#include <Arduino.h>
#include <WiFi.h>
#include <lwip/sockets.h>

#define _SSID "ESP32-AP1"
#define _PASSWD "PASS0000"
#define UDP_PORT 6666

#define MTU 100000

IPAddress apIP(192,168,178,1);
IPAddress subnetMask(255,255,255,0);

static int udp_sock;

void udp_task(void* /*args*/) {
  struct sockaddr_in sourceAddr;
  socklen_t addrLen = sizeof(sourceAddr);
  static uint8_t udp_buf[MTU];

  while (true) {
    int len = recvfrom(udp_sock, udp_buf, MTU - 1, 0, (struct sockaddr*)&sourceAddr, &addrLen);
    if (len > 0) {
      udp_buf[len] = '\n';
      Serial.write(udp_buf, len + 1);
    }
  }
}

void setup() {
  Serial.begin(115200);
  while (!Serial) { delay(10); }

  WiFi.mode(WIFI_AP);
  WiFi.softAPConfig(apIP, apIP, subnetMask);
  WiFi.softAP(_SSID, _PASSWD, /*channel*/1, /*hidden*/false, /*maxConn*/4);

  udp_sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
  struct sockaddr_in localAddr;
  memset(&localAddr, 0, sizeof(localAddr));
  localAddr.sin_family = AF_INET;
  localAddr.sin_port = htons(UDP_PORT);
  localAddr.sin_addr.s_addr = htonl(INADDR_ANY);
  bind(udp_sock, (struct sockaddr*)&localAddr, sizeof(localAddr));

  xTaskCreatePinnedToCore(udp_task, "UDPReceiver", 4096, nullptr, 5, nullptr, 1);
}

void loop() {
  vTaskDelay(pdMS_TO_TICKS(1000));
}