From 4bd52cf3ed19acbb9c041f344df7b5f9632e5c48 Mon Sep 17 00:00:00 2001
From: Mario Zechner <badlogicgames@gmail.com>
Date: Fri, 5 Dec 2025 22:53:51 +0100
Subject: [PATCH] feat(coding-agent): add /resume command to switch sessions
 mid-conversation

- Opens interactive session selector
- Properly aborts in-flight agent turns before switching
- Restores model and thinking level from resumed session
- Clears UI state (queued messages, pending tools, etc.)

closes #117
---
 packages/coding-agent/src/tui/tui-renderer.ts | 80 ++++++++++++++-----
 1 file changed, 61 insertions(+), 19 deletions(-)

diff --git a/packages/coding-agent/src/tui/tui-renderer.ts b/packages/coding-agent/src/tui/tui-renderer.ts
index 6254ec45..bd21490d 100644
--- a/packages/coding-agent/src/tui/tui-renderer.ts
+++ b/packages/coding-agent/src/tui/tui-renderer.ts
@@ -1489,26 +1489,9 @@ export class TuiRenderer {
 		// Create session selector
 		this.sessionSelector = new SessionSelectorComponent(
 			this.sessionManager,
-			(sessionPath) => {
-				// Set the selected session as active
-				this.sessionManager.setSessionFile(sessionPath);
-
-				// Reload the session
-				const loaded = loadSessionFromEntries(this.sessionManager.loadEntries());
-				this.agent.replaceMessages(loaded.messages);
-
-				// Clear and re-render the chat
-				this.chatContainer.clear();
-				this.isFirstUserMessage = true;
-				this.renderInitialMessages(this.agent.state);
-
-				// Show confirmation message
-				this.chatContainer.addChild(new Spacer(1));
-				this.chatContainer.addChild(new Text(theme.fg("dim", "Resumed session"), 1, 0));
-
-				// Hide selector and show editor again
+			async (sessionPath) => {
 				this.hideSessionSelector();
-				this.ui.requestRender();
+				await this.handleResumeSession(sessionPath);
 			},
 			() => {
 				// Just hide the selector
@@ -1524,6 +1507,65 @@ export class TuiRenderer {
 		this.ui.requestRender();
 	}
 
+	private async handleResumeSession(sessionPath: string): Promise<void> {
+		// Unsubscribe first to prevent processing events during transition
+		this.unsubscribe?.();
+
+		// Abort and wait for completion
+		this.agent.abort();
+		await this.agent.waitForIdle();
+
+		// Stop loading animation
+		if (this.loadingAnimation) {
+			this.loadingAnimation.stop();
+			this.loadingAnimation = null;
+		}
+		this.statusContainer.clear();
+
+		// Clear UI state
+		this.queuedMessages = [];
+		this.pendingMessagesContainer.clear();
+		this.streamingComponent = null;
+		this.pendingTools.clear();
+
+		// Set the selected session as active
+		this.sessionManager.setSessionFile(sessionPath);
+
+		// Reload the session
+		const loaded = loadSessionFromEntries(this.sessionManager.loadEntries());
+		this.agent.replaceMessages(loaded.messages);
+
+		// Restore model if saved in session
+		const savedModel = this.sessionManager.loadModel();
+		if (savedModel) {
+			const availableModels = (await getAvailableModels()).models;
+			const match = availableModels.find((m) => m.provider === savedModel.provider && m.id === savedModel.modelId);
+			if (match) {
+				this.agent.setModel(match);
+			}
+		}
+
+		// Restore thinking level if saved in session
+		const savedThinking = this.sessionManager.loadThinkingLevel();
+		if (savedThinking) {
+			this.agent.setThinkingLevel(savedThinking as ThinkingLevel);
+		}
+
+		// Resubscribe to agent
+		this.subscribeToAgent();
+
+		// Clear and re-render the chat
+		this.chatContainer.clear();
+		this.isFirstUserMessage = true;
+		this.renderInitialMessages(this.agent.state);
+
+		// Show confirmation message
+		this.chatContainer.addChild(new Spacer(1));
+		this.chatContainer.addChild(new Text(theme.fg("dim", "Resumed session"), 1, 0));
+
+		this.ui.requestRender();
+	}
+
 	private hideSessionSelector(): void {
 		// Replace selector with editor in the container
 		this.editorContainer.clear();