(.module:
  [lux (#- Type)
   ["." host (#+ import: do-to)]
   [control
    ["." function]]
   [data
    ["." product]
    [number
     ["i" int]]
    ["." text
     ["%" format (#+ format)]]
    [collection
     ["." array (#+ Array)]
     ["." list ("#@." functor)]]]
   [target
    [jvm
     [encoding
      ["." name]]
     ["." type (#+ Type Constraint)
      [category (#+ Class Value Method)]
      ["." signature]
      ["." descriptor]]]]]
  ["." //])

(def: signature (|>> type.signature signature.signature))
(def: descriptor (|>> type.descriptor descriptor.descriptor))
(def: class-name (|>> type.descriptor descriptor.class-name name.read))

(import: #long java/lang/Object)
(import: #long java/lang/String)

(import: org/objectweb/asm/Opcodes
  (#static ACC_PUBLIC int)
  (#static ACC_PROTECTED int)
  (#static ACC_PRIVATE int)

  (#static ACC_TRANSIENT int)
  (#static ACC_VOLATILE int)

  (#static ACC_ABSTRACT int)
  (#static ACC_FINAL int)
  (#static ACC_STATIC int)
  (#static ACC_SYNCHRONIZED int)
  (#static ACC_STRICT int)

  (#static ACC_SUPER int)
  (#static ACC_INTERFACE int)

  (#static V1_1 int)
  (#static V1_2 int)
  (#static V1_3 int)
  (#static V1_4 int)
  (#static V1_5 int)
  (#static V1_6 int)
  (#static V1_7 int)
  (#static V1_8 int)
  )

(import: org/objectweb/asm/FieldVisitor
  (visitEnd [] void))

(import: org/objectweb/asm/MethodVisitor
  (visitCode [] void)
  (visitMaxs [int int] void)
  (visitEnd [] void))

(import: org/objectweb/asm/ClassWriter
  (#static COMPUTE_MAXS int)
  (#static COMPUTE_FRAMES int)
  (new [int])
  (visit [int int String String String [String]] void)
  (visitEnd [] void)
  (visitField [int String String String Object] FieldVisitor)
  (visitMethod [int String String String [String]] MethodVisitor)
  (toByteArray [] [byte]))

(def: (string-array values)
  (-> (List Text) (Array Text))
  (let [output (host.array String (list.size values))]
    (exec (list@map (function (_ [idx value])
                      (host.array-write idx value output))
                    (list.enumerate values))
      output)))

(def: (version-flag version)
  (-> //.Version Int)
  (case version
    #//.V1_1 (Opcodes::V1_1)
    #//.V1_2 (Opcodes::V1_2)
    #//.V1_3 (Opcodes::V1_3)
    #//.V1_4 (Opcodes::V1_4)
    #//.V1_5 (Opcodes::V1_5)
    #//.V1_6 (Opcodes::V1_6)
    #//.V1_7 (Opcodes::V1_7)
    #//.V1_8 (Opcodes::V1_8)))

(def: (visibility-flag visibility)
  (-> //.Visibility Int)
  (case visibility
    #//.Public    (Opcodes::ACC_PUBLIC)
    #//.Protected (Opcodes::ACC_PROTECTED)
    #//.Private   (Opcodes::ACC_PRIVATE)
    #//.Default   +0))

(def: (class-flags config)
  (-> //.Class-Config Int)
  ($_ i.+
      (if (get@ #//.finalC config) (Opcodes::ACC_FINAL) +0)))

(def: (method-flags config)
  (-> //.Method-Config Int)
  ($_ i.+
      (if (get@ #//.staticM config) (Opcodes::ACC_STATIC) +0)
      (if (get@ #//.finalM config) (Opcodes::ACC_FINAL) +0)
      (if (get@ #//.synchronizedM config) (Opcodes::ACC_SYNCHRONIZED) +0)
      (if (get@ #//.strictM config) (Opcodes::ACC_STRICT) +0)))

(def: (field-flags config)
  (-> //.Field-Config Int)
  ($_ i.+
      (if (get@ #//.staticF config) (Opcodes::ACC_STATIC) +0)
      (if (get@ #//.finalF config) (Opcodes::ACC_FINAL) +0)
      (if (get@ #//.transientF config) (Opcodes::ACC_TRANSIENT) +0)
      (if (get@ #//.volatileF config) (Opcodes::ACC_VOLATILE) +0)))

(def: param-signature
  (-> (Type Class) Text)
  (|>> ..signature (format ":")))

(def: (formal-param [name super interfaces])
  (-> Constraint Text)
  (format name
          (param-signature super)
          (|> interfaces
              (list@map param-signature)
              (text.join-with ""))))

(def: (constraints-signature constraints super interfaces)
  (-> (List Constraint) (Type Class) (List (Type Class))
      Text)
  (let [formal-params (if (list.empty? constraints)
                        ""
                        (format "<"
                                (|> constraints
                                    (list@map formal-param)
                                    (text.join-with ""))
                                ">"))]
    (format formal-params
            (..signature super)
            (|> interfaces
                (list@map ..signature)
                (text.join-with "")))))

