Replace use_pack, layouts/theme and @theme by new helpers

Packs are now loaded from views, just like upstream, and are
identified by their filenames. The definition of `theme.yml` has
changed as such:
- `pack_directory` is now required
- `pack` is now unused
- `signed_in_preload` has been introduced

app/controllers/admin/base_controller.rb

@@ -7,7 +7,6 @@ class BaseController < ApplicationController
 
     layout 'admin'
 
-    before_action :set_pack
     before_action :set_body_classes
     before_action :set_cache_headers
 
@@ -19,10 +18,6 @@ def set_body_classes
       @body_classes = 'admin'
     end
 
-    def set_pack
-      use_pack 'admin'
-    end
-
     def set_cache_headers
       response.cache_control.replace(private: true, no_store: true)
     end

app/controllers/application_controller.rb

@@ -165,10 +165,7 @@ def body_class_string
 
   def respond_with_error(code)
     respond_to do |format|
-      format.any do
-        use_pack 'error'
-        render "errors/#{code}", layout: 'error', status: code, formats: [:html]
-      end
+      format.any  { render "errors/#{code}", layout: 'error', status: code, formats: [:html] }
       format.json { render json: { error: Rack::Utils::HTTP_STATUS_CODES[code] }, status: code }
     end
   end
@@ -177,10 +174,7 @@ def check_self_destruct!
     return unless self_destruct?
 
     respond_to do |format|
-      format.any do
-        use_pack 'error'
-        render 'errors/self_destruct', layout: 'auth', status: 410, formats: [:html]
-      end
+      format.any  { render 'errors/self_destruct', layout: 'auth', status: 410, formats: [:html] }
       format.json { render json: { error: Rack::Utils::HTTP_STATUS_CODES[410] }, status: 410 }
     end
   end

app/controllers/auth/challenges_controller.rb

@@ -5,7 +5,6 @@ class Auth::ChallengesController < ApplicationController
 
   layout 'auth'
 
-  before_action :set_pack
   before_action :authenticate_user!
 
   skip_before_action :check_self_destruct!
@@ -21,10 +20,4 @@ def create
       render_challenge
     end
   end
-
-  private
-
-  def set_pack
-    use_pack 'auth'
-  end
 end

app/controllers/auth/confirmations_controller.rb

@@ -6,7 +6,6 @@ class Auth::ConfirmationsController < Devise::ConfirmationsController
   layout 'auth'
 
   before_action :set_body_classes
-  before_action :set_pack
   before_action :set_confirmation_user!, only: [:show, :confirm_captcha]
   before_action :redirect_confirmed_user, if: :signed_in_confirmed_user?
 
@@ -66,10 +65,6 @@ def captcha_user_bypass?
     @confirmation_user.nil? || @confirmation_user.confirmed?
   end
 
-  def set_pack
-    use_pack 'auth'
-  end
-
   def redirect_confirmed_user
     redirect_to(current_user.approved? ? root_path : edit_user_registration_path)
   end

app/controllers/auth/passwords_controller.rb

@@ -3,7 +3,6 @@
 class Auth::PasswordsController < Devise::PasswordsController
   skip_before_action :check_self_destruct!
   before_action :redirect_invalid_reset_token, only: :edit, unless: :reset_password_token_is_valid?
-  before_action :set_pack
   before_action :set_body_classes
 
   layout 'auth'
@@ -32,8 +31,4 @@ def set_body_classes
   def reset_password_token_is_valid?
     resource_class.with_reset_password_token(params[:reset_password_token]).present?
   end
-
-  def set_pack
-    use_pack 'auth'
-  end
 end

app/controllers/auth/registrations_controller.rb

@@ -9,7 +9,6 @@ class Auth::RegistrationsController < Devise::RegistrationsController
   before_action :set_invite, only: [:new, :create]
   before_action :check_enabled_registrations, only: [:new, :create]
   before_action :configure_sign_up_params, only: [:create]
-  before_action :set_pack
   before_action :set_sessions, only: [:edit, :update]
   before_action :set_strikes, only: [:edit, :update]
   before_action :set_body_classes, only: [:new, :create, :edit, :update]
@@ -97,10 +96,6 @@ def invite_code
 
   private
 
-  def set_pack
-    use_pack %w(edit update).include?(action_name) ? 'admin' : 'auth'
-  end
-
   def set_body_classes
     @body_classes = %w(edit update).include?(action_name) ? 'admin' : 'lighter'
   end

app/controllers/auth/sessions_controller.rb

@@ -12,7 +12,6 @@ class Auth::SessionsController < Devise::SessionsController
   skip_before_action :require_functional!
   skip_before_action :update_user_sign_in
 
