/* -----------------------------------------------------------------------------
  - Project: RFID attendance system using ESP32
  - Author:  https://www.youtube.com/ElectronicsTechHaIs
  - Date:  6/03/2020
   -----------------------------------------------------------------------------
  This code was created by Electronics Tech channel for 
  the RFID attendance project with ESP32.
   ---------------------------------------------------------------------------*/
//*******************************libraries********************************
//ESP32----------------------------
#include <WiFi.h>
#include <HTTPClient.h>
#include <time.h>
//RFID-----------------------------
#include <SPI.h>
#include <MFRC522.h>
//************************************************************************
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.
//************************************************************************
/* Set these to your desired credentials. */
const char *ssid = "SSID";
const char *password = "Password";
const char* device_token  = "Device Token";
//************************************************************************
#define SS_PIN  4 // SCK-GPIO 18, MOSI-GPIO 17, MISO-GPIO 16, Vcc-3.3v, GND -GND,
#define RST_PIN 5

int timezone = x * 3600;   //Replace "x" your timezone.
int time_dst = 0;
String getData, Link;
String OldCardID = "";
unsigned long previousMillis1 = 0;
unsigned long previousMillis2 = 0;
String URL = "http://YourComputerIP/rfidattendance/getdata.php"; //computer IP or the server domain
//************************************************************************
void setup() {
  delay(1000);
  Serial.begin(115200);
  SPI.begin();  // Init SPI bus
  mfrc522.PCD_Init(); // Init MFRC522 card
  //---------------------------------------------
  connectToWiFi();
  //---------------------------------------------
  configTime(timezone, time_dst, "pool.ntp.org","time.nist.gov");
}
//************************************************************************
void loop() {
  //check if there's a connection to Wi-Fi or not
  if(!WiFi.isConnected()){
    connectToWiFi();    //Retry to connect to Wi-Fi
  }
  //---------------------------------------------
  if (millis() - previousMillis2 >= 15000) {
    previousMillis2 = millis();
    OldCardID="";
  }
  delay(50);
  //---------------------------------------------
  //look for new card
  if ( ! mfrc522.PICC_IsNewCardPresent()) {
    return;//got to start of loop if there is no card present
  }
  // Select one of the cards
  if ( ! mfrc522.PICC_ReadCardSerial()) {
    return;//if read card serial(0) returns 1, the uid struct contians the ID of the read card.
  }
  String CardID ="";
  for (byte i = 0; i < mfrc522.uid.size; i++) {
    CardID += mfrc522.uid.uidByte[i];
  }
  //---------------------------------------------
  if( CardID == OldCardID ){
    return;
  }
  else{
    OldCardID = CardID;
  }
  //---------------------------------------------
//  Serial.println(CardID);
  SendCardID(CardID);
  delay(1000);
  display.clearDisplay();
}
//************send the Card UID to the website*************
void SendCardID( String Card_uid ){
  Serial.println("Sending the Card ID");
  if(WiFi.isConnected()){
    HTTPClient http;    //Declare object of class HTTPClient
    //GET Data
    getData = "?card_uid=" + String(Card_uid) + "&device_token=" + String(device_token); // Add the Card ID to the GET array in order to send it
    //GET methode
    Link = URL + getData;
    http.begin(Link); //initiate HTTP request   //Specify content-type header
    
    int httpCode = http.GET();   //Send the request
    String payload = http.getString();    //Get the response payload

//    Serial.println(Link);   //Print HTTP return code
    Serial.println(httpCode);   //Print HTTP return code
    Serial.println(Card_uid);     //Print Card ID
    Serial.println(payload);    //Print request response payload

    if (httpCode == 200) {
      if (payload.substring(0, 5) == "login") {
        String user_name = payload.substring(5);
    //  Serial.println(user_name);
        
        display.clearDisplay();
        display.setTextSize(2);             // Normal 2:2 pixel scale
        display.setTextColor(WHITE);        // Draw white text
        display.setCursor(15,0);             // Start at top-left corner
        display.print(F("Welcome"));
        display.setCursor(0,20);
        display.print(user_name);
        display.display();
      }
      else if (payload.substring(0, 6) == "logout") {
        String user_name = payload.substring(6);
    //  Serial.println(user_name);
        
        display.clearDisplay();
        display.setTextSize(2);             // Normal 2:2 pixel scale
        display.setTextColor(WHITE);        // Draw white text
        display.setCursor(10,0);             // Start at top-left corner
        display.print(F("Good Bye"));
        display.setCursor(0,20);
        display.print(user_name);
        display.display();
      }
      else if (payload == "succesful") {
        display.clearDisplay();
        display.setTextSize(2);             // Normal 2:2 pixel scale
        display.setTextColor(WHITE);        // Draw white text
        display.setCursor(5,0);             // Start at top-left corner
        display.print(F("New Card"));
        display.display();
      }
      else if (payload == "available") {
        display.clearDisplay();
        display.setTextSize(2);             // Normal 2:2 pixel scale
        display.setTextColor(WHITE);        // Draw white text
        display.setCursor(5,0);             // Start at top-left corner
        display.print(F("Free Card"));
        display.display();
      }
      delay(100);
      http.end();  //Close connection
    }
  }
}
//********************connect to the WiFi******************
void connectToWiFi(){
    WiFi.mode(WIFI_OFF);        //Prevents reconnection issue (taking too long to connect)
    delay(1000);
    WiFi.mode(WIFI_STA);
    Serial.print("Connecting to ");
    Serial.println(ssid);
    WiFi.begin(ssid, password);

    while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
    }
    Serial.println("");
    Serial.println("Connected");
    
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());  //IP address assigned to your ESP
    
    delay(1000);
}
//======================================================================