refactor: removes need to add provider to list of supported providers…

… in error message

selfservice/strategy/oidc/provider_config.go

@@ -97,19 +97,18 @@ func (c ConfigurationCollection) Provider(id string, public *url.URL) (Provider,
 	for k := range c.Providers {
 		p := c.Providers[k]
 		if p.ID == id {
-			switch p.Provider {
-			case "generic":
-				return NewProviderGenericOIDC(&p, public), nil
-			case "google":
-				return NewProviderGoogle(&p, public), nil
-			case "github":
-				return NewProviderGitHub(&p, public), nil
-			case "gitlab":
-				return NewProviderGitLab(&p, public), nil
-			case "microsoft":
-				return NewProviderMicrosoft(&p, public), nil
+			for providerName, provider := range providers {
+				if providerName == p.Provider {
+					return provider(&p), nil
+				}
 			}
-			return nil, errors.Errorf("provider type %s is not supported, supported are: %v", p.Provider, []string{"generic", "google", "github", "gitlab", "microsoft"})
+			providerNames := make([]string, len(providers))
+			i := 0
+			for provider := range providers {
+				providerNames[i] = provider
+				i++
+			}
+			return nil, errors.Errorf("provider type %s is not supported, supported are: %v", p.Provider, providerNames)
 		}
 	}
 	return nil, errors.WithStack(herodot.ErrNotFound.WithReasonf(`OpenID Connect Provider "%s" is unknown or has not been configured`, id))