fix(background-agent): refresh stale checks from session activity

src/features/background-agent/session-activity.ts

@@ -0,0 +1,41 @@
+import { isRecord, log } from "../../shared"
+import type { OpencodeClient } from "./opencode-client"
+
+export type SessionActivityResolver = (sessionID: string) => Promise<Date | undefined>
+
+function dateFromMillis(value: unknown): Date | undefined {
+  if (typeof value !== "number") return undefined
+  if (!Number.isFinite(value) || value < 0) return undefined
+  return new Date(value)
+}
+
+export function extractSessionActivityDate(sessionInfo: unknown): Date | undefined {
+  if (!isRecord(sessionInfo)) return undefined
+  const time = isRecord(sessionInfo.time) ? sessionInfo.time : undefined
+  return dateFromMillis(time?.updated) ?? dateFromMillis(sessionInfo.time_updated)
+}
+
+export async function getSessionActivityFromClient(
+  client: OpencodeClient,
+  sessionID: string,
+  directory?: string,
+): Promise<Date | undefined> {
+  const sessionGet = client.session.get
+  if (typeof sessionGet !== "function") return undefined
+
+  try {
+    const response = await sessionGet({
+      path: { id: sessionID },
+      ...(directory ? { query: { directory } } : {}),
+    })
+    const sessionInfo = isRecord(response) && "data" in response ? response.data : response
+    return extractSessionActivityDate(sessionInfo)
+  } catch (error) {
+    if (error instanceof Error) {
+      log("[background-agent] Failed to read session activity:", { sessionID, error: error.message })
+      return undefined
+    }
+    log("[background-agent] Failed to read session activity:", { sessionID, error })
+    return undefined
+  }
+}