defmodule Pleroma.Web.MastodonAPI.MastodonAPIController do
  use Pleroma.Web, :controller
  alias Pleroma.{Repo, Activity, User, Notification, Stats}
  alias Pleroma.Web
  alias Pleroma.Web.MastodonAPI.{StatusView, AccountView, MastodonView}
  alias Pleroma.Web.ActivityPub.ActivityPub
  alias Pleroma.Web.{CommonAPI, OStatus}
  alias Pleroma.Web.OAuth.{Authorization, Token, App}
  alias Comeonin.Pbkdf2
  import Ecto.Query
  require Logger

  def create_app(conn, params) do
    with cs <- App.register_changeset(%App{}, params) |> IO.inspect(),
         {:ok, app} <- Repo.insert(cs) |> IO.inspect() do
      res = %{
        id: app.id,
        client_id: app.client_id,
        client_secret: app.client_secret
      }

      json(conn, res)
    end
  end

  def update_credentials(%{assigns: %{user: user}} = conn, params) do
    original_user = user

    params =
      if bio = params["note"] do
        Map.put(params, "bio", bio)
      else
        params
      end

    params =
      if name = params["display_name"] do
        Map.put(params, "name", name)
      else
        params
      end

    user =
      if avatar = params["avatar"] do
        with %Plug.Upload{} <- avatar,
             {:ok, object} <- ActivityPub.upload(avatar),
             change = Ecto.Changeset.change(user, %{avatar: object.data}),
             {:ok, user} = User.update_and_set_cache(change) do
          user
        else
          _e -> user
        end
      else
        user
      end

    user =
      if banner = params["header"] do
        with %Plug.Upload{} <- banner,
             {:ok, object} <- ActivityPub.upload(banner),
             new_info <- Map.put(user.info, "banner", object.data),
             change <- User.info_changeset(user, %{info: new_info}),
             {:ok, user} <- User.update_and_set_cache(change) do
          user
        else
          _e -> user
        end
      else
        user
      end

    with changeset <- User.update_changeset(user, params),
         {:ok, user} <- User.update_and_set_cache(changeset) do
      if original_user != user do
        CommonAPI.update(user)
      end

      json(conn, AccountView.render("account.json", %{user: user}))
    else
      _e ->
        conn
        |> put_status(403)
        |> json(%{error: "Invalid request"})
    end
  end

  def verify_credentials(%{assigns: %{user: user}} = conn, _) do
    account = AccountView.render("account.json", %{user: user})
    json(conn, account)
  end

  def user(conn, %{"id" => id}) do
    with %User{} = user <- Repo.get(User, id) do
      account = AccountView.render("account.json", %{user: user})
      json(conn, account)
    else
      _e ->
        conn
        |> put_status(404)
        |> json(%{error: "Can't find user"})
    end
  end

  @instance Application.get_env(:pleroma, :instance)
  @mastodon_api_level "2.3.3"

  def masto_instance(conn, _params) do
    response = %{
      uri: Web.base_url(),
      title: Keyword.get(@instance, :name),
      description: "A Pleroma instance, an alternative fediverse server",
      version: "#{@mastodon_api_level} (compatible; #{Keyword.get(@instance, :version)})",
      email: Keyword.get(@instance, :email),
      urls: %{
        streaming_api: String.replace(Pleroma.Web.Endpoint.static_url(), "http", "ws")
      },
      stats: Stats.get_stats(),
      thumbnail: Web.base_url() <> "/instance/thumbnail.jpeg",
      max_toot_chars: Keyword.get(@instance, :limit)
    }

    json(conn, response)
  end

  def peers(conn, _params) do
    json(conn, Stats.get_peers())
  end

  defp mastodonized_emoji do
    Pleroma.Formatter.get_custom_emoji()
    |> Enum.map(fn {shortcode, relative_url} ->
      url = to_string(URI.merge(Web.base_url(), relative_url))

