(.module:
  [library
   [lux #*
    ["." meta]
    [abstract
     [monad (#+ do)]]
    [control
     ["." io]
     ["<>" parser ("#\." monad)
      ["<.>" code (#+ Parser)]]]
    [data
     ["." product]
     ["." maybe]
     ["." text
      ["%" format]]
     [collection
      ["." list ("#\." functor fold)]]]
    [type
     abstract]
    [macro (#+ with_gensyms)
     [syntax (#+ syntax:)]
     ["." code]
     ["." template]]]])

(abstract: #export (Object brand)
  Any)

(template [<name>]
  [(with_expansions [<brand> (template.identifier [<name> "'"])]
     (abstract: <brand>
       Any
       
       (type: #export <name>
         (Object <brand>))))]

  [Function]
  [Symbol]
  [Null]
  [Undefined]
  )

(template [<name> <type>]
  [(type: #export <name>
     <type>)]

  [Boolean Bit]
  [Number  Frac]
  [String  Text]
  )

(type: Nullable
  [Bit Code])

(def: nullable
  (Parser Nullable)
  (let [token (' #?)]
    (<| (<>.and (<>.parses? (<code>.this! token)))
        (<>.after (<>.not (<code>.this! token)))
        <code>.any)))

(type: Constructor
  (List Nullable))

(def: constructor
  (Parser Constructor)
  (<code>.form (<>.after (<code>.this! (' new))
                         (<code>.tuple (<>.some ..nullable)))))

(type: Field
  [Bit Text Nullable])

(def: static!
  (Parser Any)
  (<code>.this! (' #static)))

(def: field
  (Parser Field)
  (<code>.form ($_ <>.and
                   (<>.parses? ..static!)
                   <code>.local_identifier
                   ..nullable)))

(type: Common_Method
  {#name Text
   #alias (Maybe Text)
   #inputs (List Nullable)
   #io? Bit
   #try? Bit
   #output Nullable})

(type: Static_Method Common_Method)
(type: Virtual_Method Common_Method)

(type: Method
  (#Static Static_Method)
  (#Virtual Virtual_Method))

(def: common_method
  (Parser Common_Method)
  ($_ <>.and
      <code>.local_identifier
      (<>.maybe (<>.after (<code>.this! (' #as)) <code>.local_identifier))
      (<code>.tuple (<>.some ..nullable))
      (<>.parses? (<code>.this! (' #io)))
      (<>.parses? (<code>.this! (' #try)))
      ..nullable))

(def: static_method
  (<>.after ..static! ..common_method))

(def: method
  (Parser Method)
  (<code>.form (<>.or ..static_method
                      ..common_method)))

(type: Member
  (#Constructor Constructor)
  (#Field Field)
  (#Method Method))

(def: member
  (Parser Member)
  ($_ <>.or
      ..constructor
      ..field
      ..method
      ))

(def: input_variables
  (-> (List Nullable) (List [Bit Code]))
  (|>> list.enumeration
       (list\map (function (_ [idx [nullable? type]])
                   [nullable? (|> idx %.nat code.local_identifier)]))))

(def: (nullable_type [nullable? type])
  (-> Nullable Code)
  (if nullable?
    (` (.Maybe (~ type)))
    type))

(def: (with_null g!temp [nullable? input])
  (-> Code [Bit Code] Code)
  (if nullable?
    (` (case (~ input)
         (#.Some (~ g!temp))
         (~ g!temp)

         #.None
         ("js object null")))
    input))

(def: #export (null _)
  (-> Any Nothing)
  (:assume ("js object null")))

(def: #export null?
  (-> Any Bit)
  (|>> "js object null?"))

(def: (without_null g!temp [nullable? outputT] output)
  (-> Code Nullable Code Code)
  (if nullable?
    (` (let [(~ g!temp) (~ output)]
         (if ("js object null?" (~ g!temp))
           #.None
           (#.Some (~ g!temp)))))
    (` (let [(~ g!temp) (~ output)]
         (if (not ("js object null?" (~ g!temp)))
           (~ g!temp)
           (.error! "Null is an invalid value."))))))

(type: Class_Declaration
  [Text (List Text)])

(type: Import
  (#Class [Class_Declaration Text (List Member)])
  (#Function Static_Method))

(def: class_declaration
  (Parser Class_Declaration)
  (<>.either (<>.and <code>.local_identifier
                     (<>\in (list)))
             (<code>.form (<>.and <code>.local_identifier
                                  (<>.some <code>.local_identifier)))))

(def: import
  (Parser Import)
  (<>.or (<>.and ..class_declaration
                 (<>.else ["" (list)]
                          (<code>.tuple (<>.and <code>.text
                                                (<>.some member)))))
         (<code>.form ..common_method)))

(def: (with_io with? without)
  (-> Bit Code Code)
  (if with?
    (` (io.io (~ without)))
    without))

(def: (io_type io? rawT)
  (-> Bit Code Code)
  (if io?
    (` (io.IO (~ rawT)))
    rawT))

(def: (with_try with? without_try)
  (-> Bit Code Code)
  (if with?
    (` (.try (~ without_try)))
    without_try))

(def: (try_type try? rawT)
  (-> Bit Code Code)
  (if try?
    (` (.Either .Text (~ rawT)))
    rawT))

