-- ============================================================
-- Allow contact deletion without wiping history.
--
-- broadcast_recipients.contact_id and deals.contact_id were declared
-- NOT NULL REFERENCES contacts(id) with no ON DELETE action, so
-- Postgres defaults to NO ACTION. The first time a user tried to
-- delete a contact that had ever received a broadcast or been
-- attached to a deal, the delete failed with:
--
--   ERROR 23503: update or delete on table "contacts" violates
--   foreign key constraint ... on table <other>
--
-- CASCADE is the wrong fix — it would silently wipe historical
-- broadcast recipient rows (breaking audit + retroactively moving
-- broadcasts.sent_count / delivered_count / read_count etc. via the
-- aggregate trigger) and deal rows.
--
-- SET NULL is the right fix: history rows survive with a NULL
-- contact_id. The UI is already null-safe (contact?.name ?? 'Unknown',
-- contact?.phone, etc.).
--
-- Idempotent — safe to run multiple times.
-- ============================================================

-- ── broadcast_recipients.contact_id ────────────────────────────
ALTER TABLE broadcast_recipients
  ALTER COLUMN contact_id DROP NOT NULL;

DO $$
BEGIN
  IF EXISTS (
    SELECT 1 FROM pg_constraint
    WHERE conname = 'broadcast_recipients_contact_id_fkey'
      AND conrelid = 'broadcast_recipients'::regclass
  ) THEN
    ALTER TABLE broadcast_recipients
      DROP CONSTRAINT broadcast_recipients_contact_id_fkey;
  END IF;
END $$;

ALTER TABLE broadcast_recipients
  ADD CONSTRAINT broadcast_recipients_contact_id_fkey
    FOREIGN KEY (contact_id) REFERENCES contacts(id)
    ON DELETE SET NULL;

-- ── deals.contact_id ───────────────────────────────────────────
ALTER TABLE deals
  ALTER COLUMN contact_id DROP NOT NULL;

DO $$
BEGIN
  IF EXISTS (
    SELECT 1 FROM pg_constraint
    WHERE conname = 'deals_contact_id_fkey'
      AND conrelid = 'deals'::regclass
  ) THEN
    ALTER TABLE deals
      DROP CONSTRAINT deals_contact_id_fkey;
  END IF;
END $$;

ALTER TABLE deals
  ADD CONSTRAINT deals_contact_id_fkey
    FOREIGN KEY (contact_id) REFERENCES contacts(id)
    ON DELETE SET NULL;