-- Regression test for pg_tre extension.
CREATE EXTENSION pg_tre;
CREATE EXTENSION
-- The access method is registered.
SELECT amname, amtype FROM pg_am WHERE amname = 'tre';
 amname | amtype 
--------+--------
 tre    | i
(1 row)

-- Legacy UDFs: basic exact match (cost 0)
SELECT tre_amatch('hello', 'hello', 0);
 tre_amatch 
------------
 t
(1 row)

-- Approximate match: 'colour' matches regex 'color' within distance 1
SELECT tre_amatch('colour', 'color', 1);
 tre_amatch 
------------
 t
(1 row)

-- Regex approximate match: enviro.*ment matches 'environment' exactly
SELECT tre_amatch('environment', 'enviro.*ment', 2);
 tre_amatch 
------------
 t
(1 row)

-- Cost function returns the actual edit cost
SELECT tre_amatch_cost('colour', 'color', 3);
 tre_amatch_cost 
-----------------
               1
(1 row)

-- No match within threshold
SELECT tre_amatch('abcdef', 'xyz', 1);
 tre_amatch 
------------
 f
(1 row)

-- Custom per-operation costs
SELECT tre_amatch('colour', 'color', 2, 1, 1, 1);
 tre_amatch 
------------
 t
(1 row)

-- Detail function shows cost breakdown
SELECT * FROM tre_amatch_detail('colour', 'color', 3);
 cost | num_ins | num_del | num_subst | match_start | match_end 
------+---------+---------+-----------+-------------+-----------
    1 |       1 |       0 |         0 |           0 |         6
(1 row)

-- Version string: shape, not literal (a pinned version goes stale on bump).
SELECT tre_version() ~ '^pg_tre [0-9]+\.[0-9]+\.[0-9]+(-dev)? \(TRE [0-9]+\.[0-9]+\.[0-9]+\)$' AS version_string_well_formed;
 version_string_well_formed 
----------------------------
 t
(1 row)

-- Edge cases: empty strings
SELECT tre_amatch('', '', 0);
 tre_amatch 
------------
 t
(1 row)

SELECT tre_amatch('a', '', 1);
 tre_amatch 
------------
 t
(1 row)

-- NULL handling (STRICT functions return NULL on NULL input)
SELECT tre_amatch(NULL, 'test', 1);
 tre_amatch 
------------
 
(1 row)

SELECT tre_amatch('test', NULL, 1);
 tre_amatch 
------------
 
(1 row)

-- CREATE INDEX succeeds syntactically (Phase 0 skeleton):
-- the actual build is a stub and raises a NOTICE.
CREATE TABLE tre_test (t text);
CREATE TABLE
INSERT INTO tre_test VALUES ('hello'), ('world');
INSERT 0 2
SET client_min_messages = 'notice';
SET
CREATE INDEX tre_test_idx ON tre_test USING tre (t);
psql:test/sql/pg_tre.sql:45: NOTICE:  pg_tre: collected 6 trigram entries from 2 heap tuples
psql:test/sql/pg_tre.sql:45: NOTICE:  pg_tre: built 6 posting trees
psql:test/sql/pg_tre.sql:45: NOTICE:  pg_tre: build complete, indexed 2 heap tuples into 6 trigrams
CREATE INDEX
RESET client_min_messages;
RESET
DROP INDEX tre_test_idx;
DROP INDEX
DROP TABLE tre_test;
DROP TABLE