From f21e343ef3653e57a6fcd917be002b8d3554875e Mon Sep 17 00:00:00 2001
From: Stefan Friese <mail@stefan.works>
Date: Thu, 2 May 2024 23:12:40 +0200
Subject: [PATCH] added solveEnc function, so that you do not have to know
 which encoding has been used to decode it

---
 Main.hs | 48 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 45 insertions(+), 3 deletions(-)

diff --git a/Main.hs b/Main.hs
index d275fff..28b6f24 100644
--- a/Main.hs
+++ b/Main.hs
@@ -33,7 +33,10 @@ import qualified Data.Bytes.Text.Ascii as ASCII
 import Data.Bytes.Get (getWord64host)
 import Data.ByteString.UTF8 as BSU      -- from utf8-string
 -- import Data.ByteString (singleton)
+import GHC.Word (Word8)
 import qualified Data.ByteString.Char8 as C
+-- Regex imports
+import Text.Regex.TDFA
 
 data Based = Decode { 
               b91 :: Bool,
@@ -51,7 +54,8 @@ data Based = Decode {
               qp  :: Bool,
               uu  :: Bool,
               xx  :: Bool,
-              yenc :: Bool
+              yenc :: Bool,
+              solve :: Bool
                     }
            | Encode { 
               b91 :: Bool,
@@ -116,7 +120,7 @@ octToInt (x : xs) = x + 8 * octToInt xs
 
 dec91 :: String -> String
 dec91 = C.unpack . B91.decode
--- dec91 input =
+
 --    case singleton . B91.decode input of
 --      Right decoded -> C.unpack decoded
 --      Left _ -> "Error decoding Base91.\n"
@@ -251,6 +255,42 @@ decy input =
 
 ency :: String -> String
 ency  = C.unpack . Y.encode  . BSU.fromString
+
+base91Regex = "^[!-~]*$"
+-- base85Regex = "^[A-Za-u0-9!\"#$%&((*+,-./;:<=@[]\\`]*$"
+base64Regex = "^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)?$"
+base58Regex = "^[1-9A-HJ-NP-Za-km-z]+$" -- incorrect
+base32Regex = "^(?:[A-Z2-7]{8})*(?:[A-Z2-7]{2}={6}|[A-Z2-7]{4}={4}|[A-Z2-7]{5}={3}|[A-Z2-7]{7}=)?$"
+base16Regex = "^[0-9A-FXx]*$"
+
+solveEnc :: String -> String
+solveEnc input =
+   -- let isBase91 = BSU.fromString input =~ base91Regex :: Bool
+   let isBase64 = BSU.fromString input =~ base64Regex :: Bool
+       isBase58 = BSU.fromString input =~ base58Regex :: Bool
+       isBase32 = BSU.fromString input =~ base32Regex :: Bool
+       isBase16 = BSU.fromString input =~ base16Regex :: Bool
+       base64Result = if isBase64 then "\nTrying base64:\n" ++ dec64 input else ""
+       base58Result = if isBase58 then "\nTrying base58:\n" ++ dec58 input else ""
+       base32Result = if isBase64 then "\nTrying base32:\n" ++ dec32 input else ""
+       base16Result = if isBase16 then "\nTrying base16:\n" ++ dec16 input else "" 
+       results = filter (not . null) [base64Result, base32Result, base16Result]
+    in 
+      if null results
+         then "Not able to solve the encoding.\n"
+         else unlines results
+
+   --
+   -- | input =~ base64Regex = dec64 input
+   -- | input =~ base32Regex = dec32 input
+   -- | otherwise = "Cannot decode: " ++ input
+   --
+   -- if BSU.fromString input =~ base64Regex :: Bool
+   --   then dec64 input
+   --   else "Not Base64.\n"
+   -- ++ if BSU.fromString input =~ base32Regex :: Bool
+   --   then dec32 input
+   --   else "Not able to solve the encoding.\n"
        
 optionHandler Decode{b91=True} = dec91
 optionHandler Encode{b91=True} = enc91
@@ -284,6 +324,7 @@ optionHandler Decode{xx=True}  = decxx
 optionHandler Encode{xx=True}  = encxx
 optionHandler Decode{yenc=True}   = decy
 optionHandler Encode{yenc=True}   = ency
+optionHandler Decode{solve=True} = solveEnc
 
 decodeMode :: Based
 decodeMode = Decode {
@@ -302,7 +343,8 @@ decodeMode = Decode {
             qp  = def &= help "decode quoted-printable",
             uu  = def &= help "decode uu",
             xx  = def &= help "decode xx",
-            yenc = def &= help "decode yEncode"
+            yenc = def &= help "decode yEncode",
+            solve = def &= help "solve encoding"
         }  &= help "Decode chosen base" &=auto
 
 encodeMode :: Based