-- Add a full-text-search GIN index to the events table so the relay can serve
-- NIP-50 search directly from Postgres, eliminating the Typesense dependency.
--
-- Shape: an EXPRESSION index on `to_tsvector('simple', content)` rather than a
-- `GENERATED ... STORED` column. Postgres maintains an expression index on every
-- INSERT/UPDATE exactly like a column index, so the write path needs no
-- application-level index maintenance (this replaces the Typesense worker
-- pipeline) — and there is no stored column, so no `ALTER TABLE ... STORED` row
-- rewrite and no `ACCESS EXCLUSIVE` backfill. The index build is therefore
-- online-safe on a fresh/small relay (this file) and pre-buildable out of band
-- on a large populated relay (operator runbook, below).
--
-- Tokenizer choice: `simple` does no stemming and preserves identifiers like
-- agent handles, nip05 strings, and slugs. The `english` config would stem
-- ("running" -> "run") and mangle handles. Chat content is heterogeneous;
-- `simple` is the safer default for v1. The query path in
-- `buzz-search/src/postgres.rs` renders the identical `to_tsvector('simple', content)`
-- expression so the planner matches this index.
--
-- kind:0 metadata: the old Typesense pipeline appended parsed
-- display_name/name/nip05 to event content before indexing. With FTS over raw
-- `content`, those strings still tokenize because they live in the kind:0 JSON
-- body — `to_tsvector('simple', '{"name":"alice"}')` matches `q=alice`.
-- Validated by the NIP-50 e2e suite.
--
-- `events` is partitioned by RANGE (created_at). `CREATE INDEX ... ON events`
-- builds a partitioned GIN index whose per-partition child indexes propagate to
-- existing and future partitions. Partition pruning on since/until narrows the
-- GIN scan further than Typesense's full-collection scan does today.
--
-- IF NOT EXISTS makes this migration idempotent against the operator runbook:
-- on a large relay the index is built per-child with CREATE INDEX CONCURRENTLY
-- and ATTACHed to a parent named `idx_events_content_fts` BEFORE this code
-- deploys, so this statement is a no-op. See
-- GUIDES/BUZZ_POSTGRES_FTS_LIVE_RELAY_RUNBOOK.md.
--
-- Managed by sqlx migrations.

CREATE INDEX IF NOT EXISTS idx_events_content_fts
    ON events USING GIN (to_tsvector('simple', content));