-- Per-connection publish governance (publish-phase gate).
--
-- connections.fields.publishGovernance selects what happens once a draft is
-- approved: unset = manual publish (today), 'auto' = dispatch on approval,
-- 'admin1' | 'admin_majority' | 'admin_consensus' = a SECOND chatgov poll
-- (subject_kind 'draft_publish', kind yes_no) must pass before the publish
-- is scheduled. The setting itself lives in the established fields jsonb;
-- this migration only teaches `polls` about the publish-phase subject.
--
--   publish_connection_id  the destination the publish poll releases to
--   publish_request        {publishAt, requiredPermission} captured at hold
--                          time; the requester is polls.created_by and stays
--                          the scheduling principal (re-checked at claim).

ALTER TABLE polls DROP CONSTRAINT polls_subject_kind_check;
ALTER TABLE polls ADD CONSTRAINT polls_subject_kind_check CHECK
  (subject_kind IN ('draft', 'chat_post', 'none', 'draft_publish'));

ALTER TABLE polls
  ADD COLUMN publish_connection_id uuid,
  ADD COLUMN publish_request jsonb CHECK (publish_request IS NULL OR jsonb_typeof(publish_request) = 'object');

ALTER TABLE polls ADD CONSTRAINT polls_publish_connection_fk
  FOREIGN KEY (publish_connection_id, workspace_id) REFERENCES connections (id, workspace_id)
  ON DELETE NO ACTION ON UPDATE RESTRICT;

ALTER TABLE polls ADD CONSTRAINT polls_publish_subject_check CHECK (
  (subject_kind = 'draft_publish') = (publish_connection_id IS NOT NULL)
  AND (subject_kind <> 'draft_publish' OR (draft_id IS NOT NULL AND publish_request IS NOT NULL))
);

-- One open REVIEW gate per draft stays index-enforced; publish gates get
-- their own slot per (draft, destination) so they never collide with it.
DROP INDEX polls_open_one_per_draft;
CREATE UNIQUE INDEX polls_open_one_per_draft ON polls (workspace_id, draft_id)
  WHERE state = 'open' AND draft_id IS NOT NULL AND subject_kind <> 'draft_publish';
CREATE UNIQUE INDEX polls_open_one_per_publish ON polls (workspace_id, draft_id, publish_connection_id)
  WHERE state = 'open' AND subject_kind = 'draft_publish';
CREATE INDEX polls_ws_publish ON polls (workspace_id, draft_id, publish_connection_id, created_at DESC)
  WHERE subject_kind = 'draft_publish';