From 78f7cd968c160cb0a730028a6e8f9346d51d20fc Mon Sep 17 00:00:00 2001
From: Sebastien Flory <sflory@gmail.com>
Date: Fri, 9 Aug 2024 17:31:46 +0200
Subject: [PATCH] Upg: improve builder UX when using a template for
 instructions (#6722)

* Upg: improve builder UX when using a template for instructions

* fix lint

* Add: comment about re-rendering cost
---
 .../assistant_builder/AssistantBuilder.tsx    |  6 ++
 .../assistant_builder/InstructionScreen.tsx   | 66 ++++++++++++++++---
 2 files changed, 64 insertions(+), 8 deletions(-)

diff --git a/front/components/assistant_builder/AssistantBuilder.tsx b/front/components/assistant_builder/AssistantBuilder.tsx
index 3dbd7e1739f6..75ee4ec2990c 100644
--- a/front/components/assistant_builder/AssistantBuilder.tsx
+++ b/front/components/assistant_builder/AssistantBuilder.tsx
@@ -377,6 +377,10 @@ export default function AssistantBuilder({
     screen,
   ]);
 
+  const [doTypewriterEffect, setDoTypewriterEffect] = useState(
+    Boolean(template !== null && builderState.instructions)
+  );
+
   const modalTitle = agentConfigurationId
     ? `Edit @${builderState.handle}`
     : "New Assistant";
@@ -454,6 +458,8 @@ export default function AssistantBuilder({
                         resetAt={instructionsResetAt}
                         isUsingTemplate={template !== null}
                         instructionsError={instructionsError}
+                        doTypewriterEffect={doTypewriterEffect}
+                        setDoTypewriterEffect={setDoTypewriterEffect}
                       />
                     );
                   case "actions":
diff --git a/front/components/assistant_builder/InstructionScreen.tsx b/front/components/assistant_builder/InstructionScreen.tsx
index dfc038b6e87d..44048e34c813 100644
--- a/front/components/assistant_builder/InstructionScreen.tsx
+++ b/front/components/assistant_builder/InstructionScreen.tsx
@@ -104,6 +104,8 @@ export function InstructionScreen({
   resetAt,
   isUsingTemplate,
   instructionsError,
+  doTypewriterEffect,
+  setDoTypewriterEffect,
 }: {
   owner: WorkspaceType;
   plan: PlanType;
@@ -115,6 +117,8 @@ export function InstructionScreen({
   resetAt: number | null;
   isUsingTemplate: boolean;
   instructionsError: string | null;
+  doTypewriterEffect: boolean;
+  setDoTypewriterEffect: (doTypewriterEffect: boolean) => void;
 }) {
   const editor = useEditor({
     extensions: [
@@ -126,19 +130,65 @@ export function InstructionScreen({
         limit: INSTRUCTIONS_MAXIMUM_CHARACTER_COUNT,
       }),
     ],
-    content: tipTapContentFromPlainText(builderState.instructions || ""),
+    editable: !doTypewriterEffect,
+    content: tipTapContentFromPlainText(
+      (!doTypewriterEffect && builderState.instructions) || ""
+    ),
     onUpdate: ({ editor }) => {
-      const json = editor.getJSON();
-      const plainText = plainTextFromTipTapContent(json);
-      setEdited(true);
-      setBuilderState((state) => ({
-        ...state,
-        instructions: plainText,
-      }));
+      if (!doTypewriterEffect) {
+        const json = editor.getJSON();
+        const plainText = plainTextFromTipTapContent(json);
+        setEdited(true);
+        setBuilderState((state) => ({
+          ...state,
+          instructions: plainText,
+        }));
+      }
     },
   });
   const editorService = useInstructionEditorService(editor);
 
+  const [letterIndex, setLetterIndex] = useState(0);
+
+  // Beware that using this useEffect will cause a lot of re-rendering until we finished the visual effect
+  // We must be careful to avoid any heavy rendering in this component
+  useEffect(() => {
+    if (doTypewriterEffect && editor && builderState.instructions) {
+      // Get the text from content and strip HTML tags for simplicity and being able to write letter by letter
+      const textContent = builderState.instructions.replace(/<[^>]*>?/gm, "");
+      const delay = 2; // Typing delay in milliseconds
+      if (letterIndex < textContent.length) {
+        const timeoutId = setTimeout(() => {
+          // Append next character
+          editor
+            .chain()
+            .focus("end")
+            .insertContent(textContent[letterIndex], {
+              updateSelection: false,
+            })
+            .run();
+          setLetterIndex(letterIndex + 1);
+        }, delay);
+        return () => clearTimeout(timeoutId);
+      } else {
+        // We reset the content at the end otherwise we lose all carriage returns (i'm not sure why)
+        editor
+          .chain()
+          .setContent(tipTapContentFromPlainText(builderState.instructions))
+          .focus("end")
+          .run();
+        editor.setEditable(true);
+        setDoTypewriterEffect(false);
+      }
+    }
+  }, [
+    editor,
+    letterIndex,
+    builderState.instructions,
+    doTypewriterEffect,
+    setDoTypewriterEffect,
+  ]);
+
   const currentCharacterCount = editor?.storage.characterCount.characters();
 
   useEffect(() => {