aux-search/src/Search.elm

module Search exposing
    ( Model
    , Msg(..)
    , Options
    , ResultItem
    , SearchResult
    , Sort(..)
    , channelDetailsFromId
    , channels
    , decodeResult
    , fromSortId
    , init
    , makeRequest
    , makeRequestBody
    , shouldLoad
    , update
    , view
    )

import Base64
import Browser.Dom
import Browser.Navigation
import Html
    exposing
        ( Html
        , a
        , button
        , div
        , em
        , form
        , h1
        , h4
        , input
        , label
        , li
        , option
        , p
        , select
        , strong
        , text
        , ul
        )
import Html.Attributes
    exposing
        ( attribute
        , autofocus
        , class
        , classList
        , href
        , id
        , placeholder
        , selected
        , type_
        , value
        )
import Html.Events
    exposing
        ( onClick
        , onInput
        , onSubmit
        )
import Http
import Json.Decode
import Json.Encode
import RemoteData
import Route exposing (Route)
import Route.SearchQuery
import Set
import Task
import Url
import Url.Builder


type alias Model a =
    { channel : String
    , query : Maybe String
    , result : RemoteData.WebData (SearchResult a)
    , show : Maybe String
    , from : Int
    , size : Int
    , sort : Sort
    }


type alias SearchResult a =
    { hits : ResultHits a
    }


type alias ResultHits a =
    { total : ResultHitsTotal
    , max_score : Maybe Float
    , hits : List (ResultItem a)
    }


type alias ResultHitsTotal =
    { value : Int
    , relation : String
    }


type alias ResultItem a =
    { index : String
    , id : String
    , score : Maybe Float
    , source : a
    , text : Maybe String
    , matched_queries : Maybe (List String)
    }


type Sort
    = Relevance
    | AlphabeticallyAsc
    | AlphabeticallyDesc


init : Route.SearchArgs -> Maybe (Model a) -> ( Model a, Cmd (Msg a) )
init args model =
    let
        channel =
            model
                |> Maybe.map (\x -> x.channel)
                |> Maybe.withDefault defaultChannel

        from =
            model
                |> Maybe.map (\x -> x.from)
                |> Maybe.withDefault 0

        size =
            model
                |> Maybe.map (\x -> x.size)
                |> Maybe.withDefault 30
    in
    ( { channel = Maybe.withDefault channel args.channel
      , query = Maybe.andThen Route.SearchQuery.searchQueryToString args.query
      , result =
            model
                |> Maybe.map (\x -> x.result)
                |> Maybe.withDefault RemoteData.NotAsked
      , show = args.show
      , from = Maybe.withDefault from args.from
      , size = Maybe.withDefault size args.size
      , sort =
            args.sort
                |> Maybe.withDefault ""
                |> fromSortId
                |> Maybe.withDefault Relevance
      }
        |> ensureLoading
    , Browser.Dom.focus "search-query-input" |> Task.attempt (\_ -> NoOp)
    )


shouldLoad : Model a -> Bool
shouldLoad model =
    model.result == RemoteData.Loading


ensureLoading : Model a -> Model a
ensureLoading model =
    if model.query /= Nothing && model.query /= Just "" && List.member model.channel channels then
        { model | result = RemoteData.Loading }

    else
        model



-- ---------------------------
-- UPDATE
-- ---------------------------


type Msg a
    = NoOp
    | SortChange String
    | ChannelChange String
    | QueryInput String
    | QueryInputSubmit
    | QueryResponse (RemoteData.WebData (SearchResult a))
    | ShowDetails String
    | ChangePage Int


update :
    Route.SearchRoute
    -> Browser.Navigation.Key
    -> Msg a
    -> Model a
    -> ( Model a, Cmd (Msg a) )
update toRoute navKey msg model =
    case msg of
        NoOp ->
            ( model
            , Cmd.none
            )

        SortChange sortId ->
            { model
                | sort = fromSortId sortId |> Maybe.withDefault Relevance
                , from = 0
            }
                |> ensureLoading
                |> pushUrl toRoute navKey

        ChannelChange channel ->
            { model
                | channel = channel
                , from = 0
            }
                |> ensureLoading
                |> pushUrl toRoute navKey

        QueryInput query ->
            ( { model | query = Just query }
            , Cmd.none
            )

