{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}

-- | Contains class instances and functions related to tokens
module GLua.TokenTypes where

import Data.Aeson
import Data.List
import GHC.Generics
import GLua.AG.Token
import Text.ParserCombinators.UU.BasicInstances

instance Show MToken where
  show (MToken _ tok) = show tok

-- | Simple EQ instance. TODO: check for position equality
instance Eq MToken where
  (MToken _ t1) == (MToken _ t2) = t1 == t2

-- | Simple Ord instance. TODO: check for position Ord
instance Ord MToken where
  compare (MToken _ t1) (MToken _ t2) = compare t1 t2

deriving instance Generic MToken

instance ToJSON MToken
instance FromJSON MToken

instance Eq LineColPos where
  (LineColPos l c p) == (LineColPos l' c' p') = l == l' && c == c' && p == p'

instance Ord LineColPos where
  compare (LineColPos l c _) (LineColPos l' c' _) =
    compare l l' `mappend` compare c c'

instance ToJSON LineColPos where
  -- this generates a Value
  toJSON (LineColPos line col p) =
    object ["line" .= line, "column" .= col, "pos" .= p]

#if MIN_VERSION_aeson(0,10,0)
  -- this encodes directly to a bytestring Builder
  toEncoding (LineColPos line col p) =
    pairs ("line" .= line <> "column" .= col <> "pos" .= p)
#endif

instance FromJSON LineColPos where
  parseJSON = withObject "LineColPos" $ \v ->
    LineColPos
      <$> v .: "line"
      <*> v .: "column"
      <*> v .: "pos"

instance Eq Region where
  Region s e == Region s' e' = s == s' && e == e'

instance Ord Region where
  compare (Region s e) (Region s' e') =
    compare s s' `mappend` compare e e'

instance ToJSON Region
instance FromJSON Region

instance ToJSON Token
instance FromJSON Token

-- | Metatoken algebra
type MTokenAlgebra mtok = Region -> Token -> mtok

mpos :: MToken -> Region
mpos (MToken p _) = p

mtok :: MToken -> Token
mtok (MToken _ t) = t

emptyRg :: Region
emptyRg = Region (LineColPos 0 0 0) (LineColPos 0 0 0)

rgOr :: Region -> Region -> Region
rgOr l r
  | l == emptyRg = r
  | otherwise = l

----------------------------------------
--  Correcting token positions
----------------------------------------
customAdvanceChr :: LineColPos -> Char -> LineColPos
customAdvanceChr (LineColPos line _ abs') '\n' = LineColPos (line + 1) 0 (abs' + 1)
customAdvanceChr (LineColPos line pos' abs') _ = LineColPos line (pos' + 1) (abs' + 1)

customAdvanceStr :: LineColPos -> String -> LineColPos
customAdvanceStr = foldl' customAdvanceChr

customAdvanceToken :: LineColPos -> Token -> LineColPos
customAdvanceToken (LineColPos line pos' abs') t = let len = tokenSize t in LineColPos line (pos' + len) (abs' + len)

-- | Whether the first region ends strictly before the second region starts
before :: Region -> Region -> Bool
before (Region _ (LineColPos _ _ p)) (Region (LineColPos _ _ p') _) = p < p'

-- | Whether the first region ends before or on the same line as the second region
beforeOrOnLine :: Region -> Region -> Bool
beforeOrOnLine (Region _ (LineColPos l _ _)) (Region (LineColPos l' _ _) _) = l <= l'

-- | Whether the first region ends before the second region ends
beforeEnd :: Region -> Region -> Bool
beforeEnd (Region _ (LineColPos _ _ p)) (Region _ (LineColPos _ _ p')) = p < p'

