From 763411b2d9eb97865ce9db2ca8512724d4af921a Mon Sep 17 00:00:00 2001
From: Cyril de Catheu <cyril@startree.ai>
Date: Sat, 2 Dec 2023 00:35:16 +0100
Subject: [PATCH 1/5] [core] clean web file

---
 jnotebook-core/src/main/jte/index.jte | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/jnotebook-core/src/main/jte/index.jte b/jnotebook-core/src/main/jte/index.jte
index eaaa3e9..79a4f90 100644
--- a/jnotebook-core/src/main/jte/index.jte
+++ b/jnotebook-core/src/main/jte/index.jte
@@ -646,7 +646,9 @@
             background-color: #ffe4e4;
         }
 
-        [x-cloak] { display: none !important; }
+        [x-cloak] {
+            display: none !important;
+        }
     </style>
 
     <script defer class="jnb-no-opti" src="https://cdn.jsdelivr.net/npm/alpinejs@3.12.1/dist/cdn.min.js"></script>
@@ -670,7 +672,7 @@
 </head>
 <body>
 <div x-cloak x-data="{ tocOpen: window.innerWidth >= 768, notebookStatus: 'Connected'}" class="flex">
-    <button x-on:click="tocOpen = ! tocOpen"
+    <button x-on:click="tocOpen=!tocOpen"
             class="toc-toggle z-20 fixed right-2 top-2 md:right-auto md:left-3 md:top-[7px] text-slate-400 font-sans text-xs hover:underline cursor-pointer flex items-center bg-white py-1 px-3 md:p-0 rounded-full md:rounded-none border md:border-0 border-slate-200 shadow md:shadow-none">
         <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke="currentColor" width="20"
              height="20">
@@ -687,7 +689,7 @@
         <div class="px-3 mb-1 mt-1 md:mt-0 text-xs md:text-[12px] uppercase tracking-wider text-slate-500 font-medium px-3 mb-1 leading-none">
             ToC
         </div>
-        <div x-on:click="tocOpen = ! tocOpen"
+        <div x-on:click="tocOpen=!tocOpen"
              class="toc-toggle text-slate-500 absolute right-2 top-[11px] cursor-pointer z-10">
             <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke="currentColor"
                  stroke-width="2" class="w-4 w-4">
@@ -697,23 +699,22 @@
         <div id="toc"></div>
     </aside>
     <div x-bind:class="tocOpen ? 'toc-offset' : ''" class="flex-auto h-screen overflow-y-auto scroll-container">
-        @if(model.render() != null)
-            <div id="notebook" class="flex flex-col items-center viewer-notebook flex-auto">
+        <div id="notebook" class="flex flex-col items-center viewer-notebook flex-auto">
+            @if(model.render() != null)
                 $unsafe{model.render()}
-            </div>
-        @else
-            <div id="notebook" class="flex flex-col items-center viewer-notebook flex-auto">
+            @else
                 <div id="helper" class="viewer viewer-result w-full max-w-prose px-8">
                     <div class="relative">
                         <div class="overflow-y-hidden">
                             <p>Welcome to <code>jnotebook</code>. Learn more on <a href="https://jnotebook.catheu.tech">jnotebook.catheu.tech</a>.
                             </p>
-                            <p>Edit a <code>.jsh</code> file in your <code>${((InteractiveConfiguration) model.config()).notebookPath}</code> folder to
+                            <p>Edit a <code>.jsh</code> file in your
+                                <code>${((InteractiveConfiguration) model.config()).notebookPath}</code> folder to
                                 make your notebook appear.</p></div>
                     </div>
                 </div>
-            </div>
-        @endif
+            @endif
+        </div>
     </div>
     @if(model.interactive())
         <script defer>

From 281e1cc3d89d36ac17385a007052bdc5f83a1544 Mon Sep 17 00:00:00 2001
From: Cyril de Catheu <cyril@startree.ai>
Date: Sat, 2 Dec 2023 02:08:00 +0100
Subject: [PATCH 2/5] wip refresh function

