{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverloadedStrings #-}

-- |
-- Module      : $header$
-- Copyright   : (c) Laurent P René de Cotret, 2019 - present
-- License     : GNU GPL, version 2 or above
-- Maintainer  : laurent.decotret@outlook.com
-- Stability   : internal
-- Portability : portable
--
-- Utilities to clean pandoc-plot output directories.
module Text.Pandoc.Filter.Plot.Clean
  ( cleanOutputDirs,
    outputDirs,
    readDoc,
  )
where

-- TODO: forConcurrently
import Control.Monad.Reader (forM)
import qualified Data.ByteString.Lazy as B
import Data.Char (toLower)
import Data.Default (def)
import Data.List (nub)
import Data.Maybe (catMaybes, fromMaybe)
import Data.Text (Text, pack)
import qualified Data.Text.IO as Text
import System.Directory (removePathForcibly)
import System.FilePath (takeExtension)
import Text.Pandoc.Class (runIO)
import Text.Pandoc.Definition (Block, Pandoc)
import Text.Pandoc.Error (handleError)
import Text.Pandoc.Filter.Plot.Monad
import Text.Pandoc.Filter.Plot.Parse
import qualified Text.Pandoc.Options as P
import qualified Text.Pandoc.Readers as P
import Text.Pandoc.Walk (Walkable, query)

-- | Clean all output related to pandoc-plot. This includes output directories specified
-- in the configuration and in the document/block, as well as log files.
-- Note that *all* files in pandoc-plot output directories will be removed.
--
-- The cleaned directories are returned.
cleanOutputDirs ::
  Walkable Block b =>
  Configuration ->
  b ->
  IO [FilePath]
cleanOutputDirs conf doc = do
  dirs <- runPlotM Nothing conf . cleanOutputDirsM $ doc
  -- Deletion of the log file must be done outside of PlotM
  -- to ensure the log file has been closed.
  case logSink conf of
    LogFile path -> removePathForcibly path
    _ -> return ()
  return dirs

-- | Analyze a document to determine where would the pandoc-plot output directories be.
outputDirs ::
  Walkable Block b =>
  b ->
  PlotM [FilePath]
outputDirs = fmap (catMaybes . nub) . sequence . query (\b -> [hasDirectory <$> parseFigureSpec b])
  where
    hasDirectory :: ParseFigureResult -> Maybe FilePath
    hasDirectory (Figure fs) = Just $ directory fs
    hasDirectory _ = Nothing

-- | PlotM version of @cleanOutputDirs@
cleanOutputDirsM ::
  Walkable Block b =>
  b ->
  PlotM [FilePath]
cleanOutputDirsM doc = do
  directories <- outputDirs doc
  forM directories $ \fp -> do
    info $ "Removing directory " <> pack fp
    -- It is important to use `removePathForcibly` here, because it does
    -- not throw exceptions if the directory doesn't exist. This means
    -- we do not have to check in advance if directories are nested in our
    -- list of directories.
    liftIO $ removePathForcibly fp
    return fp

-- | Read a document, guessing what extensions and reader options are appropriate. If
-- the file cannot be read for any reason, an error is thrown.
readDoc :: FilePath -> IO Pandoc
readDoc fp =
  handleError
    =<< runIO
      ( do
          let fmt = fromMaybe mempty (formatFromFilePath fp)
          (reader, exts) <- P.getReader fmt
          let readerOpts = def {P.readerExtensions = exts}
          case reader of
            P.TextReader fct -> do
              t <- liftIO $ Text.readFile fp
              fct readerOpts t
            P.ByteStringReader bst -> do
              b <- liftIO $ B.readFile fp
              bst readerOpts b
      )

-- | Determine format based on file extension
-- Note : this is exactly the heuristic used by pandoc here:
-- https://github.com/jgm/pandoc/blob/master/src/Text/Pandoc/App/FormatHeuristics.hs
--
-- However, this is not exported, so it must be re-defined here.
formatFromFilePath :: FilePath -> Maybe Text
formatFromFilePath x =
  case takeExtension (map toLower x) of
    ".adoc" -> Just "asciidoc"
    ".asciidoc" -> Just "asciidoc"
    ".context" -> Just "context"
    ".ctx" -> Just "context"
    ".db" -> Just "docbook"
    ".doc" -> Just "doc" -- so we get an "unknown reader" error
    ".docx" -> Just "docx"
    ".dokuwiki" -> Just "dokuwiki"
    ".epub" -> Just "epub"
    ".fb2" -> Just "fb2"
    ".htm" -> Just "html"
    ".html" -> Just "html"
    ".icml" -> Just "icml"
    ".json" -> Just "json"
    ".latex" -> Just "latex"
    ".lhs" -> Just "markdown+lhs"
    ".ltx" -> Just "latex"
    ".markdown" -> Just "markdown"
    ".mkdn" -> Just "markdown"
    ".mkd" -> Just "markdown"
    ".mdwn" -> Just "markdown"
    ".mdown" -> Just "markdown"
    ".Rmd" -> Just "markdown"
    ".md" -> Just "markdown"
    ".ms" -> Just "ms"
    ".muse" -> Just "muse"
    ".native" -> Just "native"
    ".odt" -> Just "odt"
    ".opml" -> Just "opml"
    ".org" -> Just "org"
    ".pdf" -> Just "pdf" -- so we get an "unknown reader" error
    ".pptx" -> Just "pptx"
    ".roff" -> Just "ms"
    ".rst" -> Just "rst"
    ".rtf" -> Just "rtf"
    ".s5" -> Just "s5"
    ".t2t" -> Just "t2t"
    ".tei" -> Just "tei"
    ".tei.xml" -> Just "tei"
    ".tex" -> Just "latex"
    ".texi" -> Just "texinfo"
    ".texinfo" -> Just "texinfo"
    ".text" -> Just "markdown"
    ".textile" -> Just "textile"
    ".txt" -> Just "markdown"
    ".wiki" -> Just "mediawiki"
    ".xhtml" -> Just "html"
    ".ipynb" -> Just "ipynb"
    ".csv" -> Just "csv"
    ".bib" -> Just "biblatex"
    ['.', y] | y `elem` ['1' .. '9'] -> Just "man"
    _ -> Nothing
