module Decisions.GetTableData exposing (fetchDataFromServer)

import Dict
import Http
import Json.Decode as Decode
import Json.Decode.Pipeline exposing (required, optional, decode)
import Decisions.Messages as Messages
import Decisions.Model as Model


fetchDataFromServer : String -> Cmd Messages.Msg
fetchDataFromServer path =
    let
        request =
            Http.get path apiGetDecoder
    in
        Http.send Messages.UpdateDataFromServer request


apiGetDecoder : Decode.Decoder Model.DataFromServer
apiGetDecoder =
    decode Model.DataFromServer
        |> required "headers" (Decode.list headerDecoder)
        |> required "rows" (Decode.list rowDecoder)
        |> required "stageId" Decode.int
        |> optional "hasBulkDecisions" Decode.bool True
        |> optional "bulkDecisionsOptions" (Decode.list nestedOptionDecoder) []


headerDecoder : Decode.Decoder Model.HeaderData
headerDecoder =
    decode Model.HeaderData
        |> required "id" Decode.string
        |> required "value" Decode.string
        |> required "type" Decode.string
        |> required "visible" Decode.bool
        |> optional "options" (Decode.list Decode.string) []
        |> optional "displayedTextOptions" (Decode.list Decode.string) []
        |> optional "nestedOptions" (Decode.list nestedOptionDecoder) []
        |> optional "hasNumericalValues" Decode.bool False
        |> optional "description" (Decode.maybe Decode.string) Nothing


nestedOptionDecoder : Decode.Decoder Model.NestedOption
nestedOptionDecoder =
    decode Model.NestedOption
        |> required "parent" Decode.string
        |> optional "isSelectable" Decode.bool True
        |> optional "childrenHeader" (Decode.maybe Decode.string) Nothing
        |> optional "children" (Decode.list Decode.string) []


rowDecoder : Decode.Decoder Model.ApiRowData
rowDecoder =
    decode Model.ApiRowData
        |> required "id" Decode.string
        |> required "decision" Decode.string
        |> optional "presentationType" (Decode.maybe Decode.string) Nothing
        |> required "cells" (Decode.dict cellDecoder)
        |> optional "boolCells" (Decode.dict Decode.bool) Dict.empty
        |> optional "nestedCells" (Decode.dict decodeNestedCell) Dict.empty


decodeNestedCell : Decode.Decoder Model.NestedCell
decodeNestedCell =
    decode Model.NestedCell
        |> required "parent" Decode.string
        |> optional "child" (Decode.maybe Decode.string) Nothing


cellDecoder : Decode.Decoder Model.Cell
cellDecoder =
    decode Model.Cell
        |> required "value" Decode.string
        |> optional "link" (Decode.maybe Decode.string) Nothing