool plasticSent = false;

// ================= FUNCTION =================
float getDistance(int trigPin, int echoPin) {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH, 30000);

  if (duration == 0) return -1;

  return duration * 0.0343 / 2;
}

// ================= TELEGRAM =================
void sendTelegram(String msg) {
  if (WiFi.status() == WL_CONNECTED) {
    HTTPClient http;

    String url = "https://api.telegram.org/bot" + botToken +
                 "/sendMessage?chat_id=" + chatID +
                 "&text=" + msg;

    http.begin(url);
    int code = http.GET();

    Serial.print("Telegram: ");
    Serial.println(code);

    http.end();
  }
}

// ================= CHECK BIN =================
void checkBin(float distance, String name, bool &sentFlag) {
  if (distance == -1) {
    Serial.println(name + ": No reading");
    return;
  }

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

  if (distance <= fullThreshold && !sentFlag) {
    sendTelegram("Alert: " + name + " bin is FULL");
    sentFlag = true;
  }

  if (distance > resetThreshold) {
    sentFlag = false;
  }
}

// ================= SETUP =================
void setup() {
  Serial.begin(115200);

  pinMode(trigMetal, OUTPUT);
  pinMode(echoMetal, INPUT);

  pinMode(trigPaper, OUTPUT);
  pinMode(echoPaper, INPUT);

  pinMode(trigPlastic, OUTPUT);
  pinMode(echoPlastic, INPUT);

  WiFi.begin(ssid, password);

  Serial.print("Connecting WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("\nConnected!");
  sendTelegram("Smart bin system is online");
}

// ================= LOOP =================
void loop() {
  float d1 = getDistance(trigMetal, echoMetal);
  float d2 = getDistance(trigPaper, echoPaper);
  float d3 = getDistance(trigPlastic, echoPlastic);

  checkBin(d1, "Metal", metalSent);
  checkBin(d2, "Paper", paperSent);
  checkBin(d3, "Plastic", plasticSent);

  Serial.println("------------------");
  delay(2000);
}