    {-# LANGUAGE Trustworthy #-}
    -- |
    -- Module       : Data.Text.Short.Encoding.Base64
    -- Copyright    : (c) 2019-2020 Emily Pillmore
    -- License      : BSD-style
    --
    -- Maintainer   : Emily Pillmore <emilypi@cohomolo.gy>
    -- Stability    : stable
    -- Portability  : non-portable
    --
    -- This module contains 'Data.Text.Short.ShortText'-valued combinators
    -- implementing the RFC 4648 specification for the Base64
    -- encoding format. This includes lenient decoding variants, and
    -- external + internal validations for canonicity.
    --
    module Data.Text.Short.Encoding.Base64
    ( -- * Encoding
      encodeBase64
      -- * Decoding
    , decodeBase64
    , decodeBase64With
    , decodeBase64Lenient
      -- * Validation
    , isBase64
    , isValidBase64
    ) where

    import Data.Bifunctor (first)
    import qualified Data.ByteString.Base64 as B64
    import Data.ByteString.Short (ShortByteString)
    import qualified Data.ByteString.Short.Base64 as BS64
    import Data.Text (Text)
    import qualified Data.Text.Encoding.Base64 as B64T
    import Data.Text.Encoding.Base64.Error
    import Data.Text.Short
    import Data.Text.Short.Unsafe

    -- | Encode a 'ShortText' value in Base64 with padding.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> encodeBase64 "Sun"
    -- "U3Vu"
    --
    encodeBase64 :: ShortText -> ShortText
    encodeBase64 :: ShortText -> ShortText
    encodeBase64 = ByteString -> ShortText
    fromByteStringUnsafe
      (ByteString -> ShortText)
    -> (ShortText -> ByteString) -> ShortText -> ShortText
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ByteString -> ByteString
    B64.encodeBase64'
      (ByteString -> ByteString)
    -> (ShortText -> ByteString) -> ShortText -> ByteString
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ShortText -> ByteString
    toByteString
    {-# INLINE encodeBase64 #-}

    -- | Decode a padded Base64-encoded 'ShortText' value
    --
    -- /Note:/ This function makes sure that decoding is total by deferring to
    -- 'T.decodeLatin1'. This will always round trip for any valid Base64-encoded
    -- text value, but it may not round trip for bad inputs. The onus is on the
    -- caller to make sure inputs are valid. If unsure, defer to `decodeBase64With`
    -- and pass in a custom decode function.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64 "U3Vu"
    -- Right "Sun"
    --
    -- >>> decodeBase64 "U3V"
    -- Left "Base64-encoded bytestring requires padding"
    --
    -- >>> decodebase64 "U3V="
    -- Left "non-canonical encoding detected at offset: 2"
    --
    decodeBase64 :: ShortText -> Either Text ShortText
    decodeBase64 :: ShortText -> Either Text ShortText
    decodeBase64 = (Text -> ShortText) -> Either Text Text -> Either Text ShortText
    forall a b. (a -> b) -> Either Text a -> Either Text b
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap Text -> ShortText
    fromText (Either Text Text -> Either Text ShortText)
    -> (ShortText -> Either Text Text)
    -> ShortText
    -> Either Text ShortText
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Text -> Either Text Text
    B64T.decodeBase64 (Text -> Either Text Text)
    -> (ShortText -> Text) -> ShortText -> Either Text Text
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ShortText -> Text
    toText
    {-# INLINE decodeBase64 #-}

