;; namespaces (jolt-yxqm, Phase 2) — the namespace value model.
;;
;; Chez has no ctx, so the ctx-coupled seed natives (find-ns/resolve/in-ns/…) are
;; reimplemented over the rt.ss var-table (cells carry ns + name + defined?) and
;; the multimethods.ss chez-current-ns box. A namespace VALUE is a `jns` record
;; carrying its name string — distinct from a map/record so (map? ns) is #f, but
;; the overlay's `ns-name` reads (get ns :name); that's overridden natively in
;; post-prelude.ss (loads after the overlay clobbers it).
;;
;; Loaded LAST from rt.ss. SCOPE (jolt-yxqm): the read/resolve/in-ns/*ns* ops.
;; use/require cross-ns SWITCHING is deferred (Phase 3) — the analyzer bakes a
;; def's target ns at compile time, so a runtime in-ns can't redirect later defs.

(define-record-type jns (fields name) (nongenerative chez-jns-v1))

;; registry: name-string -> jns. Seeded with the two always-present namespaces;
;; grown by in-ns / create-ns. find-ns ALSO derives existence from the var-table
;; (any cell with that ns), so a namespace that only ever had vars def'd into it
;; is still found.
(define ns-registry (make-hashtable string-hash string=?))
(define (intern-ns! name)
  (or (hashtable-ref ns-registry name #f)
      (let ((n (make-jns name))) (hashtable-set! ns-registry name n) n)))
(intern-ns! "user")
(intern-ns! "clojure.core")

;; --- namespace aliases (jolt-qjr0) -----------------------------------------
;; (require '[ns :as a]) registers a -> ns so the analyzer can resolve a/foo to
;; ns/foo. Keyed by (compile-ns . alias). On the zero-Janet spine the requires are
;; pre-registered at analyze time (compile-eval.ss) — analysis precedes eval, so a
;; runtime require no-op is fine. Also drives jolt-ns-aliases below.
(define ns-alias-table (make-hashtable equal-hash equal?))
(define (chez-register-alias! cns alias target)
  (hashtable-set! ns-alias-table (cons cns alias) target))
(define (chez-resolve-alias cns alias)
  (hashtable-ref ns-alias-table (cons cns alias) #f))
;; :refer brings an UNQUALIFIED name into cns, resolving to target-ns/name.
(define ns-refer-table (make-hashtable equal-hash equal?))
(define (chez-register-refer! cns name target)
  (hashtable-set! ns-refer-table (cons cns name) target))
(define (chez-resolve-refer cns name)
  (hashtable-ref ns-refer-table (cons cns name) #f))
;; parse a require/use spec FORM and register its :as alias + :refer names under
;; `cns`. spec: [ns :as a :refer [x y] ...] / (ns ...) / bare ns. opts are
;; keyword/value pairs after the ns symbol.
(define (chez-register-spec! cns spec)
  (let ((items (cond ((pvec? spec) (seq->list spec))
                     ((or (cseq? spec) (empty-list-t? spec)) (seq->list spec))
                     (else '()))))
    (when (and (pair? items) (symbol-t? (car items)))
      (let ((target (symbol-t-name (car items))))
        (let loop ((xs (cdr items)))
          (when (and (pair? xs) (pair? (cdr xs)))
            (let ((k (car xs)) (v (cadr xs)))
              (when (keyword? k)
                (cond
                  ((string=? (keyword-t-name k) "as")
                   (when (symbol-t? v) (chez-register-alias! cns (symbol-t-name v) target)))
                  ((string=? (keyword-t-name k) "refer")
                   (when (pvec? v)
                     (for-each (lambda (n)
                                 (when (symbol-t? n) (chez-register-refer! cns (symbol-t-name n) target)))
                               (seq->list v)))))))
            (loop (cddr xs))))))))

;; a namespace designator -> its name string (a jns or a symbol; the corpus never
;; passes a bare string).
(define (ns-desig->name d)
  (if (jns? d) (jns-name d) (symbol-t-name d)))

(define (ns-has-vars? nm)
  (let ((found #f))
    (vector-for-each
      (lambda (c) (when (and (not found) (string=? (var-cell-ns c) nm)) (set! found #t)))
      (hashtable-values var-table))
    found))

