#include <ESP8266WiFi.h>  
#include <WiFiUdp.h>
#include <spi_flash.h>

#define WIFI_SSID ""
#define WIFI_PASS ""

#define IP_BROADCAST "192.168.1.255"
#define UDP_PORT 8176

String status = "";
float distance = -1;
float duration;
WiFiUDP client;

const int triggerPin = D6;
const int echoPin = D5;

SPI_DEVICE_TXBIT_LSBFIRST;


void setup() {
  delay(5000);
  WiFi.begin(WIFI_SSID, WIFI_PASS);
  pinMode(echoPin, INPUT);
  pinMode(triggerPin, OUTPUT);

  status = "Connecting";
  while(WiFi.status() != WL_CONNECTED) {
    delay(500);
  }
  status = WiFi.localIP().toString();
  Serial.begin(9600);
  Serial.println("Got IP: " + status);
  int err = client.begin(81);
  if(err == 0) {
    Serial.println("Failed to create UDP Socket");
  }
  else {
    Serial.println("Created UDP Socket at port 81");
  }
  Serial.println(String("IP BROADCAST ID SET TO: ") + String(IP_BROADCAST));
  Serial.println(String("UDP PORT SET TO: ") + String(UDP_PORT));
}

void loop() {

  digitalWrite(triggerPin, LOW);  
	delayMicroseconds(2);  
	digitalWrite(triggerPin, HIGH);  
	delayMicroseconds(10);  
	digitalWrite(triggerPin, LOW);  
  duration = pulseIn(echoPin, HIGH);  
  distance = (duration*.0343)/2;

  if(WiFi.status() != WL_CONNECTED) {
      WiFi.begin(WIFI_SSID, WIFI_PASS);
      while(WiFi.status() != WL_CONNECTED) {
        delay(500);
      }
  }
  String d = String(distance);
  String d2 = String(duration);
  Serial.println("Distance is: " + d);
  Serial.println("Duration is: " + d2);
  byte *buff = new byte[4];
  byte *array = (byte *) &distance;
  for(int i=0;i<4;i++) {
    buff[i] = array[3-i];
  }
  Serial.print("Data flipped is: ");
  for(int i=0;i<4;i++) {
    Serial.print(buff[i], HEX);
  }
  Serial.println("");

  client.beginPacket(IP_BROADCAST, UDP_PORT);
  client.write(buff, sizeof(float));
  client.endPacket();
  delay(3000);
  delete[] buff;
}