{-# LANGUAGE DeriveFunctor #-}

module Reflex.Dom.Colonnade
  ( Cell(..)
  , cell
  , basic
  , dynamic
  , dynamicEventful
  ) where

import Colonnade.Types
import Control.Monad
import Data.Foldable
import Reflex (Dynamic,Event,switchPromptly,never)
import Reflex.Dynamic (mapDyn)
import Reflex.Dom (MonadWidget)
import Reflex.Dom.Widget.Basic
import Data.Map (Map)
import Data.Semigroup (Semigroup)
import qualified Colonnade.Encoding as Encoding
import qualified Data.Map as Map

cell :: m b -> Cell m b
cell = Cell Map.empty

-- data NewCell b = NewCell
--   { newCellAttrs :: !(Map String String)
--   , newCellContents :: !b
--   } deriving (Functor)

data Cell m b = Cell
  { cellAttrs :: !(Map String String)
  , cellContents :: !(m b)
  } deriving (Functor)

basic :: (MonadWidget t m, Foldable f)
      => Map String String -- ^ Table element attributes
      -> f a -- ^ Values
      -> Encoding Headed (Cell m ()) a -- ^ Encoding of a value into cells
      -> m ()
basic tableAttrs as encoding = do
  elAttr "table" tableAttrs $ do
    theadBuild encoding
    el "tbody" $ forM_ as $ \a -> do
      el "tr" $ Encoding.runRowMonadic encoding (elFromCell "td") a

elFromCell :: MonadWidget t m => String -> Cell m b -> m b
elFromCell name (Cell attrs contents) = elAttr name attrs contents

theadBuild :: (MonadWidget t m, Monoid b) => Encoding Headed (Cell m b) a -> m b
theadBuild encoding = el "thead" . el "tr"
  $ Encoding.runHeaderMonadic encoding (elFromCell "th")

dynamic :: (MonadWidget t m, Foldable f)
        => Map String String -- ^ Table element attributes
        -> f (Dynamic t a) -- ^ Dynamic values
        -> Encoding Headed (Cell m ()) a -- ^ Encoding of a value into cells
        -> m ()
dynamic tableAttrs as encoding@(Encoding v) = do
  elAttr "table" tableAttrs $ do
    b1 <- theadBuild encoding
    b2 <- el "tbody" $ forM_ as $ \a -> do
      el "tr" $ forM_ v $ \(OneEncoding _ encode) -> do
        dynPair <- mapDyn encode a
        dynAttrs <- mapDyn cellAttrs dynPair
        dynContent <- mapDyn cellContents dynPair
        elDynAttr "td" dynAttrs $ dyn dynContent
    return (mappend b1 b2)

dynamicEventful :: (MonadWidget t m, Foldable f, Semigroup e)
  => Map String String -- ^ Table element attributes
  -> f (Dynamic t a) -- ^ Dynamic values
  -> Encoding Headed (Cell m (Event t e)) a -- ^ Encoding of a value into cells
  -> m (Event t e)
dynamicEventful tableAttrs as encoding@(Encoding v) = do
  elAttr "table" tableAttrs $ do
    b1 <- theadBuild encoding
    b2 <- el "tbody" $ flip foldMapM as $ \a -> do
      el "tr" $ flip foldMapM v $ \(OneEncoding _ encode) -> do
        dynPair <- mapDyn encode a
        dynAttrs <- mapDyn cellAttrs dynPair
        dynContent <- mapDyn cellContents dynPair
        e <- elDynAttr "td" dynAttrs $ dyn dynContent
        -- TODO: This might actually be wrong. Revisit this.
        switchPromptly never e
    return (mappend b1 b2)

foldMapM :: (Foldable t, Monoid b, Monad m) => (a -> m b) -> t a -> m b
foldMapM f = foldrM (\a b -> fmap (flip mappend b) (f a)) mempty

foldAlternativeM :: (Foldable t, Monoid b, Monad m) => (a -> m b) -> t a -> m b
foldAlternativeM f = foldrM (\a b -> fmap (flip mappend b) (f a)) mempty

-- dynamicEventfulWith :: (MonadWidget t m, Foldable f, Semigroup e, Monoid b)
--   => (e -> b)
--   -> Map String String -- ^ Table element attributes
--   -> f (Dynamic t a) -- ^ Dynamic values
--   -> Encoding Headed (Cell m (Event t e)) a -- ^ Encoding of a value into cells
--   -> m (Event t e)
-- dynamicEventfulWith f tableAttrs as encoding@(Encoding v) = do
--   elAttr "table" tableAttrs $ do
--     b1 <- theadBuild encoding
--     b2 <- el "tbody" $ flip foldMapM as $ \a -> do
--       el "tr" $ flip foldMapM v $ \(OneEncoding _ encode) -> do
--         dynPair <- mapDyn encode a
--         dynAttrs <- mapDyn cellAttrs dynPair
--         dynContent <- mapDyn cellContents dynPair
--         e <- elDynAttr "td" dynAttrs $ dyn dynContent
--         flattenedEvent <- switchPromptly never e
--         return (f flattenedEvent)
--     return (mappend b1 b2)
--
-- dynamicEventfulMany :: (MonadWidget t m, Foldable f, Alternative g)
--   => Map String String -- ^ Table element attributes
--   -> f (Dynamic t a) -- ^ Dynamic values
--   -> Encoding Headed (NewCell (g (Compose m (Event t)))) a -- ^ Encoding of a value into cells
--   -> m (g (Event t e))
-- dynamicEventfulMany tableAttrs as encoding@(Encoding v) = do
--   elAttr "table" tableAttrs $ do
--     -- b1 <- theadBuild encoding
--     b2 <- el "tbody" $ flip foldMapM as $ \a -> do
--       el "tr" $ flip foldMapM v $ \(OneEncoding _ encode) -> do
--         dynPair <- mapDyn encode a
--         dynAttrs <- mapDyn cellAttrs dynPair
--         dynContent <- mapDyn cellContents dynPair
--         e <- elDynAttr "td" dynAttrs $ dyn dynContent
--         switchPromptly never e
--     return (mappend b1 b2)

-- data Update f = UpdateName (f Text) | UpdateAge (f Int) | ...