(.module:
  [lux #- or and function]
  (lux (data [text]
             text/format
             (coll [list "list/" Functor<List> Fold<List>]))))

(type: #export JS Text)

(type: #export Expression JS)

(type: #export Statement JS)

(def: #export (number value)
  (-> Frac Expression)
  (%f value))

(def: #export (string value)
  (-> Text Expression)
  (%t value))

(def: #export (apply func args)
  (-> Expression (List Expression) Expression)
  (format func "(" (text.join-with "," args) ")"))

(def: #export (var! name value)
  (-> Text (Maybe Expression) Statement)
  (case value
    #.None
    (format "var " name ";")
    
    (#.Some value)
    (format "var " name " = " value ";")))

(def: #export (set! name value)
  (-> Text Expression Statement)
  (format name " = " value ";"))

(def: #export (if! test then! else!)
  (-> Expression Statement Statement Statement)
  (format "if(" test ") "
          then!
          " else "
          else!))

(def: #export (cond! clauses else!)
  (-> (List [Expression Statement]) Statement Statement)
  (list/fold (.function (_ [test then!] next!)
               (if! test then! next!))
             else!
             (list.reverse clauses)))

(def: #export (block! statements)
  (-> (List Statement) Statement)
  (format "{" (text.join-with "" statements) "}"))

(def: #export (while! test body)
  (-> Expression (List Statement) Statement)
  (format "while(" test ") " (block! body)))

(def: #export (throw! message)
  (-> Expression Statement)
  (format "throw Error(" message ");"))

(def: #export (return! value)
  (-> Expression Statement)
  (format "return " value ";"))

(def: #export (function name args body)
  (-> Text (List Text) (List Statement) Expression)
  (let [args (format "(" (text.join-with ", " args) ")")
        function (format "function " name args " " (block! body))]
    (format "(" function ")")))

(def: #export (? test then else)
  (-> Expression Expression Expression Expression)
  (format "(" test " ? " then " : " else ")"))

(def: #export (object fields)
  (-> (List [Text Expression]) Expression)
  (format "({"
          (|> fields
              (list/map (.function (_ [key val])
                          (format key ": " val)))
              (text.join-with ", "))
          "})"))

(do-template [<name> <op>]
  [(def: #export (<name> param subject)
     (-> Expression Expression Expression)
     (format "(" subject " " <op> " " param ")"))]

  [=       "==="]
  [<       "<"]
  [<=      "<="]
  [>       ">"]
  [>=      ">="]
  [+       "+"]
  [-       "-"]
  [*       "*"]
  [/       "/"]
  [%       "%"]
  )

(do-template [<name> <op>]
  [(def: #export (<name> param subject)
     (-> Expression Expression Expression)
     (format "(" param " " <op> " " subject ")"))]

  [or      "||"]
  [and     "&&"]
  [bit-or  "|"]
  [bit-and "&"]
  )