Form.elm

module Form.Form (selectField, selectCountryField, dateOfBirthField) where

import Html exposing (..)
import Html.Attributes exposing (..)
import Html.Events exposing (..)
import List.Extra exposing (zip)
import Date exposing (Date)
import Date.Core exposing (monthList)
import Date.Utils exposing (dateFromFields)
import Json.Decode as JD
import Task exposing (Task)

type alias SelectFieldOpts valueType actionType = 
  { label : String
  , value : valueType
  , action : actionType }


selectField : Signal.Address actionType -> valueType -> List (SelectFieldOpts valueType actionType) -> Html
selectField address currentValue opts =
  let
    -- Build a list of a numerical key matched with the settings for each option
    ids = List.map toString [0..(List.length opts)]
    idAndOpts = zip ids opts
    
    -- Given an id, this returns the action for that id
    getActionForId id =
      let
        selectFieldOpts = case (List.filter (\(listId, _) -> listId == id) idAndOpts |> List.head) of
          Just opt -> opt |> snd
          Nothing -> Debug.crash "Somehow an option without a matching id was selected (this should be impossible!)"
        
      in
      selectFieldOpts.action
    
    isSelected opt =
      currentValue == opt.value
    
    valueDecoder : JD.Decoder String
    valueDecoder =
      JD.at ["target", "value"] JD.string
    
    makeOption (id, opt) =
      option [ value id
             , selected (isSelected opt)
             ] [ text opt.label ]
  in
  select [ on "change" valueDecoder (\id -> Signal.message address (getActionForId id)) ] (List.map makeOption idAndOpts)


selectCountryField : Signal.Address a -> String -> (String -> a) -> Html
selectCountryField address currentCountry action =
  let
    countries = ["Afghanistan","Albania","Algeria","Andorra","Angola","Anguilla","Antigua & Barbuda","Argentina","Armenia","Aruba","Australia","Austria","Azerbaijan","Bahamas" ,"Bahrain","Bangladesh","Barbados","Belarus","Belgium","Belize","Benin","Bermuda","Bhutan","Bolivia","Bosnia & Herzegovina","Botswana","Brazil","British Virgin Islands" ,"Brunei","Bulgaria","Burkina Faso","Burundi","Cambodia","Cameroon","Cape Verde","Cayman Islands","Chad","Chile","China","Colombia","Congo","Cook Islands","Costa Rica" ,"Cote D Ivoire","Croatia","Cruise Ship","Cuba","Cyprus","Czech Republic","Denmark","Djibouti","Dominica","Dominican Republic","Ecuador","Egypt","El Salvador","Equatorial Guinea" ,"Estonia","Ethiopia","Falkland Islands","Faroe Islands","Fiji","Finland","France","French Polynesia","French West Indies","Gabon","Gambia","Georgia","Germany","Ghana" ,"Gibraltar","Greece","Greenland","Grenada","Guam","Guatemala","Guernsey","Guinea","Guinea Bissau","Guyana","Haiti","Honduras","Hong Kong","Hungary","Iceland","India" ,"Indonesia","Iran","Iraq","Ireland","Isle of Man","Israel","Italy","Jamaica","Japan","Jersey","Jordan","Kazakhstan","Kenya","Kuwait","Kyrgyz Republic","Laos","Latvia" ,"Lebanon","Lesotho","Liberia","Libya","Liechtenstein","Lithuania","Luxembourg","Macau","Macedonia","Madagascar","Malawi","Malaysia","Maldives","Mali","Malta","Mauritania" ,"Mauritius","Mexico","Moldova","Monaco","Mongolia","Montenegro","Montserrat","Morocco","Mozambique","Namibia","Nepal","Netherlands","Netherlands Antilles","New Caledonia" ,"New Zealand","Nicaragua","Niger","Nigeria","Norway","Oman","Pakistan","Palestine","Panama","Papua New Guinea","Paraguay","Peru","Philippines","Poland","Portugal" ,"Puerto Rico","Qatar","Reunion","Romania","Russia","Rwanda","Saint Pierre & Miquelon","Samoa","San Marino","Satellite","Saudi Arabia","Senegal","Serbia","Seychelles" ,"Sierra Leone","Singapore","Slovakia","Slovenia","South Africa","South Korea","Spain","Sri Lanka","St Kitts & Nevis","St Lucia","St Vincent","St. Lucia","Sudan" ,"Suriname","Swaziland","Sweden","Switzerland","Syria","Taiwan","Tajikistan","Tanzania","Thailand","Timor L'Este","Togo","Tonga","Trinidad & Tobago","Tunisia" ,"Turkey","Turkmenistan","Turks & Caicos","Uganda","Ukraine","United Arab Emirates","United Kingdom","Uruguay","Uzbekistan","Venezuela","Vietnam","Virgin Islands (US)" ,"Yemen","Zambia","Zimbabwe"]
    opts = List.map (\country -> { label = country, value = country, action = action country }) countries
  in
  selectField address currentCountry opts


type DateOfBirthAction = Noop | ChangeDay Int | ChangeMonth Date.Month | ChangeYear Int


dateOfBirthField : Signal.Address a -> Date -> (Date -> a) -> Html
dateOfBirthField address currentDate action =
  let
    mailbox : Signal.Mailbox DateOfBirthAction
    mailbox = Signal.mailbox Noop
    
    -- So now I need to somehow turn the Signal from this mailbox into a date and send it out on address as action.
    -- I think maybe I can use forwardTo.  Maybe I need map too?  Actually I think this is a case for foldp.  But how?
    -- Maybe the problem is that this foldp is disconnected from any other foldp, and it should integrate address/action
    -- or something.  I kind of need something like 'on', but that is native
    --date : Signal Date
    date = 
      let
        dateUpdate : DateOfBirthAction -> Date -> Date
        dateUpdate action date = case action of
          ChangeDay day -> dateFromFields day (Date.month date) (Date.year date) 0 0 0 0
          ChangeMonth month -> dateFromFields (Date.day date) month (Date.year date) 0 0 0 0
          ChangeYear year -> dateFromFields (Date.day date) (Date.month date) year 0 0 0 0
          otherwise -> date
        
        sendDate : Date -> Signal.Message
        sendDate date =
          Signal.message address (action date)
        
        date : Signal Date
        date = Signal.foldp (dateUpdate >> sendDate) currentDate mailbox.signal
      in
      -- the thing I want to send to 'address' is 'action latestSignalInDate'
      1
    
    dateSelect = selectField
      mailbox.address
      (Date.day currentDate)
      (List.map (\day -> { label = toString day, value = day, action = ChangeDay day }) [1..31])
    
    monthSelect = selectField
      mailbox.address
      (Date.month currentDate)
      (List.map (\month -> { label = toString month, value = month, action = ChangeMonth month }) monthList)
    
    yearSelect = selectField
      mailbox.address
      (Date.day currentDate)
      (List.map (\year -> { label = toString year, value = year, action = ChangeYear year }) [1935..2015]) -- TODO: up to the current year?
  in
  div []
    [ dateSelect
    , monthSelect
    , yearSelect ]