---
 .../catheu/jnotebook/InteractiveNotebook.java | 41 ++++++++++++++-----
 .../jnotebook/server/InteractiveServer.java   | 30 +++++++++++++-
 jnotebook-core/src/main/jte/index.jte         |  8 +++-
 3 files changed, 66 insertions(+), 13 deletions(-)

diff --git a/jnotebook-core/src/main/java/tech/catheu/jnotebook/InteractiveNotebook.java b/jnotebook-core/src/main/java/tech/catheu/jnotebook/InteractiveNotebook.java
index d988026..0bd0920 100644
--- a/jnotebook-core/src/main/java/tech/catheu/jnotebook/InteractiveNotebook.java
+++ b/jnotebook-core/src/main/java/tech/catheu/jnotebook/InteractiveNotebook.java
@@ -8,7 +8,10 @@
 package tech.catheu.jnotebook;
 
 import io.methvin.watcher.DirectoryChangeEvent;
+import io.methvin.watcher.hashing.FileHash;
 import io.reactivex.rxjava3.core.Observable;
+import io.reactivex.rxjava3.subjects.PublishSubject;
+import org.jetbrains.annotations.NotNull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import tech.catheu.jnotebook.evaluate.GreedyInterpreter;
@@ -32,7 +35,8 @@ public class InteractiveNotebook {
 
   private static final Logger LOG = LoggerFactory.getLogger(InteractiveNotebook.class);
 
-  private static final String RESOURCES_HELLO_WORLD_NOTEBOOK = "/jnb_interactive/hello_world.jsh";
+  private static final String RESOURCES_HELLO_WORLD_NOTEBOOK =
+          "/jnb_interactive/hello_world.jsh";
   private static final String FILESYSTEM_HELLO_WORLD_NAME = "hello_world.jsh";
 
   private final Main.InteractiveConfiguration configuration;
@@ -40,7 +44,7 @@ public class InteractiveNotebook {
   private final StaticParser staticParser;
   private final Interpreter interpreter;
   private final Renderer renderer;
-  private final InteractiveServer server;
+  private InteractiveServer server;
 
   public InteractiveNotebook(final Main.InteractiveConfiguration configuration) {
     this.configuration = configuration;
@@ -48,20 +52,21 @@ public InteractiveNotebook(final Main.InteractiveConfiguration configuration) {
     this.staticParser = new StaticParser(shellProvider);
     this.interpreter = new GreedyInterpreter(shellProvider);
     this.renderer = new Renderer(configuration);
-    this.server = new InteractiveServer(configuration);
   }
 
   public void run() throws IOException {
     prepare();
-    server.start();
-    final Observable<DirectoryChangeEvent> notebookEvents =
+    final Observable<DirectoryChangeEvent> fileChangeEvents =
             PathObservables.of(Paths.get(configuration.notebookPath))
                            .filter(e -> e.path().toString().endsWith(JSHELL_SUFFIX));
-    //.subscribe(s -> server.sendReload()); to subscribe on a side scheduler
-
+    final PublishSubject<DirectoryChangeEvent> manualTriggers = PublishSubject.create();
+    this.server = new InteractiveServer(configuration,
+                                        path -> manualTriggers.onNext(
+                                                directoryChangeEvent(path)));
+    server.start();
     LOG.info("Notebook server started. Go to http://localhost:" + configuration.port);
-
-    notebookEvents
+    manualTriggers
+            .mergeWith(fileChangeEvents)
             .doOnEach(e -> server.sendStatus(NotebookServerStatus.COMPUTE))
             .map(staticParser::staticSnippets)
             .doOnError(InteractiveNotebook::logError)
@@ -72,6 +77,20 @@ public void run() throws IOException {
             .subscribe(server::sendUpdate, InteractiveNotebook::logError);
   }
 