-- | Whether the first region ends before or on the same line as the END of the second region
beforeEndLine :: Region -> Region -> Bool
beforeEndLine (Region _ (LineColPos l _ _)) (Region _ (LineColPos l' _ _)) = l <= l'

rgStart :: Region -> LineColPos
rgStart (Region s _) = s

rgEnd :: Region -> LineColPos
rgEnd (Region _ e) = e

-- | Returns a region that starts at the start of the first region
-- and ends BEFORE the start of the second region
upto :: Region -> Region -> Region
upto lr rr = case (rgEnd lr, rgStart rr) of
  (_, LineColPos 0 0 0) -> lr
  (LineColPos l c _, LineColPos l' c' _)
    | l' > l || (l' == l && c' > c) -> lr
    | otherwise -> Region (rgStart lr) (rgStart rr)

-- | Fold over metatoken
foldMToken :: MTokenAlgebra t -> MToken -> t
foldMToken alg (MToken p t) = alg p t

-- | mFold: Apply a TokenAlgebra to an MToken
mFold :: TokenAlgebra a -> MToken -> a
mFold alg = foldMToken f
  where
    f _ = foldToken alg

-- | Huge token algebra
type TokenAlgebra token =
  ( ( -- Comments and whitespace
      String -> token
    , String -> token -- DashComment
    , Int -> String -> token -- DashBlockComment
    , String -> token -- SlashComment
    , String -> token -- SlashBlockComment
    , token -- Semicolon
    )
  , ( -- Constants
      String -> token -- TNumber
    , String -> token -- DQString
    , String -> token -- SQString
    , String -> token -- MLString
    , token -- TTrue
    , token -- TFalse
    , token -- Nil
    , token -- VarArg
    ) -- operators
  , ( token -- Plus
    , token -- Minus
    , token -- Multiply
    , token -- Divide
    , token -- Modulus
    , token -- Power
    , token -- TEq
    , token -- TNEq
    , token -- TCNEq
    , token -- TLEQ
    , token -- TGEQ
    , token -- TLT
    , token -- TGT
    , token -- Equals
    , token -- Concatenate
    , token -- Colon
    , token -- Dot
    , token -- Comma
    , token -- Hash
    , token -- Not
    , token -- CNot
    , token -- And
    , token -- CAnd
    , token -- Or
    , token -- COr
    )
  , ( -- Keywords
      token -- Function
    , token -- Local
    , token -- If
    , token -- Then
    , token -- Elseif
    , token -- Else
    , token -- For
    , token -- In
    , token -- Do
    , token -- While
    , token -- Until
    , token -- Repeat
    , token -- Continue
    , token -- Break
    , token -- Return
    , token -- End
    )
  , ( -- Brackets
      token -- LRound
    , token -- RRound
    , token -- LCurly
    , token -- RCurly
    , token -- LSquare
    , token -- RSquare
    )
  , ( -- Other
      String -> String -> String -> token -- Label
    , String -> token -- Identifier
    )
  )

