module LoggedIn.Home.View.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.Home.Action as HomeAction
import LoggedIn.Home.Model as HomeModel

import Action exposing (Action)
import LoggedData exposing (LoggedData)
import Model.Payment exposing (Payments, perPage)

import View.Icon exposing (renderIcon)

showedPages : Int
showedPages = 5

paymentsPaging : Address Action -> Payments -> HomeModel.Model -> Html
paymentsPaging address payments homeModel =
  let maxPage = ceiling (toFloat (List.length payments) / toFloat perPage)
      pages = truncatePages homeModel.currentPage [1..maxPage]
  in  if maxPage == 1
        then
          text ""
        else
          div
            [ class "pages" ]
            (  ( if homeModel.currentPage > 1
                   then [ firstPage address, previousPage address homeModel ]
                   else []
               )
            ++ ( List.map (paymentsPage address homeModel) pages)
            ++ ( if homeModel.currentPage < maxPage
                   then [ nextPage address homeModel, 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 (Action.UpdateLoggedIn << LoggedInAction.HomeAction << HomeAction.UpdatePage <| 1)
    ]
    [ renderIcon "fast-backward" ]

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

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

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

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