{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE CPP #-}
module Yesod.Form.Fields
    ( FormMessage (..)
    , defaultFormMessage
    , textField
    , passwordField
    , textareaField
    , hiddenField
    , intField
    , dayField
    , timeField
    , htmlField
    , emailField
    , searchField
    , selectField
    , AutoFocus
    , urlField
    , doubleField
    , parseDate
    , parseTime
    , Textarea (..)
    ) where

import Yesod.Form.Types
import Yesod.Widget
import Text.Hamlet hiding (renderHtml)
import Text.Blaze (ToHtml (..))
import Text.Cassius
import Data.Time (Day, TimeOfDay(..))
import qualified Text.Email.Validate as Email
import Network.URI (parseURI)
import Database.Persist (PersistField)
import Text.HTML.SanitizeXSS (sanitizeBalance)
import Control.Monad (when)

import qualified Blaze.ByteString.Builder.Html.Utf8 as B
import Blaze.ByteString.Builder (writeByteString, toLazyByteString)
import Blaze.ByteString.Builder.Internal.Write (fromWriteList)

import Text.Blaze.Renderer.String (renderHtml)
import qualified Data.ByteString as S
import qualified Data.ByteString.Lazy as L
import Data.Text (Text, unpack, pack)
import qualified Data.Text.Read
import Data.Monoid (mappend)

#if __GLASGOW_HASKELL__ >= 700
#define WHAMLET whamlet
#define HAMLET hamlet
#define CASSIUS cassius
#define JULIUS julius
#else
#define WHAMLET $whamlet
#define HAMLET $hamlet
#define CASSIUS $cassius
#define JULIUS $julius
#endif

data FormMessage = MsgInvalidInteger Text
                 | MsgInvalidNumber Text
                 | MsgInvalidEntry Text
                 | MsgInvalidUrl Text
                 | MsgInvalidEmail Text
                 | MsgInvalidTimeFormat
                 | MsgInvalidHour Text
                 | MsgInvalidMinute Text
                 | MsgInvalidSecond Text
                 | MsgInvalidDay

defaultFormMessage :: FormMessage -> Text
defaultFormMessage (MsgInvalidInteger t) = "Invalid integer: " `mappend` t
defaultFormMessage (MsgInvalidNumber t) = "Invalid number: " `mappend` t
defaultFormMessage (MsgInvalidEntry t) = "Invalid entry: " `mappend` t
defaultFormMessage MsgInvalidTimeFormat = "Invalid time, must be in HH:MM[:SS] format"
defaultFormMessage MsgInvalidDay = "Invalid day, must be in YYYY-MM-DD format"
defaultFormMessage (MsgInvalidUrl t) = "Invalid URL: " `mappend` t
defaultFormMessage (MsgInvalidEmail t) = "Invalid e-mail address: " `mappend` t
defaultFormMessage (MsgInvalidHour t) = "Invalid hour: " `mappend` t
defaultFormMessage (MsgInvalidMinute t) = "Invalid minute: " `mappend` t
defaultFormMessage (MsgInvalidSecond t) = "Invalid second: " `mappend` t

intField :: (Monad monad, Integral i) => Field (GGWidget master monad ()) FormMessage i
intField = Field
    { fieldParse = \s -> maybe (Left $ MsgInvalidInteger s) Right . readMayI $ unpack s -- FIXME Data.Text.Read
    , fieldRender = pack . showI
    , fieldView = \theId name val isReq -> addHamlet
        [HAMLET|\
<input id="#{theId}" name="#{name}" type="number" :isReq:required="" value="#{val}">
|]
    }
  where
    showI x = show (fromIntegral x :: Integer)
    readMayI s = case reads s of
                    (x, _):_ -> Just $ fromInteger x
                    [] -> Nothing

doubleField :: Monad monad => Field (GGWidget master monad ()) FormMessage Double
doubleField = Field
    { fieldParse = \s -> maybe (Left $ MsgInvalidNumber s) Right . readMay $ unpack s -- FIXME use Data.Text.Read
    , fieldRender = pack . show
    , fieldView = \theId name val isReq -> addHamlet
        [HAMLET|\
<input id="#{theId}" name="#{name}" type="text" :isReq:required="" value="#{val}">
|]
    }