+  // build a DirectoryChangeEvent manually
+  // assumes rootPath is never used - it may be incorrect
+  @NotNull
+  private static DirectoryChangeEvent directoryChangeEvent(final Path path) {
+    return new DirectoryChangeEvent(
+            DirectoryChangeEvent.EventType.MODIFY,
+            false,
+            path,
+            FileHash.fromLong(0),
+            0,
+            // assume this is not used - may be incorrect
+            path.getRoot());
+  }
+
   private void prepare() {
     // ensure notebook folder exists, if not, create it.
     final Path notebooksFolder = Paths.get(configuration.notebookPath);
@@ -91,7 +110,9 @@ private static void logError(Throwable e) {
 
 
   public void stop() throws IOException {
-    server.stop();
+    if (server != null) {
+      server.stop();
+    }
     staticParser.stop();
     interpreter.stop();
     renderer.stop();
diff --git a/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/InteractiveServer.java b/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/InteractiveServer.java
index 9f37731..e22ee9c 100644
--- a/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/InteractiveServer.java
+++ b/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/InteractiveServer.java
@@ -15,6 +15,8 @@
 import io.undertow.util.Headers;
 import io.undertow.websockets.WebSocketConnectionCallback;
 import io.undertow.websockets.WebSocketProtocolHandshakeHandler;
+import io.undertow.websockets.core.AbstractReceiveListener;
+import io.undertow.websockets.core.BufferedTextMessage;
 import io.undertow.websockets.core.WebSocketChannel;
 import io.undertow.websockets.core.WebSockets;
 import io.undertow.websockets.spi.WebSocketHttpExchange;
@@ -28,22 +30,27 @@
 import tech.catheu.jnotebook.render.Rendering;
 
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.function.Consumer;
 
 public class InteractiveServer {
 
-  private static final Logger LOG = LoggerFactory.getLogger(Main.class);
+  private static final Logger LOG = LoggerFactory.getLogger(InteractiveServer.class);
 
   private final Main.InteractiveConfiguration configuration;
+  private final Consumer<Path> renderTrigger;
 
   private Undertow server;
   private final List<WebSocketChannel> channels = new ArrayList<>();
   XnioWorker worker;
   private Rendering lastUpdate;
 
-  public InteractiveServer(final Main.InteractiveConfiguration configuration) {
+  public InteractiveServer(final Main.InteractiveConfiguration configuration,
+                           Consumer<Path> renderTrigger) {
     this.configuration = configuration;
+    this.renderTrigger = renderTrigger;
   }
 
 
@@ -144,10 +151,29 @@ public void onConnect(WebSocketHttpExchange webSocketHttpExchange,
       channels.add(channel);
       // resend to every channel - not very correct but simpler for the moment
       sendStatus(NotebookServerStatus.CONNECTED);
+      setupReceiver(channel);
       if (lastUpdate != null) {
         // resend to every channel - not necessary but simpler for the moment
         sendUpdate(lastUpdate);
       }
     }
+
+    private void setupReceiver(WebSocketChannel channel) {
+      channel.getReceiveSetter().set(new AbstractReceiveListener() {
+        @Override
+        protected void onFullTextMessage(WebSocketChannel channel,
+                                         BufferedTextMessage message) throws IOException {
+          final String messageText = message.getData();
+          if (messageText.startsWith("refresh_")) {
+            final String substring = messageText.substring(8);
+            LOG.info("Triggering refresh for file {}", substring);
+            renderTrigger.accept(Path.of(substring));
+          } else {
+            LOG.error("Received unsupported message from websocket: {}", messageText);
+          }
+        }
+      });
+      channel.resumeReceives();
+    }
   }
 }
diff --git a/jnotebook-core/src/main/jte/index.jte b/jnotebook-core/src/main/jte/index.jte
index 79a4f90..0e80f17 100644
--- a/jnotebook-core/src/main/jte/index.jte
+++ b/jnotebook-core/src/main/jte/index.jte
@@ -710,7 +710,9 @@
                             </p>
                             <p>Edit a <code>.jsh</code> file in your
                                 <code>${((InteractiveConfiguration) model.config()).notebookPath}</code> folder to
-                                make your notebook appear.</p></div>
+                                make your notebook appear.</p>
+                            <button class="test-cyril">doc/book.jsh</button>
+                        </div>
                     </div>
                 </div>
             @endif
@@ -762,6 +764,10 @@
                         update(socketEvent.data);
                     }
                 };
+
+                // something like this for the message passing
+                const textAreas = document.querySelectorAll("button.test-cyril")
+                    .forEach(e => e.addEventListener('click', ev => {socket.send("refresh_"+e.textContent)}));
             }
 
             const port = "${Optional.ofNullable(((InteractiveConfiguration) model.config()).port).orElse(5002)}";

