Add --resume flag with session selector

- New SessionSelectorComponent to browse and select sessions
- Lists sessions sorted by last modified date
- Shows first message, created/modified dates, message count
- Automatically truncates long messages and formats dates
- Adds --resume/-r flag to CLI
- Session selector integrates with main flow

packages/coding-agent/src/main.ts

@@ -1,11 +1,13 @@
 import { Agent, ProviderTransport, type ThinkingLevel } from "@mariozechner/pi-agent";
 import { getModel } from "@mariozechner/pi-ai";
+import { ProcessTerminal, TUI } from "@mariozechner/pi-tui";
 import chalk from "chalk";
 import { readFileSync } from "fs";
 import { dirname, join } from "path";
 import { fileURLToPath } from "url";
 import { SessionManager } from "./session-manager.js";
 import { codingTools } from "./tools/index.js";
+import { SessionSelectorComponent } from "./tui/session-selector.js";
 import { TuiRenderer } from "./tui/tui-renderer.js";
 
 // Get version from package.json
@@ -20,6 +22,7 @@ interface Args {
 	apiKey?: string;
 	systemPrompt?: string;
 	continue?: boolean;
+	resume?: boolean;
 	help?: boolean;
 	messages: string[];
 }
@@ -36,6 +39,8 @@ function parseArgs(args: string[]): Args {
 			result.help = true;
 		} else if (arg === "--continue" || arg === "-c") {
 			result.continue = true;
+		} else if (arg === "--resume" || arg === "-r") {
+			result.resume = true;
 		} else if (arg === "--provider" && i + 1 < args.length) {
 			result.provider = args[++i];
 		} else if (arg === "--model" && i + 1 < args.length) {
@@ -64,6 +69,7 @@ ${chalk.bold("Options:")}
   --api-key <key>         API key (defaults to env vars)
   --system-prompt <text>  System prompt (default: coding assistant prompt)
   --continue, -c          Continue previous session
+  --resume, -r            Select a session to resume
   --help, -h              Show this help
 
 ${chalk.bold("Examples:")}
@@ -114,6 +120,30 @@ Guidelines:
 
 Current directory: ${process.cwd()}`;
 
+async function selectSession(sessionManager: SessionManager): Promise<string | null> {
+	return new Promise((resolve) => {
+		const ui = new TUI(new ProcessTerminal());
+		let selectedPath: string | null = null;
+
+		const selector = new SessionSelectorComponent(
+			sessionManager,
+			(path: string) => {
+				selectedPath = path;
+				ui.stop();
+				resolve(path);
+			},
+			() => {
+				ui.stop();
+				resolve(null);
+			},
+		);
+
+		ui.addChild(selector);
+		ui.setFocus(selector.getSelectList());
+		ui.start();
+	});
+}
+
 async function runInteractiveMode(agent: Agent, sessionManager: SessionManager, version: string): Promise<void> {
 	const renderer = new TuiRenderer(agent, sessionManager, version);
 
@@ -176,7 +206,18 @@ export async function main(args: string[]) {
 	}
 
 	// Setup session manager
-	const sessionManager = new SessionManager(parsed.continue);
+	const sessionManager = new SessionManager(parsed.continue && !parsed.resume);
+
+	// Handle --resume flag: show session selector
+	if (parsed.resume) {
+		const selectedSession = await selectSession(sessionManager);
+		if (!selectedSession) {
+			console.log(chalk.dim("No session selected"));
+			return;
+		}
+		// Set the selected session as the active session
+		sessionManager.setSessionFile(selectedSession);
+	}
 
 	// Determine provider and model
 	const provider = (parsed.provider || "anthropic") as any;
@@ -259,8 +300,8 @@ export async function main(args: string[]) {
 		}),
 	});
 
-	// Load previous messages if continuing
-	if (parsed.continue) {
+	// Load previous messages if continuing or resuming
+	if (parsed.continue || parsed.resume) {
 		const messages = sessionManager.loadMessages();
 		if (messages.length > 0) {
 			console.log(chalk.dim(`Loaded ${messages.length} messages from previous session`));

