;; _hyperscript runtime shims
;;
;; Thin wrappers over web/lib/dom.sx and web/lib/browser.sx primitives
;; that implement hyperscript-specific semantics (async transparency,
;; class toggling, event waiting, iteration, type coercion).
;;
;; These are the functions that hs-to-sx (compiler.sx) emits calls to.
;; Each is a pure define — no platform dependency beyond the DOM/browser
;; primitives already available in the SX web platform.

;; ── Event handling ──────────────────────────────────────────────

;; Register an event listener. Returns unlisten function.
;; (hs-on target event-name handler) → unlisten-fn
(define
  hs-on
  (fn (target event-name handler) (dom-listen target event-name handler)))

;; Register for every occurrence (no queuing — each fires independently).
;; Stock hyperscript queues by default; "every" disables queuing.
(define
  hs-on-every
  (fn (target event-name handler) (dom-listen target event-name handler)))

;; Run an initializer function immediately.
;; (hs-init thunk) — called at element boot time
(define hs-init (fn (thunk) (thunk)))

;; ── Async / timing ──────────────────────────────────────────────

;; Wait for a duration in milliseconds.
;; In hyperscript, wait is async-transparent — execution pauses.
;; Here we use perform/IO suspension for true pause semantics.
(define hs-wait (fn (ms) (perform (list (quote io-sleep) ms))))

;; Wait for a DOM event on a target.
;; (hs-wait-for target event-name) — suspends until event fires
(define
  hs-wait-for
  (fn
    (target event-name)
    (perform (list (quote io-wait-event) target event-name))))

;; Wait for CSS transitions/animations to settle on an element.
(define hs-settle (fn (target) (perform (list (quote io-settle) target))))

;; ── Class manipulation ──────────────────────────────────────────

;; Toggle a single class on an element.
(define
  hs-toggle-class!
  (fn
    (target cls)
    (if
      (dom-has-class? target cls)
      (dom-remove-class target cls)
      (dom-add-class target cls))))

;; Toggle between two classes — exactly one is active at a time.
(define
  hs-toggle-between!
  (fn
    (target cls1 cls2)
    (if
      (dom-has-class? target cls1)
      (do (dom-remove-class target cls1) (dom-add-class target cls2))
      (do (dom-remove-class target cls2) (dom-add-class target cls1)))))

;; Take a class from siblings — add to target, remove from others.
;; (hs-take! target cls) — like radio button class behavior
(define
  hs-take!
  (fn
    (target cls)
    (let
      ((parent (dom-parent target)))
      (when
        parent
        (for-each
          (fn (child) (dom-remove-class child cls))
          (dom-child-list parent)))
      (dom-add-class target cls))))

;; ── DOM insertion ───────────────────────────────────────────────

;; Put content at a position relative to a target.
;; pos: "into" | "before" | "after"
(define
  hs-put!
  (fn
    (value pos target)
    (cond
      ((= pos "into") (dom-set-inner-html target value))
      ((= pos "before")
        (dom-insert-adjacent-html target "beforebegin" value))
      ((= pos "after") (dom-insert-adjacent-html target "afterend" value)))))

;; ── Navigation / traversal ──────────────────────────────────────

;; Navigate to a URL.
(define hs-navigate! (fn (url) (perform (list (quote io-navigate) url))))

;; Find next sibling matching a selector (or any sibling).
(define
  hs-next
  (fn
    (target sel)
    (if
      (= sel "*")
      (dom-next-sibling target)
      (let
        ((sibling (dom-next-sibling target)))
        (define
          find-next
          (fn
            (el)
            (cond
              ((nil? el) nil)
              ((dom-matches? el sel) el)
              (true (find-next (dom-next-sibling el))))))
        (find-next sibling)))))

