;; Erlang runtime tests — scheduler + process-record primitives.

(define er-rt-test-count 0)
(define er-rt-test-pass 0)
(define er-rt-test-fails (list))

(define
  er-rt-test
  (fn
    (name actual expected)
    (set! er-rt-test-count (+ er-rt-test-count 1))
    (if
      (= actual expected)
      (set! er-rt-test-pass (+ er-rt-test-pass 1))
      (append! er-rt-test-fails {:actual actual :expected expected :name name}))))

;; ── queue ─────────────────────────────────────────────────────────
(er-rt-test "queue empty len" (er-q-len (er-q-new)) 0)
(er-rt-test "queue empty?" (er-q-empty? (er-q-new)) true)

(define q1 (er-q-new))
(er-q-push! q1 "a")
(er-q-push! q1 "b")
(er-q-push! q1 "c")
(er-rt-test "queue push len" (er-q-len q1) 3)
(er-rt-test "queue empty? after push" (er-q-empty? q1) false)
(er-rt-test "queue peek" (er-q-peek q1) "a")
(er-rt-test "queue pop 1" (er-q-pop! q1) "a")
(er-rt-test "queue pop 2" (er-q-pop! q1) "b")
(er-rt-test "queue len after pops" (er-q-len q1) 1)
(er-rt-test "queue pop 3" (er-q-pop! q1) "c")
(er-rt-test "queue empty again" (er-q-empty? q1) true)
(er-rt-test "queue pop empty" (er-q-pop! q1) nil)

;; Queue FIFO under interleaved push/pop
(define q2 (er-q-new))
(er-q-push! q2 1)
(er-q-push! q2 2)
(er-q-pop! q2)
(er-q-push! q2 3)
(er-rt-test "queue interleave peek" (er-q-peek q2) 2)
(er-rt-test "queue to-list" (er-q-to-list q2) (list 2 3))

;; ── scheduler init ─────────────────────────────────────────────
(er-sched-init!)
(er-rt-test "sched process count 0" (er-sched-process-count) 0)
(er-rt-test "sched runnable count 0" (er-sched-runnable-count) 0)
(er-rt-test "sched current nil" (er-sched-current-pid) nil)

;; ── pid allocation ─────────────────────────────────────────────
(define pa (er-pid-new!))
(define pb (er-pid-new!))
(er-rt-test "pid tag" (get pa :tag) "pid")
(er-rt-test "pid ids distinct" (= (er-pid-id pa) (er-pid-id pb)) false)
(er-rt-test "pid? true" (er-pid? pa) true)
(er-rt-test "pid? false" (er-pid? 42) false)
(er-rt-test
  "pid-equal same"
  (er-pid-equal? pa (er-mk-pid (er-pid-id pa)))
  true)
(er-rt-test "pid-equal diff" (er-pid-equal? pa pb) false)

;; ── process lifecycle ──────────────────────────────────────────
(er-sched-init!)
(define p1 (er-proc-new! {}))
(define p2 (er-proc-new! {}))
(er-rt-test "proc count 2" (er-sched-process-count) 2)
(er-rt-test "runnable count 2" (er-sched-runnable-count) 2)
(er-rt-test
  "proc state runnable"
  (er-proc-field (get p1 :pid) :state)
  "runnable")
(er-rt-test
  "proc mailbox empty"
  (er-proc-mailbox-size (get p1 :pid))
  0)
(er-rt-test
  "proc lookup"
  (er-pid-equal? (get (er-proc-get (get p1 :pid)) :pid) (get p1 :pid))
  true)
(er-rt-test "proc exists" (er-proc-exists? (get p1 :pid)) true)
(er-rt-test
  "proc no-such-pid"
  (er-proc-exists? (er-mk-pid 9999))
  false)

;; runnable queue dequeue order
(er-rt-test
  "dequeue first"
  (er-pid-equal? (er-sched-next-runnable!) (get p1 :pid))
  true)
(er-rt-test
  "dequeue second"
  (er-pid-equal? (er-sched-next-runnable!) (get p2 :pid))
  true)
(er-rt-test "dequeue empty" (er-sched-next-runnable!) nil)

;; current-pid get/set
(er-sched-set-current! (get p1 :pid))
(er-rt-test
  "current pid set"
  (er-pid-equal? (er-sched-current-pid) (get p1 :pid))
  true)

;; ── mailbox push ──────────────────────────────────────────────
(er-proc-mailbox-push! (get p1 :pid) {:tag "atom" :name "ping"})
(er-proc-mailbox-push! (get p1 :pid) 42)
(er-rt-test "mailbox size 2" (er-proc-mailbox-size (get p1 :pid)) 2)

;; ── field update ──────────────────────────────────────────────
(er-proc-set! (get p1 :pid) :state "waiting")
(er-rt-test
  "proc state waiting"
  (er-proc-field (get p1 :pid) :state)
  "waiting")
(er-proc-set! (get p1 :pid) :trap-exit true)
(er-rt-test
  "proc trap-exit"
  (er-proc-field (get p1 :pid) :trap-exit)
  true)

;; ── fresh scheduler ends in clean state ───────────────────────
(er-sched-init!)
(er-rt-test
  "sched init resets count"
  (er-sched-process-count)
  0)
(er-rt-test
  "sched init resets queue"
  (er-sched-runnable-count)
  0)
(er-rt-test
  "sched init resets current"
  (er-sched-current-pid)
  nil)

(define
  er-rt-test-summary
  (str "runtime " er-rt-test-pass "/" er-rt-test-count))