      %{
        "shortcode" => shortcode,
        "static_url" => url,
        "url" => url
      }
    end)
  end

  def custom_emojis(conn, _params) do
    mastodon_emoji = mastodonized_emoji()
    json(conn, mastodon_emoji)
  end

  defp add_link_headers(conn, method, activities, param \\ false) do
    last = List.last(activities)
    first = List.first(activities)

    if last do
      min = last.id
      max = first.id

      {next_url, prev_url} =
        if param do
          {
            mastodon_api_url(Pleroma.Web.Endpoint, method, param, max_id: min),
            mastodon_api_url(Pleroma.Web.Endpoint, method, param, since_id: max)
          }
        else
          {
            mastodon_api_url(Pleroma.Web.Endpoint, method, max_id: min),
            mastodon_api_url(Pleroma.Web.Endpoint, method, since_id: max)
          }
        end

      conn
      |> put_resp_header("link", "<#{next_url}>; rel=\"next\", <#{prev_url}>; rel=\"prev\"")
    else
      conn
    end
  end

  def home_timeline(%{assigns: %{user: user}} = conn, params) do
    params =
      params
      |> Map.put("type", ["Create", "Announce"])
      |> Map.put("blocking_user", user)
      |> Map.put("user", user)

    activities =
      ActivityPub.fetch_activities([user.ap_id | user.following], params)
      |> Enum.reverse()

    conn
    |> add_link_headers(:home_timeline, activities)
    |> render(StatusView, "index.json", %{activities: activities, for: user, as: :activity})
  end

  def public_timeline(%{assigns: %{user: user}} = conn, params) do
    params =
      params
      |> Map.put("type", ["Create", "Announce"])
      |> Map.put("local_only", params["local"] in [true, "True", "true", "1"])
      |> Map.put("blocking_user", user)

    activities =
      ActivityPub.fetch_public_activities(params)
      |> Enum.reverse()

    conn
    |> add_link_headers(:public_timeline, activities)
    |> render(StatusView, "index.json", %{activities: activities, for: user, as: :activity})
  end

  def user_statuses(%{assigns: %{user: reading_user}} = conn, params) do
    with %User{} = user <- Repo.get(User, params["id"]) do
      # Since Pleroma has no "pinned" posts feature, we'll just set an empty list here
      activities =
        if params["pinned"] == "true" do
          []
        else
          ActivityPub.fetch_user_activities(user, reading_user, params)
        end

      conn
      |> add_link_headers(:user_statuses, activities, params["id"])
      |> render(StatusView, "index.json", %{activities: activities, for: user, as: :activity})
    end
  end

  def dm_timeline(%{assigns: %{user: user}} = conn, params) do
    query = ActivityPub.fetch_activities_query([user.ap_id], %{visibility: "direct"})
    activities = Repo.all(query)

    conn
    |> add_link_headers(:user_statuses, activities, user.ap_id)
    |> render(StatusView, "index.json", %{activities: activities, for: user, as: :activity})
  end

  def get_status(%{assigns: %{user: user}} = conn, %{"id" => id}) do
    with %Activity{} = activity <- Repo.get(Activity, id),
         true <- ActivityPub.visible_for_user?(activity, user) do
      render(conn, StatusView, "status.json", %{activity: activity, for: user})
    end
  end

  def get_context(%{assigns: %{user: user}} = conn, %{"id" => id}) do
    with %Activity{} = activity <- Repo.get(Activity, id),
         activities <-
           ActivityPub.fetch_activities_for_context(activity.data["context"], %{
             "blocking_user" => user,
             "user" => user
           }),
         activities <-
           activities |> Enum.filter(fn %{id: aid} -> to_string(aid) != to_string(id) end),
         activities <-
           activities |> Enum.filter(fn %{data: %{"type" => type}} -> type == "Create" end),
         grouped_activities <- Enum.group_by(activities, fn %{id: id} -> id < activity.id end) do
      result = %{
        ancestors:
          StatusView.render(
            "index.json",
            for: user,
            activities: grouped_activities[true] || [],
            as: :activity
          )
          |> Enum.reverse(),
        descendants:
          StatusView.render(
            "index.json",
            for: user,
            activities: grouped_activities[false] || [],
            as: :activity
          )
          |> Enum.reverse()
      }

      json(conn, result)
    end
  end

  def post_status(%{assigns: %{user: user}} = conn, %{"status" => _} = params) do
    params =
      params
      |> Map.put("in_reply_to_status_id", params["in_reply_to_id"])
      |> Map.put("no_attachment_links", true)

    idempotency_key =
      case get_req_header(conn, "idempotency-key") do
        [key] -> key
        _ -> Ecto.UUID.generate()
      end

