(ns clje.core
  "CljElixir core — stubs for clj-kondo/clojure-lsp.

   These are builtin functions and special forms handled directly by the
   CljElixir transformer. Standard Clojure forms (defn, let, fn, if, etc.)
   are mapped via :lint-as in .clj-kondo/config.edn."
  (:refer-clojure :exclude [case send pr pr-str prn print-str
                            vec vector subvec vector?
                            str println cons list
                            inc dec
                            map filter concat take drop
                            sort sort-by group-by frequencies distinct
                            mapcat partition
                            keys vals select-keys merge into
                            get assoc dissoc update get-in assoc-in update-in
                            count first rest seq
                            conj nth peek pop
                            reduce reduce-kv
                            contains? empty? nil?
                            not= with-open throw]))

;; ===== Special Forms (hooks handle these) =====
(defmacro receive
  "BEAM message receive with pattern matching.
   (receive
     [:hello sender] (send sender :hi)
     [:quit] (System/halt 0)
     :after 5000 (println \"timeout\"))"
  [& clauses])
(defmacro defmodule
  "Defines an Elixir module.
   (defmodule MyModule
     (defn my-func [x] (* x 2)))"
  [name & body])
(defmacro case
  "Pattern matching (not constant matching like Clojure).
   (case val
     [a b] (+ a b)
     {:key v} v
     _ :default)"
  [expr & clauses])
(defmacro with
  "Monadic binding — chains pattern matches, short-circuits on mismatch.
   (with [{:ok val1} (step1)
          {:ok val2} (step2 val1)]
     (+ val1 val2))"
  [bindings & body])
(defmacro ns
  "Declares the module namespace (primary module declaration).
   (ns MyApp.Router
     (require [Logger])
     (use [CljElixir.Core]))"
  [name & body])

;; ===== BEAM Concurrency =====
(defn spawn
  "Spawns a new BEAM process. Returns PID.
   (spawn (fn [] (IO/puts \"hello from new process\")))"
  [f])
(defn send
  "Sends a message to a process. Returns the message.
   (send pid {:hello \"world\"})"
  [pid msg])
(defn monitor
  "Monitors a process. Returns a reference.
   (monitor pid)
   (monitor :process pid)"
  ([pid]) ([type pid]))
(defn link
  "Creates a bidirectional link between processes.
   (link pid)"
  [pid])
(defn unlink
  "Removes a link between processes.
   (unlink pid)"
  [pid])
(defn alive?
  "Returns true if the process is alive.
   (alive? pid) ;=> true"
  [pid])

;; ===== Arithmetic =====
(defn inc
  "Increments by 1.
   (inc 5) ;=> 6"
  [x])
(defn dec
  "Decrements by 1.
   (dec 5) ;=> 4"
  [x])

;; ===== String & Output =====
(defn str
  "Concatenates arguments into a string.
   (str \"hello\" \" \" \"world\") ;=> \"hello world\""
  [& args])
(defn println
  "Prints arguments followed by newline.
   (println \"hello\")"
  [& args])
(defn pr-str
  "Returns a string representation (EDN-like).
   (pr-str {:a 1}) ;=> \"{:a 1}\""
  [& args])
(defn prn
  "Prints EDN representation followed by newline."
  [& args])
(defn pr
  "Prints EDN representation (no newline)."
  [& args])
(defn print-str
  "Returns a human-readable string."
  [& args])

;; ===== BEAM Types & Interop =====
(defn tuple
  "Creates a BEAM tuple from arguments.
   (tuple :ok \"value\") ;=> #el[:ok \"value\"]"
  [& args])
(defn clojurify
  "Converts Elixir types to Clojure equivalents (keyword lists → maps, etc.).
   (clojurify elixir-val)"
  [val])
(defn elixirify
  "Converts Clojure types to Elixir equivalents (maps → keyword lists, etc.).
   (elixirify clj-val)"
  [val])
(defn hd
  "Returns the head (first element) of a list.
   (hd [1 2 3]) ;=> 1"
  [coll])
(defn tl
  "Returns the tail (rest) of a list.
   (tl [1 2 3]) ;=> [2 3]"
  [coll])
(defn cons
  "Prepends an element to a list.
   (cons 1 [2 3]) ;=> [1 2 3]"
  [head tail])
(defn list
  "Creates a list from arguments.
   (list 1 2 3) ;=> [1 2 3]"
  [& args])