packages/coding-agent/src/session-manager.ts

@@ -242,4 +242,99 @@ export class SessionManager {
 	getSessionFile(): string {
 		return this.sessionFile;
 	}
+
+	/**
+	 * Load all sessions for the current directory with metadata
+	 */
+	loadAllSessions(): Array<{
+		path: string;
+		id: string;
+		created: Date;
+		modified: Date;
+		messageCount: number;
+		firstMessage: string;
+	}> {
+		const sessions: Array<{
+			path: string;
+			id: string;
+			created: Date;
+			modified: Date;
+			messageCount: number;
+			firstMessage: string;
+		}> = [];
+
+		try {
+			const files = readdirSync(this.sessionDir)
+				.filter((f) => f.endsWith(".jsonl"))
+				.map((f) => join(this.sessionDir, f));
+
+			for (const file of files) {
+				try {
+					const stats = statSync(file);
+					const content = readFileSync(file, "utf8");
+					const lines = content.trim().split("\n");
+
+					let sessionId = "";
+					let created = stats.birthtime;
+					let messageCount = 0;
+					let firstMessage = "";
+
+					for (const line of lines) {
+						try {
+							const entry = JSON.parse(line);
+
+							// Extract session ID from first session entry
+							if (entry.type === "session" && !sessionId) {
+								sessionId = entry.id;
+								created = new Date(entry.timestamp);
+							}
+
+							// Count messages
+							if (entry.type === "message") {
+								messageCount++;
+
+								// Get first user message
+								if (!firstMessage && entry.message.role === "user") {
+									const textContent = entry.message.content
+										.filter((c: any) => c.type === "text")
+										.map((c: any) => c.text)
+										.join(" ");
+									firstMessage = textContent || "";
+								}
+							}
+						} catch {
+							// Skip malformed lines
+						}
+					}
+
+					sessions.push({
+						path: file,
+						id: sessionId || "unknown",
+						created,
+						modified: stats.mtime,
+						messageCount,
+						firstMessage: firstMessage || "(no messages)",
+					});
+				} catch (error) {
+					// Skip files that can't be read
+					console.error(`Failed to read session file ${file}:`, error);
+				}
+			}
+
+			// Sort by modified date (most recent first)
+			sessions.sort((a, b) => b.modified.getTime() - a.modified.getTime());
+		} catch (error) {
+			console.error("Failed to load sessions:", error);
+		}
+
+		return sessions;
+	}
+
+	/**
+	 * Set the session file to an existing session
+	 */
+	setSessionFile(path: string): void {
+		this.sessionFile = path;
+		this.loadSessionId();
+	}
 }

packages/coding-agent/src/tui/session-selector.ts

@@ -0,0 +1,108 @@
+import { type Component, Container, type SelectItem, SelectList, Text } from "@mariozechner/pi-tui";
+import chalk from "chalk";
+import type { SessionManager } from "../session-manager.js";
+
+/**
+ * Dynamic border component that adjusts to viewport width
+ */
+class DynamicBorder implements Component {
+	render(width: number): string[] {
+		return [chalk.blue("─".repeat(Math.max(1, width)))];
+	}
+}
+
+interface SessionItem {
+	path: string;
+	id: string;
+	created: Date;
+	modified: Date;
+	messageCount: number;
+	firstMessage: string;
+}
+
+/**
+ * Component that renders a session selector
+ */
+export class SessionSelectorComponent extends Container {
+	private selectList: SelectList;
+
+	constructor(sessionManager: SessionManager, onSelect: (sessionPath: string) => void, onCancel: () => void) {
+		super();
+
+		// Load all sessions
+		const sessions = sessionManager.loadAllSessions();
+
+		if (sessions.length === 0) {
+			this.addChild(new DynamicBorder());
+			this.addChild(new Text(chalk.gray("  No previous sessions found"), 0, 0));
+			this.addChild(new DynamicBorder());
+			this.selectList = new SelectList([], 0);
+			this.addChild(this.selectList);
+
+			// Auto-cancel if no sessions
+			setTimeout(() => onCancel(), 100);
+			return;
+		}
+
+		// Format sessions as select items
+		const items: SelectItem[] = sessions.map((session) => {
+			// Format dates
+			const formatDate = (date: Date): string => {
+				const now = new Date();
+				const diffMs = now.getTime() - date.getTime();
+				const diffMins = Math.floor(diffMs / 60000);
+				const diffHours = Math.floor(diffMs / 3600000);
+				const diffDays = Math.floor(diffMs / 86400000);
+
+				if (diffMins < 1) return "just now";
+				if (diffMins < 60) return `${diffMins}m ago`;
+				if (diffHours < 24) return `${diffHours}h ago`;
+				if (diffDays === 1) return "yesterday";
+				if (diffDays < 7) return `${diffDays}d ago`;
+
+				// Fallback to date string
+				return date.toLocaleDateString();
+			};
+
+			// Truncate first message to single line
+			const truncatedMessage = session.firstMessage.replace(/\n/g, " ").trim();
+
+			// Build description with metadata
+			const created = formatDate(session.created);
+			const modified = formatDate(session.modified);
+			const msgCount = `${session.messageCount} msg${session.messageCount !== 1 ? "s" : ""}`;
+
+			const description = `${truncatedMessage}\n${chalk.dim(`Created: ${created} • Modified: ${modified} • ${msgCount}`)}`;
+
+			return {
+				value: session.path,
+				label: truncatedMessage.substring(0, 80),
+				description,
+			};
+		});
+
+		// Add top border
+		this.addChild(new DynamicBorder());
+		this.addChild(new Text(chalk.bold("Select a session to resume:"), 1, 0));
+
+		// Create selector
+		this.selectList = new SelectList(items, Math.min(10, items.length));
+
+		this.selectList.onSelect = (item) => {
+			onSelect(item.value);
+		};
+
+		this.selectList.onCancel = () => {
+			onCancel();
+		};
+
+		this.addChild(this.selectList);
+
+		// Add bottom border
+		this.addChild(new DynamicBorder());
+	}
+
+	getSelectList(): SelectList {
+		return this.selectList;
+	}
+}