namespace IceImportBLL.IceImportRun;

// In-memory, per-instance registry mapping a RunId to the CancellationTokenSource driving its
// background pipeline execution — the mechanism CancelImportRun uses to actually interrupt a
// still-in-process run on the SAME instance that is executing it.
//
// Deliberate, documented limitation: this is single-instance, in-memory state (a
// ConcurrentDictionary, never a distributed store). If the background task happens to be running on
// a different instance than the one that receives the CancelImportRun call (multi-replica
// deployment), TryCancel simply returns false for that instance — the run's TICEIMPORTRUN row is
// still flipped to 'Cancelled' by IceImportRunBLL.CancelRunAsync regardless (via
// IceImportRunQB.CANCEL_RUN), and IceImportRunQB.UPDATE_STAGE's own
// "WHERE STATUS IN ('Queued','Running')" guard means the background task's subsequent DB writes
// become no-ops even without ever observing the CancellationToken — so cancellation still "sticks"
// from the DB's point of view, just without interrupting in-flight work early on another replica.
// True cross-instance interruption would need a distributed signal (e.g. Redis pub/sub) — out of
// scope for this phase.
public interface IIceImportRunCancellationRegistry
{
    // Creates (or replaces) the CancellationTokenSource for runId, linked to callerToken so the
    // background task still observes the caller's own cancellation (e.g. app shutdown) in addition
    // to an explicit CancelImportRun. Returns the token the background pipeline should pass through
    // every pipeline-stage call.
    CancellationToken Register(long runId, CancellationToken callerToken);

    // Signals cancellation for runId if it is currently registered on this instance.
    // Returns true if found and cancelled, false if not tracked here (already completed, or running
    // on a different instance).
    bool TryCancel(long runId);

    // Removes and disposes the CancellationTokenSource for runId — always call this once the
    // background task reaches a terminal state (success, failure, or cancellation), in a finally
    // block, to avoid an unbounded dictionary per CLAUDE.md's "Static Collections" guidance.
    void Complete(long runId);
}