;; Find previous sibling matching a selector.
(define
  hs-previous
  (fn
    (target sel)
    (if
      (= sel "*")
      (dom-get-prop target "previousElementSibling")
      (let
        ((sibling (dom-get-prop target "previousElementSibling")))
        (define
          find-prev
          (fn
            (el)
            (cond
              ((nil? el) nil)
              ((dom-matches? el sel) el)
              (true (find-prev (dom-get-prop el "previousElementSibling"))))))
        (find-prev sibling)))))

;; First element matching selector within a scope.
(define hs-query-first (fn (sel) (dom-query sel)))

;; Last element matching selector.
(define
  hs-query-last
  (fn
    (sel)
    (let
      ((all (dom-query-all (dom-body) sel)))
      (if (> (len all) 0) (nth all (- (len all) 1)) nil))))

;; First/last within a specific scope.
(define hs-first (fn (scope sel) (dom-query-all scope sel)))

(define
  hs-last
  (fn
    (scope sel)
    (let
      ((all (dom-query-all scope sel)))
      (if (> (len all) 0) (nth all (- (len all) 1)) nil))))

;; ── Iteration ───────────────────────────────────────────────────

;; Repeat a thunk N times.
(define
  hs-repeat-times
  (fn
    (n thunk)
    (define
      do-repeat
      (fn (i) (when (< i n) (thunk) (do-repeat (+ i 1)))))
    (do-repeat 0)))

;; Repeat forever (until break — relies on exception/continuation).
(define
  hs-repeat-forever
  (fn
    (thunk)
    (define do-forever (fn () (thunk) (do-forever)))
    (do-forever)))

;; ── Fetch ───────────────────────────────────────────────────────

;; Fetch a URL, parse response according to format.
;; (hs-fetch url format) — format is "json" | "text" | "html"
(define
  hs-fetch
  (fn
    (url format)
    (let
      ((response (perform (list (quote io-fetch) url))))
      (cond
        ((= format "json") (perform (list (quote io-parse-json) response)))
        ((= format "text") (perform (list (quote io-parse-text) response)))
        ((= format "html") (perform (list (quote io-parse-html) response)))
        (true response)))))

;; ── Type coercion ───────────────────────────────────────────────

;; Coerce a value to a type by name.
;; (hs-coerce value type-name) — type-name is "Int", "Float", "String", etc.
(define
  hs-coerce
  (fn
    (value type-name)
    (cond
      ((= type-name "Int") (+ value 0))
      ((= type-name "Integer") (+ value 0))
      ((= type-name "Float") (+ value 0))
      ((= type-name "Number") (+ value 0))
      ((= type-name "String") (str value))
      ((= type-name "Boolean") (if value true false))
      ((= type-name "Array") (if (list? value) value (list value)))
      (true value))))

;; ── Object creation ─────────────────────────────────────────────

;; Make a new object of a given type.
;; (hs-make type-name) — creates empty object/collection
(define
  hs-make
  (fn
    (type-name)
    (cond
      ((= type-name "Object") (dict))
      ((= type-name "Array") (list))
      ((= type-name "Set") (list))
      ((= type-name "Map") (dict))
      (true (dict)))))

;; ── Behavior installation ───────────────────────────────────────

;; Install a behavior on an element.
;; A behavior is a function that takes (me ...params) and sets up features.
;; (hs-install behavior-fn me ...args)
(define hs-install (fn (behavior-fn) (behavior-fn me)))

;; ── Measurement ─────────────────────────────────────────────────

;; Measure an element's bounding rect, store as local variables.
;; Returns a dict with x, y, width, height, top, left, right, bottom.
(define
  hs-measure
  (fn (target) (perform (list (quote io-measure) target))))

;; ── Transition ──────────────────────────────────────────────────

;; Transition a CSS property to a value, optionally with duration.
;; (hs-transition target prop value duration)
(define
  hs-transition
  (fn
    (target prop value duration)
    (when
      duration
      (dom-set-style
        target
        "transition"
        (str prop " " (/ duration 1000) "s")))
    (dom-set-style target prop value)
    (when duration (hs-settle target))))