(def: class-computes
  Int
  ($_ i.+
      (ClassWriter::COMPUTE_MAXS)
      ## (ClassWriter::COMPUTE_FRAMES)
      ))

(def: binary-name (|>> name.internal name.read))

(template [<name> <flag>]
  [(def: #export (<name> version visibility config name constraints super interfaces
                         definitions)
     (-> //.Version //.Visibility //.Class-Config Text (List Constraint) (Type Class) (List (Type Class)) //.Def
         (host.type [byte]))
     (let [writer (|> (do-to (ClassWriter::new class-computes)
                        (ClassWriter::visit (version-flag version)
                                            ($_ i.+
                                                (Opcodes::ACC_SUPER)
                                                <flag>
                                                (visibility-flag visibility)
                                                (class-flags config))
                                            (..binary-name name)
                                            (constraints-signature constraints super interfaces)
                                            (..class-name super)
                                            (|> interfaces
                                                (list@map ..class-name)
                                                string-array)))
                      definitions)
           _ (ClassWriter::visitEnd writer)]
       (ClassWriter::toByteArray writer)))]

  [class    +0]
  [abstract (Opcodes::ACC_ABSTRACT)]
  )

(def: $Object
  (Type Class)
  (type.class "java.lang.Object" (list)))

(def: #export (interface version visibility config name constraints interfaces
                         definitions)
  (-> //.Version //.Visibility //.Class-Config Text (List Constraint) (List (Type Class)) //.Def
      (host.type [byte]))
  (let [writer (|> (do-to (ClassWriter::new class-computes)
                     (ClassWriter::visit (version-flag version)
                                         ($_ i.+
                                             (Opcodes::ACC_SUPER)
                                             (Opcodes::ACC_INTERFACE)
                                             (visibility-flag visibility)
                                             (class-flags config))
                                         (..binary-name name)
                                         (constraints-signature constraints $Object interfaces)
                                         (..class-name $Object)
                                         (|> interfaces
                                             (list@map ..class-name)
                                             string-array)))
                   definitions)
        _ (ClassWriter::visitEnd writer)]
    (ClassWriter::toByteArray writer)))

(def: #export (method visibility config name type then)
  (-> //.Visibility //.Method-Config Text (Type Method) //.Inst
      //.Def)
  (function (_ writer)
    (let [=method (ClassWriter::visitMethod ($_ i.+
                                                (visibility-flag visibility)
                                                (method-flags config))
                                            (..binary-name name)
                                            (..descriptor type)
                                            (..signature type)
                                            (string-array (list))
                                            writer)
          _ (MethodVisitor::visitCode =method)
          _ (then =method)
          _ (MethodVisitor::visitMaxs +0 +0 =method)
          _ (MethodVisitor::visitEnd =method)]
      writer)))

(def: #export (abstract-method visibility config name type)
  (-> //.Visibility //.Method-Config Text (Type Method)
      //.Def)
  (function (_ writer)
    (let [=method (ClassWriter::visitMethod ($_ i.+
                                                (visibility-flag visibility)
                                                (method-flags config)
                                                (Opcodes::ACC_ABSTRACT))
                                            (..binary-name name)
                                            (..descriptor type)
                                            (..signature type)
                                            (string-array (list))
                                            writer)
          _ (MethodVisitor::visitEnd =method)]
      writer)))

(def: #export (field visibility config name type)
  (-> //.Visibility //.Field-Config Text (Type Value) //.Def)
  (function (_ writer)
    (let [=field (do-to (ClassWriter::visitField ($_ i.+
                                                     (visibility-flag visibility)
                                                     (field-flags config))
                                                 (..binary-name name)
                                                 (..descriptor type)
                                                 (..signature type)
                                                 (host.null)
                                                 writer)
                   (FieldVisitor::visitEnd))]
      writer)))

(template [<name> <lux-type> <jvm-type> <prepare>]
  [(def: #export (<name> visibility config name value)
     (-> //.Visibility //.Field-Config Text <lux-type> //.Def)
     (function (_ writer)
       (let [=field (do-to (ClassWriter::visitField ($_ i.+
                                                        (visibility-flag visibility)
                                                        (field-flags config))
                                                    (..binary-name name)
                                                    (..descriptor <jvm-type>)
                                                    (..signature <jvm-type>)
                                                    (<prepare> value)
                                                    writer)
                      (FieldVisitor::visitEnd))]
         writer)))]

  [boolean-field Bit  type.boolean                           function.identity]
  [byte-field    Int  type.byte                              host.long-to-byte]
  [short-field   Int  type.short                             host.long-to-short]
  [int-field     Int  type.int                               host.long-to-int]
  [long-field    Int  type.long                              function.identity]
  [float-field   Frac type.float                             host.double-to-float]
  [double-field  Frac type.double                            function.identity]
  [char-field    Nat  type.char                              (|>> .int host.long-to-int host.int-to-char)]
  [string-field  Text (type.class "java.lang.String" (list)) function.identity]
  )

(def: #export (fuse defs)
  (-> (List //.Def) //.Def)
  (case defs
    #.Nil
    function.identity

    (#.Cons singleton #.Nil)
    singleton

    (#.Cons head tail)
    (function.compose (fuse tail) head)))