{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE OverloadedStrings #-}

-- | Local HTTP names resolver for chat tests, copied from simplexmq's
-- NamesResolverServer and made dynamic: it answers /v2/resolve/<query> from a
-- mutable name -> NameRecord registry, so a test can resolve a name to the
-- address it just created.
module NameResolver
  ( NameRegistry,
    withNameResolver,
    registerName,
    registerExpiredName,
    registerReservedName,
    registerAvailableName,
    unregisterName,
    failNameResolution,
    emptyRecord,
    contactNameRecord,
    channelNameRecord,
    contactAndChannelNameRecord,
    resolverNamesConfig,
  )
where

import Control.Concurrent.STM
import qualified Data.Aeson as J
import Data.Map.Strict (Map)
import qualified Data.Map.Strict as M
import Data.Text (Text)
import Data.Text.Encoding (decodeLatin1)
import Network.HTTP.Types (hContentType, internalServerError500, notFound404, ok200)
import Network.Wai (Application, pathInfo, responseLBS)
import qualified Network.Wai.Handler.Warp as Warp
import Simplex.Messaging.Encoding.String (strEncode)
import Simplex.Messaging.Names.Record (NamePricing (..), NameRecord (..), NameRegistration (..), NameReservedReason, NameResponse (..), USDCents (..))
import Simplex.Messaging.Server.Names (NamesConfig (..))
import Simplex.Messaging.SimplexName (SimplexDomain (..), SimplexNameInfo (..), labelHash)
import Simplex.Messaging.SystemTime (RoundedSystemTime (..), getSystemSeconds)

data TestNameAnswer = AnswerRegistration NameRegistration | AnswerFails

type NameRegistry = TVar (Map Text TestNameAnswer)

-- | Run an action with a local resolver on a free port and its registry (keyed
-- by the query the resolver looks the name up by).
withNameResolver :: (Int -> NameRegistry -> IO a) -> IO a
withNameResolver action = do
  reg <- newTVarIO M.empty
  Warp.withApplication (pure (app reg)) $ \port -> action port reg
  where
    app :: NameRegistry -> Application
    app reg req send = do
      (st, body) <- case pathInfo req of
        ["health"] -> pure (ok200, "{}")
        ["v2", "resolve", q] -> answer . M.lookup q <$> readTVarIO reg
        _ -> pure (notFound404, "{}")
      send $ responseLBS st [(hContentType, "application/json")] body
    answer = \case
      Just AnswerFails -> (internalServerError500, "{}")
      Just (AnswerRegistration registration) -> (ok200, J.encode NameResponse {lastBlockTs = Nothing, registration})
      Nothing -> (ok200, J.encode NameResponse {lastBlockTs = Nothing, registration = NRAvailable {pricing = testPricing 1}})

-- | Register a name's domain to resolve to the given record.
registerName :: NameRegistry -> SimplexNameInfo -> NameRecord -> IO ()
registerName reg ni nameRecord =
  registerRegistration reg ni NRRegistered {expires = Nothing, graceUntil = Nothing, reservedReason_ = Nothing, nameRecord}

registerRegistration :: NameRegistry -> SimplexNameInfo -> NameRegistration -> IO ()
registerRegistration reg ni r = atomically $ modifyTVar' reg $ M.insert (registryKey ni) (AnswerRegistration r)

registerExpiredName :: NameRegistry -> SimplexNameInfo -> NameRecord -> IO ()
registerExpiredName reg ni nameRecord = do
  RoundedSystemTime now <- getSystemSeconds
  let expires = Just $ RoundedSystemTime (now - 86400)
      graceUntil = Just $ RoundedSystemTime (now + 30 * 86400)
  registerRegistration reg ni NRRegistered {expires, graceUntil, reservedReason_ = Nothing, nameRecord}

registerReservedName :: NameRegistry -> SimplexNameInfo -> NameReservedReason -> IO ()
registerReservedName reg ni reservedReason = registerRegistration reg ni NRReserved {reservedReason}

registerAvailableName :: NameRegistry -> SimplexNameInfo -> Int -> IO ()
registerAvailableName reg ni minLen = registerRegistration reg ni NRAvailable {pricing = testPricing minLen}

failNameResolution :: NameRegistry -> SimplexNameInfo -> IO ()
failNameResolution reg ni = atomically $ modifyTVar' reg $ M.insert (registryKey ni) AnswerFails

unregisterName :: NameRegistry -> SimplexNameInfo -> IO ()
unregisterName reg ni = atomically $ modifyTVar' reg $ M.delete (registryKey ni)

registryKey :: SimplexNameInfo -> Text
registryKey SimplexNameInfo {nameDomain = SimplexDomain {nameTLD, domain}} =
  decodeLatin1 $ strEncode (labelHash domain) <> strEncode nameTLD

testPricing :: Int -> NamePricing
testPricing minLabelLength = NamePricing {registrationPrices = M.empty, basePrice = USDCents 1000, minLabelLength}

contactNameRecord :: Text -> Text -> NameRecord
contactNameRecord name link = (emptyRecord name) {nrSimplexContact = [link]}

channelNameRecord :: Text -> Text -> NameRecord
channelNameRecord name link = (emptyRecord name) {nrSimplexChannel = [link]}

-- | A record whose domain resolves to both a direct contact link and a channel link.
contactAndChannelNameRecord :: Text -> Text -> Text -> NameRecord
contactAndChannelNameRecord name contactLink channelLink =
  (emptyRecord name) {nrSimplexContact = [contactLink], nrSimplexChannel = [channelLink]}

emptyRecord :: Text -> NameRecord
emptyRecord name =
  NameRecord
    { nrName = name,
      nrNickname = "",
      nrWebsite = "",
      nrLocation = "",
      nrSimplexContact = [],
      nrSimplexChannel = [],
      nrEth = Nothing,
      nrBtc = Nothing,
      nrXmr = Nothing,
      nrDot = Nothing,
      nrOwner = "",
      nrResolver = ""
    }

-- | NamesConfig for a chat test SMP server pointing at this resolver.
resolverNamesConfig :: Int -> NamesConfig
resolverNamesConfig port =
  NamesConfig
    { resolverEndpoint = "http://127.0.0.1:" <> show port,
      resolverAuth = Nothing,
      resolverTimeoutMs = 1000,
      resolverMaxResponseBytes = 65536
    }