// Source: https://www.hackster.io/edison0215/mini-wifi-scanner-using-oled-42a7a7
// with Modifications by MM
//#include "WiFi.h"
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#if defined(ESP8266)
  #include <ESP8266WiFi.h>
 // #include <ESP8266WebServer.h>
  // Pin definitions (ESP-01 / ESP8266):
  const uint8_t SDA_PIN = 0;           // I2C SDA connected to GPIO0
  const uint8_t SCL_PIN = 2;           // I2C SCL connected to GPIO2
  const uint8_t BUTTON_PIN = 3;        // Button on GPIO3 (RX pin)
#elif defined(ESP32)
  #include <WiFi.h>
 // #include <WebServer.h>
    // MM:
    // Pin definitions (ESP32):
    const uint8_t SDA_PIN = 21;           // I2C SDA connected to GPIO0
    const uint8_t SCL_PIN = 22;           // I2C SCL connected to GPIO2
    const uint8_t BUTTON_PIN = 16;        // Button on GPIO3 (RX pin)
#endif


//Adafruit_SSD1306 display(-1);

  Adafruit_SSD1306 display(128, 64, &Wire, -1);



// anschauen: https://robojax.com/learn/arduino/?vid=robojax_ESP8266_wifi_scan&srsltid=AfmBOopcXQ_1hl7aT2WaeIrP_TXjjseQpsNVfaHBbiChRkehD-V8dNtv

/*
 * @brief returns the encryption type as String
 * @param "id" network ID integer
 * @return String text of network type
 *    Usage: encType(i)
 *    //where i is id of scanned network
 * Written by Ahmad Shamshiri on August 10, 2019 at 17:33
 * in Ajax, Ontario, Canada
 * www.Robojax.com 
 */
/* 
String encType(int id){

String type;
  if(WiFi.encryptionType(id) == ENC_TYPE_WEP){
    type=" WEP";
  }else if(WiFi.encryptionType(id) == ENC_TYPE_TKIP){
    type="WPA / PSK";    
  }else if(WiFi.encryptionType(id) == ENC_TYPE_CCMP){
    type="WPA2 / PSK";    
  }else if(WiFi.encryptionType(id) == ENC_TYPE_AUTO){
    type="WPA / WPA2 / PSK";    
  }else if(WiFi.encryptionType(id) == ENC_TYPE_NONE){
    type="<<OPEN>>";    
  }
  return type;
//1:  ENC_TYPE_WEP – WEP
//2 : ENC_TYPE_TKIP – WPA / PSK
//4 : ENC_TYPE_CCMP – WPA2 / PSK
//7 : ENC_TYPE_NONE – open network
//8 : ENC_TYPE_AUTO – WPA / WPA2 / PSK
}
*/
/*
 * Written by Ahmad Shamshiri
  * with lots of research, this sources was used:
 * https://support.randomsolutions.nl/827069-Best-dBm-Values-for-Wifi 
 * This is approximate percentage calculation of RSSI
 * Wifi Signal Strength Calculation
 * Written Aug 08, 2019 at 21:45 in Ajax, Ontario, Canada
 */
/*
int dBmtoPercentage(int dBm)
{
  int quality;
    if(dBm <= RSSI_MIN)
    {
        quality = 0;
    }
    else if(dBm >= RSSI_MAX)
    {  
        quality = 100;
    }
    else
    {
        quality = 2 * (dBm + 100);
   }

     return quality;
}//dBmtoPercentage 
*/

void setup()
{

  Serial.begin(115200);
  Serial.println();
  Serial.println(F("Booting..."));


// Initialize display
  Wire.begin(SDA_PIN, SCL_PIN);
  if (display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
//    displayInitialized = true;
    display.setRotation(2);
    display.clearDisplay();
    display.setTextColor(SSD1306_WHITE);
    display.print("Booting...");
    display.display();
//    displayReady = true;
  } else {
    Serial.println(F("SSD1306 allocation failed"));
    // Leave displayInitialized as false
  }

  
    // Set WiFi to station mode and disconnect from an AP if it was previously connected
    WiFi.mode(WIFI_STA);
    WiFi.disconnect();
    delay(100);

    // initialize with the I2C addr 0x3C
    display.begin(SSD1306_SWITCHCAPVCC, 0x3C);  

    // Clear the buffer.
    display.clearDisplay();
    display.setTextSize(2);
    display.setTextColor(WHITE);
    
    display.setCursor(0,12);
    display.println(" WIFI SCAN");
    display.display();
    delay(2000);
    
}

void loop()
{
    // WiFi.scanNetworks will return the number of networks found
    //MatchState ms;
    int n = WiFi.scanNetworks();
    String ssid[n];
    String rssi[n];
    int channel[n];
      
    if (n == 0) {
        Serial.println("no networks found");
    } else {
        Serial.print(n);
        Serial.println(" networks found");
      
        for (int i = 0; i < n; ++i) {
            // Print SSID and RSSI for each network found
           // display.clearDisplay();
            ssid[i] = WiFi.SSID(i); // String("MyOwnSSIDNetworkNo") + i; //
            rssi[i] = WiFi.RSSI(i); // -10* i - i; //
            channel[i] = WiFi.channel(i); // i; //
            // Serial.println((WiFi.encryptionType(i) == WIFI_AUTH_OPEN)?" ":"*");
        }
    }
     display.setTextSize(1);
     display.setTextColor(WHITE);
     // 8 rows per screen..  8 pixel each...
     for (int j = 0; j <= (n/8); j++) { // pages per 8 entries. 
       display.clearDisplay();
       for (int i = j*8; i < min(n, ((j+1)*8)); i++) {
             
              display.setCursor(0, 8*(i%8));  // 8 rows per page modulo
              String ssid2 = ssid[i];
              ssid2=ssid2.substring(0,14);  //replace("unifi", "u"); //I customize so that it the display format is in single line
              display.print(channel[i]);
              display.println("" + ssid2+":" + rssi[i]);              
          }
          display.display();
          delay(5000);
     } 
}

// 15 -> 2 pages
// 16 =? 2 pages
// 1 -> 1 page
//17 -> 3 pages