;; ==========================================================================
;; test-cek-reactive.sx — Tests for deref-as-shift reactive rendering
;;
;; Tests that (deref signal) inside a reactive-reset boundary performs
;; continuation capture: the rest of the expression becomes the subscriber.
;;
;; Requires: test-framework.sx, frames.sx, cek.sx, signals.sx loaded first.
;; ==========================================================================


;; --------------------------------------------------------------------------
;; Basic deref behavior through CEK
;; --------------------------------------------------------------------------

(defsuite "deref pass-through"
  (deftest "deref non-signal passes through"
    (let ((result (eval-expr-cek
                    (sx-parse-one "(deref 42)")
                    (test-env))))
      (assert-equal 42 result)))

  (deftest "deref nil passes through"
    (let ((result (eval-expr-cek
                    (sx-parse-one "(deref nil)")
                    (test-env))))
      (assert-nil result)))

  (deftest "deref string passes through"
    (let ((result (eval-expr-cek
                    (sx-parse-one "(deref \"hello\")")
                    (test-env))))
      (assert-equal "hello" result))))


;; --------------------------------------------------------------------------
;; Deref signal without reactive-reset (no shift)
;; --------------------------------------------------------------------------

(defsuite "deref signal without reactive-reset"
  (deftest "deref signal returns current value"
    (let ((s (signal 99)))
      (env-set! (test-env) "test-sig" s)
      (let ((result (eval-expr-cek
                      (sx-parse-one "(deref test-sig)")
                      (test-env))))
        (assert-equal 99 result))))

  (deftest "deref signal in expression returns computed value"
    (let ((s (signal 10)))
      (env-set! (test-env) "test-sig" s)
      (let ((result (eval-expr-cek
                      (sx-parse-one "(+ 5 (deref test-sig))")
                      (test-env))))
        (assert-equal 15 result)))))


;; --------------------------------------------------------------------------
;; Reactive reset + deref: continuation capture
;; --------------------------------------------------------------------------

(defsuite "reactive-reset shift"
  (deftest "deref signal with reactive-reset captures continuation"
    (let ((s (signal 42))
          (captured-val nil))
      ;; Run CEK with a ReactiveResetFrame
      (let ((result (cek-run
                      (make-cek-state
                        (sx-parse-one "(deref test-sig)")
                        (let ((e (env-extend (test-env))))
                          (env-set! e "test-sig" s)
                          e)
                        (list (make-reactive-reset-frame
                                (test-env)
                                (fn (v) (set! captured-val v))
                                true))))))
        ;; Initial render: returns current value, update-fn NOT called (first-render)
        (assert-equal 42 result)
        (assert-nil captured-val))))

  (deftest "signal change invokes subscriber with update-fn"
    (let ((s (signal 10))
          (update-calls (list)))
      ;; Set up reactive-reset with tracking update-fn
      (scope-push! "sx-island-scope" nil)
      (let ((e (env-extend (test-env))))
        (env-set! e "test-sig" s)
        (cek-run
          (make-cek-state
            (sx-parse-one "(deref test-sig)")
            e
            (list (make-reactive-reset-frame
                    e
                    (fn (v) (append! update-calls v))
                    true)))))
      ;; Change signal — subscriber should fire
      (reset! s 20)
      (assert-equal 1 (len update-calls))
      (assert-equal 20 (first update-calls))
      ;; Change again
      (reset! s 30)
      (assert-equal 2 (len update-calls))
      (assert-equal 30 (nth update-calls 1))
      (scope-pop! "sx-island-scope")))

  (deftest "expression with deref captures rest as continuation"
    (let ((s (signal 5))
          (update-calls (list)))
      (scope-push! "sx-island-scope" nil)
      (let ((e (env-extend (test-env))))
        (env-set! e "test-sig" s)
        ;; (str "val=" (deref test-sig)) — continuation captures (str "val=" [HOLE])
        (let ((result (cek-run
                        (make-cek-state
                          (sx-parse-one "(str \"val=\" (deref test-sig))")
                          e
                          (list (make-reactive-reset-frame
                                  e
                                  (fn (v) (append! update-calls v))
                                  true))))))
          (assert-equal "val=5" result)))
      ;; Change signal — should get updated string
      (reset! s 42)
      (assert-equal 1 (len update-calls))
      (assert-equal "val=42" (first update-calls))
      (scope-pop! "sx-island-scope"))))


;; --------------------------------------------------------------------------
;; Disposal and cleanup
;; --------------------------------------------------------------------------

(defsuite "disposal"
  (deftest "scope cleanup unsubscribes continuation"
    (let ((s (signal 1))
          (update-calls (list))
          (disposers (list)))
      ;; Create island scope with collector that accumulates disposers
      (scope-push! "sx-island-scope" (fn (d) (append! disposers d)))
      (let ((e (env-extend (test-env))))
        (env-set! e "test-sig" s)
        (cek-run
          (make-cek-state
            (sx-parse-one "(deref test-sig)")
            e
            (list (make-reactive-reset-frame
                    e
                    (fn (v) (append! update-calls v))
                    true)))))
      ;; Pop scope — call all disposers
      (scope-pop! "sx-island-scope")
      (for-each (fn (d) (invoke d)) disposers)
      ;; Change signal — no update should fire
      (reset! s 999)
      (assert-equal 0 (len update-calls)))))