ACK Lifecycle

NotificationDelivery sent to company user
    |
    |-- [Web dashboard button]
    |     POST /api/v1/notifications/{id}/ack
    |     AckIngestionService::ackByUser(notification, user, AckSource::Web)
    |
    |-- [Inbound transport reply (SMS, email, webhook)]
    |     POST /api/v1/inbound/sms  or  /api/v1/inbound/email
    |     Validate inbound signature → AckIngestionService::ackByTransport(...)
    |
    v
AckIngestionService (sole ACK writer)
    ├── notification.ack_status = AckStatus::Acked
    ├── notification.acked_at = now()
    ├── notification.ack_source = <triggering stream>
    ├── notification.escalation_cancelled_at = now()
    ├── Mark ALL NotificationDeliveries for this notification as acknowledged
    ├── Dispatch EscalationCancelMessage
    └── CommunicationLogger::log(
            type: AckReceived,
            content: "ACK received via sms_reply — all 3 delivery streams marked acknowledged"
        )

Cross-Stream Rule

When any one delivery stream ACKs a notification, all delivery streams for that notification are immediately marked acknowledged. The AckIngestionService logs a single AckReceived event naming the triggering stream and total stream count.

Partial acknowledgement does not exist in this system.

ACK Routing Back to PSAP

After ACK, Cloud routes the confirmation back to the originating PSAPLink PSAP instance:

Mode	Mechanism
poll	PSAPLink PSAP polls GET /api/v1/core/ack-queue/{psapId}?after=<cursor>. Cursor stored in var/ack_poll_cursor.txt.
callback	Cloud POSTs to PSAPLink PSAP's POST /api/v1/core/callback/ack (HMAC-signed). Requires PSAP to be reachable.

ACK Sources

Source	ack_source value
Web dashboard button	web
Inbound SMS reply	sms_reply
Inbound email reply	email_reply
Inbound webhook	webhook