;; lib/host/tests/compose.sx — the composition CORE + render-fold (lib/host/compose.sx).
;; Tests host/comp-fold's shared dispatch (seq/alt/each + when + each-source + recursion +
;; depth guard) through the RENDER domain (render → HTML). The execute domain is tested in
;; tests/execute.sx; together they show one core, two folds (plans/composition-objects.md).

(define host-cp-pass 0)
(define host-cp-fail 0)
(define host-cp-fails (list))
(define host-cp-test
  (fn (name actual expected)
    (if (= actual expected)
      (set! host-cp-pass (+ host-cp-pass 1))
      (begin
        (set! host-cp-fail (+ host-cp-fail 1))
        (append! host-cp-fails {:name name :actual actual :expected expected})))))

;; -- leaves --
(host-cp-test "text leaf passes markup through"
  (host/comp-render (quote (text "<p>hi</p>")) {}) "<p>hi</p>")
(host-cp-test "field wraps the value in a span; reads the context"
  (host/comp-render (quote (field :title)) {"title" "Hello"}) "<span>Hello</span>")
(host-cp-test "val is the raw value (no markup) — for attributes"
  (host/comp-render (quote (val :slug)) {"slug" "p1"}) "p1")
(host-cp-test "a missing field renders empty, not an error"
  (host/comp-render (quote (field :nope)) {}) "<span></span>")

;; -- seq: render all in order --
(host-cp-test "seq renders children in order"
  (host/comp-render (quote (seq (text "a") (text "b") (text "c"))) {}) "abc")

;; -- row/grid: layout combinators wrap + recurse via the core --
(host-cp-test "row wraps its children in a flex div"
  (host/comp-render (quote (row (text "A") (text "B"))) {})
  "<div class=\"row\" style=\"display:flex;gap:1em\">AB</div>")

;; -- alt + when: render the first branch whose predicate holds --
(host-cp-test "alt renders the when-branch when the predicate holds"
  (host/comp-render (quote (alt (when (has "auth") (text "in")) (else (text "out")))) {"auth" "y"}) "in")
(host-cp-test "alt falls through to else"
  (host/comp-render (quote (alt (when (has "auth") (text "in")) (else (text "out")))) {}) "out")
(host-cp-test "alt eq predicate matches a context value"
  (host/comp-render (quote (alt (when (eq "t" "dark") (text "D")) (else (text "L")))) {"t" "dark"}) "D")
(host-cp-test "alt not predicate negates"
  (host/comp-render (quote (alt (when (not (has "auth")) (text "anon")) (else (text "user")))) {}) "anon")

;; -- each: iterate a source, binding :item, with field resolution --
(host-cp-test "each renders the template per item (items source)"
  (host/comp-render (quote (each (items {:n "x"} {:n "y"}) (seq (text "<li>") (field :n) (text "</li>")))) {})
  "<li><span>x</span></li><li><span>y</span></li>")
(host-cp-test "each over an empty source renders empty"
  (host/comp-render (quote (each (items) (field :n))) {}) "")
(host-cp-test "each query source delegates to the context resolver"
  (host/comp-render (quote (each (query is-a t) (field :title)))
    {"query" (fn (qargs ctx) (list {:title "One"} {:title "Two"}))})
  "<span>One</span><span>Two</span>")

;; -- recursion via named templates + a depth guard --
(host/comp--def-tmpl! "node"
  (quote (seq (field :name) (each (children) (tmpl "node")))))
(host-cp-test "tmpl recurses over a (children) tree until the source runs dry"
  (host/comp-render (quote (tmpl "node"))
    {"item" {:name "root" :children (list {:name "a" :children (list)} {:name "b" :children (list)})}})
  "<span>root</span><span>a</span><span>b</span>")

;; -- ref: transclude via the context resolver --
(host-cp-test "ref transcludes via the context resolver"
  (host/comp-render (quote (ref "c1")) {"ref" (fn (id ctx) (str "<card:" id ">"))}) "<card:c1>")
(host-cp-test "ref with no resolver renders empty"
  (host/comp-render (quote (ref "c1")) {}) "")

;; -- the unifying property: ONE object renders differently per context --
(host-cp-test "the SAME object renders two ways by context (anon vs authed)"
  (let ((obj (quote (alt (when (has "auth") (text "member")) (else (text "guest"))))))
    (list (host/comp-render obj {}) (host/comp-render obj {"auth" "y"})))
  (list "guest" "member"))

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