Add option to delay commands after terminal start (#78)

* Wait a bit when creating a new terminal

* Make delay a user setting (defaults to 0)

* Add docstrings

* Add "Python" to markdown description

* small spelling fix

---------

Co-authored-by: Vladimir Fokow <[email protected]>

Author: Splines

package.json

@@ -91,9 +91,14 @@
           "markdownDescription": "Configures the number of milliseconds (ms) to wait before your clipboard is restored. (Your clipboard is used to temporarily copy the selected code to be accessible by Manim)."
         },
         "manim-notebook.confirmKillingActiveSceneToStartNewOne": {
-        "type": "boolean",
+          "type": "boolean",
           "default": true,
           "markdownDescription": "If enabled, you will be prompted to confirm killing an old session when you want to start a new scene at the cursor while an active scene is running."
+        },
+        "manim-notebook.delayNewTerminal": {
+          "type": "number",
+          "default": 0,
+          "markdownDescription": "Number of milliseconds (ms) to wait before executing any command in a newly opened terminal. This is useful when you have custom terminal startup commands that need to be executed before running Manim, e.g. a virtual environment activation (Python venv)."
         }
       }
     }

src/manimShell.ts

@@ -354,7 +354,7 @@ export class ManimShell {
                 Logger.debug("🔆 User confirmed to kill active scene");
                 await this.forceQuitActiveShell();
             }
-            this.activeShell = window.createTerminal();
+            await this.openNewTerminal();
         } else {
             Logger.debug("🔆 Executing start command that is requested for another command");
         }
@@ -512,7 +512,7 @@ export class ManimShell {
     private async retrieveOrInitActiveShell(startLine: number): Promise<Terminal> {
         if (!this.hasActiveShell()) {
             Logger.debug("🔍 No active shell found, requesting startScene");
-            this.activeShell = window.createTerminal();
+            await this.openNewTerminal();
             await startScene(startLine);
             Logger.debug("🔍 Started new scene to retrieve new shell");
         } else {
@@ -521,6 +521,44 @@ export class ManimShell {
         return this.activeShell as Terminal;
     }
 
+    /**
+     * Opens a new terminal and sets it as the active shell. Afterwards, waits
+     * for a user-defined delay before allowing the terminal to be used, which
+     * might be useful for some activation scripts to load like virtualenvs etc.
+     */
+    private async openNewTerminal() {
+        const delay: number = await vscode.workspace
+            .getConfiguration("manim-notebook").get("delayNewTerminal")!;
+
+        // We don't want to detect shell execution ends here, since commands like
+        // `source venv/bin/activate` might on their own trigger a terminal
+        // execution end.
+        this.detectShellExecutionEnd = false;
+
+        this.activeShell = window.createTerminal();
+
+        if (delay > 600) {
+            await window.withProgress({
+                location: vscode.ProgressLocation.Notification,
+                title: "Waiting a user-defined delay for the new terminal...",
+                cancellable: false
+            }, async (progress, token) => {
+                progress.report({ increment: 0 });
+
+                // split user-defined timeout into 500ms chunks and show progress
+                const numChunks = Math.ceil(delay / 500);
+                for (let i = 0; i < numChunks; i++) {
+                    await new Promise(resolve => setTimeout(resolve, 500));
+                    progress.report({ increment: 100 / numChunks });
+                }
+            });
+        } else {
+            await new Promise(resolve => setTimeout(resolve, delay));
+        }
+
+        this.detectShellExecutionEnd = true;
+    }
+
     /**
      * Waits until the current command has finished executing by waiting for
      * the start of the next IPython cell. This is used to ensure that the