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

#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701
#define DISTANCE 2.0

#define PUSHOVER_URL "https://api.pushover.net/1/messages.json"

const int trigPin = 5;
const int echoPin = 18;

const char* ssid = "********";
const char* password = "********";

long duration;
float distanceCm;

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

    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);

    WiFi.begin(ssid, password);

    while (WiFi.status() != WL_CONNECTED) {
        delay(1000);
        Serial.println("Connecting to WiFi...");
    }

    Serial.println("Connected to the WiFi network");
}

void loop() {
    if ((WiFi.status() == WL_CONNECTED)) {
        digitalWrite(trigPin, LOW);
        delayMicroseconds(2);

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

        // Reads the echoPin, returns the sound wave travel time in microseconds
        duration = pulseIn(echoPin, HIGH);

        // Calculate the distance
        distanceCm = (duration * SOUND_SPEED) / 2;

        if (distanceCm < DISTANCE) {
            HTTPClient http;
    
            http.begin(PUSHOVER_URL);
            http.addHeader("Content-Type", "application/x-www-form-urlencoded");

            String form = "device=device&user=********&title=IoT - ESP32&message=Flood!!&token=********";

            int httpCode = http.POST(form);
    
            if (httpCode > 0) {
                String payload = http.getString();

                Serial.println(httpCode);
                Serial.println(payload);
            }

            http.end();

            delay(2000);
        } else {
            Serial.println("Error on HTTP request");
        }
    }
}