    {:ok, activity} =
      Cachex.get!(
        :idempotency_cache,
        idempotency_key,
        fallback: fn _ -> CommonAPI.post(user, params) end
      )

    render(conn, StatusView, "status.json", %{activity: activity, for: user, as: :activity})
  end

  def delete_status(%{assigns: %{user: user}} = conn, %{"id" => id}) do
    with {:ok, %Activity{}} <- CommonAPI.delete(id, user) do
      json(conn, %{})
    else
      _e ->
        conn
        |> put_status(403)
        |> json(%{error: "Can't delete this post"})
    end
  end

  def reblog_status(%{assigns: %{user: user}} = conn, %{"id" => ap_id_or_id}) do
    with {:ok, announce, _activity} = CommonAPI.repeat(ap_id_or_id, user) do
      render(conn, StatusView, "status.json", %{activity: announce, for: user, as: :activity})
    end
  end

  def unreblog_status(%{assigns: %{user: user}} = conn, %{"id" => ap_id_or_id}) do
    with {:ok, _, _, %{data: %{"id" => id}}} = CommonAPI.unrepeat(ap_id_or_id, user),
         %Activity{} = activity <- Activity.get_create_activity_by_object_ap_id(id) do
      render(conn, StatusView, "status.json", %{activity: activity, for: user, as: :activity})
    end
  end

  def fav_status(%{assigns: %{user: user}} = conn, %{"id" => ap_id_or_id}) do
    with {:ok, _fav, %{data: %{"id" => id}}} = CommonAPI.favorite(ap_id_or_id, user),
         %Activity{} = activity <- Activity.get_create_activity_by_object_ap_id(id) do
      render(conn, StatusView, "status.json", %{activity: activity, for: user, as: :activity})
    end
  end

  def unfav_status(%{assigns: %{user: user}} = conn, %{"id" => ap_id_or_id}) do
    with {:ok, _, _, %{data: %{"id" => id}}} = CommonAPI.unfavorite(ap_id_or_id, user),
         %Activity{} = activity <- Activity.get_create_activity_by_object_ap_id(id) do
      render(conn, StatusView, "status.json", %{activity: activity, for: user, as: :activity})
    end
  end

  def notifications(%{assigns: %{user: user}} = conn, params) do
    notifications = Notification.for_user(user, params)

    result =
      Enum.map(notifications, fn x ->
        render_notification(user, x)
      end)
      |> Enum.filter(& &1)

    conn
    |> add_link_headers(:notifications, notifications)
    |> json(result)
  end

  def get_notification(%{assigns: %{user: user}} = conn, %{"id" => id} = _params) do
    with {:ok, notification} <- Notification.get(user, id) do
      json(conn, render_notification(user, notification))
    else
      {:error, reason} ->
        conn
        |> put_resp_content_type("application/json")
        |> send_resp(403, Jason.encode!(%{"error" => reason}))
    end
  end

  def clear_notifications(%{assigns: %{user: user}} = conn, _params) do
    Notification.clear(user)
    json(conn, %{})
  end

  def dismiss_notification(%{assigns: %{user: user}} = conn, %{"id" => id} = _params) do
    with {:ok, _notif} <- Notification.dismiss(user, id) do
      json(conn, %{})
    else
      {:error, reason} ->
        conn
        |> put_resp_content_type("application/json")
        |> send_resp(403, Jason.encode!(%{"error" => reason}))
    end
  end

  def relationships(%{assigns: %{user: user}} = conn, %{"id" => id}) do
    id = List.wrap(id)
    q = from(u in User, where: u.id in ^id)
    targets = Repo.all(q)
    render(conn, AccountView, "relationships.json", %{user: user, targets: targets})
  end

  def upload(%{assigns: %{user: _}} = conn, %{"file" => file}) do
    with {:ok, object} <- ActivityPub.upload(file) do
      data =
        object.data
        |> Map.put("id", object.id)

