module Page exposing
  ( Page(..)
  , toHash
  , fromLocation
  )

import Navigation exposing (Location)
import UrlParser exposing (Parser, (</>), s)
import String

type Page =
  Home
  | Income
  | Categories
  | Statistics
  | NotFound

toHash : Page -> String
toHash page =
  case page of
    Home -> "#"
    Income -> "#income"
    Categories -> "#categories"
    Statistics -> "#statistics"
    NotFound -> "#notFound"

fromLocation : Location -> Page
fromLocation location =
  if location.hash == ""
    then
      Home
    else
      case UrlParser.parseHash pageParser location of
        Just page -> page
        Nothing -> NotFound

pageParser : Parser (Page -> a) a
pageParser =
  UrlParser.oneOf
    [ UrlParser.map Income (s "income")
    , UrlParser.map Categories (s "categories")
    , UrlParser.map Statistics (s "statistics")
    ]