;; ===== BEAM Type Guards =====
(defn is-binary
  "Returns true if `x` is a binary (string). Allowed in guards.
   (is-binary \"hello\") ;=> true"
  [x])
(defn is-integer
  "Returns true if `x` is an integer. Allowed in guards."
  [x])
(defn is-float
  "Returns true if `x` is a float. Allowed in guards."
  [x])
(defn is-number
  "Returns true if `x` is a number. Allowed in guards."
  [x])
(defn is-atom
  "Returns true if `x` is an atom. Allowed in guards."
  [x])
(defn is-list
  "Returns true if `x` is a list. Allowed in guards."
  [x])
(defn is-map
  "Returns true if `x` is a map. Allowed in guards."
  [x])
(defn is-tuple
  "Returns true if `x` is a tuple. Allowed in guards."
  [x])
(defn is-pid
  "Returns true if `x` is a PID. Allowed in guards."
  [x])
(defn is-boolean
  "Returns true if `x` is a boolean. Allowed in guards."
  [x])
(defn is-nil
  "Returns true if `x` is nil. Allowed in guards."
  [x])
(defn is-function
  "Returns true if `x` is a function, optionally with given `arity`.
   (is-function f) ;=> true
   (is-function f 2) ;=> true if f takes 2 args"
  ([x]) ([x arity]))

;; ===== Vectors =====
(defn vec
  "Converts a collection to a PersistentVector.
   (vec [1 2 3])"
  [coll])
(defn vector
  "Creates a PersistentVector from arguments.
   (vector 1 2 3)"
  [& args])
(defn subvec
  "Returns a subvector from `start` to `end`.
   (subvec v 1 3)"
  ([v start]) ([v start end]))
(defn vector?
  "Returns true if `x` is a PersistentVector.
   (vector? (vector 1 2 3)) ;=> true"
  [x])

;; ===== Core Data Operations =====
(defn get
  "Gets value at `key` from collection. Returns `default` if missing.
   (get {:a 1} :a) ;=> 1
   (get {:a 1} :b :not-found) ;=> :not-found"
  ([coll key]) ([coll key default]))
(defn assoc
  "Associates `key` with `val` in collection.
   (assoc {:a 1} :b 2) ;=> {:a 1 :b 2}"
  [coll key val])
(defn dissoc
  "Dissociates `key` from collection.
   (dissoc {:a 1 :b 2} :a) ;=> {:b 2}"
  [coll key])
(defn update
  "Updates value at `key` by applying `f`.
   (update {:a 1} :a inc) ;=> {:a 2}"
  ([coll key f]) ([coll key f & args]))
(defn get-in
  "Gets value at nested `path`.
   (get-in {:a {:b 1}} [:a :b]) ;=> 1"
  ([coll path]) ([coll path default]))
(defn assoc-in
  "Associates value at nested `path`.
   (assoc-in {} [:a :b] 1) ;=> {:a {:b 1}}"
  [coll path val])
(defn update-in
  "Updates value at nested `path` by applying `f`.
   (update-in {:a {:b 1}} [:a :b] inc) ;=> {:a {:b 2}}"
  [coll path f])
(defn contains?
  "Returns true if `coll` contains `key`.
   (contains? {:a 1} :a) ;=> true"
  [coll key])
(defn empty?
  "Returns true if `coll` is empty.
   (empty? []) ;=> true"
  [coll])
(defn nil?
  "Returns true if `x` is nil.
   (nil? nil) ;=> true"
  [x])
(defn count
  "Returns the number of elements.
   (count [1 2 3]) ;=> 3"
  [coll])
(defn first
  "Returns the first element.
   (first [1 2 3]) ;=> 1"
  [coll])
(defn rest
  "Returns all but the first element.
   (rest [1 2 3]) ;=> [2 3]"
  [coll])
(defn seq
  "Returns a seq on the collection, or nil if empty.
   (seq [1 2 3]) ;=> (1 2 3)"
  [coll])
(defn conj
  "Adds element to collection (position depends on type).
   (conj [1 2] 3) ;=> [1 2 3]"
  [coll x])
(defn nth
  "Returns element at `index`.
   (nth [10 20 30] 1) ;=> 20"
  ([coll index]) ([coll index not-found]))
(defn peek
  "Returns the most accessible element.
   (peek [1 2 3]) ;=> 3"
  [coll])
(defn pop
  "Returns collection without the most accessible element.
   (pop [1 2 3]) ;=> [1 2]"
  [coll])

