1 files changed, 179 insertions, 0 deletions
diff --git a/app/models/user_role.rb b/app/models/user_role.rb
new file mode 100644
index 000000000..833b96d71
--- /dev/null
+++ b/app/models/user_role.rb
@@ -0,0 +1,179 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: user_roles
+#
+#  id          :bigint(8)        not null, primary key
+#  name        :string           default(""), not null
+#  color       :string           default(""), not null
+#  position    :integer          default(0), not null
+#  permissions :bigint(8)        default(0), not null
+#  highlighted :boolean          default(FALSE), not null
+#  created_at  :datetime         not null
+#  updated_at  :datetime         not null
+#
+
+class UserRole < ApplicationRecord
+  FLAGS = {
+    administrator: (1 << 0),
+    view_devops: (1 << 1),
+    view_audit_log: (1 << 2),
+    view_dashboard: (1 << 3),
+    manage_reports: (1 << 4),
+    manage_federation: (1 << 5),
+    manage_settings: (1 << 6),
+    manage_blocks: (1 << 7),
+    manage_taxonomies: (1 << 8),
+    manage_appeals: (1 << 9),
+    manage_users: (1 << 10),
+    manage_invites: (1 << 11),
+    manage_rules: (1 << 12),
+    manage_announcements: (1 << 13),
+    manage_custom_emojis: (1 << 14),
+    manage_webhooks: (1 << 15),
+    invite_users: (1 << 16),
+    manage_roles: (1 << 17),
+    manage_user_access: (1 << 18),
+    delete_user_data: (1 << 19),
+  }.freeze
+
+  module Flags
+    NONE = 0
+    ALL  = FLAGS.values.reduce(&:|)
+
+    DEFAULT = FLAGS[:invite_users]
+
+    CATEGORIES = {
+      invites: %i(
+        invite_users
+      ).freeze,
+
+      moderation: %w(
+        view_dashboard
+        view_audit_log
+        manage_users
+        manage_user_access
+        delete_user_data
+        manage_reports
+        manage_appeals
+        manage_federation
+        manage_blocks
+        manage_taxonomies
+        manage_invites
+      ).freeze,
+
+      administration: %w(
+        manage_settings
+        manage_rules
+        manage_roles
+        manage_webhooks
+        manage_custom_emojis
+        manage_announcements
+      ).freeze,
+
+      devops: %w(
+        view_devops
+      ).freeze,
+
+      special: %i(
+        administrator
+      ).freeze,
+    }.freeze
+  end
+
+  attr_writer :current_account
+
+  validates :name, presence: true, unless: :everyone?
+  validates :color, format: { with: /\A#?(?:[A-F0-9]{3}){1,2}\z/i }, unless: -> { color.blank? }
+
+  validate :validate_permissions_elevation
+  validate :validate_position_elevation
+  validate :validate_dangerous_permissions
+
+  before_validation :set_position
+
+  scope :assignable, -> { where.not(id: -99).order(position: :asc) }
+
+  has_many :users, inverse_of: :role, foreign_key: 'role_id', dependent: :nullify
+
+  def self.nobody
+    @nobody ||= UserRole.new(permissions: Flags::NONE, position: -1)
+  end
+
+  def self.everyone
+    UserRole.find(-99)
+  rescue ActiveRecord::RecordNotFound
+    UserRole.create!(id: -99, permissions: Flags::DEFAULT)
+  end
+
+  def self.that_can(*any_of_privileges)
+    all.select { |role| role.can?(*any_of_privileges) }
+  end
+
+  def everyone?
+    id == -99
+  end
+
+  def nobody?
+    id.nil?
+  end
+
+  def permissions_as_keys
+    FLAGS.keys.select { |privilege| permissions & FLAGS[privilege] == FLAGS[privilege] }.map(&:to_s)
+  end
+
+  def permissions_as_keys=(value)
+    self.permissions = value.map(&:presence).compact.reduce(Flags::NONE) { |bitmask, privilege| FLAGS.key?(privilege.to_sym) ? (bitmask | FLAGS[privilege.to_sym]) : bitmask }
+  end
+
+  def can?(*any_of_privileges)
+    any_of_privileges.any? { |privilege| in_permissions?(privilege) }
+  end
+
+  def overrides?(other_role)
+    other_role.nil? || position > other_role.position
+  end
+
+  def computed_permissions
+    # If called on the everyone role, no further computation needed
+    return permissions if everyone?
+
+    # If called on the nobody role, no permissions are there to be given
+    return Flags::NONE if nobody?
+
+    # Otherwise, compute permissions based on special conditions
+    @computed_permissions ||= begin
+      permissions = self.class.everyone.permissions | self.permissions
+
+      if permissions & FLAGS[:administrator] == FLAGS[:administrator]
+        Flags::ALL
+      else
+        permissions
+      end
+    end
+  end
+
+  private
+
+  def in_permissions?(privilege)
+    raise ArgumentError, "Unknown privilege: #{privilege}" unless FLAGS.key?(privilege)
+    computed_permissions & FLAGS[privilege] == FLAGS[privilege]
+  end
+
+  def set_position
+    self.position = -1 if everyone?
+  end
+
+  def validate_permissions_elevation
+    errors.add(:permissions_as_keys, :elevated) if defined?(@current_account) && @current_account.user_role.computed_permissions & permissions != permissions
+  end
+
+  def validate_position_elevation
+    errors.add(:position, :elevated) if defined?(@current_account) && @current_account.user_role.position < position
+  end
+
+  def validate_dangerous_permissions
+    errors.add(:permissions_as_keys, :dangerous) if everyone? && Flags::DEFAULT & permissions != permissions
+  end
+end