Improv - BLE WiFi provisioning (#1807)

Co-authored-by: Paulus Schoutsen <balloob@gmail.com>

esphome/components/wifi/wifi_component.h

@@ -27,6 +27,11 @@ extern "C" {
 namespace esphome {
 namespace wifi {
 
+struct SavedWifiSettings {
+  char ssid[33];
+  char password[65];
+} PACKED;  // NOLINT
+
 enum WiFiComponentState {
   /** Nothing has been initialized yet. Internal AP, if configured, is disabled at this point. */
   WIFI_COMPONENT_STATE_OFF = 0,
@@ -156,6 +161,7 @@ class WiFiComponent : public Component {
 
   void set_sta(const WiFiAP &ap);
   void add_sta(const WiFiAP &ap);
+  void clear_sta();
 
   /** Setup an Access Point that should be created if no connection to a station can be made.
    *
@@ -185,6 +191,7 @@ class WiFiComponent : public Component {
   void set_power_save_mode(WiFiPowerSaveMode power_save);
   void set_output_power(float output_power) { output_power_ = output_power; }
 
+  void save_wifi_sta(const std::string &ssid, const std::string &password);
   // ========== INTERNAL METHODS ==========
   // (In most use cases you won't need these)
   /// Setup WiFi interface.
@@ -253,6 +260,7 @@ class WiFiComponent : public Component {
   bool wifi_disconnect_();
 
   bool is_captive_portal_active_();
+  bool is_esp32_improv_active_();
 
 #ifdef ARDUINO_ARCH_ESP8266
   static void wifi_event_callback(System_Event_t *event);
@@ -288,6 +296,8 @@ class WiFiComponent : public Component {
   bool scan_done_{false};
   bool ap_setup_{false};
   optional<float> output_power_;
+  ESPPreferenceObject pref_;
+  bool has_saved_wifi_settings_{false};
 };
 
 extern WiFiComponent *global_wifi_component;