text: /**************************************************************
     WiFiManager is a library for the ESP8266/Arduino platform
     (https://github.com/esp8266/Arduino) to enable easy
     configuration and reconfiguration of WiFi credentials using a Captive Portal
     inspired by:
     http://www.esp8266.com/viewtopic.php?f=29&t=2520
     https://github.com/chriscook8/esp-arduino-apboot
     https://github.com/esp8266/Arduino/tree/master/libraries/DNSServer/examples/CaptivePortalAdvanced
     Built by AlexT https://github.com/tzapu
     Licensed under MIT license
   **************************************************************/
  
  #ifndef WiFiManager_h
  #define WiFiManager_h
  
  #include <ESP8266WiFi.h>
  #include <ESP8266WebServer.h>
  #include <DNSServer.h>
  #include <memory>
  
  extern "C" {
    #include "user_interface.h"
  }
  
  const char HTTP_HEADER[] PROGMEM          = "<!DOCTYPE html><html lang=\"en\"><head><meta charset=\"UTF-8\"><meta name=\"viewport\" content=\"width=device-width, initial-scale=1, user-scalable=no\"/><title>{v}</title>";
  const char HTTP_STYLE[] PROGMEM           = "<style>.c{text-align: center;} div,input{padding:5px;font-size:1em;} input{width:95%;} body{text-align: center;font-family:verdana;} button{border:0;border-radius:0.3rem;background-color:#1fa3ec;color:#fff;line-height:2.4rem;font-size:1.2rem;width:100%;} .q{float: right;width: 64px;text-align: right;} .l{background: url(\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAMAAABEpIrGAAAALVBMVEX///8EBwfBwsLw8PAzNjaCg4NTVVUjJiZDRUUUFxdiZGSho6OSk5Pg4eFydHTCjaf3AAAAZElEQVQ4je2NSw7AIAhEBamKn97/uMXEGBvozkWb9C2Zx4xzWykBhFAeYp9gkLyZE0zIMno9n4g19hmdY39scwqVkOXaxph0ZCXQcqxSpgQpONa59wkRDOL93eAXvimwlbPbwwVAegLS1HGfZAAAAABJRU5ErkJggg==\") no-repeat left center;background-size: 1em;}</style>";
  const char HTTP_SCRIPT[] PROGMEM          = "<script>function c(l){document.getElementById('s').value=l.innerText||l.textContent;document.getElementById('p').focus();}</script>";
  const char HTTP_HEADER_END[] PROGMEM        = "</head><body><div style='text-align:left;display:inline-block;min-width:260px;'>";
  const char HTTP_PORTAL_OPTIONS[] PROGMEM  = "<form action=\"/wifi\" method=\"get\"><button>Configure WiFi</button></form><br/><form action=\"/0wifi\" method=\"get\"><button>Configure WiFi (No Scan)</button></form><br/><form action=\"/i\" method=\"get\"><button>Info</button></form><br/><form action=\"/r\" method=\"post\"><button>Reset</button></form>";
  const char HTTP_ITEM[] PROGMEM            = "<div><a href='#p' onclick='c(this)'>{v}</a>&nbsp;<span class='q {i}'>{r}%</span></div>";
  const char HTTP_FORM_START[] PROGMEM      = "<form method='get' action='wifisave'><input id='s' name='s' length=32 placeholder='SSID'><br/><input id='p' name='p' length=64 type='password' placeholder='password'><br/>";
  const char HTTP_FORM_PARAM[] PROGMEM      = "<br/><input id='{i}' name='{n}' maxlength={l} placeholder='{p}' value='{v}' {c}>";
  const char HTTP_FORM_END[] PROGMEM        = "<br/><button type='submit'>save</button></form>";
  const char HTTP_SCAN_LINK[] PROGMEM       = "<br/><div class=\"c\"><a href=\"/wifi\">Scan</a></div>";
  const char HTTP_SAVED[] PROGMEM           = "<div>Credentials Saved<br />Trying to connect ESP to network.<br />If it fails reconnect to AP to try again</div>";
  const char HTTP_END[] PROGMEM             = "</div></body></html>";
  
  #ifndef WIFI_MANAGER_MAX_PARAMS
  #define WIFI_MANAGER_MAX_PARAMS 10
  #endif
  
  class WiFiManagerParameter {
    public:
      /** 
          Create custom parameters that can be added to the WiFiManager setup web page
          @id is used for HTTP queries and must not contain spaces nor other special characters
      */
      WiFiManagerParameter(const char *custom);
      WiFiManagerParameter(const char *id, const char *placeholder, const char *defaultValue, int length);
      WiFiManagerParameter(const char *id, const char *placeholder, const char *defaultValue, int length, const char *custom);
      ~WiFiManagerParameter();
  
      const char *getID();
      const char *getValue();
      const char *getPlaceholder();
      int         getValueLength();
      const char *getCustomHTML();
    protected:
      void init(const char *id, const char *placeholder, const char *defaultValue, int length, const char *custom);
      
    private:
      const char *_id;
      const char *_placeholder;
      char       *_value;
      int         _length;
      const char *_customHTML;
  
  
      friend class WiFiManager;
  };
  
  
  class WiFiManager
  {
    public:
      WiFiManager();
      ~WiFiManager();
  
      boolean       autoConnect();
      boolean       autoConnect(char const *apName, char const *apPassword = NULL);
  