-  prepend_before_action :set_pack
   prepend_before_action :check_suspicious!, only: [:create]
 
   include Auth::TwoFactorAuthenticationConcern
@@ -104,10 +103,6 @@ def require_no_authentication
 
   private
 
-  def set_pack
-    use_pack 'auth'
-  end
-
   def set_body_classes
     @body_classes = 'lighter'
   end

app/controllers/auth/setup_controller.rb

@@ -3,7 +3,6 @@
 class Auth::SetupController < ApplicationController
   layout 'auth'
 
-  before_action :set_pack
   before_action :authenticate_user!
   before_action :require_unconfirmed_or_pending!
   before_action :set_body_classes
@@ -43,8 +42,4 @@ def set_body_classes
   def user_params
     params.require(:user).permit(:email)
   end
-
-  def set_pack
-    use_pack 'sign_up'
-  end
 end

app/controllers/concerns/auth/two_factor_authentication_concern.rb

@@ -83,8 +83,6 @@ def authenticate_with_two_factor_via_otp(user)
   def prompt_for_two_factor(user)
     register_attempt_in_session(user)
 
-    use_pack 'auth'
-
     @body_classes     = 'lighter'
     @webauthn_enabled = user.webauthn_enabled?
     @scheme_type      = if user.webauthn_enabled? && user_params[:otp_attempt].blank?

app/controllers/concerns/theming_concern.rb

@@ -3,45 +3,22 @@
 module ThemingConcern
   extend ActiveSupport::Concern
 
-  def use_pack(pack_name)
-    @theme = resolve_pack(Themes.instance.flavour(current_flavour), pack_name)
-  end
-
   private
 
   def current_flavour
-    [current_user&.setting_flavour, Setting.flavour, 'glitch', 'vanilla'].find { |flavour| Themes.instance.flavours.include?(flavour) }
+    @current_flavour ||= [current_user&.setting_flavour, Setting.flavour, 'glitch', 'vanilla'].find { |flavour| Themes.instance.flavours.include?(flavour) }
   end
 
   def current_skin
-    skins = Themes.instance.skins_for(current_flavour)
-    [current_user&.setting_skin, Setting.skin, 'default'].find { |skin| skins.include?(skin) }
+    @current_skin ||= begin
+      skins = Themes.instance.skins_for(current_flavour)
+      [current_user&.setting_skin, Setting.skin, 'default'].find { |skin| skins.include?(skin) }
+    end
   end
 
   def current_theme
     # NOTE: this is slightly different from upstream, as it's a derived value used
     # for the sole purpose of pointing to the appropriate stylesheet pack
     "skins/#{current_flavour}/#{current_skin}"
   end
-
-  def resolve_pack(data, pack_name)
-    pack_data = {
-      flavour: data['name'],
-      pack: nil,
-      preload: nil,
-      supported_locales: data['locales'],
-    }
-    return pack_data unless data['pack'].is_a?(Hash) && data['pack'][pack_name].present?
-
-    pack_data[:pack] = pack_name
-    return pack_data unless data['pack'][pack_name].is_a?(Hash)
-
-    pack_data[:pack] = nil unless data['pack'][pack_name]['filename']
-
-    preloads = data['pack'][pack_name]['preload']
-    pack_data[:preload] = [preloads] if preloads.is_a?(String)
-    pack_data[:preload] = preloads if preloads.is_a?(Array)
-
-    pack_data
-  end
 end

app/controllers/concerns/web_app_controller_concern.rb

@@ -7,7 +7,6 @@ module WebAppControllerConcern
     vary_by 'Accept, Accept-Language, Cookie'
 
     before_action :redirect_unauthenticated_to_permalinks!
-    before_action :set_pack
     before_action :set_app_body_class
   end
 
@@ -37,8 +36,4 @@ def redirect_unauthenticated_to_permalinks!
       end
     end
   end
-
-  def set_pack
-    use_pack 'application'
-  end
 end

app/controllers/disputes/base_controller.rb

@@ -9,15 +9,10 @@ class Disputes::BaseController < ApplicationController
 
   before_action :set_body_classes
   before_action :authenticate_user!
-  before_action :set_pack
   before_action :set_cache_headers
 
   private
 
-  def set_pack
-    use_pack 'admin'
-  end
-
   def set_body_classes
     @body_classes = 'admin'
   end

app/controllers/filters/statuses_controller.rb

@@ -6,7 +6,6 @@ class Filters::StatusesController < ApplicationController
   before_action :authenticate_user!
   before_action :set_filter
   before_action :set_status_filters
-  before_action :set_pack
   before_action :set_body_classes
   before_action :set_cache_headers
 
