-- One row per account whose arrival as a direct disciple of Śrīla Prabhupāda
-- has been announced to the community.
--
-- This table exists purely for idempotency. Announcing writes a notification
-- to *every* user, so it must happen at most once per devotee — not again when
-- an admin corrects which disciple record they're linked to, not again on a
-- double-clicked button, and not again if the process restarts mid-fan-out.
-- The insert is `ON CONFLICT DO NOTHING` and only a caller that actually
-- inserted the row goes on to broadcast, which makes the guard atomic.
--
-- Keyed on user_id (not disciple_id) deliberately: we are announcing that a
-- *person* has joined. Re-pointing their link at a different disciple record
-- corrects a mistake; it isn't a second arrival.
CREATE TABLE IF NOT EXISTS disciple_announcements (
    user_id      UUID        PRIMARY KEY REFERENCES users(id) ON DELETE CASCADE,
    -- The Mongo disciple ObjectID they were linked to at announcement time,
    -- kept for auditing (which record prompted the announcement).
    disciple_id  TEXT        NOT NULL,
    announced_at TIMESTAMPTZ NOT NULL DEFAULT now()
);