      render(conn, StatusView, "attachment.json", %{attachment: data})
    end
  end

  def favourited_by(conn, %{"id" => id}) do
    with %Activity{data: %{"object" => %{"likes" => likes}}} <- Repo.get(Activity, id) do
      q = from(u in User, where: u.ap_id in ^likes)
      users = Repo.all(q)
      render(conn, AccountView, "accounts.json", %{users: users, as: :user})
    else
      _ -> json(conn, [])
    end
  end

  def reblogged_by(conn, %{"id" => id}) do
    with %Activity{data: %{"object" => %{"announcements" => announces}}} <- Repo.get(Activity, id) do
      q = from(u in User, where: u.ap_id in ^announces)
      users = Repo.all(q)
      render(conn, AccountView, "accounts.json", %{users: users, as: :user})
    else
      _ -> json(conn, [])
    end
  end

  def hashtag_timeline(%{assigns: %{user: user}} = conn, params) do
    params =
      params
      |> Map.put("type", "Create")
      |> Map.put("local_only", !!params["local"])
      |> Map.put("blocking_user", user)

    activities =
      ActivityPub.fetch_public_activities(params)
      |> Enum.reverse()

    conn
    |> add_link_headers(:hashtag_timeline, activities, params["tag"])
    |> render(StatusView, "index.json", %{activities: activities, for: user, as: :activity})
  end

  # TODO: Pagination
  def followers(conn, %{"id" => id}) do
    with %User{} = user <- Repo.get(User, id),
         {:ok, followers} <- User.get_followers(user) do
      render(conn, AccountView, "accounts.json", %{users: followers, as: :user})
    end
  end

  def following(conn, %{"id" => id}) do
    with %User{} = user <- Repo.get(User, id),
         {:ok, followers} <- User.get_friends(user) do
      render(conn, AccountView, "accounts.json", %{users: followers, as: :user})
    end
  end

  def follow(%{assigns: %{user: follower}} = conn, %{"id" => id}) do
    with %User{} = followed <- Repo.get(User, id),
         {:ok, follower} <- User.follow(follower, followed),
         {:ok, _activity} <- ActivityPub.follow(follower, followed) do
      render(conn, AccountView, "relationship.json", %{user: follower, target: followed})
    else
      {:error, message} ->
        conn
        |> put_resp_content_type("application/json")
        |> send_resp(403, Jason.encode!(%{"error" => message}))
    end
  end

  def follow(%{assigns: %{user: follower}} = conn, %{"uri" => uri}) do
    with %User{} = followed <- Repo.get_by(User, nickname: uri),
         {:ok, follower} <- User.follow(follower, followed),
         {:ok, _activity} <- ActivityPub.follow(follower, followed) do
      render(conn, AccountView, "account.json", %{user: followed})
    else
      {:error, message} ->
        conn
        |> put_resp_content_type("application/json")
        |> send_resp(403, Jason.encode!(%{"error" => message}))
    end
  end

  # TODO: Clean up and unify
  def unfollow(%{assigns: %{user: follower}} = conn, %{"id" => id}) do
    with %User{} = followed <- Repo.get(User, id),
         {:ok, follower, follow_activity} <- User.unfollow(follower, followed),
         {:ok, _activity} <-
           ActivityPub.insert(%{
             "type" => "Undo",
             "actor" => follower.ap_id,
             # get latest Follow for these users
             "object" => follow_activity.data["id"]
           }) do
      render(conn, AccountView, "relationship.json", %{user: follower, target: followed})
    end
  end

  def block(%{assigns: %{user: blocker}} = conn, %{"id" => id}) do
    with %User{} = blocked <- Repo.get(User, id),
         {:ok, blocker} <- User.block(blocker, blocked) do
      render(conn, AccountView, "relationship.json", %{user: blocker, target: blocked})
    else
      {:error, message} ->
        conn
        |> put_resp_content_type("application/json")
        |> send_resp(403, Jason.encode!(%{"error" => message}))
    end
  end

  def unblock(%{assigns: %{user: blocker}} = conn, %{"id" => id}) do
    with %User{} = blocked <- Repo.get(User, id),
         {:ok, blocker} <- User.unblock(blocker, blocked) do
      render(conn, AccountView, "relationship.json", %{user: blocker, target: blocked})
    else
      {:error, message} ->
        conn
        |> put_resp_content_type("application/json")
        |> send_resp(403, Jason.encode!(%{"error" => message}))
    end
  end

