Add a basic front end written in elm

.gitignore

@@ -2,3 +2,4 @@
 *.bak
 result
 .pls_cache
+elm-stuff

elm.json

@@ -0,0 +1,27 @@
+{
+    "type": "application",
+    "source-directories": [
+        "src"
+    ],
+    "elm-version": "0.19.1",
+    "dependencies": {
+        "direct": {
+            "elm/browser": "1.0.2",
+            "elm/core": "1.0.5",
+            "elm/html": "1.0.0",
+            "elm/http": "2.0.0",
+            "elm/json": "1.1.3"
+        },
+        "indirect": {
+            "elm/bytes": "1.0.8",
+            "elm/file": "1.0.5",
+            "elm/time": "1.0.0",
+            "elm/url": "1.0.0",
+            "elm/virtual-dom": "1.0.3"
+        }
+    },
+    "test-dependencies": {
+        "direct": {},
+        "indirect": {}
+    }
+}

flake.nix

@@ -20,7 +20,7 @@
         in {
           pr-status = pkgs.perlPackages.buildPerlPackage {
             pname = "pr-status";
-            version = "v0.0.1";
+            version = "v0.0.2";
             src = ./.;
             buildInputs = with pkgs; [ makeWrapper ];
             propagatedBuildInputs = with pkgs.perlPackages; [
@@ -43,6 +43,11 @@
         forAllSystems (system: self.packages.${system}.pr-status);
       devShells = forAllSystems (system:
         let pkgs = nixpkgsFor.${system};
+        npPackages = with pkgs; [
+          elmPackages.elm
+          elmPackages.elm-test
+          elmPackages.elm-live
+        ];
         in {
           default = pkgs.mkShell {
             shellHook = ''
@@ -57,7 +62,7 @@
               perl
               PerlCritic
               PerlTidy
-            ];
+            ] ++ npPackages;
           };
         });
     };

src/Main.elm

@@ -0,0 +1,204 @@
+module Main exposing (..)
+
+import Browser
+import Html exposing (..)
+import Html.Attributes exposing (href, placeholder, style)
+import Html.Events exposing (onClick, onInput)
+import Http
+import Json.Decode as Decode exposing (Decoder, field, int, list, map5, map6, string)
+
+
+type Status
+    = Complete
+    | Open
+
+
+type Msg
+    = RunSearch
+    | GotResult (Result Http.Error Model)
+    | SetPR String
+
+
+type alias Branches =
+    List String
+
+
+type alias Model =
+    { pull_request : Int
+    , release : String
+    , status : Status
+    , title : String
+    , branches : Branches
+    , error : String
+    }
+
+
+main : Program () Model Msg
+main =
+    Browser.element
+        { init = init
+        , view = view
+        , update = update
+        , subscriptions = \_ -> Sub.none
+        }
+
+
+update : Msg -> Model -> ( Model, Cmd Msg )
+update msg model =
+    case msg of
+        RunSearch ->
+            ( model, getResult model )
+
+        GotResult (Err _) ->
+            ( { model | error = "Can't load data!" }, Cmd.none )
+
+        GotResult (Ok pr) ->
+            ( pr, Cmd.none )
+
+        SetPR pr ->
+            ( { model
+                | pull_request =
+                    case String.toInt pr of
+                        Just a ->
+                            a
+
+                        Nothing ->
+                            0
+              }
+            , Cmd.none
+            )
+
+
+initialModel : Model
+initialModel =
+    { pull_request = 0
+    , release = ""
+    , status = Open
+    , title = ""
+    , branches = []
+    , error = ""
+    }
+
+
+init : () -> ( Model, Cmd Msg )
+init _ =
+    ( initialModel, Cmd.none )
+
+
+view : Model -> Html Msg
+view model =
+    div []
+        [ div []
+            [ input [ placeholder "search...", onInput SetPR ] []
+            , button [ onClick RunSearch ] [ text "Search" ]
+            ]
+        , div []
+            [ viewResult model ]
+        ]
+
+
+viewResult : Model -> Html Msg
+viewResult data =
+    case data.title of
+        "" ->
+            text ""
+
+        _ ->
+            let
+                prStr =
+                    String.fromInt data.pull_request
+            in
+            table []
+                [ tr []
+                    [ td [] [ b [] [ text "Title:" ] ]
+                    , td []
+                        [ a [ href ("https://github.com/NixOS/nixpkgs/pull/" ++ prStr) ]
+                            [ text data.title
+                            ]
+                        ]
+                    ]
+                , makeRow "Release:" data.release
+                , makeRow "Status:"
+                    (case data.status of
+                        Complete ->
+                            "complete"
+
+                        Open ->
+                            "open"
+                    )
+                , viewBranches data.branches
+                , case data.error of
+                    "" ->
+                        text ""
+
+                    _ ->
+                        span [ style "color" "red" ] [ text data.error ]
+                ]
+
+
+viewBranches : List String -> Html Msg
+viewBranches blist =
+    tr []
+        [ td [] [ b [] [ text "Branches:" ] ]
+        , td []
+            [ ul []
+                (List.map viewBranch blist)
+            ]
+        ]
+
+
+viewBranch : String -> Html Msg
+viewBranch branch =
+    li [] [ text branch ]
+
+
+makeRow : String -> String -> Html Msg
+makeRow title data =
+    tr []
+        [ td [] [ b [] [ text title ] ]
+        , td [] [ text data ]
+        ]
+
+
+getResult : Model -> Cmd Msg
+getResult model =
+    Http.get
+        { url = "/" ++ String.fromInt model.pull_request
+        , expect = Http.expectJson GotResult resultDecoder
+        }
+
+
+resultDecoder : Decoder Model
+resultDecoder =
+    map5
+        (\pull_request release status title branches ->
+            { pull_request = pull_request
+            , release = release
+            , status = status
+            , title = title
+            , branches = branches
+            , error = ""
+            }
+        )
+        (field "pull_request" int)
+        (field "release" string)
+        (field "status" statusDecoder)
+        (field "title" string)
+        (field "branches" (list string))
+
+
+statusDecoder : Decoder Status
+statusDecoder =
+    Decode.string
+        |> Decode.andThen
+            (\str ->
+                case str of
+                    "complete" ->
+                        Decode.succeed Complete
+
+                    "open" ->
+                        Decode.succeed Open
+
+                    _ ->
+                        Decode.fail "invalid status"
+            )