      //if you want to always start the config portal, without trying to connect first
      boolean       startConfigPortal();
      boolean       startConfigPortal(char const *apName, char const *apPassword = NULL);
  
      // get the AP name of the config portal, so it can be used in the callback
      String        getConfigPortalSSID();
  
      void          resetSettings();
  
      //sets timeout before webserver loop ends and exits even if there has been no setup.
      //useful for devices that failed to connect at some point and got stuck in a webserver loop
      //in seconds setConfigPortalTimeout is a new name for setTimeout
      void          setConfigPortalTimeout(unsigned long seconds);
      void          setTimeout(unsigned long seconds);
  
      //sets timeout for which to attempt connecting, useful if you get a lot of failed connects
      void          setConnectTimeout(unsigned long seconds);
  
  
      void          setDebugOutput(boolean debug);
      //defaults to not showing anything under 8% signal quality if called
      void          setMinimumSignalQuality(int quality = 8);
      //sets a custom ip /gateway /subnet configuration
      void          setAPStaticIPConfig(IPAddress ip, IPAddress gw, IPAddress sn);
      //sets config for a static IP
      void          setSTAStaticIPConfig(IPAddress ip, IPAddress gw, IPAddress sn);
      //called when AP mode and config portal is started
      void          setAPCallback( void (*func)(WiFiManager*) );
      //called when settings have been changed and connection was successful
      void          setSaveConfigCallback( void (*func)(void) );
      //adds a custom parameter, returns false on failure
      bool          addParameter(WiFiManagerParameter *p);
      //if this is set, it will exit after config, even if connection is unsuccessful.
      void          setBreakAfterConfig(boolean shouldBreak);
      //if this is set, try WPS setup when starting (this will delay config portal for up to 2 mins)
      //TODO
      //if this is set, customise style
      void          setCustomHeadElement(const char* element);
      //if this is true, remove duplicated Access Points - defaut true
      void          setRemoveDuplicateAPs(boolean removeDuplicates);
  
    private:
      std::unique_ptr<DNSServer>        dnsServer;
      std::unique_ptr<ESP8266WebServer> server;
  
      //const int     WM_DONE                 = 0;
      //const int     WM_WAIT                 = 10;
  
      //const String  HTTP_HEADER = "<!DOCTYPE html><html lang=\"en\"><head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\"/><title>{v}</title>";
  
      void          setupConfigPortal();
      void          startWPS();
  
      const char*   _apName                 = "no-net";
      const char*   _apPassword             = NULL;
      String        _ssid                   = "";
      String        _pass                   = "";
      unsigned long _configPortalTimeout    = 0;
      unsigned long _connectTimeout         = 0;
      unsigned long _configPortalStart      = 0;
  
      IPAddress     _ap_static_ip;
      IPAddress     _ap_static_gw;
      IPAddress     _ap_static_sn;
      IPAddress     _sta_static_ip;
      IPAddress     _sta_static_gw;
      IPAddress     _sta_static_sn;
  
      int           _paramsCount            = 0;
      int           _minimumQuality         = -1;
      boolean       _removeDuplicateAPs     = true;
      boolean       _shouldBreakAfterConfig = false;
      boolean       _tryWPS                 = false;
  
      const char*   _customHeadElement      = "";
  
      //String        getEEPROMString(int start, int len);
      //void          setEEPROMString(int start, int len, String string);
  
      int           status = WL_IDLE_STATUS;
      int           connectWifi(String ssid, String pass);
      uint8_t       waitForConnectResult();
  
      void          handleRoot();
      void          handleWifi(boolean scan);
      void          handleWifiSave();
      void          handleInfo();
      void          handleReset();
      void          handleNotFound();
      void          handle204();
      boolean       captivePortal();
      boolean       configPortalHasTimeout();
  
      // DNS server
      const byte    DNS_PORT = 53;
  
      //helpers
      int           getRSSIasQuality(int RSSI);
      boolean       isIp(String str);
      String        toStringIp(IPAddress ip);
  
      boolean       connect;
      boolean       _debug = true;
  
      void (*_apcallback)(WiFiManager*) = NULL;
      void (*_savecallback)(void) = NULL;
  
      int                    _max_params;
      WiFiManagerParameter** _params;
  
      template <typename Generic>
      void          DEBUG_WM(Generic text);
  
      template <class T>
      auto optionalIPFromString(T *obj, const char *s) -> decltype(  obj->fromString(s)  ) {
        return  obj->fromString(s);
      }
      auto optionalIPFromString(...) -> bool {
        DEBUG_WM("NO fromString METHOD ON IPAddress, you need ESP8266 core 2.1.0 or newer for Custom IP configuration to work.");
        return false;
      }
  };
  
  #endif
  