-- | Fold over token definition
foldToken :: TokenAlgebra t -> Token -> t
foldToken ((tWhitespace, tDashComment, tDashBlockComment, tSlashComment, tSlashBlockComment, tSemicolon), (tTNumber, tDQString, tSQString, tMLString, tTTrue, tTFalse, tNil, tVarArg), (tPlus, tMinus, tMultiply, tDivide, tModulus, tPower, tTEq, tTNEq, tTCNEq, tTLEQ, tTGEQ, tTLT, tTGT, tEquals, tConcatenate, tColon, tDot, tComma, tHash, tNot, tCNot, tAnd, tCAnd, tOr, tCOr), (tFunction, tLocal, tIf, tThen, tElseif, tElse, tFor, tIn, tDo, tWhile, tUntil, tRepeat, tContinue, tBreak, tReturn, tEnd), (tLRound, tRRound, tLCurly, tRCurly, tLSquare, tRSquare), (tLabel, tIdentifier)) = fold
  where
    fold (Whitespace str) = tWhitespace str
    fold (DashComment str) = tDashComment str
    fold (DashBlockComment depth str) = tDashBlockComment depth str
    fold (SlashComment str) = tSlashComment str
    fold (SlashBlockComment str) = tSlashBlockComment str
    fold (TNumber str) = tTNumber str
    fold (Label whitespaceBefore str whitespaceAfter) = tLabel whitespaceBefore str whitespaceAfter
    fold (Identifier str) = tIdentifier str
    fold (DQString str) = tDQString str
    fold (SQString str) = tSQString str
    fold (MLString str) = tMLString str
    fold And = tAnd
    fold CAnd = tCAnd
    fold Break = tBreak
    fold Do = tDo
    fold Else = tElse
    fold Elseif = tElseif
    fold End = tEnd
    fold TFalse = tTFalse
    fold For = tFor
    fold Function = tFunction
    fold If = tIf
    fold In = tIn
    fold Local = tLocal
    fold Nil = tNil
    fold Not = tNot
    fold CNot = tCNot
    fold Or = tOr
    fold COr = tCOr
    fold Repeat = tRepeat
    fold Continue = tContinue
    fold Return = tReturn
    fold Then = tThen
    fold TTrue = tTTrue
    fold Until = tUntil
    fold While = tWhile
    fold Plus = tPlus
    fold Minus = tMinus
    fold Multiply = tMultiply
    fold Divide = tDivide
    fold Modulus = tModulus
    fold Power = tPower
    fold Hash = tHash
    fold TEq = tTEq
    fold TNEq = tTNEq
    fold TCNEq = tTCNEq
    fold TLEQ = tTLEQ
    fold TGEQ = tTGEQ
    fold TLT = tTLT
    fold TGT = tTGT
    fold Equals = tEquals
    fold LRound = tLRound
    fold RRound = tRRound
    fold LCurly = tLCurly
    fold RCurly = tRCurly
    fold LSquare = tLSquare
    fold RSquare = tRSquare
    fold Semicolon = tSemicolon
    fold Colon = tColon
    fold Comma = tComma
    fold Dot = tDot
    fold Concatenate = tConcatenate
    fold VarArg = tVarArg

-- | Simple show instance
instance Show Token where
  show =
    foldToken
      (
        ( id
        , ("--" ++) -- DashComment
        , \d s -> let n = replicate d '=' in "--[" ++ n ++ '[' : s ++ ']' : n ++ "]" -- DashBlockComment
        , ("//" ++) -- SlashComment
        , \s -> "/*" ++ s ++ "*/" -- SlashBlockComment
        , ";" -- Semicolon
        )
      ,
        ( id -- TNumber
        , \s -> "\"" ++ s ++ "\"" -- DQString
        , \s -> "'" ++ s ++ "'" -- SQString
        , id -- MLString
        , "true" -- TTrue
        , "false" -- TFalse
        , "nil" -- Nil
        , "..." -- VarArg
        )
      ,
        ( "+" -- Plus
        , "-" -- Minus
        , "*" -- Multiply
        , "/" -- Divide
        , "%" -- Modulus
        , "^" -- Power
        , "==" -- TEq
        , "~=" -- TNEq
        , "!=" -- TCNEq
        , "<=" -- TLEQ
        , ">=" -- TGEQ
        , "<" -- TLT
        , ">" -- TGT
        , "=" -- Equals
        , ".." -- Concatenate
        , ":" -- Colon
        , "." -- Dot
        , "," -- Comma
        , "#" -- Hash
        , "not" -- Not
        , "!" -- CNot
        , "and" -- And
        , "&&" -- CAnd
        , "or" -- Or
        , "||" -- COr
        )
      ,
        ( "function" -- Function
        , "local" -- Local
        , "if" -- If
        , "then" -- Then
        , "elseif" -- Elseif
        , "else" -- Else
        , "for" -- For
        , "in" -- In
        , "do" -- Do
        , "while" -- While
        , "until" -- Until
        , "repeat" -- Repeat
        , "continue" -- Continue
        , "break" -- Break
        , "return" -- Return
        , "end" -- End
        )
      ,
        ( "(" -- LRound
        , ")" -- RRound
        , "{" -- LCurly
        , "}" -- RCurly
        , "[" -- LSquare
        , "]" -- RSquare
        )
      ,
        ( \spaceBefore ident spaceAfter -> spaceBefore ++ ident ++ spaceAfter -- Label
        , id -- Identifier
        )
      )

