{-|
Module      : VeriFuzz
Description : VeriFuzz
Copyright   : (c) 2018-2019, Yann Herklotz
License     : BSD-3
Maintainer  : ymherklotz [at] gmail [dot] com
Stability   : experimental
Portability : POSIX
-}

{-# LANGUAGE TemplateHaskell #-}

module VeriFuzz
    ( runEquivalence
    , runSimulation
    , runReduce
    , draw
    , SourceInfo(..)
    , module VeriFuzz.Verilog
    , module VeriFuzz.Config
    , module VeriFuzz.Circuit
    , module VeriFuzz.Sim
    , module VeriFuzz.Fuzz
    , module VeriFuzz.Report
    )
where

import           Control.Lens
import qualified Crypto.Random.DRBG       as C
import           Data.ByteString          (ByteString)
import           Data.ByteString.Builder  (byteStringHex, toLazyByteString)
import qualified Data.ByteString.Lazy     as L
import qualified Data.Graph.Inductive     as G
import qualified Data.Graph.Inductive.Dot as G
import           Data.Maybe               (isNothing)
import           Data.Text                (Text)
import qualified Data.Text                as T
import           Data.Text.Encoding       (decodeUtf8)
import qualified Data.Text.IO             as T
import           Hedgehog                 (Gen)
import qualified Hedgehog.Gen             as Hog
import           Hedgehog.Internal.Seed   (Seed)
import           Prelude                  hiding (FilePath)
import           Shelly
import           Shelly.Lifted            (liftSh)
import           VeriFuzz.Circuit
import           VeriFuzz.Config
import           VeriFuzz.Fuzz
import           VeriFuzz.Reduce
import           VeriFuzz.Report
import           VeriFuzz.Result
import           VeriFuzz.Sim
import           VeriFuzz.Sim.Internal
import           VeriFuzz.Verilog

-- | Generate a specific number of random bytestrings of size 256.
randomByteString :: C.CtrDRBG -> Int -> [ByteString] -> [ByteString]
randomByteString gen n bytes
    | n == 0    = ranBytes : bytes
    | otherwise = randomByteString newGen (n - 1) $ ranBytes : bytes
    where Right (ranBytes, newGen) = C.genBytes 32 gen

-- | generates the specific number of bytestring with a random seed.
generateByteString :: Int -> IO [ByteString]
generateByteString n = do
    gen <- C.newGenIO :: IO C.CtrDRBG
    return $ randomByteString gen n []

makeSrcInfo :: ModDecl -> SourceInfo
makeSrcInfo m = SourceInfo (getIdentifier $ m ^. modId) (Verilog [m])

-- | Draw a randomly generated DAG to a dot file and compile it to a png so it
-- can be seen.
draw :: IO ()
draw = do
    gr <- Hog.sample $ rDups . getCircuit <$> Hog.resize 10 randomDAG
    let dot = G.showDot . G.fglToDotString $ G.nemap show (const "") gr
    writeFile "file.dot" dot
    shelly $ run_ "dot" ["-Tpng", "-o", "file.png", "file.dot"]

-- | Function to show a bytestring in a hex format.
showBS :: ByteString -> Text
showBS = decodeUtf8 . L.toStrict . toLazyByteString . byteStringHex

-- | Run a simulation on a random DAG or a random module.
runSimulation :: IO ()
runSimulation = do
  -- gr <- Hog.generate $ rDups <$> Hog.resize 100 (randomDAG :: Gen (G.Gr Gate ()))
  -- let dot = G.showDot . G.fglToDotString $ G.nemap show (const "") gr
  -- writeFile "file.dot" dot
  -- shelly $ run_ "dot" ["-Tpng", "-o", "file.png", "file.dot"]
  -- let circ =
  --       head $ (nestUpTo 30 . generateAST $ Circuit gr) ^.. getVerilog . traverse . getDescription
    rand  <- generateByteString 20
    rand2 <- Hog.sample (randomMod 10 100)
    val   <- shelly . runResultT $ runSim defaultIcarus (makeSrcInfo rand2) rand
    case val of
        Pass a -> T.putStrLn $ showBS a
        _      -> T.putStrLn "Test failed"


-- | Code to be executed on a failure. Also checks if the failure was a timeout,
-- as the timeout command will return the 124 error code if that was the
-- case. In that case, the error will be moved to a different directory.
onFailure :: Text -> RunFailed -> Sh (Result Failed ())
onFailure t _ = do
    ex <- lastExitCode
    case ex of
        124 -> do
            logger "Test TIMEOUT"
            chdir ".." $ cp_r (fromText t) $ fromText (t <> "_timeout")
            return $ Fail EmptyFail
        _ -> do
            logger "Test FAIL"
            chdir ".." $ cp_r (fromText t) $ fromText (t <> "_failed")
            return $ Fail EmptyFail

checkEquivalence :: SourceInfo -> Text -> IO Bool
checkEquivalence src dir = shellyFailDir $ do
    mkdir_p (fromText dir)
    curr <- toTextIgnore <$> pwd
    setenv "VERIFUZZ_ROOT" curr
    cd (fromText dir)
    catch_sh
        (  (runResultT $ runEquiv defaultYosys (Just defaultVivado) src)
        >> return True
        )
        ((\_ -> return False) :: RunFailed -> Sh Bool)

-- | Run a fuzz run and check if all of the simulators passed by checking if the
-- generated Verilog files are equivalent.
runEquivalence
    :: Maybe Seed
    -> Gen Verilog -- ^ Generator for the Verilog file.
    -> Text        -- ^ Name of the folder on each thread.
    -> Text        -- ^ Name of the general folder being used.
    -> Bool        -- ^ Keep flag.
    -> Int         -- ^ Used to track the recursion.
    -> IO ()
runEquivalence seed gm t d k i = do
    (_, m) <- shelly $ sampleSeed seed gm
    let srcInfo = SourceInfo "top" m
    rand <- generateByteString 20
    shellyFailDir $ do
        mkdir_p (fromText d </> fromText n)
        curr <- toTextIgnore <$> pwd
        setenv "VERIFUZZ_ROOT" curr
        cd (fromText "output" </> fromText n)
        _ <-
            catch_sh
                    (  runResultT
                    $  runEquiv defaultYosys (Just defaultVivado) srcInfo
                    >> liftSh (logger "Test OK")
                    )
                $ onFailure n
        _ <-
            catch_sh
                    (   runResultT
                    $   runSim (Icarus "iverilog" "vvp") srcInfo rand
                    >>= (\b -> liftSh $ logger ("RTL Sim: " <> showBS b))
                    )
                $ onFailure n
        cd ".."
        unless k . rm_rf $ fromText n
    when (i < 5 && isNothing seed) (runEquivalence seed gm t d k $ i + 1)
    where n = t <> "_" <> T.pack (show i)

runReduce :: SourceInfo -> IO SourceInfo
runReduce s = reduce (\s -> not <$> checkEquivalence s "reduce") s