(def: (make_function g!method g!temp source inputsT io? try? outputT)
  (-> Code Code Text (List Nullable) Bit Bit Nullable Code)
  (let [g!inputs (input_variables inputsT)]
    (` (def: ((~ g!method)
              [(~+ (list\map product.right g!inputs))])
         (-> [(~+ (list\map nullable_type inputsT))]
             (~ (|> (nullable_type outputT)
                    (try_type try?)
                    (io_type io?))))
         (:assume
          (~ (<| (with_io io?)
                 (with_try try?)
                 (without_null g!temp outputT)
                 (` ("js apply"
                     ("js constant" (~ (code.text source)))
                     (~+ (list\map (with_null g!temp) g!inputs)))))))))))

(syntax: #export (import: {import ..import})
  (with_gensyms [g!temp]
    (case import
      (#Class [[class_name class_parameters] format members])
      (with_gensyms [g!object]
        (let [qualify (: (-> Text Code)
                         (function (_ member_name)
                           (|> format
                               (text.replace_all "#" class_name)
                               (text.replace_all "." member_name)
                               code.local_identifier)))
              class_parameters (list\map code.local_identifier class_parameters)
              declaration (` ((~ (code.local_identifier class_name))
                              (~+ class_parameters)))
              real_class (text.replace_all "/" "." class_name)]
          (in (list& (` (type: (~ declaration)
                          (..Object (primitive (~ (code.text real_class))))))
                     (list\map (function (_ member)
                                 (case member
                                   (#Constructor inputsT)
                                   (let [g!inputs (input_variables inputsT)]
                                     (` (def: ((~ (qualify "new"))
                                               [(~+ (list\map product.right g!inputs))])
                                          (All [(~+ class_parameters)]
                                            (-> [(~+ (list\map nullable_type inputsT))]
                                                (~ declaration)))
                                          (:assume
                                           ("js object new"
                                            ("js constant" (~ (code.text real_class)))
                                            [(~+ (list\map (with_null g!temp) g!inputs))])))))
                                   
                                   (#Field [static? field fieldT])
                                   (if static?
                                     (` ((~! syntax:) ((~ (qualify field)))
                                         (\ (~! meta.monad) (~' in)
                                            (list (` (.:as (~ (nullable_type fieldT))
                                                           ("js constant" (~ (code.text (%.format real_class "." field))))))))))
                                     (` (def: ((~ (qualify field))
                                               (~ g!object))
                                          (All [(~+ class_parameters)]
                                            (-> (~ declaration)
                                                (~ (nullable_type fieldT))))
                                          (:assume
                                           (~ (without_null g!temp fieldT (` ("js object get" (~ (code.text field)) (~ g!object)))))))))
                                   
                                   (#Method method)
                                   (case method
                                     (#Static [method alias inputsT io? try? outputT])
                                     (..make_function (qualify (maybe.else method alias))
                                                      g!temp
                                                      (%.format real_class "." method)
                                                      inputsT
                                                      io?
                                                      try?
                                                      outputT)
                                     
                                     (#Virtual [method alias inputsT io? try? outputT])
                                     (let [g!inputs (input_variables inputsT)]
                                       (` (def: ((~ (qualify (maybe.else method alias)))
                                                 [(~+ (list\map product.right g!inputs))]
                                                 (~ g!object))
                                            (All [(~+ class_parameters)]
                                              (-> [(~+ (list\map nullable_type inputsT))]
                                                  (~ declaration)
                                                  (~ (|> (nullable_type outputT)
                                                         (try_type try?)
                                                         (io_type io?)))))
                                            (:assume
                                             (~ (<| (with_io io?)
                                                    (with_try try?)
                                                    (without_null g!temp outputT)
                                                    (` ("js object do"
                                                        (~ (code.text method))
                                                        (~ g!object)
                                                        [(~+ (list\map (with_null g!temp) g!inputs))])))))))))))
                               members)))))
      
      (#Function [name alias inputsT io? try? outputT])
      (in (list (..make_function (code.local_identifier (maybe.else name alias))
                                 g!temp
                                 name
                                 inputsT
                                 io?
                                 try?
                                 outputT)))
      )))

(template: #export (type_of object)
  ("js type-of" object))

(syntax: #export (constant type
                           {[head tail] (<code>.tuple (<>.and <code>.local_identifier (<>.some <code>.local_identifier)))})
  (with_gensyms [g!_]
    (let [constant (` ("js constant" (~ (code.text head))))]
      (case tail
        #.End
        (in (list (` (: (.Maybe (~ type))
                        (case (..type_of (~ constant))
                          "undefined"
                          #.None

                          (~ g!_)
                          (#.Some (:as (~ type) (~ constant))))))))
        
        (#.Item [next tail])
        (let [separator "."]
          (in (list (` (: (.Maybe (~ type))
                          (case (..type_of (~ constant))
                            "undefined"
                            #.None

                            (~ g!_)
                            (..constant (~ type) [(~ (code.local_identifier (%.format head "." next)))
                                                  (~+ (list\map code.local_identifier tail))])))))))))))

(template: (!defined? <constant>)
  (.case (..constant Any <constant>)
    #.None
    .false

    (#.Some _)
    .true))

(template [<name> <constant>]
  [(def: #export <name>
     Bit
     (!defined? <constant>))]

  [on_browser? [window]]
  [on_nashorn? [java lang Object]]
  )

(def: #export on_node_js?
  Bit
  (case (..constant (Object Any) [process])
    (#.Some process)
    (case (:as Text
               ("js apply" ("js constant" "Object.prototype.toString.call") process))
      "[object process]"
      true

      _
      false)

    #.None
    false))

(template: #export (closure <inputs> <output>)
  (.:as ..Function
        (`` ("js function"
             (~~ (template.amount <inputs>))
             (.function (_ [<inputs>])
               <output>)))))