module Gemini where

import Control.Exception
import Data.ByteString.UTF8
import Data.Text
import Network.Mime
import System.Directory (doesDirectoryExist, doesFileExist)
import Text.Regex
import Text.Regex.PCRE


getFile :: FilePath -> IO (Maybe String)
getFile s = do
  result <- try (readFile s) :: IO (Either SomeException String)
  case result of
    Left ex -> return Nothing
    Right ex -> return (pure ex)

-- return components of the url
-- gemini:// | hostname | uri | ? | query
parse_url :: String -> [[String]]
parse_url url =
  (sanitize_uri url) =~ "^(gemini:\\/\\/)([^\\/]*)\\/?([^\\?]*)(\\?)?(.*)?(\\r\\n)$"

-- remove any .. in the uri that could escape the location
sanitize_uri :: String -> String
sanitize_uri path =
  subRegex (mkRegex "\\.\\.\\/") path ""

-- return a file as a string
read_file :: String -> IO String
read_file path = do
  text <- readFile path
  pure text

-- read from stdin
get_request :: IO String
get_request = do
  stdin <- getContents
  pure stdin

data Gemini = MkGemini
  { domain :: String,
    file :: String,
    query :: String
  }

data Answer = MkAnswer
  { code :: Int,
    lang :: String,
    content :: String,
    mime :: String
  }

get_mime :: String -> String
get_mime filename
  | (fileNameExtensions (pack filename)) == [(pack "gmi" :: Extension)] = "text/gemini"
  | (fileNameExtensions (pack filename)) == [(pack "gemini" :: Extension)] = "text/gemini"
  | otherwise = (toString (defaultMimeLookup (pack filename)))

parse_to_gemini :: [[String]] -> Gemini
parse_to_gemini tab =
  MkGemini
    { domain = tab !! 0 !! 2,
      file = tab !! 0 !! 3,
      query = tab !! 0 !! 5
    }

create_answer :: Gemini -> String -> String -> IO Answer
create_answer (MkGemini domain file query) language basedir = do
  content <- getFile $ basedir ++ file
  case content of
    Just x ->
      return
        ( MkAnswer
            { code = 20,
              lang = language,
              mime = get_mime file,
              content = x
            }
        )
    Nothing -> do
      content' <- getFile $ baseDir' ++ file ++ "index.gmi"
      case content' of
        Just y ->
          return
            ( MkAnswer
                { code = 20,
                  lang = language,
                  mime = get_mime $ file ++ "index.gmi",
                  content = y
                }
            )
        Nothing -> do
          isdir <- doesDirectoryExist $ baseDir' ++ file
          if isdir
            then
              return
                ( MkAnswer
                    { code = 31,
                      lang = "",
                      mime = "/" ++ file ++ "/",
                      content = ""
                    }
                )
            else
              return
                ( MkAnswer
                    { code = 50,
                      lang = language,
                      mime = "",
                      content = "error ici " ++ baseDir' ++ file ++ "/index.gmi"
                    }
                )

make_reply :: Answer -> String
make_reply (MkAnswer code lang content mime)
  | lang /= "" = (show code) ++ " " ++ mime ++ "; lang=" ++ lang ++ " \r\n"
  | code == 20 && lang == "" = (show code) ++ " " ++ mime ++ "; \r\n"
  | code == 31 = "31 " ++ mime ++ "\r\n"
  | otherwise = "50\r\n"