From a8bf58b5711afcb0f466b75dd49ddd2456fbff74 Mon Sep 17 00:00:00 2001
From: Cyril de Catheu <cyril@startree.ai>
Date: Sat, 2 Dec 2023 12:37:20 +0100
Subject: [PATCH 3/5] [core] add list of notebooks to start screen

---
 .../catheu/jnotebook/NotebookRenderer.java    | 11 +++---
 .../jnotebook/server/HtmlTemplateEngine.java  |  7 ++--
 .../jnotebook/server/InteractiveServer.java   | 25 +++++++++++---
 jnotebook-core/src/main/jte/index.jte         | 34 +++++++++++++++----
 4 files changed, 59 insertions(+), 18 deletions(-)

diff --git a/jnotebook-core/src/main/java/tech/catheu/jnotebook/NotebookRenderer.java b/jnotebook-core/src/main/java/tech/catheu/jnotebook/NotebookRenderer.java
index ed32a3b..2b9e65f 100644
--- a/jnotebook-core/src/main/java/tech/catheu/jnotebook/NotebookRenderer.java
+++ b/jnotebook-core/src/main/java/tech/catheu/jnotebook/NotebookRenderer.java
@@ -75,13 +75,15 @@ public void render(final Main.RenderConfiguration config) {
       final Interpreted interpreted = interpreter.interpret(staticParsing);
       final Rendering render = renderer.render(interpreted);
       final HtmlTemplateEngine templateEngine = new HtmlTemplateEngine();
-      String html = templateEngine.render(config, false, render.html());
+      final HtmlTemplateEngine.TemplateData model =
+              new HtmlTemplateEngine.TemplateData(config, false, render.html(), null);
+      String html = templateEngine.render(model);
       if (!config.noOptimize) {
         html = optimizeHtml(html);
       }
 
-      final String outputPath = optional(config.outputPath)
-              .orElse(Files.getNameWithoutExtension(config.inputPath) + ".html");
+      final String outputPath =
+              optional(config.outputPath).orElse(Files.getNameWithoutExtension(config.inputPath) + ".html");
       final File outputFile = FileUtils.getFile(outputPath);
       FileUtils.write(outputFile, html, StandardCharsets.UTF_8);
       LOG.info("Notebook rendered successfully and written to {}", outputFile);
@@ -139,7 +141,8 @@ public void handle(HttpExchange exchange) throws IOException {
           responseStream.close();
         }
       });
-      final HtmlFileServer result = new HtmlFileServer("http://localhost:" + port, server);
+      final HtmlFileServer result =
+              new HtmlFileServer("http://localhost:" + port, server);
       return result;
     } catch (Exception e) {
       LOG.error("Failed to create a server: ", e);
diff --git a/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/HtmlTemplateEngine.java b/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/HtmlTemplateEngine.java
index 8d876a1..b7208bc 100644
--- a/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/HtmlTemplateEngine.java
+++ b/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/HtmlTemplateEngine.java
@@ -19,6 +19,7 @@
 import tech.catheu.jnotebook.utils.JavaUtils;
 
 import java.nio.file.Path;
+import java.util.List;
 
 public class HtmlTemplateEngine {
 
@@ -36,15 +37,13 @@ public HtmlTemplateEngine() {
   }
 
   // render is the generated notebook html
-  public String render(final Main.SharedConfiguration config, final boolean interactive,
-                       final String render) {
-    final TemplateModel model =  new TemplateModel(config, interactive, render);
+  public String render(TemplateData model) {
     final TemplateOutput output = new StringOutput();
     delegate.render("index.jte", model, output);
     return output.toString();
   }
 