    -- | Attempt to decode a 'ShortByteString' value as Base64, converting from
    -- 'ByteString' to 'ShortText' according to some encoding function. In practice,
    -- This is something like 'decodeUtf8'', which may produce an error.
    --
    -- See: <https://tools.ietf.org/html/rfc4648#section-4 RFC-4648 section 4>
    --
    -- === __Example__:
    --
    -- @
    -- 'decodeBase64With' 'T.decodeUtf8''
    --   :: 'ShortByteString' -> 'Either' ('Base64Error' 'UnicodeException') 'ShortText'
    -- @
    --
    decodeBase64With
        :: (ShortByteString -> Either err ShortText)
          -- ^ convert a bytestring to text (e.g. 'T.decodeUtf8'')
        -> ShortByteString
          -- ^ Input text to decode
        -> Either (Base64Error err) ShortText
    decodeBase64With :: forall err.
    (ShortByteString -> Either err ShortText)
    -> ShortByteString -> Either (Base64Error err) ShortText
    decodeBase64With ShortByteString -> Either err ShortText
    f ShortByteString
    t = case ShortByteString -> Either Text ShortByteString
    BS64.decodeBase64 ShortByteString
    t of
      Left Text
    de -> Base64Error err -> Either (Base64Error err) ShortText
    forall a b. a -> Either a b
    Left (Base64Error err -> Either (Base64Error err) ShortText)
    -> Base64Error err -> Either (Base64Error err) ShortText
    forall a b. (a -> b) -> a -> b
    $ Text -> Base64Error err
    forall e. Text -> Base64Error e
    DecodeError Text
    de
      Right ShortByteString
    a -> (err -> Base64Error err)
    -> Either err ShortText -> Either (Base64Error err) ShortText
    forall a b c. (a -> b) -> Either a c -> Either b c
    forall (p :: * -> * -> *) a b c.
    Bifunctor p =>
    (a -> b) -> p a c -> p b c
    first err -> Base64Error err
    forall e. e -> Base64Error e
    ConversionError (ShortByteString -> Either err ShortText
    f ShortByteString
    a)
    {-# INLINE decodeBase64With #-}

    -- | Leniently decode a Base64-encoded 'ShortText' value. This function
    -- will not generate parse errors. If input data contains padding chars,
    -- then the input will be parsed up until the first pad character.
    --
    -- __Note:__ This is not RFC 4648-compliant.
    --
    -- === __Examples__:
    --
    -- >>> decodeBase64Lenient "U3Vu"
    -- "Sun"
    --
    -- >>> decodeBase64Lenient "U3V"
    -- "Su"
    --
    -- >>> decodebase64Lenient "U3V="
    -- "Su"
    --
    decodeBase64Lenient :: ShortText -> ShortText
    decodeBase64Lenient :: ShortText -> ShortText
    decodeBase64Lenient = Text -> ShortText
    fromText (Text -> ShortText)
    -> (ShortText -> Text) -> ShortText -> ShortText
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . Text -> Text
    B64T.decodeBase64Lenient (Text -> Text) -> (ShortText -> Text) -> ShortText -> Text
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ShortText -> Text
    toText
    {-# INLINE decodeBase64Lenient #-}

    -- | Tell whether a 'ShortText' value is Base64-encoded.
    --
    -- === __Examples__:
    --
    -- >>> isBase64 "U3Vu"
    -- True
    --
    -- >>> isBase64 "U3V"
    -- False
    --
    -- >>> isBase64 "U3V="
    -- False
    --
    isBase64 :: ShortText -> Bool
    isBase64 :: ShortText -> Bool
    isBase64 = ByteString -> Bool
    B64.isBase64 (ByteString -> Bool)
    -> (ShortText -> ByteString) -> ShortText -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ShortText -> ByteString
    toByteString
    {-# INLINE isBase64 #-}

    -- | Tell whether a 'ShortText' value is a valid Base64 format.
    --
    -- This will not tell you whether or not this is a correct Base64 representation,
    -- only that it conforms to the correct shape. To check whether it is a true
    -- Base64 encoded 'ShortText' value, use 'isBase64'.
    --
    -- === __Examples__:
    --
    -- >>> isValidBase64 "U3Vu"
    -- True
    --
    -- >>> isValidBase64 "U3V"
    -- True
    --
    -- >>> isValidBase64 "U3V="
    -- True
    --
    -- >>> isValidBase64 "%"
    -- False
    --
    isValidBase64 :: ShortText -> Bool
    isValidBase64 :: ShortText -> Bool
    isValidBase64 = ByteString -> Bool
    B64.isValidBase64 (ByteString -> Bool)
    -> (ShortText -> ByteString) -> ShortText -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . ShortText -> ByteString
    toByteString
    {-# INLINE isValidBase64 #-}