(define (jolt-find-ns desig)
  (let ((nm (ns-desig->name desig)))
    (or (hashtable-ref ns-registry nm #f)
        (and (ns-has-vars? nm) (intern-ns! nm))
        jolt-nil)))

(define (jolt-the-ns desig)
  (if (jns? desig) desig
      (let ((n (jolt-find-ns desig)))
        (if (jns? n) n (error #f "No namespace" desig)))))

(define (jolt-create-ns desig) (intern-ns! (ns-desig->name desig)))

;; in-ns: register + switch the current ns + re-bind *ns* + return the jns. NOTE
;; (Phase-3 deferral): this updates only the RUNTIME current ns — subsequent defs
;; in the same program were already ns-baked by the analyzer, so it does not
;; redirect them. It is enough for *ns* / str-of-ns to track the switch.
(define (jolt-in-ns desig)
  (let* ((nm (ns-desig->name desig)) (n (intern-ns! nm)))
    (set-chez-ns! nm)
    (def-var! "clojure.core" "*ns*" n)
    n))

;; ns-name: a namespace's name as a (no-ns) symbol. Overrides the overlay (which
;; reads (get ns :name) = nil on a jns record) — wired in via post-prelude.ss.
(define (jolt-ns-name desig)
  (jolt-symbol #f (jns-name (jolt-the-ns desig))))

(define (jolt-all-ns)
  (let ((seen (make-hashtable string-hash string=?)))
    (vector-for-each (lambda (k) (hashtable-set! seen k #t)) (hashtable-keys ns-registry))
    (vector-for-each (lambda (c) (hashtable-set! seen (var-cell-ns c) #t)) (hashtable-values var-table))
    (list->cseq (map intern-ns! (vector->list (hashtable-keys seen))))))

;; ns-publics / ns-map / ns-interns: a {sym -> var-cell} jolt map built by scanning
;; the var-table for defined cells in the namespace. (Private vars are not tracked
;; yet, so ns-publics == ns-interns.) ns-aliases is an empty map (map? is true).
(define (ns-vars-pmap nm)
  (let ((m (jolt-hash-map)))
    (vector-for-each
      (lambda (c)
        (when (and (string=? (var-cell-ns c) nm) (var-cell-defined? c))
          (set! m (jolt-assoc m (jolt-symbol #f (var-cell-name c)) c))))
      (hashtable-values var-table))
    m))
(define (jolt-ns-publics desig) (ns-vars-pmap (ns-desig->name desig)))
(define (jolt-ns-aliases desig) (jolt-hash-map))

;; resolve: an unqualified symbol resolves in the current ns then clojure.core; a
;; qualified one in its own ns. Returns the var iff genuinely defined, else nil —
;; never interns an empty cell (var-cell-lookup is non-creating).
(define (jolt-resolve sym)
  (let* ((sns (symbol-t-ns sym)) (nm (symbol-t-name sym))
         (c (if (string? sns)
                (var-cell-lookup sns nm)
                (or (var-cell-lookup (chez-current-ns) nm)
                    (var-cell-lookup "clojure.core" nm)))))
    (if (and c (var-cell-defined? c)) c jolt-nil)))

(define (jolt-find-var sym)
  (let ((sns (symbol-t-ns sym)) (nm (symbol-t-name sym)))
    (if (string? sns)
        (let ((c (var-cell-lookup sns nm))) (if (and c (var-cell-defined? c)) c jolt-nil))
        (error #f "find-var requires a fully-qualified symbol" sym))))

;; ns-unmap: clear the mapping — drop defined? and reset the root to unbound, so a
;; later resolve returns nil.
(define (jolt-ns-unmap ns-desig sym)
  (let ((c (var-cell-lookup (ns-desig->name ns-desig) (symbol-t-name sym))))
    (when c (var-cell-defined?-set! c #f) (var-cell-root-set! c jolt-unbound)))
  jolt-nil)

