(.module:
  [lux #*
   [control
    ["." function]]
   [data
    ["." text
     format]
    ["." product]
    [collection
     ["." array (#+ Array)]
     ["." list ("#/." functor)]]]
   ["." host (#+ import: do-to)]]
  ["$" //
   ["$t" type]])

(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 (Array String)] void)
  (visitEnd [] void)
  (visitField [int String String String Object] FieldVisitor)
  (visitMethod [int String String String (Array String)] MethodVisitor)
  (toByteArray [] (Array 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: exceptions-array
  (-> $.Method (Array Text))
  (|>> (get@ #$.exceptions)
       (list/map (|>> #$.Generic $t.descriptor))
       string-array))

(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: class-to-type
  (-> $.Class $.Type)
  (|>> #$.Class #$.Generic))

(def: param-signature
  (-> $.Class Text)
  (|>> class-to-type $t.signature (format ":")))

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

(def: (parameters-signature parameters super interfaces)
  (-> (List $.Parameter) $.Class (List $.Class)
      Text)
  (let [formal-params (if (list.empty? parameters)
                        ""
                        (format "<"
                                (|> parameters
                                    (list/map formal-param)
                                    (text.join-with ""))
                                ">"))]
    (format formal-params
            (|> super class-to-type $t.signature)
            (|> interfaces
                (list/map (|>> class-to-type $t.signature))
                (text.join-with "")))))

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

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

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

(def: $Object $.Class ["java.lang.Object" (list)])

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

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

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

  [boolean-field Bit  $t.boolean function.identity]
  [byte-field    Int  $t.byte    host.long-to-byte]
  [short-field   Int  $t.short   host.long-to-short]
  [int-field     Int  $t.int     host.long-to-int]
  [long-field    Int  $t.long    function.identity]
  [float-field   Frac $t.float   host.double-to-float]
  [double-field  Frac $t.double  function.identity]
  [char-field    Nat  $t.char    (|>> .int host.long-to-int host.int-to-char)]
  [string-field  Text ($t.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)))