# Guidance provides information from organisations to Users, helping them when
# answering questions. (e.g. "Here's how to think about your data
# protection responsibilities...")
#
# == Schema Information
#
# Table name: guidances
#
#  id                :integer          not null, primary key
#  published         :boolean
#  text              :text
#  created_at        :datetime         not null
#  updated_at        :datetime         not null
#  guidance_group_id :integer
#
# Indexes
#
#  index_guidances_on_guidance_group_id  (guidance_group_id)
#
# Foreign Keys
#
#  fk_rails_...  (guidance_group_id => guidance_groups.id)
#

# [+Project:+] DMPRoadmap
# [+Description:+]
#   This class keeps the information organisations enter to support users when answering questions.
#   It always belongs to a guidance group class and it can be linked directly to a question or through one or more themes
# [+Created:+] 07/07/2014
# [+Copyright:+] Digital Curation Centre and California Digital Library

class Guidance < ActiveRecord::Base
  include GlobalHelpers
  include ValidationMessages
  include ValidationValues

  # ================
  # = Associations =
  # ================

  belongs_to :guidance_group

  has_and_belongs_to_many :themes, join_table: "themes_in_guidance"


  # ===============
  # = Validations =
  # ===============

  validates :text, presence: { message:  PRESENCE_MESSAGE }

  validates :guidance_group, presence: { message: PRESENCE_MESSAGE }

  validates :published, inclusion: { message: INCLUSION_MESSAGE,
                                     in: BOOLEAN_VALUES}

  # Retrieves every guidance associated to an org
  scope :by_org, -> (org) {
    joins(:guidance_group).merge(GuidanceGroup.by_org(org))
  }

  scope :search, -> (term) {
    search_pattern = "%#{term}%"
    joins(:guidance_group)
      .where("guidances.text LIKE ? OR guidance_groups.name LIKE ?",
             search_pattern,
             search_pattern)
  }

  # =================
  # = Class methods =
  # =================

  ##
  # Returns whether or not a given user can view a given guidance
  # we define guidances viewable to a user by those owned by a guidance group:
  #   owned by the managing curation center
  #   owned by a funder organisation
  #   owned by an organisation, of which the user is a member
  #
  # @param id [Integer] the integer id for a guidance
  # @param user [User] a user object
  # @return [Boolean] true if the specified user can view the specified
  # guidance, false otherwise
  def self.can_view?(user, id)
    guidance = Guidance.find_by(id: id)
    viewable = false

    unless guidance.nil?
      unless guidance.guidance_group.nil?
        # guidances are viewable if they are owned by the user's org
        if guidance.guidance_group.org == user.org
          viewable = true
        end
        # guidance groups are viewable if they are owned by the Managing
        # Curation Center
        if Org.managing_orgs.include?(guidance.guidance_group.org)
          viewable = true
        end

        # guidance groups are viewable if they are owned by a funder
        if Org.funder.include?(guidance.guidance_group.org)
          viewable = true
        end
      end
    end

    return viewable
  end

  ##
  # Returns a list of all guidances which a specified user can view
  # we define guidances viewable to a user by those owned by a guidance group:
  #   owned by the Managing Curation Center
  #   owned by a funder organisation
  #   owned by an organisation, of which the user is a member
  #
  # @param user [User] a user object
  # @return [Array<Guidance>] a list of all "viewable" guidances to a user
  def self.all_viewable(user)
    managing_groups = Org.includes(guidance_groups: :guidances)
                         .managing_orgs.collect{|o| o.guidance_groups}
    # find all groups owned by a Funder organisation
    funder_groups = Org.includes(guidance_groups: :guidances)
                       .funder.collect{|org| org.guidance_groups}
    # find all groups owned by any of the user's organisations
    organisation_groups = user.org.guidance_groups

    # find all guidances belonging to any of the viewable groups
    all_viewable_groups = (managing_groups +
                            funder_groups +
                            organisation_groups).flatten
    all_viewable_guidances = all_viewable_groups.collect do |group|
      group.guidances
    end
    # pass the list of viewable guidances to the view
    return all_viewable_guidances.flatten
  end

  ##
  # Determine if a guidance is in a group which belongs to a specified
  # organisation
  #
  # @param org_id [Integer] the integer id for an organisation
  # @return [Boolean] true if this guidance is in a group belonging to the
  # specified organisation, false otherwise
  def in_group_belonging_to?(org_id)
    unless guidance_group.nil?
      if guidance_group.org.id == org_id
        return true
      end
    end
    return false
  end
end