        QueryInputSubmit ->
            { model | from = 0 }
                |> ensureLoading
                |> pushUrl toRoute navKey

        QueryResponse result ->
            ( { model | result = result }
            , Cmd.none
            )

        ShowDetails selected ->
            { model
                | show =
                    if model.show == Just selected then
                        Nothing

                    else
                        Just selected
            }
                |> pushUrl toRoute navKey

        ChangePage from ->
            { model | from = from }
                |> ensureLoading
                |> pushUrl toRoute navKey


pushUrl : Route.SearchRoute -> Browser.Navigation.Key -> Model a -> ( Model a, Cmd msg )
pushUrl toRoute navKey model =
    Tuple.pair model <|
        if model.query == Nothing || model.query == Just "" then
            Cmd.none

        else
            Browser.Navigation.pushUrl navKey <| createUrl toRoute model


createUrl : Route.SearchRoute -> Model a -> String
createUrl toRoute model =
    Route.routeToString <|
        toRoute
            { channel = Just model.channel
            , query = Maybe.map Route.SearchQuery.toSearchQuery model.query
            , show = model.show
            , from = Just model.from
            , size = Just model.size
            , sort = Just <| toSortId model.sort
            }



-- VIEW


type Channel
    = Unstable
    | Release_20_03
    | Release_20_09


{-| TODO: we should consider using more dynamic approach here
and load channels from apis similar to what status page does
-}
type alias ChannelDetails =
    { id : String
    , title : String
    , jobset : String
    , branch : String
    }


defaultChannel : String
defaultChannel =
    "20.09"


channelDetails : Channel -> ChannelDetails
channelDetails channel =
    case channel of
        Unstable ->
            ChannelDetails "unstable" "unstable" "nixos/trunk-combined" "nixos-unstable"

        Release_20_03 ->
            ChannelDetails "20.03" "20.03" "nixos/release-20.03" "nixos-20.03"

        Release_20_09 ->
            ChannelDetails "20.09" "20.09" "nixos/release-20.09" "nixos-20.09"


channelFromId : String -> Maybe Channel
channelFromId channel_id =
    case channel_id of
        "unstable" ->
            Just Unstable

        "20.03" ->
            Just Release_20_03

        "20.09" ->
            Just Release_20_09

        _ ->
            Nothing


channelDetailsFromId : String -> Maybe ChannelDetails
channelDetailsFromId channel_id =
    channelFromId channel_id
        |> Maybe.map channelDetails


channels : List String
channels =
    [ "20.03"
    , "20.09"
    , "unstable"
    ]


sortBy : List Sort
sortBy =
    [ Relevance
    , AlphabeticallyAsc
    , AlphabeticallyDesc
    ]


toSortQuery :
    Sort
    -> String
    -> ( String, Json.Encode.Value )
toSortQuery sort field =
    ( "sort"
    , case sort of
        AlphabeticallyAsc ->
            Json.Encode.list Json.Encode.object
                [ [ ( field, Json.Encode.string "asc" )
                  ]
                ]

        AlphabeticallyDesc ->
            Json.Encode.list Json.Encode.object
                [ [ ( field, Json.Encode.string "desc" )
                  ]
                ]

        Relevance ->
            Json.Encode.list Json.Encode.string
                [ "_score"
                ]
    )


toSortTitle : Sort -> String
toSortTitle sort =
    case sort of
        AlphabeticallyAsc ->
            "Alphabetically Ascending"

        AlphabeticallyDesc ->
            "Alphabetically Descending"

        Relevance ->
            "Relevance"


toSortId : Sort -> String
toSortId sort =
    case sort of
        AlphabeticallyAsc ->
            "alpha_asc"

        AlphabeticallyDesc ->
            "alpha_desc"

        Relevance ->
            "relevance"


fromSortId : String -> Maybe Sort
fromSortId id =
    case id of
        "alpha_asc" ->
            Just AlphabeticallyAsc

        "alpha_desc" ->
            Just AlphabeticallyDesc

        "relevance" ->
            Just Relevance

        _ ->
            Nothing


view :
    { toRoute : Route.SearchRoute
    , categoryName : String
    }
    -> String
    -> Model a
    -> (String -> Maybe String -> SearchResult a -> Html b)
    -> (Msg a -> b)
    -> Html b
view { toRoute, categoryName } title model viewSuccess outMsg =
    div
        [ class "search-page"
        ]
        [ h1 [ class "page-header" ] [ text title ]
        , div
            [ class "search-input"
            ]
            [ form [ onSubmit (outMsg QueryInputSubmit) ]
                [ p
                    []
                    ([]
                        |> List.append
                            (if List.member model.channel channels then
                                []