  # TODO: Use proper query
  def blocks(%{assigns: %{user: user}} = conn, _) do
    with blocked_users <- user.info["blocks"] || [],
         accounts <- Enum.map(blocked_users, fn ap_id -> User.get_cached_by_ap_id(ap_id) end) do
      res = AccountView.render("accounts.json", users: accounts, for: user, as: :user)
      json(conn, res)
    end
  end

  def search(%{assigns: %{user: user}} = conn, %{"q" => query} = params) do
    accounts = User.search(query, params["resolve"] == "true")

    fetched =
      if Regex.match?(~r/https?:/, query) do
        with {:ok, activities} <- OStatus.fetch_activity_from_url(query) do
          activities
          |> Enum.filter(fn
            %{data: %{"type" => "Create"}} -> true
            _ -> false
          end)
        else
          _e -> []
        end
      end || []

    q =
      from(
        a in Activity,
        where: fragment("?->>'type' = 'Create'", a.data),
        where: "https://www.w3.org/ns/activitystreams#Public" in a.recipients,
        where:
          fragment(
            "to_tsvector('english', ?->'object'->>'content') @@ plainto_tsquery('english', ?)",
            a.data,
            ^query
          ),
        limit: 20,
        order_by: [desc: :id]
      )

    statuses = Repo.all(q) ++ fetched

    tags =
      String.split(query)
      |> Enum.uniq()
      |> Enum.filter(fn tag -> String.starts_with?(tag, "#") end)
      |> Enum.map(fn tag -> String.slice(tag, 1..-1) end)

    res = %{
      "accounts" => AccountView.render("accounts.json", users: accounts, for: user, as: :user),
      "statuses" =>
        StatusView.render("index.json", activities: statuses, for: user, as: :activity),
      "hashtags" => tags
    }

    json(conn, res)
  end

  def account_search(%{assigns: %{user: user}} = conn, %{"q" => query} = params) do
    accounts = User.search(query, params["resolve"] == "true")

    res = AccountView.render("accounts.json", users: accounts, for: user, as: :user)

    json(conn, res)
  end

  def favourites(%{assigns: %{user: user}} = conn, _) do
    params =
      %{}
      |> Map.put("type", "Create")
      |> Map.put("favorited_by", user.ap_id)
      |> Map.put("blocking_user", user)

    activities =
      ActivityPub.fetch_public_activities(params)
      |> Enum.reverse()

    conn
    |> render(StatusView, "index.json", %{activities: activities, for: user, as: :activity})
  end

  def index(%{assigns: %{user: user}} = conn, _params) do
    token =
      conn
      |> get_session(:oauth_token)

    if user && token do
      mastodon_emoji = mastodonized_emoji()
      accounts = Map.put(%{}, user.id, AccountView.render("account.json", %{user: user}))

      initial_state =
        %{
          meta: %{
            streaming_api_base_url:
              String.replace(Pleroma.Web.Endpoint.static_url(), "http", "ws"),
            access_token: token,
            locale: "en",
            domain: Pleroma.Web.Endpoint.host(),
            admin: "1",
            me: "#{user.id}",
            unfollow_modal: false,
            boost_modal: false,
            delete_modal: true,
            auto_play_gif: false,
            reduce_motion: false
          },
          compose: %{
            me: "#{user.id}",
            default_privacy: "public",
            default_sensitive: false
          },
          media_attachments: %{
            accept_content_types: [
              ".jpg",
              ".jpeg",
              ".png",
              ".gif",
              ".webm",
              ".mp4",
              ".m4v",
              "image\/jpeg",
              "image\/png",
              "image\/gif",
              "video\/webm",
              "video\/mp4"
            ]
          },
          settings:
            Map.get(user.info, "settings") ||
              %{
                onboarded: true,
                home: %{
                  shows: %{
                    reblog: true,
                    reply: true
                  }
                },
                notifications: %{
                  alerts: %{
                    follow: true,
                    favourite: true,
                    reblog: true,
                    mention: true
                  },
                  shows: %{
                    follow: true,
                    favourite: true,
                    reblog: true,
                    mention: true
                  },
                  sounds: %{
                    follow: true,
                    favourite: true,
                    reblog: true,
                    mention: true
                  }
                }
              },
          push_subscription: nil,
          accounts: accounts,
          custom_emojis: mastodon_emoji,
          char_limit: Keyword.get(@instance, :limit)
        }
        |> Jason.encode!()

