-----------------------------------------------------------------------------
-- |
-- Module    : Data.SBV.SMT.Utils
-- Copyright : (c) Levent Erkok
-- License   : BSD3
-- Maintainer: erkokl@gmail.com
-- Stability : experimental
--
-- A few internally used types/routines
-----------------------------------------------------------------------------

{-# LANGUAGE NamedFieldPuns #-}

{-# OPTIONS_GHC -Wall -Werror #-}

module Data.SBV.SMT.Utils (
          SMTLibConverter
        , SMTLibIncConverter
        , addAnnotations
        , showTimeoutValue
        , alignDiagnostic
        , alignPlain
        , debug
        , mergeSExpr
        , SBVException(..)
       )
       where

import qualified Control.Exception as C

import Control.Monad.Trans (MonadIO, liftIO)

import Data.SBV.Core.Data
import Data.SBV.Core.Symbolic (QueryContext)
import Data.SBV.Utils.Lib (joinArgs)

import Data.List (intercalate)
import qualified Data.Set      as Set (Set)
import qualified Data.Sequence as S   (Seq)

import System.Exit (ExitCode(..))

-- | An instance of SMT-Lib converter; instantiated for SMT-Lib v1 and v2. (And potentially for newer versions in the future.)
type SMTLibConverter a =  QueryContext                                  -- ^ Internal or external query?
                       -> Set.Set Kind                                  -- ^ Kinds used in the problem
                       -> Bool                                          -- ^ is this a sat problem?
                       -> [String]                                      -- ^ extra comments to place on top
                       -> ([(Quantifier, NamedSymVar)], [NamedSymVar])  -- ^ inputs and aliasing names and trackers
                       -> [Either SV (SV, [SV])]                        -- ^ skolemized inputs
                       -> [(SV, CV)]                                    -- ^ constants
                       -> [((Int, Kind, Kind), [SV])]                   -- ^ auto-generated tables
                       -> [(Int, ArrayInfo)]                            -- ^ user specified arrays
                       -> [(String, SBVType)]                           -- ^ uninterpreted functions/constants
                       -> [(String, [String])]                          -- ^ user given axioms
                       -> SBVPgm                                        -- ^ assignments
                       -> S.Seq (Bool, [(String, String)], SV)          -- ^ extra constraints
                       -> SV                                            -- ^ output variable
                       -> SMTConfig                                     -- ^ configuration
                       -> a

-- | An instance of SMT-Lib converter; instantiated for SMT-Lib v1 and v2. (And potentially for newer versions in the future.)
type SMTLibIncConverter a =  [NamedSymVar]                         -- ^ inputs
                          -> Set.Set Kind                          -- ^ new kinds
                          -> [(SV, CV)]                            -- ^ constants
                          -> [(Int, ArrayInfo)]                    -- ^ newly created arrays
                          -> [((Int, Kind, Kind), [SV])]           -- ^ newly created tables
                          -> [(String, SBVType)]                   -- ^ newly created uninterpreted functions/constants
                          -> SBVPgm                                -- ^ assignments
                          -> S.Seq (Bool, [(String, String)], SV)  -- ^ extra constraints
                          -> SMTConfig                             -- ^ configuration
                          -> a

-- | Create an annotated term
addAnnotations :: [(String, String)] -> String -> String
addAnnotations []   x = x
addAnnotations atts x = "(! " ++ x ++ " " ++ unwords (map mkAttr atts) ++ ")"
  where mkAttr (a, v) = a ++ " |" ++ concatMap sanitize v ++ "|"
        sanitize '|'  = "_bar_"
        sanitize '\\' = "_backslash_"
        sanitize c    = [c]

-- | Show a millisecond time-out value somewhat nicely
showTimeoutValue :: Int -> String
showTimeoutValue i = case (i `quotRem` 1000000, i `quotRem` 500000) of
                       ((s, 0), _)  -> shows s                              "s"
                       (_, (hs, 0)) -> shows (fromIntegral hs / (2::Float)) "s"
                       _            -> shows i "ms"

-- | Nicely align a potentially multi-line message with some tag, but prefix with three stars
alignDiagnostic :: String -> String -> String
alignDiagnostic = alignWithPrefix "*** "

-- | Nicely align a potentially multi-line message with some tag, no prefix.
alignPlain :: String -> String -> String
alignPlain = alignWithPrefix ""

-- | Align with some given prefix
alignWithPrefix :: String -> String -> String -> String
alignWithPrefix pre tag multi = intercalate "\n" $ zipWith (++) (tag : repeat (pre ++ replicate (length tag - length pre) ' ')) (filter (not . null) (lines multi))

-- | Diagnostic message when verbose
debug :: MonadIO m => SMTConfig -> [String] -> m ()
debug cfg
  | not (verbose cfg)             = const (return ())
  | Just f <- redirectVerbose cfg = liftIO . mapM_ (appendFile f . (++ "\n"))
  | True                          = liftIO . mapM_ putStrLn