-- | Whether an mtoken is a comment
isWhitespace :: MToken -> Bool
isWhitespace = mFold ((const True, const False, \_ _ -> False, const False, const False, False), (const False, const False, const False, const False, False, False, False, False), (False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False), (False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False), (False, False, False, False, False, False), (\_ _ _ -> False, const False))

-- | Whether an mtoken is a comment
isComment :: MToken -> Bool
isComment = mFold ((const False, const True, \_ _ -> True, const True, const True, False), (const False, const False, const False, const False, False, False, False, False), (False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False), (False, False, False, False, False, False, False, False, False, False, False, False, False, False, False, False), (False, False, False, False, False, False), (\_ _ _ -> False, const False))

-- | Split the tokens by comments and other tokens
splitComments :: [MToken] -> ([MToken], [MToken])
splitComments = partition isComment

tokenLabel :: MToken -> String
tokenLabel = mFold ((const "", const "", \_ _ -> "", const "", const "", ""), (const "", const "", const "", const "", "", "", "", ""), ("", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", ""), ("", "", "", "", "", "", "", "", "", "", "", "", "", "", "", ""), ("", "", "", "", "", ""), (\_ ident _ -> ident, id))

-- | The size of a token in characters
tokenSize :: Token -> Int
tokenSize =
  foldToken
    (
      ( length -- whitespace
      , (+ 2) . length -- DashComment
      , \d s -> 6 + length s + 2 * d -- DashBlockComment
      , (+ 2) . length -- SlashComment
      , (+ 4) . length -- SlashBlockComment
      , 1 -- Semicolon
      )
    ,
      ( length -- TNumber
      , (+ 2) . length -- DQString
      , (+ 2) . length -- SQString
      , length -- MLString
      , 4 -- TTrue
      , 5 -- TFalse
      , 3 -- Nil
      , 3 -- VarArg
      )
    ,
      ( 1 -- Plus
      , 1 -- Minus
      , 1 -- Multiply
      , 1 -- Divide
      , 1 -- Modulus
      , 1 -- Power
      , 2 -- TEq
      , 2 -- TNEq
      , 2 -- TCNEq
      , 2 -- TLEQ
      , 2 -- TGEQ
      , 1 -- TLT
      , 1 -- TGT
      , 1 -- Equals
      , 2 -- Concatenate
      , 1 -- Colon
      , 1 -- Dot
      , 1 -- Comma
      , 1 -- Hash
      , 3 -- Not
      , 1 -- CNot
      , 3 -- And
      , 2 -- CAnd
      , 2 -- Or
      , 2 -- COr
      )
    ,
      ( 8 -- Function
      , 5 -- Local
      , 2 -- If
      , 4 -- Then
      , 6 -- Elseif
      , 4 -- Else
      , 3 -- For
      , 2 -- In
      , 2 -- Do
      , 5 -- While
      , 5 -- Until
      , 6 -- Repeat
      , 8 -- Continue
      , 5 -- Break
      , 6 -- Return
      , 3 -- End
      )
    ,
      ( 1 -- LRound
      , 1 -- RRound
      , 1 -- LCurly
      , 1 -- RCurly
      , 1 -- LSquare
      , 1 -- RSquare
      )
    ,
      ( \spaceBefore ident spaceAfter ->
          2 + length spaceBefore + length ident + length spaceAfter + 2 -- Label
      , length -- Identifier
      )
    )

isSingleLineComment :: Token -> Bool
isSingleLineComment = \case
  DashComment _ -> True
  SlashComment _ -> True
  _ -> False