module LoggedIn.Home.View.Paging exposing
  ( view
  )

import Color exposing (Color)

import FontAwesome

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

import LoggedIn.Msg as LoggedInMsg

import LoggedIn.Home.Msg as HomeMsg
import LoggedIn.Home.Model as HomeModel

import Msg exposing (Msg)
import LoggedData exposing (LoggedData)
import Model.Payment as Payment exposing (Payments, perPage)

showedPages : Int
showedPages = 5

view : HomeModel.Model -> Payments -> Html Msg
view homeModel payments =
  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" ]
            (  [ firstPage homeModel, previousPage homeModel ]
            ++ ( List.map (paymentsPage homeModel) pages)
            ++ [ nextPage homeModel maxPage, lastPage homeModel maxPage ]
            )

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 + 1)..totalPages]
        else
          [(currentPage - showedLeftPages)..(currentPage + showedRightPages)]
  in  List.filter (flip List.member pages) truncatedPages

firstPage : HomeModel.Model -> Html Msg
firstPage homeModel =
  button
    [ classList
        [ ("page", True)
        , ("disable", homeModel.currentPage <= 1)
        ]
    , onClick (Msg.UpdateLoggedIn << LoggedInMsg.HomeMsg << HomeMsg.UpdatePage <| 1)
    ]
    [ FontAwesome.fast_backward grey 13 ]

previousPage : HomeModel.Model -> Html Msg
previousPage homeModel =
  button
    [ class "page"
    , onClick <|
        if homeModel.currentPage > 1
          then (Msg.UpdateLoggedIn << LoggedInMsg.HomeMsg << HomeMsg.UpdatePage <| homeModel.currentPage - 1)
          else Msg.NoOp
    ]
    [ FontAwesome.backward grey 13 ]

nextPage : HomeModel.Model -> Int -> Html Msg
nextPage homeModel maxPage =
  button
    [ class "page"
    , onClick <|
        if homeModel.currentPage < maxPage
          then (Msg.UpdateLoggedIn << LoggedInMsg.HomeMsg << HomeMsg.UpdatePage <| homeModel.currentPage + 1)
          else Msg.NoOp
    ]
    [ FontAwesome.forward grey 13 ]

lastPage : HomeModel.Model -> Int -> Html Msg
lastPage homeModel maxPage =
  button
    [ class "page"
    , onClick (Msg.UpdateLoggedIn << LoggedInMsg.HomeMsg << HomeMsg.UpdatePage <| maxPage)
    ]
    [ FontAwesome.fast_forward grey 13 ]

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

grey : Color
grey = Color.greyscale 0.35