module View.Payment.Header
  ( view
  , In(..)
  , Out(..)
  ) where

import           Control.Monad          (forM_)
import           Control.Monad.IO.Class (liftIO)
import qualified Data.List              as L hiding (groupBy)
import qualified Data.Map               as M
import           Data.Maybe             (fromMaybe)
import           Data.Text              (Text)
import qualified Data.Text              as T
import           Data.Time              (NominalDiffTime)
import qualified Data.Time              as Time
import qualified Data.Validation        as V
import           Prelude                hiding (init)
import           Reflex.Dom             (Dynamic, Event, MonadWidget, Reflex)
import qualified Reflex.Dom             as R

import           Common.Model           (Category, Currency,
                                         ExceedingPayer (..), Frequency (..),
                                         Income (..), Payment (..),
                                         PaymentCategory, SavedPayment (..),
                                         User (..))
import qualified Common.Model           as CM
import qualified Common.Msg             as Msg
import qualified Common.View.Format     as Format

import qualified Component.Button       as Button
import qualified Component.Input        as Input
import qualified Component.Modal        as Modal
import qualified Component.Select       as Select
import qualified Util.List              as L
import qualified View.Payment.Form      as Form
import           View.Payment.Init      (Init (..))

data In t = In
  { _in_init              :: Init
  , _in_currency          :: Currency
  , _in_payments          :: Dynamic t [Payment]
  , _in_searchPayments    :: Dynamic t [Payment]
  , _in_paymentCategories :: Dynamic t [PaymentCategory]
  }

data Out t = Out
  { _out_searchName      :: Dynamic t Text
  , _out_searchFrequency :: Dynamic t Frequency
  , _out_addPayment      :: Event t SavedPayment
  }

view :: forall t m. MonadWidget t m => In t -> m (Out t)
view input =
  R.divClass "header" $ do
    rec
      addPayment <-
        payerAndAdd
          incomes
          payments
          users
          categories
          paymentCategories
          currency
          searchFrequency
      let resetSearchName = fmap (const ()) $ addPayment
      (searchName, searchFrequency)  <- searchLine resetSearchName

      infos (_in_searchPayments input) users currency

    return $ Out
      { _out_searchName = searchName
      , _out_searchFrequency = searchFrequency
      , _out_addPayment = addPayment
      }
  where
    init = _in_init input
    incomes = _init_incomes init
    initPayments = _init_payments init
    payments = _in_payments input
    users = _init_users init
    categories = _init_categories init
    currency = _in_currency input
    paymentCategories = _in_paymentCategories input

payerAndAdd
  :: forall t m. MonadWidget t m
  => [Income]
  -> Dynamic t [Payment]
  -> [User]
  -> [Category]
  -> Dynamic t [PaymentCategory]
  -> Currency
  -> Dynamic t Frequency
  -> m (Event t SavedPayment)
payerAndAdd incomes payments users categories paymentCategories currency frequency = do
  time <- liftIO Time.getCurrentTime
  R.divClass "payerAndAdd" $ do

    let exceedingPayers =
          R.ffor payments $ \ps ->
            CM.getExceedingPayers time users incomes $
              filter ((==) Punctual . _payment_frequency) ps

    R.divClass "exceedingPayers" $
      R.simpleList exceedingPayers $ \exceedingPayer ->
        R.elClass "span" "exceedingPayer" $ do
          R.elClass "span" "userName" $
            R.dynText . R.ffor exceedingPayer $ \ep ->
              fromMaybe "" . fmap _user_name $ CM.findUser (_exceedingPayer_userId ep) users
          R.elClass "span" "amount" $ do
            R.text "+ "
            R.dynText . R.ffor exceedingPayer $ \ep ->
              Format.price currency $ _exceedingPayer_amount ep

    addPayment <- Button._out_clic <$>
      (Button.view $
        (Button.defaultIn (R.text $ Msg.get Msg.Payment_Add))
          { Button._in_class = R.constDyn "addPayment"
          })

    Modal.view $ Modal.In
      { Modal._in_show    = addPayment
      , Modal._in_content = \_ -> return (R.never, R.never) -- TODO
      }

searchLine
  :: forall t m. MonadWidget t m
  => Event t ()
  -> m (Dynamic t Text, Dynamic t Frequency)
searchLine reset = do
  R.divClass "searchLine" $ do
    searchName <- Input._out_raw <$> (Input.view
      ( Input.defaultIn { Input._in_label = Msg.get Msg.Search_Name })
      ("" <$ reset)
      R.never)

    let frequencies = M.fromList
          [ (Punctual, Msg.get Msg.Payment_PunctualMale)
          , (Monthly, Msg.get Msg.Payment_MonthlyMale)
          ]

    searchFrequency <- Select._out_raw <$> (Select.view $ Select.In
        { Select._in_label        = ""
        , Select._in_initialValue = Punctual
        , Select._in_value        = R.never
        , Select._in_values       = R.constDyn frequencies
        , Select._in_reset        = R.never
        , Select._in_isValid      = V.Success
        , Select._in_validate     = R.never
        })

    return (searchName, searchFrequency)

infos
  :: forall t m. MonadWidget t m
  => Dynamic t [Payment]
  -> [User]
  -> Currency -> m ()
infos payments users currency =
  R.divClass "infos" $ do

    R.elClass "span" "total" $ do
      R.dynText $ do
        ps <- payments
        let paymentCount = length ps
            total = sum . map _payment_cost $ ps
        pure . Msg.get $ Msg.Payment_Worth
          (T.intercalate " "
            [ (Format.number paymentCount)
            , if paymentCount > 1
                then Msg.get Msg.Payment_Many
                else Msg.get Msg.Payment_One
            ])
          (Format.price currency total)

    R.elClass "span" "partition" . R.dynText $ do
      ps <- payments
      let totalByUser =
            L.sortBy (\(_, t1) (_, t2) -> compare t2 t1)
              . map (\(u, xs) -> (u, sum . map snd $ xs))
              . L.groupBy fst
              . map (\p -> (_payment_user p, _payment_cost p))
              $ ps
      pure . T.intercalate ", " . flip map totalByUser $ \(userId, userTotal) ->
        Msg.get $ Msg.Payment_By
          (fromMaybe "" . fmap _user_name $ CM.findUser userId users)
          (Format.price currency userTotal)