module Fedi.Activity where

import Data.Aeson qualified as A
import Data.Text qualified as T
import Fedi.Types
import Fedi.Actor
import Data.Time (UTCTime)

data Activity
  = Create
    { id :: ActivityUrl
    , actor :: ActorId
    , object :: Object
    }

activityUrl :: Activity -> ActivityUrl
activityUrl = \case
  create@Create{} -> create.id

type ActivityUrl = Url

data Object
  = NoteObject Note

objectUrl :: Object -> Url
objectUrl = \case
  NoteObject note -> note.id

data Note
  = Note
    { id :: NoteId
    , published :: UTCTime
    , actor :: ActorId
    , content :: T.Text
    , name :: Maybe String
    , url :: Maybe Url
    , replies :: Collection Unordered Note
    }

type NoteId = Url

type Followers = [Actor]
type Following = [Actor]

type Inbox = Collection Ordered Activity
type Outbox = Collection Unordered Activity
type OutboxPage = OrderedCollectionPage Activity

data Ordered
data Unordered

data OrderedCollectionPage a
  = OrderedCollectionPage
    { id :: Url
    , partOf :: Url
    , orderedItems :: [a]
    }

data Collection order a
  = Collection
    { id :: Url
    , summary :: String
    , items :: [a]
    , first :: Maybe Url
    , last :: Maybe Url
    }

instance A.ToJSON Note where
  toJSON note =
    A.object $
        [ "type" A..= ("Note" :: String)
        , "id" A..= note.id
        , "published" A..= note.published
        , "attributedTo" A..= note.actor
        , "content" A..= note.content
        , "name" A..= note.name
        , "replies" A..= note.replies
        ]
        <> [ "name" A..= name | Just name <- [note.name] ]
        <> [ "url" A..= url | Just url <- [note.url] ]

instance A.ToJSON Object where
  toJSON = \case
    NoteObject note -> A.toJSON note

instance A.ToJSON Activity where
  toJSON = \case
    create@Create{} ->
      A.object
        [ "@context" A..=
          [ "https://www.w3.org/ns/activitystreams" :: String
          ]
        , "type" A..= ("Create" :: String)
        , "id" A..= create.id
        , "actor" A..= create.actor
        , "object" A..= create.object
        ]

instance A.ToJSON a => A.ToJSON (Collection Ordered a) where
  toJSON collection =
    A.object
      [ "@context" A..=
        [ "https://www.w3.org/ns/activitystreams" :: String
        ]
      , "id" A..= collection.id
      , "type" A..= ("OrderedCollection" :: String)
      , "summary" A..= collection.summary
      , "totalItems" A..= length collection.items
      , "orderedItems" A..= collection.items
      , "first" A..= collection.first
      , "last" A..= collection.last
      ]

instance A.ToJSON a => A.ToJSON (Collection Unordered a) where
  toJSON collection =
    A.object
      [ "@context" A..=
        [ "https://www.w3.org/ns/activitystreams" :: String
        ]
      , "id" A..= collection.id
      , "type" A..= ("Collection" :: String)
      , "summary" A..= collection.summary
      , "totalItems" A..= length collection.items
      , "items" A..= collection.items
      , "first" A..= collection.first
      , "last" A..= collection.last
      ]

instance A.ToJSON a => A.ToJSON (OrderedCollectionPage a) where
  toJSON collection =
    A.object
      [ "@context" A..=
        [ "https://www.w3.org/ns/activitystreams" :: String
        ]
      , "type" A..= ("OrderedCollectionPage" :: String)
      , "partOf" A..= collection.partOf
      , "orderedItems" A..= collection.orderedItems
      ]