{- This Source Code Form is subject to the terms of the Mozilla Public License,
   v. 2.0. If a copy of the MPL was not distributed with this file, You can
   obtain one at https://mozilla.org/MPL/2.0/. -}

-- | Convenience wrappers for working with font files.
module Graphics.Fountainhead
    ( dumpFontFile
    , parseFontDirectoryFromFile
    ) where

import Data.ByteString (ByteString)
import Data.Void (Void)
import Graphics.Fountainhead.Dumper (dumpTable, dumpTables, DumpError(..))
import Graphics.Fountainhead.Parser (ParseErrorBundle, fontDirectoryP)
import Graphics.Fountainhead.TrueType (FontDirectory(..))
import qualified Text.Megaparsec as Megaparsec
import Text.Megaparsec (PosState(..), State(..))
import System.IO (IOMode(..), withBinaryFile)
import Data.Bifunctor (Bifunctor(..))
import qualified Data.Text.Lazy.Builder as Text.Builder
import Graphics.Fountainhead.Compression (hDecompress)

parseFontDirectoryFromFile :: FilePath
    -> IO (State ByteString Void, Either ParseErrorBundle FontDirectory)
parseFontDirectoryFromFile fontFile =
    withBinaryFile fontFile ReadMode withFontHandle
  where
    withFontHandle fontHandle = doParsing
        <$> hDecompress fontHandle
    doParsing ttfContents =
        let initialState = Megaparsec.State
                { stateInput = ttfContents
                , stateOffset = 0
                , statePosState = Megaparsec.PosState
                    { pstateInput = ttfContents
                    , pstateOffset = 0
                    , pstateSourcePos = Megaparsec.initialPos fontFile
                    , pstateTabWidth = Megaparsec.defaultTabWidth
                    , pstateLinePrefix = ""
                    }
                , stateParseErrors = []
                }
         in Megaparsec.runParser' fontDirectoryP initialState 

dumpFontFile :: FilePath -> Maybe String -> IO (Either DumpError Text.Builder.Builder)
dumpFontFile fontFile tableName = do
    let dumpRequest = maybe dumpTables dumpTable tableName
    (processedState, initialResult) <- parseFontDirectoryFromFile fontFile
    pure $ first DumpParseError initialResult >>= dumpRequest processedState