                             else
                                [ p [ class "alert alert-error" ]
                                    [ h4 [] [ text "Wrong channel selected!" ]
                                    , text <| "Please select one of the channels above!"
                                    ]
                                ]
                            )
                        |> List.append
                            [ p []
                                [ strong []
                                    [ text "Channel: " ]
                                , div
                                    [ class "btn-group"
                                    , attribute "data-toggle" "buttons-radio"
                                    ]
                                    (List.filterMap
                                        (\channel_id ->
                                            channelDetailsFromId channel_id
                                                |> Maybe.map
                                                    (\channel ->
                                                        button
                                                            [ type_ "button"
                                                            , classList
                                                                [ ( "btn", True )
                                                                , ( "active", channel.id == model.channel )
                                                                ]
                                                            , onClick <| outMsg (ChannelChange channel.id)
                                                            ]
                                                            [ text channel.title ]
                                                    )
                                        )
                                        channels
                                    )
                                ]
                            ]
                    )
                , p
                    [ class "input-append"
                    ]
                    [ input
                        [ type_ "text"
                        , id "search-query-input"
                        , autofocus True
                        , placeholder <| "Search for " ++ categoryName
                        , onInput (outMsg << QueryInput)
                        , value <| Maybe.withDefault "" model.query
                        ]
                        []
                    , div [ class "loader" ] []
                    , div [ class "btn-group" ]
                        [ button [ class "btn", type_ "submit" ]
                            [ text "Search" ]
                        ]
                    ]
                ]
            ]
        , div [] <|
            case model.result of
                RemoteData.NotAsked ->
                    [ text "" ]

                RemoteData.Loading ->
                    [ p [] [ em [] [ text "Searching..." ] ]
                    , div []
                        [ viewSortSelection outMsg model
                        , viewPager outMsg model 0 toRoute
                        ]
                    , div [ class "loader-wrapper" ] [ div [ class "loader" ] [ text "Loading..." ] ]
                    , viewPager outMsg model 0 toRoute
                    ]

                RemoteData.Success result ->
                    if result.hits.total.value == 0 then
                        [ h4 [] [ text <| "No " ++ categoryName ++ " found!" ] ]

                    else
                        [ p []
                            [ em []
                                [ text
                                    ("Showing results "
                                        ++ String.fromInt model.from
                                        ++ "-"
                                        ++ String.fromInt
                                            (if model.from + model.size > result.hits.total.value then
                                                result.hits.total.value

                                             else
                                                model.from + model.size
                                            )
                                        ++ " of "
                                        ++ (if result.hits.total.value == 10000 then
                                                "more than 10000 results, please provide more precise search terms."

                                            else
                                                String.fromInt result.hits.total.value
                                                    ++ "."
                                           )
                                    )
                                ]
                            ]
                        , div []
                            [ viewSortSelection outMsg model
                            , viewPager outMsg model result.hits.total.value toRoute
                            ]
                        , viewSuccess model.channel model.show result
                        , viewPager outMsg model result.hits.total.value toRoute
                        ]

                RemoteData.Failure error ->
                    let
                        ( errorTitle, errorMessage ) =
                            case error of
                                Http.BadUrl text ->
                                    ( "Bad Url!", text )

                                Http.Timeout ->
                                    ( "Timeout!", "Request to the server timeout." )

                                Http.NetworkError ->
                                    ( "Network Error!", "A network request bonsaisearch.net domain failed. This is either due to a content blocker or a networking issue." )

                                Http.BadStatus code ->
                                    ( "Bad Status", "Server returned " ++ String.fromInt code )

