-- | The Atom language.
module Language.Atom.Language
  (
    module Language.Atom.Expressions
  -- * Primary Language Containers
  , Atom
  -- * Hierarchical Rule Declarations
  , atom
  , period
  , getPeriod
  -- * Action Directives
  , cond
  , Assign (..)
  , incr
  , decr
  -- * Variable Declarations
  , var
  , var'
  , array
  , bool
  , bool'
  , int8
  , int8'
  , int16
  , int16'
  , int32
  , int32'
  , int64
  , int64'
  , word8
  , word8'
  , word16
  , word16'
  , word32
  , word32'
  , word64
  , word64'
  , float
  , float'
  , double
  , double'
  -- * Custom Actions
  , action
  -- * Probing
  , probe
  , probes
  -- * Utilities
  , Name
  , liftIO
  , path
  , clock
  -- * Code Coverage
  , nextCoverage
  ) where

import Control.Monad.Trans
import Data.Int
import Data.List
import Data.Word

import Language.Atom.Elaboration hiding (Atom)
import qualified Language.Atom.Elaboration as E
import Language.Atom.Expressions

infixr 1 <==

-- | The Atom monad captures variable and transition rule declarations.
type Atom = E.Atom

-- | Creates a hierarical node, where each node could be a atomic rule.
atom :: Name -> Atom a -> Atom a
atom name design = do
  name <- addName name
  (g, parent) <- get
  (a, (g, child)) <- liftIO $ buildAtom g name design
  put (g, parent { atomSubs = atomSubs parent ++ [child] })
  return a

-- | Defines the period of execution of sub rules as a factor of the base rate of the system.
--   Rule period is bound by the closest period assertion.  For example:
--
--   > period 10 $ period 2 a   -- Rules in 'a' have a period of 2, not 10.
period :: Int -> Atom a -> Atom a
period n _ | n <= 0 = error "ERROR: Execution period must be greater than 0."
period n atom = do
  (g, a) <- get
  put (g { gPeriod = n }, a)
  r <- atom
  (g', a) <- get
  put (g' { gPeriod = gPeriod g }, a)
  return r

-- | Returns the execution period of the current scope.
getPeriod :: Atom Int
getPeriod = do
  (g, _) <- get
  return $ gPeriod g

-- | Returns the current atom heirarchical path.
path :: Atom String
path = do
  (_, atom) <- get
  return $ atomName atom

-- | Local boolean variable declaration.
bool :: Name -> Bool -> Atom (V Bool)
bool = var

-- | External boolean variable declaration.
bool' :: Name -> Atom (V Bool)
bool' name = var' name Bool

-- | Local int8 variable declaration.
int8 :: Name -> Int8 -> Atom (V Int8)
int8 = var

-- | External int8 variable declaration.
int8' :: Name -> Atom (V Int8)
int8' name = var' name Int8

-- | Local int16 variable declaration.
int16 :: Name -> Int16 -> Atom (V Int16)
int16 = var

-- | External int16 variable declaration.
int16' :: Name -> Atom (V Int16)
int16' name = var' name Int16

-- | Local int32 variable declaration.
int32 :: Name -> Int32 -> Atom (V Int32)
int32 = var

-- | External int32 variable declaration.
int32' :: Name -> Atom (V Int32)
int32' name = var' name Int32

-- | Local int64 variable declaration.
int64 :: Name -> Int64 -> Atom (V Int64)
int64 = var

-- | External int64 variable declaration.
int64' :: Name -> Atom (V Int64)
int64' name = var' name Int64

-- | Local word8 variable declaration.
word8 :: Name -> Word8 -> Atom (V Word8)
word8 = var

-- | External word8 variable declaration.
word8' :: Name -> Atom (V Word8)
word8' name = var' name Word8

-- | Local word16 variable declaration.
word16 :: Name -> Word16 -> Atom (V Word16)
word16 = var

-- | External word16 variable declaration.
word16' :: Name -> Atom (V Word16)
word16' name = var' name Word16

-- | Local word32 variable declaration.
word32 :: Name -> Word32 -> Atom (V Word32)
word32 = var

-- | External word32 variable declaration.
word32' :: Name -> Atom (V Word32)
word32' name = var' name Word32

-- | Local word64 variable declaration.
word64 :: Name -> Word64 -> Atom (V Word64)
word64 = var

-- | External word64 variable declaration.
word64' :: Name -> Atom (V Word64)
word64' name = var' name Word64

-- | Local float variable declaration.
float :: Name -> Float -> Atom (V Float)
float = var

-- | External float variable declaration.
float' :: Name -> Atom (V Float)
float' name = var' name Float

-- | Local double variable declaration.
double :: Name -> Double -> Atom (V Double)
double = var

-- | External double variable declaration.
double' :: Name -> Atom (V Double)
double' name = var' name Double

-- | Declares an action.
action :: ([String] -> String) -> [UE] -> Atom ()
action f ues = do
  (g, a) <- get
  put (g, a { atomActions = atomActions a ++ [(f, ues)] })

-- | Declares a probe.
probe :: Expr a => Name -> E a -> Atom ()
probe name a = do
  (g, atom) <- get
  if any (\ (n, _, _) -> name == n) $ gProbes g
    then error $ "ERROR: Duplicated probe name: " ++ name
    else put (g { gProbes = (name, eType a, rawBits a) : gProbes g }, atom)


-- | Fetches all declared probes to current design point.
probes :: Atom [(String, Type, E Word64)]
probes = do
  (g, _) <- get
  return $ gProbes g


-- | Increments a NumE 'V'.
incr :: (Assign a, NumE a) => V a -> Atom ()
incr a = a <== value a + 1

-- | Decrements a NumE 'V'.
decr :: (Assign a, NumE a) => V a -> Atom ()
decr a = a <== value a - 1


class Expr a => Assign a where
  -- | Assign an 'E' to a 'V'.
  (<==) :: V a -> E a -> Atom ()
  v <== e = do
    (g, atom) <- get
    put (g, atom { atomAssigns = (uv v, ue e) : atomAssigns atom })

instance Assign Bool
instance Assign Int8
instance Assign Int16
instance Assign Int32
instance Assign Int64
instance Assign Word8
instance Assign Word16
instance Assign Word32
instance Assign Word64
instance Assign Float
instance Assign Double

-- | Adds an enabling condition to an atom subtree of rules.
--   This condition must be true before any rules in heirarchy
--   are allowed to execute.
cond :: E Bool -> Atom ()
cond c = do
  (g, atom) <- get
  put (g, atom { atomEnable = uand (atomEnable atom) (ue c) })

-- | Reference to the 64-bit free running clock.
clock :: E Word64
clock = value $ V $ UV $ External "__clock" Word64

-- | Rule coverage information.  (current coverage index, coverage data)
nextCoverage :: Atom (E Word32, E Word32)
nextCoverage = do
  action (\_ -> "__coverage_index = (__coverage_index + 1) % __coverage_len") []
  return (value $ V $ UV $ External "__coverage_index" Word32, value $ V $ UV $ External "__coverage[__coverage_index]" Word32)