dayField :: Monad monad => Field (GGWidget master monad ()) FormMessage Day
dayField = Field
    { fieldParse = parseDate . unpack
    , fieldRender = pack . show
    , fieldView = \theId name val isReq -> addHamlet
        [HAMLET|\
<input id="#{theId}" name="#{name}" type="date" :isReq:required="" value="#{val}">
|]
    }

timeField :: Monad monad => Field (GGWidget master monad ()) FormMessage TimeOfDay
timeField = Field
    { fieldParse = parseTime . unpack
    , fieldRender = pack . show . roundFullSeconds
    , fieldView = \theId name val isReq -> addHamlet
        [HAMLET|\
<input id="#{theId}" name="#{name}" :isReq:required="" value="#{val}">
|]
    }
  where
    roundFullSeconds tod =
        TimeOfDay (todHour tod) (todMin tod) fullSec
      where
        fullSec = fromInteger $ floor $ todSec tod

htmlField :: Monad monad => Field (GGWidget master monad ()) FormMessage Html
htmlField = Field
    { fieldParse = Right . preEscapedString . sanitizeBalance . unpack -- FIXME make changes to xss-sanitize
    , fieldRender = pack . renderHtml
    , fieldView = \theId name val _isReq -> addHamlet
        [HAMLET|\
<textarea id="#{theId}" name="#{name}" .html>#{val}
|]
    }

-- | A newtype wrapper around a 'String' that converts newlines to HTML
-- br-tags.
newtype Textarea = Textarea { unTextarea :: Text }
    deriving (Show, Read, Eq, PersistField)
instance ToHtml Textarea where
    toHtml =
        unsafeByteString
        . S.concat
        . L.toChunks
        . toLazyByteString
        . fromWriteList writeHtmlEscapedChar
        . unpack
        . unTextarea
      where
        -- Taken from blaze-builder and modified with newline handling.
        writeHtmlEscapedChar '\n' = writeByteString "<br>"
        writeHtmlEscapedChar c    = B.writeHtmlEscapedChar c

textareaField :: Monad monad => Field (GGWidget master monad ()) FormMessage Textarea
textareaField = Field
    { fieldParse = Right . Textarea
    , fieldRender = unTextarea
    , fieldView = \theId name val _isReq -> addHamlet
        [HAMLET|\
<textarea id="#{theId}" name="#{name}">#{val}
|]
    }

hiddenField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
hiddenField = Field
    { fieldParse = Right
    , fieldRender = id
    , fieldView = \theId name val _isReq -> addHamlet
        [HAMLET|\
<input type="hidden" id="#{theId}" name="#{name}" value="#{val}">
|]
    }

textField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
textField = Field
    { fieldParse = Right
    , fieldRender = id
    , fieldView = \theId name val isReq ->
        [WHAMLET|
<input id="#{theId}" name="#{name}" type="text" :isReq:required value="#{val}">
|]
    }

passwordField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
passwordField = Field
    { fieldParse = Right
    , fieldRender = id
    , fieldView = \theId name val isReq -> addHamlet
        [HAMLET|\
<input id="#{theId}" name="#{name}" type="password" :isReq:required="" value="#{val}">
|]
    }

readMay :: Read a => String -> Maybe a
readMay s = case reads s of
                (x, _):_ -> Just x
                [] -> Nothing

parseDate :: String -> Either FormMessage Day
parseDate = maybe (Left MsgInvalidDay) Right
              . readMay . replace '/' '-'

