-- | Updateable objects
module Calamity.Internal.Updateable (Updateable (..)) where

import Calamity.Internal.Utils
import Calamity.Types.Model.Channel
import Calamity.Types.Model.Channel.UpdatedMessage
import Calamity.Types.Model.Guild.Guild
import Calamity.Types.Model.User
import Control.Lens
import Data.Generics.Product.Fields
import Data.Maybe
import GHC.TypeLits

class Updateable a where
    type Updated a
    type Updated a = a

    update :: Updated a -> a -> a

-- | sets original field to new field
setF :: forall (f :: Symbol) o n b. (HasField' f o b, HasField' f o b, HasField' f n b) => n -> o -> o
setF n = field' @f .~ n ^. field' @f

-- | sets original field to unwrapped new field if new field is not Nothing
mergeF :: forall (f :: Symbol) o n b. (HasField' f o b, HasField' f o b, HasField' f n (Maybe b)) => n -> o -> o
mergeF n = field' @f %~ \oldv -> fromMaybe oldv (n ^. field' @f)

-- | sets original field to new field if new field is not nothing
mergeF' ::
    forall (f :: Symbol) old new v.
    ( HasField' f old (Maybe v)
    , HasField' f new (Maybe v)
    ) =>
    new ->
    old ->
    old
mergeF' new = field' @f %~ \oldv -> lastMaybe oldv (new ^. field' @f)

-- | sets original field to new field if new field was present
updateNullableDest ::
    forall (f :: Symbol) old new v.
    ( HasField' f old (Maybe v)
    , HasField' f new (Maybe (MaybeNull v))
    ) =>
    new ->
    old ->
    old
updateNullableDest new = case new ^. field' @f of
    Just (NotNull x) -> field' @f ?~ x
    Just WasNull -> field' @f .~ Nothing
    Nothing -> Prelude.id

-- NOTE: afaik only messages get partial updates
instance Updateable Message where
    type Updated Message = UpdatedMessage

    update n o = o
      & mergeF @"content" n
      & updateNullableDest @"editedTimestamp" n
      & mergeF @"tts" n
      & mergeF @"mentionEveryone" n
      & mergeF @"mentions" n
      & mergeF @"mentionRoles" n
      & mergeF' @"mentionChannels" n
      & mergeF @"attachments" n
      & mergeF @"embeds" n
      & mergeF @"reactions" n
      & mergeF @"pinned" n
      & updateNullableDest @"webhookID" n
      & mergeF @"type_" n
      & updateNullableDest @"activity" n
      & updateNullableDest @"application" n
      & updateNullableDest @"messageReference" n
      & mergeF @"flags" n
      & updateNullableDest @"stickers" n
      & updateNullableDest @"referencedMessage" n
      & updateNullableDest @"interaction" n
      & mergeF @"components" n

instance Updateable Channel where
    update n _ = n

instance Updateable DMChannel where
    update n _ = n

instance Updateable GuildChannel where
    update n _ = n

instance Updateable Guild where
    type Updated Guild = UpdatedGuild

    update n o =
        o
            & setF @"name" n
            & setF @"icon" n
            & setF @"splash" n
            & setF @"owner" n
            & setF @"ownerID" n
            & mergeF @"permissions" n
            & setF @"region" n
            & setF @"afkChannelID" n
            & setF @"afkTimeout" n
            & mergeF @"embedEnabled" n
            & setF @"embedChannelID" n
            & setF @"verificationLevel" n
            & setF @"defaultMessageNotifications" n
            & setF @"explicitContentFilter" n
            & setF @"roles" n
            & setF @"features" n
            & setF @"mfaLevel" n
            & setF @"applicationID" n
            & mergeF @"widgetEnabled" n
            & setF @"widgetChannelID" n
            & setF @"systemChannelID" n

instance Updateable User where
    update n o =
        o
            & setF @"username" n
            & setF @"discriminator" n
            & mergeF' @"bot" n
            & mergeF' @"avatar" n
            & mergeF' @"mfaEnabled" n
            & mergeF' @"verified" n
            & mergeF' @"email" n
            & mergeF' @"flags" n
            & mergeF' @"premiumType" n