fix oauth login on admin panel for production

pkg/hold/admin/admin.go

@@ -11,6 +11,7 @@ import (
 	"crypto/rand"
 	"embed"
 	"encoding/base64"
+	"encoding/json"
 	"fmt"
 	"html/template"
 	"io/fs"
@@ -83,45 +84,50 @@ func NewAdminUI(ctx context.Context, holdPDS *pds.HoldPDS, quotaMgr *quota.Manag
 		return nil, fmt.Errorf("PublicURL is required for admin panel")
 	}
 
-	// Determine OAuth base URL
-	// - For IP addresses (Docker network IPs), substitute 127.0.0.1 (ATProto requires localhost for public clients)
-	// - For real domains, use as-is (works with ATProto OAuth)
-	oauthBaseURL := cfg.PublicURL
+	// Determine OAuth configuration based on URL type
 	u, err := url.Parse(cfg.PublicURL)
 	if err != nil {
 		return nil, fmt.Errorf("invalid PublicURL: %w", err)
 	}
 
-	host := u.Hostname()
-	if isIPAddress(host) {
-		// IP address (e.g., 172.28.0.3) - substitute localhost
-		port := u.Port()
-		if port == "" {
-			port = "8080"
-		}
-		oauthBaseURL = "http://127.0.0.1:" + port
-	}
-
 	// Use in-memory store for OAuth sessions
 	oauthStore := indigooauth.NewMemStore()
 
 	// Use minimal scopes for admin (only need basic auth, no blob access)
 	adminScopes := []string{"atproto"}
 
-	// Admin panel uses localhost callback for OAuth (ATProto requirement for public clients)
-	redirectURI := oauthBaseURL + "/admin/auth/oauth/callback"
+	var oauthConfig indigooauth.ClientConfig
+	var redirectURI string
 
-	// Use simple public client - no need for confidential client complexity
-	oauthConfig := indigooauth.NewLocalhostConfig(redirectURI, adminScopes)
+	host := u.Hostname()
+	if isIPAddress(host) || host == "localhost" || host == "127.0.0.1" {
+		// Development mode: IP address or localhost - use localhost OAuth config
+		// Substitute 127.0.0.1 for Docker network IPs
+		port := u.Port()
+		if port == "" {
+			port = "8080"
+		}
+		oauthBaseURL := "http://127.0.0.1:" + port
+		redirectURI = oauthBaseURL + "/admin/auth/oauth/callback"
+		oauthConfig = indigooauth.NewLocalhostConfig(redirectURI, adminScopes)
+
+		slog.Info("Admin OAuth configured (localhost mode)",
+			"redirect_uri", redirectURI,
+			"public_url", cfg.PublicURL)
+	} else {
+		// Production mode: real domain - use public client with metadata endpoint
+		clientID := cfg.PublicURL + "/admin/oauth-client-metadata.json"
+		redirectURI = cfg.PublicURL + "/admin/auth/oauth/callback"
+		oauthConfig = indigooauth.NewPublicConfig(clientID, redirectURI, adminScopes)
+
+		slog.Info("Admin OAuth configured (production mode)",
+			"client_id", clientID,
+			"redirect_uri", redirectURI)
+	}
 
 	clientApp := indigooauth.NewClientApp(&oauthConfig, oauthStore)
 	clientApp.Dir = atproto.GetDirectory()
 
-	slog.Info("Admin OAuth configured",
-		"redirect_uri", redirectURI,
-		"public_url", cfg.PublicURL,
-		"oauth_base_url", oauthBaseURL)
-
 	// Parse templates
 	templates, err := parseTemplates()
 	if err != nil {
@@ -286,6 +292,9 @@ func (ui *AdminUI) RegisterRoutes(r chi.Router) {
 	staticSub, _ := fs.Sub(staticFS, "static")
 	r.Handle("/admin/static/*", http.StripPrefix("/admin/static/", http.FileServer(http.FS(staticSub))))
 
+	// OAuth client metadata endpoint (required for production OAuth)
+	r.Get("/admin/oauth-client-metadata.json", ui.handleClientMetadata)
+
 	// Public auth routes
 	r.Get("/admin/auth/login", ui.handleLogin)
 	r.Get("/admin/auth/oauth/authorize", ui.handleAuthorize)
@@ -320,6 +329,20 @@ func (ui *AdminUI) RegisterRoutes(r chi.Router) {
 	})
 }
 
+// handleClientMetadata serves the OAuth client metadata for production deployments
+func (ui *AdminUI) handleClientMetadata(w http.ResponseWriter, r *http.Request) {
+	metadata := ui.clientApp.Config.ClientMetadata()
+
+	// Set client name for display in OAuth consent screen
+	clientName := "Hold Admin Panel"
+	metadata.ClientName = &clientName
+	metadata.ClientURI = &ui.config.PublicURL
+
+	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Cache-Control", "public, max-age=3600")
+	json.NewEncoder(w).Encode(metadata)
+}
+
 // Close cleans up resources (no-op now, but keeps interface consistent)
 func (ui *AdminUI) Close() error {
 	return nil