                                Http.BadBody text ->
                                    ( "Bad Body", text )
                    in
                    [ div [ class "alert alert-error" ]
                        [ h4 [] [ text errorTitle ]
                        , text errorMessage
                        ]
                    ]
        ]


viewSortSelection : (Msg a -> b) -> Model a -> Html b
viewSortSelection outMsg model =
    form [ class "form-horizontal pull-right sort-form" ]
        [ div [ class "control-group sort-group" ]
            [ label [ class "control-label" ] [ text "Sort by:" ]
            , div
                [ class "controls" ]
                [ select
                    [ onInput (\x -> outMsg (SortChange x))
                    ]
                    (List.map
                        (\sort ->
                            option
                                [ selected (model.sort == sort)
                                , value (toSortId sort)
                                ]
                                [ text <| toSortTitle sort ]
                        )
                        sortBy
                    )
                ]
            ]
        ]


viewPager :
    (Msg a -> b)
    -> Model a
    -> Int
    -> Route.SearchRoute
    -> Html b
viewPager outMsg model total toRoute =
    Html.map outMsg <|
        ul [ class "pager" ]
            [ li [ classList [ ( "disabled", model.from == 0 ) ] ]
                [ a
                    [ Html.Events.onClick <|
                        if model.from == 0 then
                            NoOp

                        else
                            ChangePage 0
                    ]
                    [ text "First" ]
                ]
            , li [ classList [ ( "disabled", model.from == 0 ) ] ]
                [ a
                    [ Html.Events.onClick <|
                        if model.from - model.size < 0 then
                            NoOp

                        else
                            ChangePage <| model.from - model.size
                    ]
                    [ text "Previous" ]
                ]
            , li [ classList [ ( "disabled", model.from + model.size >= total ) ] ]
                [ a
                    [ Html.Events.onClick <|
                        if model.from + model.size >= total then
                            NoOp

                        else
                            ChangePage <| model.from + model.size
                    ]
                    [ text "Next" ]
                ]
            , li [ classList [ ( "disabled", model.from + model.size >= total ) ] ]
                [ a
                    [ Html.Events.onClick <|
                        if model.from + model.size >= total then
                            NoOp

                        else
                            let
                                remainder =
                                    if remainderBy model.size total == 0 then
                                        1

                                    else
                                        0
                            in
                            ChangePage <| ((total // model.size) - remainder) * model.size
                    ]
                    [ text "Last" ]
                ]
            ]



-- API


type alias Options =
    { mappingSchemaVersion : Int
    , url : String
    , username : String
    , password : String
    }


filter_by_type :
    String
    -> List ( String, Json.Encode.Value )
filter_by_type type_ =
    [ ( "term"
      , Json.Encode.object
            [ ( "type"
              , Json.Encode.object
                    [ ( "value", Json.Encode.string type_ )
                    , ( "_name", Json.Encode.string <| "filter_" ++ type_ ++ "s" )
                    ]
              )
            ]
      )
    ]


searchFields :
    String
    -> List ( String, Float )
    -> List (List ( String, Json.Encode.Value ))
searchFields query fields =
    let
        queryVariations q =
            case ( List.head q, List.tail q ) of
                ( Just h, Just t ) ->
                    let
                        tail : List (List String)
                        tail =
                            queryVariations t
                    in
                    List.append
                        (List.map (\x -> List.append [ h ] x) tail)
                        (List.map (\x -> List.append [ String.reverse h ] x) tail)
                        |> Set.fromList
                        |> Set.toList

                ( Just h, Nothing ) ->
                    [ [ h ], [ String.reverse h ] ]

                ( _, _ ) ->
                    [ [], [] ]

        reverseFields =
            List.map (\( field, score ) -> ( field ++ "_reverse", score * 0.8 )) fields

        allFields =
            List.append fields reverseFields
                |> List.map (\( field, score ) -> [ field ++ "^" ++ String.fromFloat score, field ++ ".edge^" ++ String.fromFloat score ])
                |> List.concat
    in
    List.map
        (\queryWords ->
            [ ( "multi_match"
              , Json.Encode.object
                    [ ( "type", Json.Encode.string "cross_fields" )
                    , ( "query", Json.Encode.string <| String.join " " queryWords )
                    , ( "analyzer", Json.Encode.string "whitespace" )
                    , ( "auto_generate_synonyms_phrase_query", Json.Encode.bool False )
                    , ( "operator", Json.Encode.string "and" )
                    , ( "_name", Json.Encode.string <| "multi_match_" ++ String.join "_" queryWords )
                    , ( "fields", Json.Encode.list Json.Encode.string allFields )
                    ]
              )
            ]
        )
        (queryVariations (String.words query))


