module PostVisibleColumns exposing (post)

import Http
import Json.Decode as Decode
import Json.Encode as Encode
import InputTable.Model exposing (Column)


type alias VisibleColumns =
    List Int


post : String -> List (Column a) -> (Result Http.Error String -> msg) -> String -> Cmd msg
post url columns msg id =
    let
        visibleColumns =
            columns
                |> List.map toggleColumnsIfHasId
                |> List.indexedMap (\i c -> { visible = c.visible, i = i })
                |> List.filter .visible
                |> List.map .i

        toggleColumnsIfHasId column =
            if column.id == id then
                { column | visible = not column.visible }
            else
                column
    in
        postVisibleColumns url visibleColumns msg


postVisibleColumns : String -> VisibleColumns -> (Result Http.Error String -> msg) -> Cmd msg
postVisibleColumns url visibleColumns msg =
    let
        request =
            Http.post url (Http.jsonBody (encodeVisibleColumns visibleColumns)) postReplyDecoder
    in
        Http.send msg request


encodeVisibleColumns : VisibleColumns -> Encode.Value
encodeVisibleColumns visibleColumns =
    Encode.list (List.map Encode.int visibleColumns)


postReplyDecoder : Decode.Decoder String
postReplyDecoder =
    Decode.string