module ElmHub exposing (..)

import Html exposing (..)
import Html.Attributes exposing (class, target, href, property, defaultValue)
import Html.Events exposing (..)
import Auth
import Json.Decode exposing (Decoder)
import Json.Decode.Pipeline exposing (..)
import Dict exposing (Dict)
import Http
import Task


searchFeed : String -> Cmd Msg
searchFeed query =
    let
        url =
            "https://api.github.com/search/repositories?access_token="
                ++ Auth.token
                ++ "&q="
                ++ query
                ++ "+language:elm&sort=stars&order=desc"
    in
        Task.perform HandleSearchError HandleSearchResponse (Http.get responseDecoder url)


responseDecoder : Decoder (List SearchResult)
responseDecoder =
    Json.Decode.at [ "items" ] (Json.Decode.list searchResultDecoder)


searchResultDecoder : Decoder SearchResult
searchResultDecoder =
    decode SearchResult
        |> required "id" Json.Decode.int
        |> required "full_name" Json.Decode.string
        |> required "stargazers_count" Json.Decode.int


type alias Model =
    { query : String
    , results : Dict Int SearchResult
    , errorMessage : Maybe String
    }


type alias SearchResult =
    { id : Int
    , name : String
    , stars : Int
    }


initialModel : Model
initialModel =
    { query = "tutorial"
    , results = Dict.empty
    , errorMessage = Nothing
    }


view : Model -> Html Msg
view model =
    div [ class "content" ]
        [ header []
            [ h1 [] [ text "ElmHub" ]
            , span [ class "tagline" ] [ text "Like GitHub, but for Elm things." ]
            ]
        , input [ class "search-query", onInput SetQuery, defaultValue model.query ] []
        , button [ class "search-button", onClick Search ] [ text "Search" ]
        , ul [ class "results" ] (viewSearchResults model.results)
        ]


viewSearchResults : Dict Int SearchResult -> List (Html Msg)
viewSearchResults results =
    -- TODO sort by star count and render
    []


viewSearchResult : SearchResult -> Html Msg
viewSearchResult result =
    li []
        [ span [ class "star-count" ] [ text (toString result.stars) ]
        , a [ href ("https://github.com/" ++ result.name), target "_blank" ]
            [ text result.name ]
        , button [ class "hide-result", onClick (DeleteById result.id) ]
            [ text "X" ]
        ]


type Msg
    = Search
    | SetQuery String
    | DeleteById Int
    | HandleSearchResponse (List SearchResult)
    | HandleSearchError Http.Error
    | DoNothing


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    case msg of
        Search ->
            model ! [ searchFeed model.query ]

        SetQuery query ->
            { model | query = query } ! []

        HandleSearchError error ->
            case error of
                Http.UnexpectedPayload str ->
                    { model | errorMessage = Just str } ! []

                _ ->
                    { model | errorMessage = Just "Error loading search results" } ! []

        HandleSearchResponse results ->
            let
                resultsById : Dict Int SearchResult
                resultsById =
                    -- TODO convert results list into a Dict
                    Dict.empty
            in
                { model | results = resultsById } ! []

        DeleteById id ->
            -- TODO delete the result with the given id
            model ! []

        DoNothing ->
            model ! []