makeRequestBody :
    String
    -> Int
    -> Int
    -> Sort
    -> String
    -> String
    -> List ( String, Float )
    -> Http.Body
makeRequestBody query from sizeRaw sort type_ sortField fields =
    let
        -- you can not request more then 10000 results otherwise it will return 404
        size =
            if from + sizeRaw > 10000 then
                10000 - from

            else
                sizeRaw
    in
    Http.jsonBody
        (Json.Encode.object
            [ ( "from"
              , Json.Encode.int from
              )
            , ( "size"
              , Json.Encode.int size
              )
            , toSortQuery sort sortField
            , ( "query"
              , Json.Encode.object
                    [ ( "bool"
                      , Json.Encode.object
                            [ ( "filter"
                              , Json.Encode.list Json.Encode.object
                                    [ filter_by_type type_ ]
                              )
                            , ( "must"
                              , Json.Encode.list Json.Encode.object
                                    [ [ ( "dis_max"
                                        , Json.Encode.object
                                            [ ( "tie_breaker", Json.Encode.float 0.7 )
                                            , ( "queries"
                                              , Json.Encode.list Json.Encode.object
                                                    (searchFields query fields)
                                                -- [ [ ( "bool"
                                                --     , Json.Encode.object
                                                --         [ ( "must"
                                                --           , Json.Encode.list Json.Encode.object <|
                                                --                 searchFields query fields
                                                --           )
                                                --         ]
                                                --     )
                                                --   ]
                                                -- ]
                                                -- , [ ( "bool"
                                                --     , Json.Encode.object
                                                --         [ ( "must"
                                                --           , Json.Encode.list Json.Encode.object <|
                                                --                 searchFields
                                                --                     0.8
                                                --                     (String.words query |> List.map String.reverse)
                                                --           )
                                                --         ]
                                                --     )
                                                --   ]
                                                --]
                                              )
                                            ]
                                        )
                                      ]
                                    ]
                              )
                            ]
                      )
                    ]
              )
            ]
        )


makeRequest :
    Http.Body
    -> String
    -> Json.Decode.Decoder a
    -> Options
    -> (RemoteData.WebData (SearchResult a) -> Msg a)
    -> Maybe String
    -> Cmd (Msg a)
makeRequest body index decodeResultItemSource options responseMsg tracker =
    Http.riskyRequest
        { method = "POST"
        , headers =
            [ Http.header "Authorization" ("Basic " ++ Base64.encode (options.username ++ ":" ++ options.password))
            ]
        , url = options.url ++ "/" ++ index ++ "/_search"
        , body = body
        , expect =
            Http.expectJson
                (RemoteData.fromResult >> responseMsg)
                (decodeResult decodeResultItemSource)
        , timeout = Nothing
        , tracker = tracker
        }



-- JSON


decodeResult :
    Json.Decode.Decoder a
    -> Json.Decode.Decoder (SearchResult a)
decodeResult decodeResultItemSource =
    Json.Decode.map SearchResult
        (Json.Decode.field "hits" (decodeResultHits decodeResultItemSource))


decodeResultHits : Json.Decode.Decoder a -> Json.Decode.Decoder (ResultHits a)
decodeResultHits decodeResultItemSource =
    Json.Decode.map3 ResultHits
        (Json.Decode.field "total" decodeResultHitsTotal)
        (Json.Decode.field "max_score" (Json.Decode.nullable Json.Decode.float))
        (Json.Decode.field "hits" (Json.Decode.list (decodeResultItem decodeResultItemSource)))


decodeResultHitsTotal : Json.Decode.Decoder ResultHitsTotal
decodeResultHitsTotal =
    Json.Decode.map2 ResultHitsTotal
        (Json.Decode.field "value" Json.Decode.int)
        (Json.Decode.field "relation" Json.Decode.string)


decodeResultItem : Json.Decode.Decoder a -> Json.Decode.Decoder (ResultItem a)
decodeResultItem decodeResultItemSource =
    Json.Decode.map6 ResultItem
        (Json.Decode.field "_index" Json.Decode.string)
        (Json.Decode.field "_id" Json.Decode.string)
        (Json.Decode.field "_score" (Json.Decode.nullable Json.Decode.float))
        (Json.Decode.field "_source" decodeResultItemSource)
        (Json.Decode.maybe (Json.Decode.field "text" Json.Decode.string))
        (Json.Decode.maybe (Json.Decode.field "matched_queries" (Json.Decode.list Json.Decode.string)))