#include <SPI.h>
#include <LoRa.h>

#define LORA_SCK D8
#define LORA_MISO D9
#define LORA_MOSI D10
#define LORA_CS D1
#define LORA_RST D5
#define LORA_IRQ -1

void setup() {
  Serial.begin(115200);
  delay(1000);
  Serial.println("🔧 LoRa Receiver (XIAO ESP32-C3)");

  SPI.begin(LORA_SCK, LORA_MISO, LORA_MOSI, LORA_CS);

  LoRa.setSPI(SPI);
  LoRa.setPins(LORA_CS, LORA_RST, LORA_IRQ);

  if (!LoRa.begin(433E6)) {
    Serial.println("❌ LoRa initialization failed. Check wiring.");
    while (1)
      ;
  }

  LoRa.setSpreadingFactor(12);
  LoRa.setSignalBandwidth(125E3);
  LoRa.setCodingRate4(5);
  LoRa.enableCrc();

  Serial.println("✅ LoRa receiver ready.");
}

void loop() {
  int packetSize = LoRa.parsePacket();
  if (packetSize) {
    if (LoRa.packetRssi() < -120) return;
    if (LoRa.packetSnr() < 0) return;

    Serial.print("📥 Received packet: ");
    while (LoRa.available()) {
      Serial.print((char)LoRa.read());
    }
    Serial.print("  [RSSI: ");
    Serial.print(LoRa.packetRssi());
    Serial.print(" dBm] [SNR: ");
    Serial.print(LoRa.packetSnr());
    Serial.println("]");
  }
}