{-# LANGUAGE NoImplicitPrelude #-}
{- |
   Module      : Tests.Command
   Copyright   : © 2006-2020 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley@edu>
   Stability   : alpha
   Portability : portable

Run commands, and test results, defined in markdown files.
-}
module Tests.Command (findPandoc, runTest, tests)
where

import Prelude
import Data.Algorithm.Diff
import qualified Data.ByteString as BS
import qualified Data.Text as T
import Data.List (isSuffixOf, intercalate)
import Data.Maybe (catMaybes)
import System.Directory
import qualified System.Environment as Env
import System.Exit
import System.FilePath (joinPath, splitDirectories, takeDirectory, (</>))
import System.IO (hPutStr, stderr)
import System.IO.Unsafe (unsafePerformIO)
import System.Process
import Test.Tasty
import Test.Tasty.HUnit
import Tests.Helpers
import Text.Pandoc
import qualified Text.Pandoc.UTF8 as UTF8

-- | Run a test with normalize function, return True if test passed.
runTest :: String    -- ^ Title of test
        -> FilePath  -- ^ Path to pandoc
        -> String    -- ^ Shell command
        -> String    -- ^ Input text
        -> String    -- ^ Expected output
        -> TestTree
runTest testname pandocpath cmd inp norm = testCase testname $ do
  mldpath   <- Env.lookupEnv "LD_LIBRARY_PATH"
  mdyldpath <- Env.lookupEnv "DYLD_LIBRARY_PATH"
  let findDynlibDir []           = Nothing
      findDynlibDir ("build":xs) = Just $ joinPath (reverse xs) </> "build"
      findDynlibDir (_:xs)       = findDynlibDir xs
  let mbDynlibDir = findDynlibDir (reverse $ splitDirectories $
                                   takeDirectory $ takeWhile (/=' ') cmd)
  let dynlibEnv = [("DYLD_LIBRARY_PATH", intercalate ":" $ catMaybes [mbDynlibDir, mdyldpath])
                  ,("LD_LIBRARY_PATH",   intercalate ":" $ catMaybes [mbDynlibDir, mldpath])]
  let env' = dynlibEnv ++ [("PATH",takeDirectory pandocpath),("TMP","."),("LANG","en_US.UTF-8"),("HOME", "./"),("pandoc_datadir", "..")]
  let pr = (shell cmd){ env = Just env' }
  (ec, out', err') <- readCreateProcessWithExitCode pr inp
  -- filter \r so the tests will work on Windows machines
  let out = filter (/= '\r') $ err' ++ out'
  result  <- if ec == ExitSuccess
                then
                  if out == norm
                     then return TestPassed
                     else return
                          $ TestFailed cmd "expected"
                          $ getDiff (lines out) (lines norm)
                else do
                  hPutStr stderr err'
                  return $ TestError ec
  assertBool (show result) (result == TestPassed)

tests :: FilePath -> TestTree
{-# NOINLINE tests #-}
tests pandocPath = unsafePerformIO $ do
  files <- filter (".md" `isSuffixOf`) <$>
               getDirectoryContents "command"
  let cmds = map (extractCommandTest pandocPath) files
  return $ testGroup "Command:" cmds

isCodeBlock :: Block -> Bool
isCodeBlock (CodeBlock _ _) = True
isCodeBlock _               = False

extractCode :: Block -> String
extractCode (CodeBlock _ code) = T.unpack code
extractCode _                  = ""

dropPercent :: String -> String
dropPercent ('%':xs) = dropWhile (== ' ') xs
dropPercent xs       = xs

runCommandTest :: FilePath -> Int -> String -> TestTree
runCommandTest pandocpath num code =
  let codelines = lines code
      (continuations, r1) = span ("\\" `isSuffixOf`) codelines
      (cmd, r2) = (dropPercent (unwords (map init continuations ++ take 1 r1)),
                   drop 1 r1)
      (inplines, r3) = break (=="^D") r2
      normlines = takeWhile (/=".") (drop 1 r3)
      input = unlines inplines
      norm = unlines normlines
      shcmd = cmd -- trimr $ takeDirectory pandocpath </> cmd
  in  runTest ("#" ++ show num) pandocpath shcmd input norm

extractCommandTest :: FilePath -> FilePath -> TestTree
extractCommandTest pandocpath fp = unsafePerformIO $ do
  contents <- UTF8.toText <$> BS.readFile ("command" </> fp)
  Pandoc _ blocks <- runIOorExplode (readMarkdown
                        def{ readerExtensions = pandocExtensions } contents)
  let codeblocks = map extractCode $ filter isCodeBlock blocks
  let cases = zipWith (runCommandTest pandocpath) [1..] codeblocks
  return $ testGroup fp cases