-- test/sql/match_early_exit.sql
--
-- The k=0 recheck asks TRE for no submatch offsets (nmatch=0) so the
-- exact matcher stops at the first match instead of scanning the whole
-- value for the leftmost-longest one (4.6.1).  This must not change any
-- result: boolean %~~ / tre_amatch, the edit cost, and -- crucially --
-- tre_amatch_detail's offsets (which DO request offsets, so the early
-- exit must not apply there).

CREATE EXTENSION IF NOT EXISTS pg_tre;
\set VERBOSITY terse
SET client_min_messages = warning;

-- boolean recheck unchanged, including repeated/overlapping matches where
-- "first match" differs from "leftmost-longest".
SELECT 'abcabcabc' %~~ tre_pattern('abc', 0)      AS b1,   -- t
       'xxsuuuyy'  %~~ tre_pattern('su{3}', 0)     AS b2,   -- t
       'nope'      %~~ tre_pattern('abc', 0)       AS b3,   -- f
       'aXbXc'     %~~ tre_pattern('a.b.c', 0)     AS b4;   -- t

-- tre_amatch_detail still returns correct offsets at k=0 (it requests
-- offsets, so the early exit is disabled for it).  Match 'bcd' inside
-- 'abcde': bytes [1,4).
SELECT match_start, match_end FROM tre_amatch_detail('abcde', 'bcd', 0);

-- the edit cost is unchanged at k=0 (always 0 for an exact match) and the
-- boolean agrees with a forced sequential scan on a small table.
DROP TABLE IF EXISTS mee;
CREATE TABLE mee (id int, s text);
INSERT INTO mee VALUES
  (1,'the quick brown fox'), (2,'suuu here'), (3,'has su and uuu apart: su ... uuu'),
  (4,'aabcb match'), (5,'aa then bc then cb, not contiguous'), (6,'plain');
INSERT INTO mee SELECT g, 'filler '||g||' quick' FROM generate_series(100,300) g;
CREATE INDEX mee_tre ON mee USING tre (s);
ANALYZE mee;

CREATE FUNCTION mee_agree(pat text) RETURNS boolean LANGUAGE plpgsql AS $$
DECLARE a int[]; b int[];
BEGIN
  PERFORM set_config('enable_seqscan','off',true);
  PERFORM set_config('enable_bitmapscan','on',true);
  PERFORM set_config('enable_indexscan','off',true);
  EXECUTE 'SELECT array_agg(id ORDER BY id) FROM mee WHERE s %~~ tre_pattern($1,0)' INTO a USING pat;
  PERFORM set_config('enable_seqscan','on',true);
  PERFORM set_config('enable_bitmapscan','off',true);
  EXECUTE 'SELECT array_agg(id ORDER BY id) FROM mee WHERE tre_amatch(s,$1,0)' INTO b USING pat;
  RETURN a IS NOT DISTINCT FROM b;
END $$;

SELECT bool_and(mee_agree(p)) AS index_eq_seq_at_k0
FROM (VALUES ('quick'),('su{3}'),('aa[bc]c[b-d]'),('a.b'),('o.*x')) v(p);

DROP TABLE mee;
DROP FUNCTION mee_agree(text);