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

showedPages : Int
showedPages = 5

view : Int -> Int -> msg -> (Int -> msg) -> Html msg
view currentPage payments noOp pageMsg =
  let maxPage = ceiling (toFloat payments / toFloat perPage)
      pages = truncatePages currentPage (List.range 1 maxPage)
  in  if maxPage <= 1
        then
          text ""
        else
          div
            [ class "pages" ]
            (  [ firstPage currentPage pageMsg
               , previousPage currentPage noOp pageMsg
               ]
            ++ ( List.map (paymentsPage currentPage noOp pageMsg) pages)
            ++ [ nextPage currentPage maxPage noOp pageMsg
               , lastPage currentPage maxPage pageMsg
               ]
            )

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
          (List.range 1 showedPages)
        else if currentPage > totalPages - showedRightPages then
          (List.range (totalPages - showedPages + 1) totalPages)
        else
          (List.range (currentPage - showedLeftPages) (currentPage + showedRightPages))
  in  List.filter (flip List.member pages) truncatedPages

firstPage : Int -> (Int -> msg) -> Html msg
firstPage currentPage pageMsg =
  button
    [ classList
        [ ("page", True)
        , ("disable", currentPage <= 1)
        ]
    , onClick (pageMsg 1)
    ]
    [ FontAwesome.fast_backward grey 13 ]

previousPage : Int -> msg -> (Int -> msg) -> Html msg
previousPage currentPage noOp pageMsg =
  button
    [ class "page"
    , onClick <|
        if currentPage > 1
          then (pageMsg <| currentPage - 1)
          else noOp
    ]
    [ FontAwesome.backward grey 13 ]

nextPage : Int -> Int -> msg -> (Int -> msg) -> Html msg
nextPage currentPage maxPage noOp pageMsg =
  button
    [ class "page"
    , onClick <|
        if currentPage < maxPage
          then (pageMsg <| currentPage + 1)
          else noOp
    ]
    [ FontAwesome.forward grey 13 ]

lastPage : Int -> Int -> (Int -> msg) -> Html msg
lastPage currentPage maxPage pageMsg =
  button
    [ class "page"
    , onClick (pageMsg maxPage)
    ]
    [ FontAwesome.fast_forward grey 13 ]

paymentsPage : Int -> msg -> (Int -> msg) -> Int -> Html msg
paymentsPage currentPage noOp pageMsg page =
  let onCurrentPage = page == currentPage
  in  button
        [ classList
            [ ("page", True)
            , ("current", onCurrentPage)
            ]
        , onClick <|
            if onCurrentPage
              then noOp
              else pageMsg page
        ]
        [ text (toString page) ]

grey : Color
grey = Color.greyscale 0.35