;; lib/minikanren/tests/matche.sx — Phase 5 piece D tests for `matche`.

;; --- literal patterns ---

(mk-test
  "matche-literal-number"
  (run* q (matche q (1 (== q 1))))
  (list 1))

(mk-test
  "matche-literal-string"
  (run* q (matche q ("hello" (== q "hello"))))
  (list "hello"))

(mk-test
  "matche-literal-no-clause-matches"
  (run*
    q
    (matche 7 (1 (== q :a)) (2 (== q :b))))
  (list))

;; --- variable patterns ---

(mk-test
  "matche-symbol-pattern"
  (run* q (fresh (x) (== x 99) (matche x (a (== q a)))))
  (list 99))

(mk-test
  "matche-wildcard"
  (run* q (fresh (x) (== x 7) (matche x (_ (== q :any)))))
  (list :any))

;; --- list patterns ---

(mk-test
  "matche-empty-list"
  (run* q (matche (list) (() (== q :ok))))
  (list :ok))

(mk-test
  "matche-pair-binds"
  (run*
    q
    (fresh
      (x)
      (== x (list 1 2))
      (matche x ((a b) (== q (list b a))))))
  (list (list 2 1)))

(mk-test
  "matche-triple-binds"
  (run*
    q
    (fresh
      (x)
      (== x (list 1 2 3))
      (matche x ((a b c) (== q (list :sum a b c))))))
  (list (list :sum 1 2 3)))

(mk-test
  "matche-mixed-literal-and-var"
  (run*
    q
    (fresh
      (x)
      (== x (list 1 99 3))
      (matche x ((1 m 3) (== q m)))))
  (list 99))

;; --- multi-clause dispatch ---

(mk-test
  "matche-multi-clause-shape"
  (run*
    q
    (fresh
      (x)
      (== x (list 5 6))
      (matche
        x
        (() (== q :empty))
        ((a) (== q (list :one a)))
        ((a b) (== q (list :two a b))))))
  (list (list :two 5 6)))

(mk-test
  "matche-three-shapes-via-fresh"
  (run*
    q
    (fresh
      (x)
      (matche
        x
        (() (== q :empty))
        ((a) (== q (list :one a)))
        ((a b) (== q (list :two a b))))))
  (list
    :empty (list :one (make-symbol "_.0"))
    (list :two (make-symbol "_.0") (make-symbol "_.1"))))

;; --- nested patterns ---

(mk-test
  "matche-nested"
  (run*
    q
    (fresh
      (x)
      (==
        x
        (list (list 1 2) (list 3 4)))
      (matche x (((a b) (c d)) (== q (list a b c d))))))
  (list (list 1 2 3 4)))

;; --- repeated var names create the same fresh var → must unify ---

(mk-test
  "matche-repeated-var-implies-equality"
  (run*
    q
    (fresh
      (x)
      (== x (list 7 7))
      (matche x ((a a) (== q a)))))
  (list 7))

(mk-test
  "matche-repeated-var-mismatch-fails"
  (run*
    q
    (fresh
      (x)
      (== x (list 7 8))
      (matche x ((a a) (== q a)))))
  (list))

(mk-tests-run!)