{- sv2v
 - Author: Zachary Snow <zach@zachjs.com>
 - Initial Verilog AST Author: Tom Hawkins <tomahawkins@gmail.com>
 -
 - SystemVerilog procedural statements
 -}

module Language.SystemVerilog.AST.Stmt
    ( Stmt   (..)
    , Timing (..)
    , Sense  (..)
    , CaseKW (..)
    , Case
    ) where

import Text.Printf (printf)

import Language.SystemVerilog.AST.ShowHelp (commas, indent, unlines', showPad, showCase)
import Language.SystemVerilog.AST.Decl (Decl)
import Language.SystemVerilog.AST.Expr (Expr)
import Language.SystemVerilog.AST.LHS (LHS)
import Language.SystemVerilog.AST.Op (AsgnOp)
import Language.SystemVerilog.AST.Type (Identifier)

data Stmt
    = Block   (Maybe Identifier) [Decl] [Stmt]
    | Case    Bool CaseKW Expr [Case] (Maybe Stmt)
    | For     (Identifier, Expr) Expr (Identifier, Expr) Stmt
    | AsgnBlk AsgnOp LHS Expr
    | Asgn    (Maybe Timing) LHS Expr
    | While   Expr Stmt
    | RepeatL Expr Stmt
    | DoWhile Expr Stmt
    | Forever Stmt
    | If      Expr Stmt Stmt
    | Timing  Timing Stmt
    | Return  Expr
    | Subroutine Identifier [Maybe Expr]
    | Null
    deriving Eq

instance Show Stmt where
    show (Block name decls stmts) =
        printf "begin%s\n%s\nend" header body
        where
            header = maybe "" (" : " ++) name
            bodyLines = (map show decls) ++ (map show stmts)
            body = indent $ unlines' bodyLines
    show (Case u kw e cs def) =
        printf "%s%s (%s)\n%s%s\nendcase" uniqStr (show kw) (show e) bodyStr defStr
        where
            uniqStr = if u then "unique " else ""
            bodyStr = indent $ unlines' $ map showCase cs
            defStr = case def of
                Nothing -> ""
                Just c -> printf "\n\tdefault: %s" (show c)
    show (For (a,b) c (d,e) f) =
        printf "for (%s = %s; %s; %s = %s)\n%s" a (show b) (show c) d (show e) (indent $ show f)
    show (Subroutine x a) = printf "%s(%s);" x (commas $ map (maybe "" show) a)
    show (AsgnBlk o v e) = printf "%s %s %s;" (show v) (show o) (show e)
    show (Asgn    t v e) = printf "%s <= %s%s;" (show v) (maybe "" showPad t) (show e)
    show (While   e s) = printf  "while (%s) %s" (show e) (show s)
    show (RepeatL e s) = printf "repeat (%s) %s" (show e) (show s)
    show (DoWhile e s) = printf "do %s while (%s);" (show s) (show e)
    show (Forever s  ) = printf "forever %s" (show s)
    show (If a b Null) = printf "if (%s) %s"         (show a) (show b)
    show (If a b c   ) = printf "if (%s) %s\nelse %s" (show a) (show b) (show c)
    show (Return e   ) = printf "return %s;" (show e)
    show (Timing t s ) = printf "%s %s" (show t) (show s)
    show (Null       ) = ";"

data CaseKW
    = CaseN
    | CaseZ
    | CaseX
    deriving Eq

instance Show CaseKW where
    show CaseN = "case"
    show CaseZ = "casez"
    show CaseX = "casex"

type Case = ([Expr], Stmt)

data Timing
    = Event Sense
    | Delay Expr
    | Cycle Expr
    deriving Eq

instance Show Timing where
    show (Event s) = printf  "@(%s)" (show s)
    show (Delay e) = printf  "#(%s)" (show e)
    show (Cycle e) = printf "##(%s)" (show e)

data Sense
    = Sense        LHS
    | SenseOr      Sense Sense
    | SensePosedge LHS
    | SenseNegedge LHS
    | SenseStar
    deriving Eq

instance Show Sense where
    show (Sense        a  ) = show a
    show (SenseOr      a b) = printf "%s or %s" (show a) (show b)
    show (SensePosedge a  ) = printf "posedge %s" (show a)
    show (SenseNegedge a  ) = printf "negedge %s" (show a)
    show (SenseStar       ) = "*"