Change user settings to be stored in a more optimal way (#23630)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/models/user_settings.rb

@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+class UserSettings
+  class Error < StandardError; end
+  class KeyError < Error; end
+
+  include UserSettings::DSL
+  include UserSettings::Glue
+
+  setting :always_send_emails, default: false
+  setting :aggregate_reblogs, default: true
+  setting :theme, default: -> { ::Setting.theme }
+  setting :noindex, default: -> { ::Setting.noindex }
+  setting :show_application, default: true
+  setting :default_language, default: nil
+  setting :default_sensitive, default: false
+  setting :default_privacy, default: nil
+
+  namespace :web do
+    setting :crop_images, default: true
+    setting :advanced_layout, default: false
+    setting :trends, default: true
+    setting :use_blurhash, default: true
+    setting :use_pending_items, default: false
+    setting :use_system_font, default: false
+    setting :disable_swiping, default: false
+    setting :delete_modal, default: true
+    setting :reblog_modal, default: false
+    setting :unfollow_modal, default: true
+    setting :reduce_motion, default: false
+    setting :expand_content_warnings, default: false
+    setting :display_media, default: 'default', in: %w(default show_all hide_all)
+    setting :auto_play, default: false
+  end
+
+  namespace :notification_emails do
+    setting :follow, default: true
+    setting :reblog, default: false
+    setting :favourite, default: false
+    setting :mention, default: true
+    setting :follow_request, default: true
+    setting :report, default: true
+    setting :pending_account, default: true
+    setting :trends, default: true
+    setting :appeal, default: true
+  end
+
+  namespace :interactions do
+    setting :must_be_follower, default: false
+    setting :must_be_following, default: false
+    setting :must_be_following_dm, default: false
+  end
+
+  def initialize(original_hash)
+    @original_hash = original_hash || {}
+  end
+
+  def [](key)
+    key = key.to_sym
+
+    raise KeyError, "Undefined setting: #{key}" unless self.class.definition_for?(key)
+
+    if @original_hash.key?(key)
+      @original_hash[key]
+    else
+      self.class.definition_for(key).default_value
+    end
+  end
+
+  def []=(key, value)
+    key = key.to_sym
+
+    raise KeyError, "Undefined setting: #{key}" unless self.class.definition_for?(key)
+
+    typecast_value = self.class.definition_for(key).type_cast(value)
+
+    if typecast_value.nil?
+      @original_hash.delete(key)
+    else
+      @original_hash[key] = typecast_value
+    end
+  end
+
+  def update(params)
+    params.each do |k, v|
+      self[k] = v unless v.nil?
+    end
+  end
+
+  keys.each do |key|
+    define_method(key) do
+      self[key]
+    end
+  end
+
+  def as_json
+    @original_hash
+  end
+end