1 files changed, 62 insertions, 0 deletions
diff --git a/packages/app/src/context/global-sync/session-cache.ts b/packages/app/src/context/global-sync/session-cache.ts
new file mode 100644
index 000000000..0177ebbe1
--- /dev/null
+++ b/packages/app/src/context/global-sync/session-cache.ts
@@ -0,0 +1,62 @@
+import type {
+  FileDiff,
+  Message,
+  Part,
+  PermissionRequest,
+  QuestionRequest,
+  SessionStatus,
+  Todo,
+} from "@opencode-ai/sdk/v2/client"
+
+export const SESSION_CACHE_LIMIT = 40
+
+type SessionCache = {
+  session_status: Record<string, SessionStatus | undefined>
+  session_diff: Record<string, FileDiff[] | undefined>
+  todo: Record<string, Todo[] | undefined>
+  message: Record<string, Message[] | undefined>
+  part: Record<string, Part[] | undefined>
+  permission: Record<string, PermissionRequest[] | undefined>
+  question: Record<string, QuestionRequest[] | undefined>
+}
+
+export function dropSessionCaches(store: SessionCache, sessionIDs: Iterable<string>) {
+  const stale = new Set(Array.from(sessionIDs).filter(Boolean))
+  if (stale.size === 0) return
+
+  for (const key of Object.keys(store.part)) {
+    const parts = store.part[key]
+    if (!parts?.some((part) => stale.has(part?.sessionID ?? ""))) continue
+    delete store.part[key]
+  }
+
+  for (const sessionID of stale) {
+    delete store.message[sessionID]
+    delete store.todo[sessionID]
+    delete store.session_diff[sessionID]
+    delete store.session_status[sessionID]
+    delete store.permission[sessionID]
+    delete store.question[sessionID]
+  }
+}
+
+export function pickSessionCacheEvictions(input: {
+  seen: Set<string>
+  keep: string
+  limit: number
+  preserve?: Iterable<string>
+}) {
+  const stale: string[] = []
+  const keep = new Set([input.keep, ...Array.from(input.preserve ?? [])])
+  if (input.seen.has(input.keep)) input.seen.delete(input.keep)
+  input.seen.add(input.keep)
+  for (const id of input.seen) {
+    if (input.seen.size - stale.length <= input.limit) break
+    if (keep.has(id)) continue
+    stale.push(id)
+  }
+  for (const id of stale) {
+    input.seen.delete(id)
+  }
+  return stale
+}