-- test/sql/dnf_resolution.sql
--
-- Regression test for the DNF (k>0) within-tile resolution semantics.
--
-- The bug fixed in commit 34c5e52 caused the AM to intersect
-- (AND) the within-tile trigram alternatives instead of unioning
-- (OR) them.  The full p5_read fixture has enough rows that the
-- bug masked itself: with ~50 rows, the wrong-mode result still
-- happened to match the right-mode result.  The fixtures here
-- are deliberately tiny so that a single misplaced operator
-- changes the row count.
--
-- Each subtest constructs a row whose body matches the canonical
-- pattern under k=1 by exactly one edit, then asserts that the
-- index returns it.  If the within-tile semantics regress to
-- AND, the row is dropped because the canonical trigrams aren't
-- all present.

CREATE EXTENSION IF NOT EXISTS pg_tre;

DROP TABLE IF EXISTS dnf_t;
CREATE TABLE dnf_t (id int PRIMARY KEY, body text);

-- Each row is at edit distance 1 from 'foobar' via a different
-- single-edit class:
INSERT INTO dnf_t VALUES
  (1, 'foobar'),       -- exact (k=0)
  (2, 'fooar'),        -- delete 'b'
  (3, 'foovbar'),      -- insert 'v' at position 3
  (4, 'foopar'),       -- substitute 'b' -> 'p'
  (5, 'unrelated');    -- must NOT match

CREATE INDEX dnf_idx ON dnf_t USING tre (body);

SET enable_seqscan = off;

-- Sanity: k=0 returns only the exact row.
SELECT id FROM dnf_t WHERE body %~~ tre_pattern('foobar', 0) ORDER BY id;

-- The real test: k=1 must return rows 1, 2, 3, 4 (every kind of
-- single edit) but not row 5.  If the AM regresses to AND-within-
-- tile, row 1 is the only one that has every spine trigram of
-- 'foobar' and the test fails.
SELECT id FROM dnf_t WHERE body %~~ tre_pattern('foobar', 1) ORDER BY id;

-- k=2 should additionally tolerate a 2-edit miss.
INSERT INTO dnf_t VALUES (6, 'fopar');   -- 2 edits from 'foobar'
SELECT id FROM dnf_t WHERE body %~~ tre_pattern('foobar', 2) ORDER BY id;

-- Cross-check with seq-scan: index and seq must agree exactly.
DO $$
DECLARE
  ix int[]; sq int[];
BEGIN
  EXECUTE 'SET LOCAL enable_seqscan = off';
  EXECUTE 'SELECT array_agg(id ORDER BY id) FROM dnf_t '
          'WHERE body %~~ tre_pattern($1, $2)'
    USING 'foobar', 1
    INTO ix;
  EXECUTE 'SET LOCAL enable_seqscan = on';
  EXECUTE 'SET LOCAL enable_indexscan = off';
  EXECUTE 'SET LOCAL enable_bitmapscan = off';
  EXECUTE 'SELECT array_agg(id ORDER BY id) FROM dnf_t '
          'WHERE tre_amatch(body, $1, $2)'
    USING 'foobar', 1
    INTO sq;
  IF ix IS NOT DISTINCT FROM sq THEN
    RAISE NOTICE 'OK: idx=% seq=%', ix, sq;
  ELSE
    RAISE EXCEPTION 'DNF resolution mismatch: idx=% seq=%', ix, sq;
  END IF;
END$$;

-- Multi-tile case: k=2 with a longer pattern produces multiple
-- tiles; verify the inter-tile OR also works correctly.
DROP TABLE IF EXISTS dnf_long;
CREATE TABLE dnf_long (id int PRIMARY KEY, body text);
INSERT INTO dnf_long VALUES
  (1, 'approximate'),       -- exact
  (2, 'aproximate'),        -- 1 edit
  (3, 'aproxmate'),         -- 2 edits
  (4, 'totally other');     -- no match
CREATE INDEX dnf_long_idx ON dnf_long USING tre (body);

SELECT id FROM dnf_long WHERE body %~~ tre_pattern('approximate', 2)
  ORDER BY id;

DROP TABLE dnf_t;
DROP TABLE dnf_long;