import Html exposing (beginnerProgram, div, button, text,input)
import Html.Events exposing (onClick, onInput)
import Html.Attributes exposing (..)

main : Program Never Model Msg
main =
  beginnerProgram { model = model, update = update, view = view}

type alias Model =
  { input : String
  , tasks : List String
  , done : Int
  , dayGoal : Int --default is 3
  , taskHistory : List String
  }

model : Model
model =
  Model "" [] 0 3 []

type Msg =
      Add
      | Del
      | DelCheckbox String
      | Input String
      | SetGoal


filterFirst : String -> List String -> List String
filterFirst str list = if str == ""
                          then list
                       else if (List.length list) == 0
                         then []
                       else if (List.take 1 list) == [str]
                         then (List.drop 1 list)
                       else List.append (List.take 1 list) (filterFirst str (List.drop 1 list))

toAdd : List String -> String -> Int
toAdd list str = if List.member str list
                    then 1
                 else 0

getFirst : String -> List String -> String
getFirst str list = if List.member str list
                      then str
                    else ""

appendHistory : String -> List String -> List String
appendHistory str list = if str == ""
                            then list
                          else
                            (List.append list [str])

--List.filter (\x-> (x/=model.input || model.input == "")
update : Msg -> Model -> Model
update msg model=
  case msg of
    Del ->
       (Model model.input (filterFirst model.input model.tasks)
                        (model.done+(toAdd model.tasks model.input)) (model.dayGoal) (appendHistory model.input model.taskHistory)) --because otherwise 1 delete with no args deletes every task
    Add ->
        (Model model.input (List.append model.tasks [model.input]) model.done (model.dayGoal) model.taskHistory)
    Input str ->
        (Model str model.tasks model.done (model.dayGoal) model.taskHistory)
    DelCheckbox str ->
        (Model model.input (filterFirst str model.tasks)
                         (model.done+(toAdd model.tasks model.input)) (model.dayGoal) (appendHistory str model.taskHistory))
    SetGoal ->
        (Model "" model.tasks model.done (Result.withDefault 0 (String.toInt model.input)) model.taskHistory)

checkIfdayGoal : Model -> Bool
checkIfdayGoal model = if model.done >= model.dayGoal
                        then True
                       else
                         False

getCongratulations : Model -> String
getCongratulations model =
                      if model.dayGoal == 0
                        then "Man, be ambitious!"
                      else if (checkIfdayGoal model)
                        then "Congratulations, goal achieved!"
                       else
                         "Keep it up, all you need is " ++ (toString (model.dayGoal - model.done))

view : Model -> Html.Html Msg
view model =
  div []
    [
    div [doneStyle] [text ("Done today: " ++ toString model.done)]
    , div [doneStyle] [text (getCongratulations model)]
    , div [alignCenter] [
            input [type_ "text", placeholder "Add new task",onInput Input] []
            , button [onClick Add] [text "Add"]
            , button [onClick Del] [text "Delete"]]
    , div [alignCenter] [input [type_ "text", placeholder "Set your day goal!",onInput Input] [] , button [onClick SetGoal] [text "Set Goal"]]
    , div [checkboxStyle] (List.map viewCheckbox model.tasks)
    , div [alignCenter] (List.map viewCheckbox model.taskHistory)
    ]

doneStyle : Html.Attribute msg
doneStyle =
  style
    [
      ("padding","10px 0")
      ,("text-align","center")
      ]

checkboxStyle : Html.Attribute msg
checkboxStyle =
  style
    [
      ("padding","20px 0")
      ,("text-align","center")
    ]

alignCenter : Html.Attribute msg
alignCenter = style [("text-align","center")]


viewMessage : String -> Html.Html msg
viewMessage msg =
  div [] [ text msg ]

viewCheckbox : String -> Html.Html Msg
viewCheckbox msg =
    div [] [ input [ Html.Attributes.type_ "checkbox", onClick (DelCheckbox msg)] []
    , text msg
    ]