-  public record TemplateModel(Main.SharedConfiguration config, boolean interactive, String render) {}
+  public record TemplateData(Main.SharedConfiguration config, boolean interactive, String render, List<Path> notebooksInPath) {}
 
 
 }
diff --git a/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/InteractiveServer.java b/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/InteractiveServer.java
index e22ee9c..beb106a 100644
--- a/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/InteractiveServer.java
+++ b/jnotebook-core/src/main/java/tech/catheu/jnotebook/server/InteractiveServer.java
@@ -30,10 +30,13 @@
 import tech.catheu.jnotebook.render.Rendering;
 
 import java.io.IOException;
+import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.ArrayList;
 import java.util.List;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.function.Consumer;
+import java.util.stream.Stream;
 
 public class InteractiveServer {
 
@@ -43,7 +46,7 @@ public class InteractiveServer {
   private final Consumer<Path> renderTrigger;
 
   private Undertow server;
-  private final List<WebSocketChannel> channels = new ArrayList<>();
+  private final Queue<WebSocketChannel> channels = new ConcurrentLinkedQueue<>();
   XnioWorker worker;
   private Rendering lastUpdate;
 
@@ -101,7 +104,20 @@ private static class TemplatedHttpHandler implements HttpHandler {
 
     @Override
     public void handleRequest(HttpServerExchange exchange) throws Exception {
-      final String html = templateEngine.render(this.configuration, true, null);
+      final List<Path> notebooksInPath;
+      try (Stream<Path> files = Files.find(Path.of(configuration.notebookPath),
+                                           10,
+                                           (path, attributes) -> attributes.isRegularFile() && path.toString()
+                                                                                                   .endsWith(
+                                                                                                           ".jsh"))) {
+        notebooksInPath = files.toList();
+      }
+      final HtmlTemplateEngine.TemplateData model = new HtmlTemplateEngine.TemplateData(
+              this.configuration,
+              true,
+              null,
+              notebooksInPath);
+      final String html = templateEngine.render(model);
       exchange.getResponseHeaders().put(Headers.CONTENT_TYPE, "text/html");
       exchange.getResponseSender().send(html);
     }
@@ -126,7 +142,8 @@ private void sendMessage(final String message) {
       }
     }
     if (!messageSent) {
-      LOG.error("ERROR: trying to send updates but no client is opened. Go to http://localhost:" + configuration.port);
+      LOG.error(
+              "ERROR: trying to send updates but no client is opened. Go to http://localhost:" + configuration.port);
     }
   }
 
diff --git a/jnotebook-core/src/main/jte/index.jte b/jnotebook-core/src/main/jte/index.jte
index 0e80f17..9113883 100644
--- a/jnotebook-core/src/main/jte/index.jte
+++ b/jnotebook-core/src/main/jte/index.jte
@@ -1,7 +1,8 @@
 @import tech.catheu.jnotebook.Main.InteractiveConfiguration
-@import tech.catheu.jnotebook.server.HtmlTemplateEngine.TemplateModel
+@import tech.catheu.jnotebook.server.HtmlTemplateEngine.TemplateData
+@import java.nio.file.Path
 @import java.util.Optional
-@param TemplateModel model
+@param TemplateData model
 <!--/*
 
