//----------------------------------------Load libraries
#include <espnow.h>
#include <ESP8266WiFi.h>
//----------------------------------------Defines PIN Button and PIN LED.
#define LED_Pin   D4
#define BTN_Pin   D2
//----------------------------------------------------------------------------------------------------------------------------

//uint8_t broadcastAddress[] = {0xE0, 0x98, 0x06, 0x9C, 0x16, 0x7F}; 
uint8_t broadcastAddress[] = {0xE0, 0x98, 0x06, 0x0B, 0x1E, 0xEF}; 
//---------------------------------------------------------------------------------------------------------------------------

int BTN_State; //--> Variable to hold the button state.
int LED_State_Send = 1; //--> Variable to hold the data to be transmitted to control the LEDs.
int LED_State_Receive; //--> Variable to receive data to control the LEDs on the ESP32 running this code.

//----------------------------------------Structure example to send data must match the receiver structure

typedef struct struct_message {
    int led;
} struct_message_send;

struct_message send_Data; // Create a struct_message to send data.
struct_message receive_Data; // Create a struct_message to receive data.
//---------------------------------------------------------------------------------------------------------------------------

//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Callback when data is sent

void OnDataSent(uint8_t *mac_addr, uint8_t status) {
  Serial.print("\r\nLast Packet Send Status:\t");
  if (status ==0){
     Serial.println("Delivery success");
  }
  else{
    Serial.println("Delivery fail");
  }
  Serial.println(">>>>>");
}
//+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Callback when data is received

void OnDataRecv(uint8_t * mac_addr, uint8_t *incomingData, uint8_t len) {
  memcpy(&receive_Data, incomingData, sizeof(receive_Data));
  Serial.println();
 // Serial.println("<<<<< Receive Data:");
 // Serial.print("Bytes received: ");
 // Serial.println(len);
  LED_State_Receive = receive_Data.led;
  Serial.print("Receive Data: ");
  Serial.println(LED_State_Receive);
  Serial.println("<<<<<");
  digitalWrite(LED_Pin, LED_State_Receive);
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ VOID SETUP
void setup() {
  Serial.begin(115200);
  pinMode(LED_Pin, OUTPUT);
  pinMode(BTN_Pin, INPUT_PULLUP); 
  WiFi.mode(WIFI_STA); //--> Set device as a Wi-Fi Station
  WiFi.disconnect();

  //----------------------------------------Init ESP-NOW
  if (esp_now_init() != 0) {
    Serial.println("Error initializing ESP-NOW");
    return;
  }
  
  //----------------------------------------Once ESPNow is successfully Init, we will register for Send CB to
  // get the status of Trasnmitted packet
  esp_now_register_send_cb(OnDataSent);
  esp_now_register_recv_cb(OnDataRecv); //--> Register for a callback function that will be called when data is received
   // Set ESP-NOW Role
  esp_now_set_self_role(ESP_NOW_ROLE_COMBO);
//----------------------------------------
  
  //----------------------------------------Register peer
   if (esp_now_add_peer(broadcastAddress, ESP_NOW_ROLE_COMBO, 1, NULL, 0) == 0) {
    Serial.println("Peer added successfully !!");
  } else {
    Serial.println("Failed to add peer !!");  
  }
  Serial.println("Initializing push button ...");
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
void loop() {
  BTN_State = digitalRead(BTN_Pin); //--> Reads and holds button states.
  
  //----------------------------------------When the button is pressed it will send data to control the LED on the ESP32 Target.
  if(BTN_State == 0) {
    LED_State_Send = !LED_State_Send; // toggle state
    send_Data.led = LED_State_Send;  // send state to the other board
    Serial.println();
    Serial.print(">>>>> ");
    Serial.println("Send data");
    //----------------------------------------Send message via ESP-NOW
  if (esp_now_send(broadcastAddress, (uint8_t *) &send_Data, sizeof(send_Data))==0)
     {
      Serial.println("Message sent successfully");
    }
    else {
      Serial.println("Error sending the data");
    }  
      //----------------------------------------Wait for the button to be released. Release the button first to send the next data.
    while(BTN_State == 0) {
      BTN_State = digitalRead(BTN_Pin);
      delay(10);
    }

  }
  
}