Fix SSL check callback function definition (#1916)

* Fix SSL check callback function definition

* Print secure client check as string

code/espurna/libs/SecureClientHelpers.h

@@ -15,11 +15,20 @@
 namespace SecureClientHelpers {
 
 using host_callback_f = std::function<String()>;
-using check_callback_f = std::function<bool()>;
+using check_callback_f = std::function<int()>;
 using fp_callback_f = std::function<String()>;
 using cert_callback_f = std::function<const char*()>;
 using mfln_callback_f = std::function<uint16_t()>;
 
+const char * _secureClientCheckAsString(int check) {
+    switch (check) {
+        case SECURE_CLIENT_CHECK_NONE: return "no validation";
+        case SECURE_CLIENT_CHECK_FINGERPRINT: return "fingerprint validation";
+        case SECURE_CLIENT_CHECK_CA: return "CA validation";
+        default: return "unknown";
+    }
+}
+
 #if SECURE_CLIENT == SECURE_CLIENT_AXTLS
 using SecureClientClass = axTLS::WiFiClientSecure;
 
@@ -60,6 +69,10 @@ struct SecureClientChecks {
 
         int check = getCheck();
 
+        if(config.debug) {
+            DEBUG_MSG_P(PSTR("[%s] Using SSL check type: %s\n"), config.tag.c_str(), _secureClientCheckAsString(check));
+        }
+
         if (check == SECURE_CLIENT_CHECK_NONE) {
             if (config.debug) DEBUG_MSG_P(PSTR("[%s] !!! Secure connection will not be validated !!!\n"), config.tag.c_str());
             result = true;
@@ -152,6 +165,10 @@ struct SecureClientChecks {
         int check = getCheck();
         bool settime = (check == SECURE_CLIENT_CHECK_CA);
 
+        if(config.debug) {
+            DEBUG_MSG_P(PSTR("[%s] Using SSL check type: %s\n"), config.tag.c_str(), _secureClientCheckAsString(check));
+        }
+
         if (!ntpSynced() && settime) {
             if (config.debug) DEBUG_MSG_P(PSTR("[%s] Time not synced! Cannot use CA validation\n"), config.tag.c_str());
             return false;