;; ===== Reducing =====
(defn reduce
  "Reduces collection with `f`.
   (reduce + [1 2 3]) ;=> 6
   (reduce + 0 [1 2 3]) ;=> 6"
  ([f coll]) ([f init coll]))
(defn reduce-kv
  "Reduces a map with `f` receiving (acc, key, value).
   (reduce-kv (fn [acc k v] (+ acc v)) 0 {:a 1 :b 2}) ;=> 3"
  [f init coll])

;; ===== Sequence Operations =====
(defn map
  "Applies `f` to each element, returns a list.
   (map inc [1 2 3]) ;=> [2 3 4]"
  [f coll])
(defn filter
  "Returns elements where `f` returns truthy.
   (filter (fn [x] (> x 2)) [1 2 3 4]) ;=> [3 4]"
  [f coll])
(defn concat
  "Concatenates collections.
   (concat [1 2] [3 4]) ;=> [1 2 3 4]"
  [& colls])
(defn take
  "Returns first `n` elements.
   (take 2 [1 2 3 4]) ;=> [1 2]"
  [n coll])
(defn drop
  "Drops first `n` elements.
   (drop 2 [1 2 3 4]) ;=> [3 4]"
  [n coll])
(defn sort
  "Sorts a collection.
   (sort [3 1 2]) ;=> [1 2 3]
   (sort > [3 1 2]) ;=> [3 2 1]"
  ([coll]) ([comp coll]))
(defn sort-by
  "Sorts by the result of `keyfn`.
   (sort-by :name [{:name \"b\"} {:name \"a\"}])"
  ([keyfn coll]) ([keyfn comp coll]))
(defn group-by
  "Groups elements by the result of `f`.
   (group-by even? [1 2 3 4]) ;=> {false [1 3] true [2 4]}"
  [f coll])
(defn frequencies
  "Returns a map of element → count.
   (frequencies [:a :b :a]) ;=> {:a 2 :b 1}"
  [coll])
(defn distinct
  "Returns unique elements.
   (distinct [1 2 1 3]) ;=> [1 2 3]"
  [coll])
(defn mapcat
  "Maps then concatenates results.
   (mapcat (fn [x] [x x]) [1 2 3]) ;=> [1 1 2 2 3 3]"
  [f coll])
(defn partition
  "Partitions collection into groups of `n`.
   (partition 2 [1 2 3 4]) ;=> [[1 2] [3 4]]"
  ([n coll]) ([n step coll]) ([n step pad coll]))
(defn keys
  "Returns keys of a map.
   (keys {:a 1 :b 2}) ;=> [:a :b]"
  [m])
(defn vals
  "Returns values of a map.
   (vals {:a 1 :b 2}) ;=> [1 2]"
  [m])
(defn select-keys
  "Selects only specified `ks` from map.
   (select-keys {:a 1 :b 2 :c 3} [:a :c]) ;=> {:a 1 :c 3}"
  [m ks])
(defn merge
  "Merges maps. Later maps take precedence.
   (merge {:a 1} {:b 2}) ;=> {:a 1 :b 2}"
  [& maps])
(defn into
  "Pours elements from `from` into `to`.
   (into {} [[:a 1] [:b 2]]) ;=> {:a 1 :b 2}"
  [to from])
(defn not=
  "Returns true if arguments are not equal.
   (not= 1 2) ;=> true"
  [& args])
(defn throw
  "Throws a value (caught by try/catch :throw).
   (throw :some-error)"
  [value])