//modified lora library by Sandeep Mistry for TTGO ESP32 Lora
// lora receiverCallBack 915Mhz with OLED
// Modified by HwThinker

#include <SPI.h>
#include <LoRa.h>
#include <Wire.h>  // Only needed for Arduino 1.6.5 and earlier
#include "SSD1306Wire.h" // legacy include: `#include "SSD1306.h"`

#ifdef ARDUINO_SAMD_MKRWAN1300
#error "This example is not compatible with the Arduino MKR WAN 1300 board!"
#endif

#define SCK     5    // GPIO5  -- lora SCK
#define MISO    19   // GPIO19 -- lora MISO
#define MOSI    27   // GPIO27 -- lora MOSI
#define SS      18   // GPIO18 -- lora CS
#define RST     14   // GPIO14/12 -- RESET (If Lora does not work, replace it with GPIO14)
#define DI0     26   // GPIO26 -- IRQ(Interrupt Request)
#define BAND    915E6

//replace default pin  OLED_SDA=4, OLED_SCL=15 with  OLED_SDA=21, OLED_SCL=22
#define OLED_SDA 4
#define OLED_SCL 15
#define OLED_RST 16

#define LED_BUILTIN 2



// Initialize the OLED display using Wire library
SSD1306Wire  display(0x3c, OLED_SDA, OLED_SCL); // OLED_SDA=4, OLED_SCL=15

int RxDataRSSI = 0;
char Str1[15];

void setup() {
  // START aktivas Oled
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(OLED_RST , OUTPUT);
  digitalWrite(OLED_RST , LOW);    // set GPIO16 low to reset OLED
  delay(50);
  digitalWrite(OLED_RST , HIGH); // while OLED is running, must set GPIO16 in high、

  // Initialising the UI will init the display too.
  display.init();
  display.flipScreenVertically();
  display.setFont(ArialMT_Plain_10);
  // clear the display
  display.clear();
  // aktivasi Oled END

  Serial.begin(9600);
  while (!Serial);
  SPI.begin(SCK, MISO, MOSI, SS);
  LoRa.setPins(SS, RST, DI0);

  Serial.println("LoRa Receiver Callback");

  if (!LoRa.begin(BAND)) {
    Serial.println("Starting LoRa failed!");
    while (1);
  }

  // register the receive callback
  LoRa.onReceive(onReceive);

  // put the radio into receive mode
  LoRa.receive();
  display.setFont(ArialMT_Plain_24);
  display.drawString(0, 0, "HwThinker");
  display.display();
  delay(1000);
  display.clear();
}

void loop() {
  // do nothing
  display.setFont(ArialMT_Plain_16);
  display.drawString(0, 0, "Lora Receiver");

  display.setFont(ArialMT_Plain_10);
  display.drawString(0, 26, "rx Data:" + String(Str1));

  display.setTextAlignment(TEXT_ALIGN_LEFT);
  display.setFont(ArialMT_Plain_10);
  display.drawString(0, 45, "RSSI : " + String(LoRa.packetRssi()));
  display.display();
}

void onReceive(int packetSize) {
  // received a packet
  Serial.print("Received packet '");
  memset(Str1, 0, sizeof(Str1));
  // read packet
  for (int i = 0; i < packetSize; i++) {
    Str1[i] = (char)LoRa.read();
  }
  Serial.print(Str1);

  // print RSSI of packet
  Serial.print("' with RSSI ");
  RxDataRSSI = LoRa.packetRssi();
  Serial.println(RxDataRSSI);
    //  digitalWrite(LED_BUILTIN, (state) ? HIGH : LOW);
  //  state = !state;
  digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
  display.clear();
}