     Copyright 2023 Cyril de Catheu
@@ -710,8 +711,27 @@
                             </p>
                             <p>Edit a <code>.jsh</code> file in your
                                 <code>${((InteractiveConfiguration) model.config()).notebookPath}</code> folder to
-                                make your notebook appear.</p>
-                            <button class="test-cyril">doc/book.jsh</button>
+                                launch your notebook, or click on one of the notebook below.</p>
+                            <div>
+                                <table>
+                                    <tr>
+                                        <td>Notebooks</td>
+                                    </tr>
+                                    @if(model.notebooksInPath() == null || model.notebooksInPath().isEmpty())
+                                        <tr>
+                                            <td>
+                                                <i>There are no notebooks in the <code>${((InteractiveConfiguration) model.config()).notebookPath}</code> folder.</i>
+                                            </td>
+                                        </tr>
+                                    @else
+                                    @for(final Path p: model.notebooksInPath())
+                                        <tr>
+                                            <td><button class="notebook-in-path"><a>${p.toString()}</a></button></td>
+                                        </tr>
+                                    @endfor
+                                    @endif
+                                </table>
+                            </div>
                         </div>
                     </div>
                 </div>
@@ -766,8 +786,10 @@
                 };
 
                 // something like this for the message passing
-                const textAreas = document.querySelectorAll("button.test-cyril")
-                    .forEach(e => e.addEventListener('click', ev => {socket.send("refresh_"+e.textContent)}));
+                const textAreas = document.querySelectorAll("button.notebook-in-path")
+                    .forEach(e => e.addEventListener('click', ev => {
+                        socket.send("refresh_" + e.textContent)
+                    }));
             }
 
             const port = "${Optional.ofNullable(((InteractiveConfiguration) model.config()).port).orElse(5002)}";

From a61f29f285ea8719b0c191a0a9da20f13a587bad Mon Sep 17 00:00:00 2001
From: Cyril de Catheu <cyril@startree.ai>
Date: Sat, 2 Dec 2023 14:46:19 +0100
Subject: [PATCH 4/5] refactor templates

---
 .gitignore                              |  3 +++
 jnotebook-core/src/main/jte/.jteroot    |  0
 jnotebook-core/src/main/jte/index.jte   | 32 +----------------------
 jnotebook-core/src/main/jte/landing.jte | 34 +++++++++++++++++++++++++
 4 files changed, 38 insertions(+), 31 deletions(-)
 create mode 100644 jnotebook-core/src/main/jte/.jteroot
 create mode 100644 jnotebook-core/src/main/jte/landing.jte

