-- doclen_slots: the resident slot-indexed doclen array (1.9.0, C1) must give
-- byte-identical scores to the page-directory cursor it short-circuits, for
-- every doc, including after deletes (tombstones), a second segment, and when a
-- segment does not fit the budget.  Scores are compared to 12 decimal places.
SET client_min_messages = warning;
SET enable_seqscan = off;
SET enable_bitmapscan = off;

-- varied lengths so quantization buckets differ; a filler table interleaved so
-- heap blocks have gaps (offsets that are not ours) -- the sparse-slot case
CREATE TABLE ds (id int PRIMARY KEY, d ftsdoc);
INSERT INTO ds SELECT g, to_ftsdoc('simple', 'alpha ' || repeat('w' || (g % 13) || ' ', 1 + (g % 97)) ||
                                   CASE WHEN g % 3 = 0 THEN 'beta' ELSE 'gamma' END)
FROM generate_series(1, 4000) g;
CREATE INDEX ds_fts ON ds USING fts (d);
VACUUM ANALYZE ds;

CREATE FUNCTION ds_scores(q text, mb int) RETURNS text LANGUAGE plpgsql AS $$
DECLARE r text;
BEGIN
  EXECUTE format('SET LOCAL pg_fts.doclen_cache_mb = %s', mb);
  EXECUTE format('SELECT string_agg(id::text || '':'' || round((1/(d <=> to_ftsquery(''simple'',%L)) - 1)::numeric, 12), '','')
                  FROM (SELECT id, d FROM ds WHERE d @@@ to_ftsquery(''simple'',%L)
                        ORDER BY d <=> to_ftsquery(''simple'',%L) LIMIT 4000) s', q, q, q) INTO r;
  RETURN r;
END $$;

-- one segment, all docs, slots on vs off
SELECT ds_scores('alpha', 64) = ds_scores('alpha', 0) AS one_seg_all,
       ds_scores('beta | w5', 64) = ds_scores('beta | w5', 0) AS one_seg_or,
       length(ds_scores('alpha', 64)) > 0 AS nonempty;

-- deletes -> tombstones; ranked results must still agree
DELETE FROM ds WHERE id % 7 = 0;
VACUUM ds;
SELECT ds_scores('alpha', 64) = ds_scores('alpha', 0) AS after_delete;

-- a second segment (pending flush via fts_merge) with new docs
INSERT INTO ds SELECT g, to_ftsdoc('simple', 'alpha delta ' || repeat('z ', g % 50)) FROM generate_series(4001, 5000) g;
SELECT fts_merge('ds_fts') IS NOT NULL AS merged;
SELECT ds_scores('alpha', 64) = ds_scores('alpha', 0) AS two_segments,
       ds_scores('delta', 64) = ds_scores('delta', 0) AS new_docs;

-- budget of 1 MB still fits this small index; the 0 path is the cursor; both must
-- agree with each other and with a full compaction
SELECT fts_vacuum('ds_fts') IS NOT NULL AS vacuumed;
SELECT ds_scores('alpha', 1) = ds_scores('alpha', 0) AS after_vacuum;

DROP FUNCTION ds_scores(text, int);
DROP TABLE ds;