-- | In case the SMT-Lib solver returns a response over multiple lines, compress them so we have
-- each S-Expression spanning only a single line.
mergeSExpr :: [String] -> [String]
mergeSExpr []       = []
mergeSExpr (x:xs)
 | d == 0 = x : mergeSExpr xs
 | True   = let (f, r) = grab d xs in unlines (x:f) : mergeSExpr r
 where d = parenDiff x

       parenDiff :: String -> Int
       parenDiff = go 0
         where go i ""       = i
               go i ('(':cs) = let i'= i+1 in i' `seq` go i' cs
               go i (')':cs) = let i'= i-1 in i' `seq` go i' cs
               go i ('"':cs) = go i (skipString cs)
               go i ('|':cs) = go i (skipBar cs)
               go i (_  :cs) = go i cs

       grab i ls
         | i <= 0    = ([], ls)
       grab _ []     = ([], [])
       grab i (l:ls) = let (a, b) = grab (i+parenDiff l) ls in (l:a, b)

       skipString ('"':'"':cs)   = skipString cs
       skipString ('"':cs)       = cs
       skipString (_:cs)         = skipString cs
       skipString []             = []             -- Oh dear, line finished, but the string didn't. We're in trouble. Ignore!

       skipBar ('|':cs) = cs
       skipBar (_:cs)   = skipBar cs
       skipBar []       = []                     -- Oh dear, line finished, but the string didn't. We're in trouble. Ignore!

-- | An exception thrown from SBV. If the solver ever responds with a non-success value for a command,
-- SBV will throw an 'SBVException', it so the user can process it as required. The provided 'Show' instance
-- will render the failure nicely. Note that if you ever catch this exception, the solver is no longer alive:
-- You should either -- throw the exception up, or do other proper clean-up before continuing.
data SBVException = SBVException {
                          sbvExceptionDescription :: String
                        , sbvExceptionSent        :: Maybe String
                        , sbvExceptionExpected    :: Maybe String
                        , sbvExceptionReceived    :: Maybe String
                        , sbvExceptionStdOut      :: Maybe String
                        , sbvExceptionStdErr      :: Maybe String
                        , sbvExceptionExitCode    :: Maybe ExitCode
                        , sbvExceptionConfig      :: SMTConfig
                        , sbvExceptionReason      :: Maybe [String]
                        , sbvExceptionHint        :: Maybe [String]
                        }

-- | SBVExceptions are throwable. A simple "show" will render this exception nicely
-- though of course you can inspect the individual fields as necessary.
instance C.Exception SBVException

-- | A fairly nice rendering of the exception, for display purposes.
instance Show SBVException where
 show SBVException { sbvExceptionDescription
                   , sbvExceptionSent
                   , sbvExceptionExpected
                   , sbvExceptionReceived
                   , sbvExceptionStdOut
                   , sbvExceptionStdErr
                   , sbvExceptionExitCode
                   , sbvExceptionConfig
                   , sbvExceptionReason
                   , sbvExceptionHint
                   }

         = let grp1 = [ ""
                      , "*** Data.SBV: " ++ sbvExceptionDescription ++ ":"
                      ]

               grp2 =  ["***    Sent      : " `alignDiagnostic` snt     | Just snt  <- [sbvExceptionSent],     not $ null snt ]
                    ++ ["***    Expected  : " `alignDiagnostic` excp    | Just excp <- [sbvExceptionExpected], not $ null excp]
                    ++ ["***    Received  : " `alignDiagnostic` rcvd    | Just rcvd <- [sbvExceptionReceived], not $ null rcvd]

               grp3 =  ["***    Stdout    : " `alignDiagnostic` out     | Just out  <- [sbvExceptionStdOut],   not $ null out ]
                    ++ ["***    Stderr    : " `alignDiagnostic` err     | Just err  <- [sbvExceptionStdErr],   not $ null err ]
                    ++ ["***    Exit code : " `alignDiagnostic` show ec | Just ec   <- [sbvExceptionExitCode]                 ]
                    ++ ["***    Executable: " `alignDiagnostic` executable (solver sbvExceptionConfig)                                   ]
                    ++ ["***    Options   : " `alignDiagnostic` joinArgs (options (solver sbvExceptionConfig) sbvExceptionConfig)        ]

               grp4 =  ["***    Reason    : " `alignDiagnostic` unlines rsn | Just rsn <- [sbvExceptionReason]]
                    ++ ["***    Hint      : " `alignDiagnostic` unlines hnt | Just hnt <- [sbvExceptionHint  ]]

               join []     = []
               join [x]    = x
               join (g:gs) = case join gs of
                               []    -> g
                               rest  -> g ++ ["***"] ++ rest

          in unlines $ join [grp1, grp2, grp3, grp4]
