//  mac add2 0x88:0x57:0x21:0xc2:0xc0:0xb4    mac add3 0x8c:0x94:0xdf:0x61:0xda:0x04  
 
// mac add1 0x00:0x70:0x07:0xa3:0x78:0x78     mac add4 0x88,0x57,0x21,0xb1,0x28,0x2c
  
#include <esp_now.h>
#include <WiFi.h>



uint8_t slave1_Address[] = {0x00,0x70,0x07,0xa3,0x78,0x78};
uint8_t slave3_Address[] = {0x8c,0x94,0xdf,0x61,0xda,0x04};
uint8_t slave4_Address[] = {0x88,0x57,0x21,0xb1,0x28,0x2c};


// Data structure for receiving and sending.
typedef struct struct_message {
    char text[32];
    int counter;
} struct_message;

struct_message myData;       // Information to send
struct_message incomingData; // Received information

//esp_now_peer_info_t peerInfo;


  




//The function is called when data is sent.
void OnDataSent(const uint8_t *mac_addr, esp_now_send_status_t status) {
  Serial.print("\r\nLatest delivery status: ");
  Serial.println(status == ESP_NOW_SEND_SUCCESS ? "Sent successfully." : "Send failed.");
}

// The function is called when data is submitted.
void OnDataRecv(const esp_now_recv_info *info, const uint8_t *incomingDataRaw, int len) {

const uint8_t *mac = info->src_addr;
//------------------------------------- check data incomming -------------
    Serial.println("\n=== [Received a new data frame.] ===");
    
    // Displays the sender's MAC address.
    Serial.printf("from MAC Address: %02X:%02X:%02X:%02X:%02X:%02X\n", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
    
    // Check the frame size (Frame Length Verification)
    Serial.printf("Size of data received. (Bytes): %d\n", len);
    Serial.printf("Expected structure dimensions(Bytes): %d\n", sizeof(struct_message));

    if (len != sizeof(struct_message)) {
        Serial.println("❌ [Error] Frame Format Incorrect! The data size does not match the structure");
        return;
    }
//-----------------------------------------------------------------------     
  
  
  memcpy(&incomingData, incomingDataRaw, sizeof(incomingData));
  Serial.print("---I received the information: ");
  Serial.print(incomingData.text);
  Serial.print(" |number: ");
  Serial.println(incomingData.counter);
}
 
void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);

  // Getting Started with ESP-NOW
  if (esp_now_init() != ESP_OK) {
    Serial.println("ESP-NOW startup failed.");
    return;
  }
//-----------------------------------------------------------------------------------
  //Register receiver 1.
  esp_now_peer_info_t peerInfo1 = {};
  memcpy(peerInfo1.peer_addr, slave1_Address, 6);
  peerInfo1.channel = 0;  
  peerInfo1.encrypt = false;
 

  if (esp_now_add_peer(&peerInfo1) != ESP_OK){
    Serial.println("Adding a peerInfo1 failed.");
    return;
  }
//----------------------------------------------------------
  //Register receiver 3.
  esp_now_peer_info_t peerInfo3 = {};
  memcpy(peerInfo3.peer_addr, slave3_Address, 6);
  peerInfo3.channel = 0;
  peerInfo3.encrypt = false;

  if (esp_now_add_peer(&peerInfo3) != ESP_OK){
    Serial.println("Adding a peerInfo3 failed.");
    return;
  }
 //------------------------------------------------------------
  //Register receiver 4.
  esp_now_peer_info_t peerInfo4 = {};
  memcpy(peerInfo4.peer_addr, slave4_Address, 6);
  peerInfo4.channel = 0;
  peerInfo4.encrypt = false;

  if (esp_now_add_peer(&peerInfo4) != ESP_OK){
    Serial.println("Adding a peerInfo4 failed.");
    return;
  }
  
  
  

  // Register the Callback function for both incoming and outgoing calls.

esp_now_register_send_cb((esp_now_send_cb_t)OnDataSent);

  
esp_now_register_recv_cb((esp_now_recv_cb_t)OnDataRecv);  
  
 
}
 
void loop() {
  // Generate and send data to board 1 every 2 seconds.
  strcpy(myData.text, "Greetings from Board 2.");
  //myData.counter++;
   myData.counter = random(1, 100);
    // Send to everyone (NULL means send to all registered peers)
  esp_err_t result = esp_now_send(0, (uint8_t *) &myData, sizeof(myData));
  if (result != ESP_OK) {
    Serial.println("An error occurred during data transmission.");
  }

  delay(2000);
}