;; --- RESOLVE FRICTION: native-op cells -------------------------------------
;; Native-op primitives (+ map reduce …) are INLINED at emit, so they have no
;; var-cell and (resolve '+) would be nil — diverging from Clojure where it is a
;; var. def-var! each to its value-position procedure so it has a real, defined
;; cell (calls still inline, so no perf hit; #'+ deref and ((resolve '+) 1 2) also
;; work now). The clojure.core prelude, loaded AFTER rt.ss, overwrites the cells
;; for names it also defines in the overlay (map/filter/…); the purely-inlined
;; scalars (+/-/</inc/…) keep these.
(for-each
  (lambda (p) (def-var! "clojure.core" (car p) (cdr p)))
  (list
    (cons "+" jolt-add) (cons "-" jolt-sub) (cons "*" jolt-mul) (cons "/" jolt-div)
    (cons "<" <) (cons ">" >) (cons "<=" <=) (cons ">=" >=)
    (cons "=" jolt=) (cons "inc" jolt-inc) (cons "dec" jolt-dec) (cons "not" jolt-not)
    (cons "min" min) (cons "max" max)
    (cons "mod" modulo) (cons "rem" remainder) (cons "quot" quotient)
    (cons "vector" jolt-vector) (cons "hash-map" jolt-hash-map) (cons "hash-set" jolt-hash-set)
    (cons "conj" jolt-conj) (cons "get" jolt-get) (cons "nth" jolt-nth) (cons "count" jolt-count)
    (cons "assoc" jolt-assoc) (cons "dissoc" jolt-dissoc) (cons "contains?" jolt-contains?)
    (cons "empty?" jolt-empty?) (cons "peek" jolt-peek) (cons "pop" jolt-pop)
    (cons "first" jolt-first) (cons "rest" jolt-rest) (cons "next" jolt-next) (cons "seq" jolt-seq)
    (cons "cons" jolt-cons) (cons "list" jolt-list) (cons "reverse" jolt-reverse) (cons "last" jolt-last)
    (cons "map" jolt-map) (cons "filter" jolt-filter) (cons "remove" jolt-remove)
    (cons "reduce" jolt-reduce) (cons "into" jolt-into) (cons "concat" jolt-concat) (cons "apply" jolt-apply)
    (cons "range" jolt-range) (cons "take" jolt-take) (cons "drop" jolt-drop)
    (cons "keys" jolt-keys) (cons "vals" jolt-vals)
    (cons "even?" jolt-even?) (cons "odd?" jolt-odd?) (cons "pos?" jolt-pos?) (cons "neg?" jolt-neg?)
    (cons "zero?" jolt-zero?) (cons "identity" jolt-identity)
    (cons "ex-info" jolt-ex-info)))

;; --- bindings + *ns* --------------------------------------------------------
(def-var! "clojure.core" "find-ns" jolt-find-ns)
(def-var! "clojure.core" "the-ns" jolt-the-ns)
(def-var! "clojure.core" "create-ns" jolt-create-ns)
(def-var! "clojure.core" "in-ns" jolt-in-ns)
(def-var! "clojure.core" "all-ns" jolt-all-ns)
(def-var! "clojure.core" "ns-publics" jolt-ns-publics)
(def-var! "clojure.core" "ns-map" jolt-ns-publics)
(def-var! "clojure.core" "ns-interns" jolt-ns-publics)
(def-var! "clojure.core" "ns-aliases" jolt-ns-aliases)
(def-var! "clojure.core" "resolve" jolt-resolve)
(def-var! "clojure.core" "find-var" jolt-find-var)
(def-var! "clojure.core" "ns-unmap" jolt-ns-unmap)
;; *ns* starts at the user namespace (the current ns for -e user code). in-ns
;; re-binds it. (ns-name is overridden natively in post-prelude.ss.)
(def-var! "clojure.core" "*ns*" (intern-ns! "user"))

;; --- printer patches: a namespace renders as its name (str / pr-str / -e) ----
(define %ns-pr-str jolt-pr-str)
(set! jolt-pr-str (lambda (x) (if (jns? x) (jns-name x) (%ns-pr-str x))))
(define %ns-pr-readable jolt-pr-readable)
(set! jolt-pr-readable (lambda (x) (if (jns? x) (jns-name x) (%ns-pr-readable x))))
(define %ns-str-render-one jolt-str-render-one)
(set! jolt-str-render-one (lambda (x) (if (jns? x) (jns-name x) (%ns-str-render-one x))))