Demo warning in /chat UI (#466)

* Add demo warning to /chat

* Missed two files!

* Function calling works now, update message

app/controllers/application_controller.rb

@@ -9,6 +9,8 @@ class ApplicationController < ActionController::Base
   before_action :set_default_chat
   before_action :set_active_storage_url_options
 
+  helper_method :demo_config, :demo_host_match?, :show_demo_warning?
+
   private
     def detect_os
       user_agent = request.user_agent
@@ -35,4 +37,20 @@ class ApplicationController < ActionController::Base
         port: request.optional_port
       }
     end
+
+    def demo_config
+      Rails.application.config_for(:demo)
+    rescue RuntimeError, Errno::ENOENT, Psych::SyntaxError
+      nil
+    end
+
+    def demo_host_match?(demo = demo_config)
+      return false unless demo.is_a?(Hash) && demo["hosts"].present?
+
+      demo["hosts"].include?(request.host)
+    end
+
+    def show_demo_warning?
+      demo_host_match?
+    end
 end

app/controllers/sessions_controller.rb

@@ -5,19 +5,13 @@ class SessionsController < ApplicationController
   layout "auth"
 
   def new
-    begin
-      demo = Rails.application.config_for(:demo)
-      @prefill_demo_credentials = demo_host_match?(demo)
-      if @prefill_demo_credentials
-        @email = params[:email].presence || demo["email"]
-        @password = params[:password].presence || demo["password"]
-      else
-        @email = params[:email]
-        @password = params[:password]
-      end
-    rescue RuntimeError, Errno::ENOENT, Psych::SyntaxError
-      # Demo config file missing or malformed - disable demo credential prefilling
-      @prefill_demo_credentials = false
+    demo = demo_config
+    @prefill_demo_credentials = demo_host_match?(demo)
+
+    if @prefill_demo_credentials
+      @email = params[:email].presence || demo["email"]
+      @password = params[:password].presence || demo["password"]
+    else
       @email = params[:email]
       @password = params[:password]
     end
@@ -91,10 +85,4 @@ class SessionsController < ApplicationController
     def set_session
       @session = Current.user.sessions.find(params[:id])
     end
-
-    def demo_host_match?(demo)
-      return false unless demo.present? && demo["hosts"].present?
-
-      demo["hosts"].include?(request.host)
-    end
 end

app/views/chats/index.html.erb

@@ -1,6 +1,12 @@
 <div data-controller="chat hotkey">
   <%= turbo_frame_tag chat_frame do %>
     <div class="flex flex-col h-full md:p-4">
+      <% if show_demo_warning? %>
+        <%= render "shared/demo_warning",
+          title: t("chats.demo_banner_title"),
+          message: t("chats.demo_banner_message") %>
+      <% end %>
+
       <% if @chats.any? %>
         <div class="grow flex flex-col">
           <div class="flex items-center justify-between my-6">

app/views/chats/new.html.erb

@@ -2,6 +2,12 @@
   <div class="flex flex-col h-full md:p-4">
     <%= render "chats/chat_nav", chat: @chat %>
 
+    <% if show_demo_warning? %>
+      <%= render "shared/demo_warning",
+        title: t("chats.demo_banner_title"),
+        message: t("chats.demo_banner_message") %>
+    <% end %>
+
     <div class="mt-auto py-8">
       <%= render "chats/ai_greeting" %>
     </div>

app/views/chats/show.html.erb

@@ -7,6 +7,12 @@
     <div class="flex flex-col h-full">
       <div class="md:p-4">
         <%= render "chats/chat_nav", chat: @chat %>
+
+        <% if show_demo_warning? %>
+          <%= render "shared/demo_warning",
+            title: t("chats.demo_banner_title"),
+            message: t("chats.demo_banner_message") %>
+        <% end %>
       </div>
 
       <div id="messages" class="grow overflow-y-auto p-4 space-y-6 pb-24 lg:pb-4" data-chat-target="messages">

app/views/shared/_demo_warning.html.erb

@@ -0,0 +1,13 @@
+<%# locals: title:, message: %>
+<div class="mb-4 rounded-lg border bg-blue-50 text-blue-700 border-blue-200 theme-dark:bg-blue-900/20 theme-dark:text-blue-400 theme-dark:border-blue-800 p-4" role="status" aria-live="polite">
+  <div class="flex items-start gap-3">
+    <div class="shrink-0">
+      <%= icon "info", size: "sm", color: "blue-600" %>
+    </div>
+    <div class="flex-1 text-sm">
+      <h3 class="font-semibold mb-1"><%= title %></h3>
+      <p><%= message %></p>
+    </div>
+  </div>
+</div>
+

config/locales/views/chats/en.yml

@@ -0,0 +1,6 @@
+---
+en:
+  chats:
+    demo_banner_title: "Demo Mode Active"
+    demo_banner_message: "You are using an open-weights Qwen3 LLM with credits provided by Cloudflare Workers AI.  Result may vary since the codebase was mostly tested on `gpt-4.1` but your tokens don't go anywhere else to be trained with! 🤖"
+