@@ -27,10 +26,6 @@ def batch
 
   private
 
-  def set_pack
-    use_pack 'admin'
-  end
-
   def set_filter
     @filter = current_account.custom_filters.find(params[:filter_id])
   end

app/controllers/filters_controller.rb

@@ -5,7 +5,6 @@ class FiltersController < ApplicationController
 
   before_action :authenticate_user!
   before_action :set_filter, only: [:edit, :update, :destroy]
-  before_action :set_pack
   before_action :set_body_classes
   before_action :set_cache_headers
 
@@ -45,10 +44,6 @@ def destroy
 
   private
 
-  def set_pack
-    use_pack 'settings'
-  end
-
   def set_filter
     @filter = current_account.custom_filters.find(params[:id])
   end

app/controllers/invites_controller.rb

@@ -6,7 +6,6 @@ class InvitesController < ApplicationController
   layout 'admin'
 
   before_action :authenticate_user!
-  before_action :set_pack
   before_action :set_body_classes
   before_action :set_cache_headers
 
@@ -40,10 +39,6 @@ def destroy
 
   private
 
-  def set_pack
-    use_pack 'settings'
-  end
-
   def invites
     current_user.invites.order(id: :desc)
   end

app/controllers/media_controller.rb

@@ -10,7 +10,6 @@ class MediaController < ApplicationController
   before_action :verify_permitted_status!
   before_action :check_playable, only: :player
   before_action :allow_iframing, only: :player
-  before_action :set_pack, only: :player
 
   content_security_policy only: :player do |policy|
     policy.frame_ancestors(false)
@@ -48,8 +47,4 @@ def check_playable
   def allow_iframing
     response.headers.delete('X-Frame-Options')
   end
-
-  def set_pack
-    use_pack 'public'
-  end
 end

app/controllers/oauth/authorizations_controller.rb

@@ -5,7 +5,6 @@ class Oauth::AuthorizationsController < Doorkeeper::AuthorizationsController
 
   before_action :store_current_location
   before_action :authenticate_resource_owner!
-  before_action :set_pack
   before_action :set_cache_headers
 
   content_security_policy do |p|
@@ -20,10 +19,6 @@ def store_current_location
     store_location_for(:user, request.url)
   end
 
-  def set_pack
-    use_pack 'auth'
-  end
-
   def render_success
     if skip_authorization? || (matching_token? && !truthy_param?('force_login'))
       redirect_or_render authorize_response

app/controllers/oauth/authorized_applications_controller.rb

@@ -5,7 +5,6 @@ class Oauth::AuthorizedApplicationsController < Doorkeeper::AuthorizedApplicatio
 
   before_action :store_current_location
   before_action :authenticate_resource_owner!
-  before_action :set_pack
   before_action :require_not_suspended!, only: :destroy
   before_action :set_body_classes
   before_action :set_cache_headers
@@ -31,10 +30,6 @@ def store_current_location
     store_location_for(:user, request.url)
   end
 
-  def set_pack
-    use_pack 'settings'
-  end
-
   def require_not_suspended!
     forbidden if current_account.unavailable?
   end

app/controllers/redirect/base_controller.rb

@@ -3,7 +3,6 @@
 class Redirect::BaseController < ApplicationController
   vary_by 'Accept-Language'
 
-  before_action :set_pack
   before_action :set_resource
   before_action :set_app_body_class
 
@@ -22,8 +21,4 @@ def set_app_body_class
   def set_resource
     raise NotImplementedError
   end
-
-  def set_pack
-    use_pack 'public'
-  end
 end

app/controllers/relationships_controller.rb

@@ -5,7 +5,6 @@ class RelationshipsController < ApplicationController
 
   before_action :authenticate_user!
   before_action :set_accounts, only: :show
-  before_action :set_pack
   before_action :set_relationships, only: :show
   before_action :set_body_classes
   before_action :set_cache_headers
@@ -73,10 +72,6 @@ def set_body_classes
     @body_classes = 'admin'
   end
 
-  def set_pack
-    use_pack 'admin'
-  end
-
   def set_cache_headers
     response.cache_control.replace(private: true, no_store: true)
   end