module Frontend.Lexer.Tokens where

import qualified Data.Text as T
import Data.Text (Text)

data IdClass = ConId | VarId
  deriving (Eq, Show, Ord)

data TokenClass
  = TokUnqual IdClass Text
  | TokQual   IdClass Text Text
  | TokUnqualOp IdClass Text
  | TokQualOp   IdClass Text Text
  | TokString Text
  | TokEof

  | TokLambda
  | TokArrow
  | TokUnder

  | TokOParen
  | TokOBrace
  | TokOSquare
  | TokOPragma

  | TokCParen
  | TokCBrace
  | TokCSquare
  | TokCPragma

  | TokDoubleColon
  | TokTick
  | TokEqual
  | TokComma
  | TokPipe

  | TokLet
  | TokIn
  | TokLStart
  | TokLEnd

  | TokModule
  | TokImport
  | TokQualified
  | TokAs
  | TokWhere
  | TokCase
  | TokOf

  | TokForeign
  | TokExport
  | TokSafe
  | TokUnsafe
  | TokCCall

  | TokData

  | TokSemi
  deriving (Eq, Ord)

instance Show TokenClass where
  show (TokUnqual   _ id)    = T.unpack id
  show (TokQual     _ ns id) = T.unpack ns ++ '.':T.unpack id
  show (TokUnqualOp _ id)    = T.unpack id
  show (TokQualOp   _ ns id) = T.unpack ns ++ '.':T.unpack id
  show (TokString   text)    = show text
  show TokEof = "<EOF>"

  show TokLambda = "\\"
  show TokArrow = "->"
  show TokUnder = "_"

  show TokOParen = "("
  show TokOBrace = "{"
  show TokOSquare = "["
  show TokOPragma = "{-"

  show TokCParen = ")"
  show TokCBrace = "}"
  show TokCSquare = "]"
  show TokCPragma = "-}"

  show TokDoubleColon = "::"
  show TokTick = "`"
  show TokEqual = "="
  show TokComma = ","
  show TokPipe = "|"
  show TokSemi = ";"

  show TokLet = "let"
  show TokIn = "in"
  show TokLStart = ""
  show TokLEnd = ""

  show TokModule = "module"
  show TokImport = "import"
  show TokQualified = "qualified"
  show TokAs = "as"
  show TokWhere = "where"
  show TokCase = "case"
  show TokOf = "of"
  show TokData = "data"

  show TokForeign = "foreign"
  show TokExport = "export"
  show TokSafe = "safe"
  show TokUnsafe = "unsafe"
  show TokCCall = "ccall"

isKeywordToken :: TokenClass -> Bool
isKeywordToken TokLet = True
isKeywordToken TokIn = True

isKeywordToken TokModule = True
isKeywordToken TokImport = True
isKeywordToken TokQualified = True
isKeywordToken TokAs = True
isKeywordToken TokWhere = True
isKeywordToken TokCase = True
isKeywordToken TokOf = True

isKeywordToken TokForeign = True
isKeywordToken TokExport = True
isKeywordToken TokSafe = True
isKeywordToken TokUnsafe = True
isKeywordToken TokCCall = True

isKeywordToken TokData = True

isKeywordToken _ = False

tokSize :: TokenClass -> Int
tokSize = length . show

data Token
  = Token { tokenClass   :: TokenClass
          , tokStartLine :: !Int
          , tokStartCol  :: !Int
          }
  deriving (Eq, Show, Ord)