-- | Replaces all instances of a value in a list by another value.
-- from http://hackage.haskell.org/packages/archive/cgi/3001.1.7.1/doc/html/src/Network-CGI-Protocol.html#replace
replace :: Eq a => a -> a -> [a] -> [a]
replace x y = map (\z -> if z == x then y else z)

parseTime :: String -> Either FormMessage TimeOfDay
parseTime (h2:':':m1:m2:[]) = parseTimeHelper ('0', h2, m1, m2, '0', '0')
parseTime (h1:h2:':':m1:m2:[]) = parseTimeHelper (h1, h2, m1, m2, '0', '0')
parseTime (h1:h2:':':m1:m2:' ':'A':'M':[]) =
    parseTimeHelper (h1, h2, m1, m2, '0', '0')
parseTime (h1:h2:':':m1:m2:' ':'P':'M':[]) =
    let [h1', h2'] = show $ (read [h1, h2] :: Int) + 12
    in parseTimeHelper (h1', h2', m1, m2, '0', '0')
parseTime (h1:h2:':':m1:m2:':':s1:s2:[]) =
    parseTimeHelper (h1, h2, m1, m2, s1, s2)
parseTime _ = Left MsgInvalidTimeFormat

parseTimeHelper :: (Char, Char, Char, Char, Char, Char)
                -> Either FormMessage TimeOfDay
parseTimeHelper (h1, h2, m1, m2, s1, s2)
    | h < 0 || h > 23 = Left $ MsgInvalidHour $ pack [h1, h2]
    | m < 0 || m > 59 = Left $ MsgInvalidMinute $ pack [m1, m2]
    | s < 0 || s > 59 = Left $ MsgInvalidSecond $ pack [s1, s2]
    | otherwise = Right $ TimeOfDay h m s
  where
    h = read [h1, h2] -- FIXME isn't this a really bad idea?
    m = read [m1, m2]
    s = fromInteger $ read [s1, s2]

emailField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
emailField = Field
    { fieldParse = \s -> if Email.isValid (unpack s)
                        then Right s
                        else Left $ MsgInvalidEmail s
    , fieldRender = id
    , fieldView = \theId name val isReq -> addHamlet
        [HAMLET|\
<input id="#{theId}" name="#{name}" type="email" :isReq:required="" value="#{val}">
|]
    }

type AutoFocus = Bool
searchField :: Monad monad => AutoFocus -> Field (GGWidget master monad ()) FormMessage Text
searchField autoFocus = Field
    { fieldParse = Right
    , fieldRender = id
    , fieldView = \theId name val isReq -> do
        addHtml [HAMLET|\
<input id="#{theId}" name="#{name}" type="search" :isReq:required="" :autoFocus:autofocus="" value="#{val}">
|]
        when autoFocus $ do
          addHtml $ [HAMLET|\<script>if (!('autofocus' in document.createElement('input'))) {document.getElementById('#{theId}').focus();}</script> 
|]
          addCassius [CASSIUS|
            #{theId}
              -webkit-appearance: textfield
            |]
    }

urlField :: Monad monad => Field (GGWidget master monad ()) FormMessage Text
urlField = Field
    { fieldParse = \s -> case parseURI $ unpack s of
                        Nothing -> Left $ MsgInvalidUrl s
                        Just _ -> Right s
    , fieldRender = id
    , fieldView = \theId name val isReq -> addHtml
        [HAMLET|
<input ##{theId} name=#{name} type=url :isReq:required value=#{val}>
|]
    }

selectField :: (Eq a, Monad monad) => [(Text, a)] -> Field (GGWidget master monad ()) FormMessage a
selectField opts = Field -- FIXME won't work for optional yet
    { fieldParse = \s ->
        case Data.Text.Read.decimal s of
            Right (a, "") ->
                case lookup a pairs of
                    Nothing -> Left $ MsgInvalidEntry s
                    Just x -> Right $ snd x
            _ -> Left $ MsgInvalidNumber s
    , fieldRender = \a -> maybe "" (pack . show) $ lookup a rpairs
    , fieldView = \theId name val isReq -> [WHAMLET|
<select id=#{theId} name=#{name}
    $if not isReq
        <option value=none>
    $forall pair <- pairs
        <option value=#{show $ fst pair} :(==) val (fst $ snd pair):selected>#{fst $ snd pair}
|]
    }
  where
    pairs = zip [1 :: Int ..] opts -- FIXME use IntMap
    rpairs = zip (map snd opts) [1 :: Int ..]