Schedule session refresh when at 80% of token lifespan

Author: JOsacky

Sources/Auth/Internal/SessionManager.swift

@@ -7,6 +7,7 @@ struct SessionRefresher: Sendable {
 
 actor SessionManager {
   private var task: Task<Session, any Error>?
+  private var autoRefreshTask: Task<Void, any Error>?
 
   private var storage: any AuthLocalStorage {
     Current.configuration.localStorage
@@ -16,6 +17,29 @@ actor SessionManager {
     Current.sessionRefresher
   }
 
+  func scheduleSessionRefresh(_ session: Session) throws {
+    if autoRefreshTask != nil {
+      return
+    }
+
+    autoRefreshTask = Task {
+      defer { autoRefreshTask = nil }
+
+      guard let expiresAt = session.expiresAt else {
+        return
+      }
+      let expiryDate = Date(timeIntervalSince1970: expiresAt)
+
+      let timeIntervalToExpiry = expiryDate.timeIntervalSinceNow
+
+      // if negative then token is expired and will refresh right away
+      let timeIntervalToRefresh = max(timeIntervalToExpiry * 0.8, 0)
+
+      try await Task.sleep(nanoseconds: UInt64(timeIntervalToRefresh * 1_000_000_000))
+      let session = try await sessionRefresher.refreshSession(session.refreshToken)
+    }
+  }
+
   func session(shouldValidateExpiration: Bool = true) async throws -> Session {
     if let task {
       return try await task.value
@@ -42,6 +66,7 @@ actor SessionManager {
 
   func update(_ session: Session) throws {
     try storage.storeSession(StoredSession(session: session))
+    try scheduleSessionRefresh(session)
   }
 
   func remove() {