Add logic to able to prefill DEFAULT_EMAIL

config.example.yaml

@@ -65,6 +65,11 @@ auth:
   # Can also be set via ADMIN_EMAIL environment variable
   admin_email: ""  # Set this to your admin email address
 
+  # Default email to pre-fill in the login form
+  # When set, this email will be automatically filled in the email input field
+  # Leave empty to show an empty email field
+  default_email: ""  # Set this to pre-fill the login form with a default email
+
 # Environment-specific overrides can be set via environment variables:
 # - PORT: Server port
 # - HOST: Server host
@@ -74,3 +79,4 @@ auth:
 # - ALLOWED_EMAILS: Comma-separated list of allowed emails
 # - ADMIN_EMAIL: Admin email address
 # - COOKIE_DOMAIN: Cookie domain for session cookies
+# - DEFAULT_EMAIL: Default email to pre-fill in login form

internal/config/config.go

@@ -42,6 +42,7 @@ type AuthConfig struct {
 	AllowedEmails   []string `yaml:"allowed_emails"`
 	AdminEmail      string   `yaml:"admin_email"`
 	CookieDomain    string   `yaml:"cookie_domain"`
+	DefaultEmail    string   `yaml:"default_email"`
 }
 
 func Load() (*Config, error) {
@@ -122,6 +123,9 @@ func Load() (*Config, error) {
 	if cookieDomain := os.Getenv("COOKIE_DOMAIN"); cookieDomain != "" {
 		config.Auth.CookieDomain = cookieDomain
 	}
+	if defaultEmail := os.Getenv("DEFAULT_EMAIL"); defaultEmail != "" {
+		config.Auth.DefaultEmail = defaultEmail
+	}
 
 	return config, nil
 }

internal/handlers/handlers.go

@@ -469,6 +469,14 @@ func (h *Handlers) GetAuthStatus(w http.ResponseWriter, r *http.Request) {
 	h.writeJSON(w, response)
 }
 
+// GetConfig returns public configuration data
+func (h *Handlers) GetConfig(w http.ResponseWriter, r *http.Request) {
+	configData := map[string]interface{}{
+		"default_email": h.config.Auth.DefaultEmail,
+	}
+	h.writeJSON(w, configData)
+}
+
 // Admin endpoints
 
 // ListUsers returns all users (admin endpoint)

main.go

@@ -49,6 +49,7 @@ func main() {
 
 	// API routes
 	api := router.PathPrefix("/api").Subrouter()
+	api.HandleFunc("/config", h.GetConfig).Methods("GET")
 	api.HandleFunc("/register/begin", h.BeginRegistration).Methods("POST")
 	api.HandleFunc("/register/finish", h.FinishRegistration).Methods("POST")
 	api.HandleFunc("/login/begin", h.BeginLogin).Methods("POST")

web/login.html

@@ -282,7 +282,7 @@
             return emailParam;
         }
 
-        // Pre-fill email input if email parameter exists
+        // Pre-fill email input if email parameter exists or from config
         function prefillEmail() {
             const email = getEmailFromUrl();
             if (email) {
@@ -290,6 +290,29 @@
                 if (emailInput) {
                     emailInput.value = decodeURIComponent(email);
                 }
+            } else {
+                // If no email parameter, try to get default email from config
+                loadDefaultEmail();
+            }
+        }
+
+        // Load default email from server configuration
+        async function loadDefaultEmail() {
+            try {
+                const response = await fetch('/api/config');
+                if (response.ok) {
+                    const config = await response.json();
+                    if (config.default_email) {
+                        const emailInput = document.getElementById('email');
+                        if (emailInput && !emailInput.value) {
+                            emailInput.value = config.default_email;
+                            console.log('Pre-filled email from config:', config.default_email);
+                        }
+                    }
+                }
+            } catch (error) {
+                console.log('Could not load default email from config:', error);
+                // Fail silently - this is not critical functionality
             }
         }