;; lib/flow/tests/distributed.sx — Phase 4: distributed nodes via fed-sx (mocked).

(define flow-dist-pass 0)
(define flow-dist-fail 0)
(define flow-dist-fails (list))

(define
  flow-dist-test
  (fn
    (name actual expected)
    (if
      (= actual expected)
      (set! flow-dist-pass (+ flow-dist-pass 1))
      (begin
        (set! flow-dist-fail (+ flow-dist-fail 1))
        (append! flow-dist-fails {:name name :expected expected :actual actual})))))

(define flow-d (fn (src) (flow-run src)))

;; A mock peer "edge" exposing double/inc, registered at the top of each program.
(define
  peer-setup
  "(flow-peer-register! (quote edge) (list (list (quote double) (lambda (x) (* x 2))) (list (quote inc) (lambda (x) (+ x 1)))))")

;; ── remote-node ─────────────────────────────────────────────────
(flow-dist-test
  "remote: a node executes on a peer"
  (flow-d
    "(flow-peer-register! (quote edge) (list (list (quote double) (lambda (x) (* x 2))))) (flow/start (remote-node (quote edge) (quote double)) 21)")
  42)
(flow-dist-test
  "remote: remote nodes compose in a sequence"
  (flow-d
    "(flow-peer-register! (quote edge) (list (list (quote inc) (lambda (x) (+ x 1))) (list (quote double) (lambda (x) (* x 2))))) (flow/start (sequence (remote-node (quote edge) (quote inc)) (remote-node (quote edge) (quote double))) 4)")
  10)
(flow-dist-test
  "remote: a remote node mixes with local nodes"
  (flow-d
    "(flow-peer-register! (quote edge) (list (list (quote double) (lambda (x) (* x 2))))) (flow/start (sequence (lambda (x) (+ x 5)) (remote-node (quote edge) (quote double)) (lambda (x) (- x 1))) 10)")
  29)
(flow-dist-test
  "remote: unreachable peer raises flow-remote-unreachable"
  (flow-d
    "(flow/start (try-catch (remote-node (quote ghost) (quote double)) (lambda (e) e)) 1)")
  "flow-remote-unreachable")
(flow-dist-test
  "remote: unknown function on a peer raises flow-remote-no-fn"
  (flow-d
    "(flow-peer-register! (quote edge) (list (list (quote double) (lambda (x) (* x 2))))) (flow/start (try-catch (remote-node (quote edge) (quote missing)) (lambda (e) e)) 1)")
  "flow-remote-no-fn")
(flow-dist-test
  "remote: a remote node can suspend the flow (peer returns control)"
  (flow-d
    "(flow-peer-register! (quote edge) (list (list (quote review) (lambda (x) x)))) (flow/start (sequence (remote-node (quote edge) (quote review)) (lambda (x) (suspend (quote human))) (lambda (v) (list (quote published) v))) 7)")
  (list "flow-suspended" 1 "human"))
(flow-dist-test
  "remote: a transient remote failure is recoverable with retry"
  (flow-d
    "(define hits 0) (flow-peer-register! (quote edge) (list (list (quote flaky) (lambda (x) (begin (set! hits (+ hits 1)) (if (< hits 2) (raise (quote down)) (* x 3))))))) (list (flow/start (retry 3 (remote-node (quote edge) (quote flaky))) 7) hits)")
  (list 21 2))

(define flow-dist-tests-run! (fn () {:total (+ flow-dist-pass flow-dist-fail) :passed flow-dist-pass :failed flow-dist-fail :fails flow-dist-fails}))