Add visibility + role-based access fields with validation for events

Author: trista-chen-29

pkg/handlers/event.go

@@ -170,6 +170,22 @@ func UpdateEventByID(c *gin.Context) {
 		return
 	}
 
+	// Validate patch fields for #36 visibility/status support
+	if err := event.ValidateUpdateFields(fields); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{
+			"error": err.Error(),
+		})
+		return
+	}
+
+	// Normalize public events: if visibility is being set to public in PATCH,
+	// clear minimum_visible_role automatically.
+	if visibilityRaw, ok := fields["visibility"]; ok {
+		if visibility, ok := visibilityRaw.(string); ok && strings.TrimSpace(visibility) == event.VisibilityPublic {
+			fields["minimum_visible_role"] = ""
+		}
+	}
+
 	err = db.UpdateEventByID(id, fields)
 	if err != nil {
 		if err == mongo.ErrNoDocuments {