wiki policy refactor

wiki_policy.rb

class WikiPolicy < ApplicationPolicy
  attr_reader :user, :wiki

  def initialize(user, wiki)
    @user = user
    @wiki = wiki
  end

  def update?
    user.present?
  end

  def manage_collaborators?
    wiki.user == user && wiki.collaborators
  end

  class Scope
    attr_reader :user, :scope

    def initialize(user, scope)
      @user = user
      @scope = scope
    end

    def resolve
      wikis = []
      if user.role == 'admin'
        wikis = scope.all # if the user is an admin, show them all the wikis
      elsif user.role == 'premium'
        all_wikis = scope.all
        all_wikis.each do |wiki|
          if wiki.private == false || wiki.user == user || wiki.users.include?(user)
            wikis << wiki # if the user is premium, only show them public wikis, or that private wikis they created, or private wikis they are a collaborator on
          end
        end
      else # this is the lowly standard user
        all_wikis = scope.all
        wikis = []
        all_wikis.each do |wiki|
          if wiki.private == false  || wiki.users.include?(user)
            wikis << wiki # only show standard users public wikis and private wikis they are a collaborator on
          end
        end
      end
      wikis # return the wikis array we've built up
    end
  end
end

# or better yet, using Ruby's Array#| - http://devdocs.io/ruby~2.4/array#method-i-7C:

class WikiPolicy < ApplicationPolicy
  attr_reader :user, :wiki

  def initialize(user, wiki)
    @user = user
    @wiki = wiki
  end

  def update?
    user.present?
  end

  def manage_collaborators?
    wiki.user == user && wiki.collaborators
  end

  class Scope
    attr_reader :user, :scope

    def initialize(user, scope)
      @user = user
      @scope = scope
    end

    def resolve
      if user.admin?
        scope.all # if the user is an admin, show them all the wikis
      elsif user.premium?
        scope.where(private: false) | user.wikis | user.wiki_collaborations
      elsif user.standard?
        scope.where(private: false) | user.wikis
      else
        scope.where(private: false)
      end
    end
  end
end