module Web.Controller.ApiDashboard where

import Web.Types
import Web.View.ApiDashboard.Show
import Generated.Types
import IHP.Prelude
import IHP.ControllerPrelude
import Web.Routes ()
import Database.PostgreSQL.Simple (Only(..))

instance Controller ApiDashboardController where
    beforeAction = ensureIsUser

    action ShowApiDashboardAction = autoRefresh do
        consumers <- query @ApiConsumer
            |> orderByAsc #name
            |> fetch
        stats <- mapM fetchStats consumers
        render ShowView { stats }

-- | Aggregate per-consumer stats from api_request_log (last 24 hours).
fetchStats :: (?modelContext :: ModelContext) => ApiConsumer -> IO ConsumerStats
fetchStats consumer = do
    rows <- sqlQuery
        "SELECT COUNT(*), \
        \       COUNT(*) FILTER (WHERE status_code >= 400), \
        \       MAX(requested_at) \
        \FROM   api_request_log \
        \WHERE  api_consumer_id = ? \
        \  AND  requested_at >= NOW() - INTERVAL '24 hours'"
        (Only consumer.id)
    case rows of
        [(total, errs, lastTs)] ->
            let errRate = if (total :: Int) == 0
                            then 0.0
                            else fromIntegral (errs :: Int) / fromIntegral total
            in pure ConsumerStats
                { consumer
                , requests24h = total
                , errorRate   = errRate
                , lastSeen    = lastTs
                }
        _ -> pure ConsumerStats
            { consumer
            , requests24h = 0
            , errorRate   = 0.0
            , lastSeen    = Nothing
            }