module View.LoggedIn.Paging
  ( paymentsPaging
  ) where

import Signal exposing (Address)

import Html exposing (..)
import Html.Attributes exposing (..)
import Html.Events exposing (..)

import LoggedIn.Action as LoggedInAction
import LoggedIn.Model as LoggedInModel

import Model.Action as Action exposing (..)
import Model.Payment exposing (perPage)

import View.Icon exposing (renderIcon)

showedPages : Int
showedPages = 5

paymentsPaging : Address Action -> LoggedInModel.Model -> Html
paymentsPaging address loggedInModel =
  let maxPage = ceiling (toFloat loggedInModel.paymentsCount / toFloat perPage)
      pages = truncatePages loggedInModel.currentPage [1..maxPage]
  in  if maxPage == 1
        then
          text ""
        else
          div
            [ class "pages" ]
            (  ( if loggedInModel.currentPage > 1
                   then [ firstPage address, previousPage address loggedInModel ]
                   else []
               )
            ++ ( List.map (paymentsPage address loggedInModel) pages)
            ++ ( if loggedInModel.currentPage < maxPage
                   then [ nextPage address loggedInModel, lastPage address maxPage ]
                   else []
               )
            )

truncatePages : Int -> List Int -> List Int
truncatePages currentPage pages =
  let totalPages = List.length pages
      showedLeftPages = ceiling ((toFloat showedPages - 1) / 2)
      showedRightPages = floor ((toFloat showedPages - 1) / 2)
      truncatedPages =
        if currentPage < showedLeftPages then
          [1..showedPages]
        else if currentPage > totalPages - showedRightPages then
          [(totalPages - showedPages)..totalPages]
        else
          [(currentPage - showedLeftPages)..(currentPage + showedRightPages)]
  in  List.filter (flip List.member pages) truncatedPages

firstPage : Address Action -> Html
firstPage address =
  button
    [ class "page"
    , onClick address (UpdateLoggedIn (LoggedInAction.UpdatePage 1))
    ]
    [ renderIcon "fast-backward" ]

previousPage : Address Action -> LoggedInModel.Model -> Html
previousPage address loggedInModel =
  button
    [ class "page"
    , onClick address (UpdateLoggedIn (LoggedInAction.UpdatePage (loggedInModel.currentPage - 1)))
    ]
    [ renderIcon "backward" ]

nextPage : Address Action -> LoggedInModel.Model -> Html
nextPage address loggedInModel =
  button
    [ class "page"
    , onClick address (UpdateLoggedIn (LoggedInAction.UpdatePage (loggedInModel.currentPage + 1)))
    ]
    [ renderIcon "forward" ]

lastPage : Address Action -> Int -> Html
lastPage address maxPage =
  button
    [ class "page"
    , onClick address (UpdateLoggedIn (LoggedInAction.UpdatePage maxPage))
    ]
    [ renderIcon "fast-forward" ]

paymentsPage : Address Action -> LoggedInModel.Model -> Int -> Html
paymentsPage address loggedInModel page =
  let onCurrentPage = page == loggedInModel.currentPage
  in  button
        [ classList
            [ ("page", True)
            , ("current", onCurrentPage)
            ]
        , onClick address <|
            if onCurrentPage then Action.NoOp else UpdateLoggedIn (LoggedInAction.UpdatePage page)
        ]
        [ text (toString page) ]