      conn
      |> put_layout(false)
      |> render(MastodonView, "index.html", %{initial_state: initial_state})
    else
      conn
      |> redirect(to: "/web/login")
    end
  end

  def put_settings(%{assigns: %{user: user}} = conn, %{"data" => settings} = _params) do
    with new_info <- Map.put(user.info, "settings", settings),
         change <- User.info_changeset(user, %{info: new_info}),
         {:ok, _user} <- User.update_and_set_cache(change) do
      conn
      |> json(%{})
    else
      e ->
        conn
        |> json(%{error: inspect(e)})
    end
  end

  def login(conn, _) do
    conn
    |> render(MastodonView, "login.html", %{error: false})
  end

  defp get_or_make_app() do
    with %App{} = app <- Repo.get_by(App, client_name: "Mastodon-Local") do
      {:ok, app}
    else
      _e ->
        cs =
          App.register_changeset(%App{}, %{
            client_name: "Mastodon-Local",
            redirect_uris: ".",
            scopes: "read,write,follow"
          })

        Repo.insert(cs)
    end
  end

  def login_post(conn, %{"authorization" => %{"name" => name, "password" => password}}) do
    with %User{} = user <- User.get_by_nickname_or_email(name),
         true <- Pbkdf2.checkpw(password, user.password_hash),
         {:ok, app} <- get_or_make_app(),
         {:ok, auth} <- Authorization.create_authorization(app, user),
         {:ok, token} <- Token.exchange_token(app, auth) do
      conn
      |> put_session(:oauth_token, token.token)
      |> redirect(to: "/web/getting-started")
    else
      _e ->
        conn
        |> render(MastodonView, "login.html", %{error: "Wrong username or password"})
    end
  end

  def logout(conn, _) do
    conn
    |> clear_session
    |> redirect(to: "/")
  end

  def relationship_noop(%{assigns: %{user: user}} = conn, %{"id" => id}) do
    Logger.debug("Unimplemented, returning unmodified relationship")

    with %User{} = target <- Repo.get(User, id) do
      render(conn, AccountView, "relationship.json", %{user: user, target: target})
    end
  end

  def empty_array(conn, _) do
    Logger.debug("Unimplemented, returning an empty array")
    json(conn, [])
  end

  def empty_object(conn, _) do
    Logger.debug("Unimplemented, returning an empty object")
    json(conn, %{})
  end

  def render_notification(user, %{id: id, activity: activity, inserted_at: created_at} = _params) do
    actor = User.get_cached_by_ap_id(activity.data["actor"])

    created_at =
      NaiveDateTime.to_iso8601(created_at)
      |> String.replace(~r/(\.\d+)?$/, ".000Z", global: false)

    case activity.data["type"] do
      "Create" ->
        %{
          id: id,
          type: "mention",
          created_at: created_at,
          account: AccountView.render("account.json", %{user: actor}),
          status: StatusView.render("status.json", %{activity: activity, for: user})
        }

      "Like" ->
        liked_activity = Activity.get_create_activity_by_object_ap_id(activity.data["object"])

        %{
          id: id,
          type: "favourite",
          created_at: created_at,
          account: AccountView.render("account.json", %{user: actor}),
          status: StatusView.render("status.json", %{activity: liked_activity, for: user})
        }

      "Announce" ->
        announced_activity = Activity.get_create_activity_by_object_ap_id(activity.data["object"])

        %{
          id: id,
          type: "reblog",
          created_at: created_at,
          account: AccountView.render("account.json", %{user: actor}),
          status: StatusView.render("status.json", %{activity: announced_activity, for: user})
        }

      "Follow" ->
        %{
          id: id,
          type: "follow",
          created_at: created_at,
          account: AccountView.render("account.json", %{user: actor})
        }

      _ ->
        nil
    end
  end
end