feat(ext): add chat history

packages/extension/src/lib/db.ts

@@ -0,0 +1,70 @@
+import type { HistoricalEvent } from '@page-agent/core'
+import { type DBSchema, type IDBPDatabase, openDB } from 'idb'
+
+const DB_NAME = 'page-agent-ext'
+const DB_VERSION = 1
+
+export interface SessionRecord {
+	id: string
+	task: string
+	history: HistoricalEvent[]
+	status: 'completed' | 'error'
+	createdAt: number
+}
+
+interface PageAgentDB extends DBSchema {
+	sessions: {
+		key: string
+		value: SessionRecord
+		indexes: { 'by-created': number }
+	}
+}
+
+let dbPromise: Promise<IDBPDatabase<PageAgentDB>> | null = null
+
+function getDB() {
+	if (!dbPromise) {
+		dbPromise = openDB<PageAgentDB>(DB_NAME, DB_VERSION, {
+			upgrade(db) {
+				const store = db.createObjectStore('sessions', { keyPath: 'id' })
+				store.createIndex('by-created', 'createdAt')
+			},
+		})
+	}
+	return dbPromise
+}
+
+export async function saveSession(
+	session: Omit<SessionRecord, 'id' | 'createdAt'>
+): Promise<SessionRecord> {
+	const db = await getDB()
+	const record: SessionRecord = {
+		...session,
+		id: crypto.randomUUID(),
+		createdAt: Date.now(),
+	}
+	await db.put('sessions', record)
+	return record
+}
+
+/** List sessions, newest first */
+export async function listSessions(): Promise<SessionRecord[]> {
+	const db = await getDB()
+	const all = await db.getAllFromIndex('sessions', 'by-created')
+	return all.reverse()
+}
+
+export async function getSession(id: string): Promise<SessionRecord | undefined> {
+	const db = await getDB()
+	return db.get('sessions', id)
+}
+
+export async function deleteSession(id: string): Promise<void> {
+	const db = await getDB()
+	await db.delete('sessions', id)
+}
+
+export async function clearSessions(): Promise<void> {
+	const db = await getDB()
+	await db.clear('sessions')
+}