{-# LANGUAGE PatternSynonyms #-}
{- sv2v
 - Author: Zachary Snow <zach@zachjs.com>
 - Initial Verilog AST Author: Tom Hawkins <tomahawkins@gmail.com>
 -
 - SystemVerilog top-level items (descriptions, package items)
 -}

module Language.SystemVerilog.AST.Description
    ( Description (..)
    , PackageItem (..)
    , PartKW      (..)
    , Lifetime    (..)
    , Qualifier   (..)
    , ClassItem
    , DPIImportProperty (..)
    , DPIExportKW (..)
    ) where

import Data.List (intercalate)
import Text.Printf (printf)

import Language.SystemVerilog.AST.ShowHelp

import Language.SystemVerilog.AST.Attr (Attr)
import Language.SystemVerilog.AST.Decl (Decl(CommentDecl))
import Language.SystemVerilog.AST.Stmt (Stmt)
import Language.SystemVerilog.AST.Type (Type, Identifier, pattern UnknownType)
import {-# SOURCE #-} Language.SystemVerilog.AST.ModuleItem (ModuleItem)

data Description
    = Part [Attr] Bool PartKW Lifetime Identifier [Identifier] [ModuleItem]
    | PackageItem PackageItem
    | Package Lifetime Identifier [PackageItem]
    | Class   Lifetime Identifier [Decl] [ClassItem]
    deriving Eq

instance Show Description where
    showList l _ = unlines' $ map show l
    show (Part attrs True  kw lifetime name _ items) =
        printf "%sextern %s %s%s %s;"
            (concatMap showPad attrs)
            (show kw) (showPad lifetime) name (indentedParenList itemStrs)
        where itemStrs = map (init . show) items
    show (Part attrs False kw lifetime name ports items) =
        printf "%s%s %s%s%s;\n%s\nend%s"
            (concatMap showPad attrs)
            (show kw) (showPad lifetime) name portsStr bodyStr (show kw)
        where
            portsStr = if null ports
                then ""
                else " " ++ indentedParenList ports
            bodyStr = indent $ unlines' $ map show items
    show (Package lifetime name items) =
        printf "package %s%s;\n%s\nendpackage"
            (showPad lifetime) name bodyStr
        where
            bodyStr = indent $ unlines' $ map show items
    show (Class lifetime name decls items) =
        printf "class %s%s%s;\n%s\nendclass"
            (showPad lifetime) name (showParamDecls decls) bodyStr
        where
            bodyStr = indent $ unlines' $ map showClassItem items
    show (PackageItem i) = show i

showParamDecls :: [Decl] -> String
showParamDecls [] = ""
showParamDecls decls = " #(\n\t" ++ showDecls decls ++ "\n)"

showDecls :: [Decl] -> String
showDecls =
    dropDelim . intercalate "\n\t" . map showDecl
    where
        dropDelim :: String -> String
        dropDelim [] = []
        dropDelim [x] = if x == ',' then [] else [x]
        dropDelim (x : xs) = x : dropDelim xs
        showDecl comment@CommentDecl{} = show comment
        showDecl decl = (init $ show decl) ++ ","

data PackageItem
    = Function Lifetime Type Identifier [Decl] [Stmt]
    | Task     Lifetime      Identifier [Decl] [Stmt]
    | Import Identifier Identifier
    | Export Identifier Identifier
    | Decl Decl
    | Directive String
    | DPIImport String DPIImportProperty Identifier Type Identifier [Decl]
    | DPIExport String Identifier DPIExportKW Identifier
    deriving Eq

instance Show PackageItem where
    show (Function ml t x i b) =
        printf "function %s%s%s;\n%s\nendfunction" (showPad ml) (showPad t) x
        (showBlock i b)
    show (Task ml x i b) =
        printf "task %s%s;\n%s\nendtask"
            (showPad ml) x (showBlock i b)
    show (Import x y) = printf "import %s::%s;" x (showWildcard y)
    show (Export x y) = printf "export %s::%s;" (showWildcard x) (showWildcard y)
    show (Decl decl) = show decl
    show (Directive str) = str
    show (DPIImport spec prop alias typ name decls) =
        printf "import %s %s%s %s %s(%s);"
            (show spec) (showPad prop) aliasStr protoStr name declsStr
        where
            aliasStr = if null alias then "" else alias ++ " = "
            protoStr =
                if typ == UnknownType
                    then "task"
                    else "function " ++ show typ
            declsStr =
                if null decls
                    then ""
                    else "\n\t" ++ showDecls decls ++ "\n"
    show (DPIExport spec alias kw name) =
        printf "export %s %s%s %s;" (show spec) aliasStr (show kw) name
        where aliasStr = if null alias then "" else alias ++ " = "

showWildcard :: Identifier -> String
showWildcard "" = "*"
showWildcard x = x

data PartKW
    = Module
    | Interface
    deriving Eq

instance Show PartKW where
    show Module    = "module"
    show Interface = "interface"

data Lifetime
    = Static
    | Automatic
    | Inherit
    deriving Eq

instance Show Lifetime where
    show Static    = "static"
    show Automatic = "automatic"
    show Inherit   = ""

type ClassItem = (Qualifier, PackageItem)

showClassItem :: ClassItem -> String
showClassItem (qualifier, item) = showPad qualifier ++ show item

data Qualifier
    = QNone
    | QStatic
    | QLocal
    | QProtected
    deriving Eq

instance Show Qualifier where
    show QNone      = ""
    show QStatic    = "static"
    show QLocal     = "local"
    show QProtected = "protected"

data DPIImportProperty
    = DPIContext
    | DPIPure
    | DPINone
    deriving Eq

instance Show DPIImportProperty where
    show DPIContext = "context"
    show DPIPure    = "pure"
    show DPINone    = ""

data DPIExportKW
    = DPIExportTask
    | DPIExportFunction
    deriving Eq

instance Show DPIExportKW where
    show DPIExportTask     = "task"
    show DPIExportFunction = "function"