diff --git a/.gitignore b/.gitignore
index 4c21526..ec3b4ba 100644
--- a/.gitignore
+++ b/.gitignore
@@ -45,3 +45,6 @@ notebook-profile-*
 ### pom release artefacts
 release.properties
 pom.xml.releaseBackup
+
+# template classes generated by jte
+jte-classes/
diff --git a/jnotebook-core/src/main/jte/.jteroot b/jnotebook-core/src/main/jte/.jteroot
new file mode 100644
index 0000000..e69de29
diff --git a/jnotebook-core/src/main/jte/index.jte b/jnotebook-core/src/main/jte/index.jte
index 9113883..0a12ad2 100644
--- a/jnotebook-core/src/main/jte/index.jte
+++ b/jnotebook-core/src/main/jte/index.jte
@@ -704,37 +704,7 @@
             @if(model.render() != null)
                 $unsafe{model.render()}
             @else
-                <div id="helper" class="viewer viewer-result w-full max-w-prose px-8">
-                    <div class="relative">
-                        <div class="overflow-y-hidden">
-                            <p>Welcome to <code>jnotebook</code>. Learn more on <a href="https://jnotebook.catheu.tech">jnotebook.catheu.tech</a>.
-                            </p>
-                            <p>Edit a <code>.jsh</code> file in your
-                                <code>${((InteractiveConfiguration) model.config()).notebookPath}</code> folder to
-                                launch your notebook, or click on one of the notebook below.</p>
-                            <div>
-                                <table>
-                                    <tr>
-                                        <td>Notebooks</td>
-                                    </tr>
-                                    @if(model.notebooksInPath() == null || model.notebooksInPath().isEmpty())
-                                        <tr>
-                                            <td>
-                                                <i>There are no notebooks in the <code>${((InteractiveConfiguration) model.config()).notebookPath}</code> folder.</i>
-                                            </td>
-                                        </tr>
-                                    @else
-                                    @for(final Path p: model.notebooksInPath())
-                                        <tr>
-                                            <td><button class="notebook-in-path"><a>${p.toString()}</a></button></td>
-                                        </tr>
-                                    @endfor
-                                    @endif
-                                </table>
-                            </div>
-                        </div>
-                    </div>
-                </div>
+                @template.landing(model=model)
             @endif
         </div>
     </div>
diff --git a/jnotebook-core/src/main/jte/landing.jte b/jnotebook-core/src/main/jte/landing.jte
new file mode 100644
index 0000000..93a1c91
--- /dev/null
+++ b/jnotebook-core/src/main/jte/landing.jte
@@ -0,0 +1,34 @@
+@import tech.catheu.jnotebook.Main.InteractiveConfiguration
+@param tech.catheu.jnotebook.server.HtmlTemplateEngine.TemplateData model
+
+<div id="helper" class="viewer viewer-result w-full max-w-prose px-8">
+    <div class="relative">
+        <div class="overflow-y-hidden">
+            <p>Welcome to <code>jnotebook</code>. Learn more on <a href="https://jnotebook.catheu.tech">jnotebook.catheu.tech</a>.
+            </p>
+            <p>Edit a <code>.jsh</code> file in your
+                <code>${((InteractiveConfiguration) model.config()).notebookPath}</code> folder to
+                launch your notebook, or click on a notebook below.</p>
+            <div>
+                <table>
+                    <tr>
+                        <td>Notebooks</td>
+                    </tr>
+                    @if(model.notebooksInPath() == null || model.notebooksInPath().isEmpty())
+                        <tr>
+                            <td>
+                                <i>There are no notebooks in the <code>${((InteractiveConfiguration) model.config()).notebookPath}</code> folder.</i>
+                            </td>
+                        </tr>
+                    @else
+                        @for(final java.nio.file.Path p: model.notebooksInPath())
+                            <tr>
+                                <td><button class="notebook-in-path"><a>${p.toString()}</a></button></td>
+                            </tr>
+                        @endfor
+                    @endif
+                </table>
+            </div>
+        </div>
+    </div>
+</div>

From aa4ec35e5b28f01da6e47f1566e0e0f13c2e549f Mon Sep 17 00:00:00 2001
From: Cyril de Catheu <cyril@startree.ai>
Date: Sat, 2 Dec 2023 14:53:40 +0100
Subject: [PATCH 5/5] clean

---
 .../java/tech/catheu/jnotebook/InteractiveNotebook.java    | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/jnotebook-core/src/main/java/tech/catheu/jnotebook/InteractiveNotebook.java b/jnotebook-core/src/main/java/tech/catheu/jnotebook/InteractiveNotebook.java
index 0bd0920..913f320 100644
--- a/jnotebook-core/src/main/java/tech/catheu/jnotebook/InteractiveNotebook.java
+++ b/jnotebook-core/src/main/java/tech/catheu/jnotebook/InteractiveNotebook.java
@@ -11,7 +11,7 @@
 import io.methvin.watcher.hashing.FileHash;
 import io.reactivex.rxjava3.core.Observable;
 import io.reactivex.rxjava3.subjects.PublishSubject;
-import org.jetbrains.annotations.NotNull;
+import org.checkerframework.checker.nullness.qual.NonNull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import tech.catheu.jnotebook.evaluate.GreedyInterpreter;
@@ -77,9 +77,7 @@ public void run() throws IOException {
             .subscribe(server::sendUpdate, InteractiveNotebook::logError);
   }
 
-  // build a DirectoryChangeEvent manually
-  // assumes rootPath is never used - it may be incorrect
-  @NotNull
+  @NonNull
   private static DirectoryChangeEvent directoryChangeEvent(final Path path) {
     return new DirectoryChangeEvent(
             DirectoryChangeEvent.EventType.MODIFY,
@@ -87,7 +85,6 @@ private static DirectoryChangeEvent directoryChangeEvent(final Path path) {
             path,
             FileHash.fromLong(0),
             0,
-            // assume this is not used - may be incorrect
             path.getRoot());
   }
 
