ontohub/ontohub

module Permissionable
  extend ActiveSupport::Concern

  included do
    has_many :permissions, :as => :item

    after_create :add_permission, if: :create_permission?
  end

  def permissions_count
    permissions.count
  end

  def highest_permission(user)
    where_hash = {item_id: self.id, item_type: self.class.to_s}
    team_permissions = user.team_permissions.where(where_hash)
    user_permissions = user.permissions.where(where_hash)
    (team_permissions + user_permissions).
      sort(&:permissions_order).last
  end

  def permission?(role, user)
    # Deny if user is nil
    return false unless user

    # Deny if user is of wrong type
    raise ArgumentError, "no user given" unless user.is_a? User

    # Allow any admin user.
    return true if user.admin? rescue nil

    # Retrieve direct user permissions.
    @perms = self.permissions.subject(user).all

    # Retrieve permissions through team.
    user.teams.each do |team|
      @perms << Permission.item(self).subject(team).all
    end

    # Deny if no permission is found.
    return false unless @perms

    # Allow if role matches any permission.
    @perms.flatten.each do |perm|
      # Requested role exists exactly as permission.
      return true if perm.role == role.to_s

      # editors have reader permissions.
      return true if perm.role == 'editor' and role == :reader

      # owners have reader and editor permissions.
      return true if perm.role == 'owner' and role == :reader
      return true if perm.role == 'owner' and role == :editor
    end

    # Deny otherwise.
    false
  end

  protected

  def create_permission?
    respond_to?(:user) && user
  end

  def add_permission
    permissions.where(subject_id: user, subject_type: user.class.to_s).
      first_or_create!(subject: user, role: 'owner')
  end

end