canvas-lms/app/models/account.rb

#
# Copyright (C) 2011 Instructure, Inc.
#
# This file is part of Canvas.
#
# Canvas is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
#

class Account < ActiveRecord::Base
  include Context
  attr_accessible :name, :parent_account_id, :turnitin_account_id,
    :turnitin_shared_secret, :turnitin_comments, :turnitin_pledge,
    :default_time_zone, :parent_account, :settings, :default_storage_quota,
    :storage_quota, :ip_filters

  include Workflow
  adheres_to_policy
  belongs_to :parent_account, :class_name => 'Account'
  belongs_to :root_account, :class_name => 'Account'
  authenticates_many :pseudonym_sessions
  has_many :courses
  has_many :all_courses, :class_name => 'Course', :foreign_key => 'root_account_id'
  has_many :groups, :as => :context
  has_many :account_groups, :as => :context, :class_name => 'Group', :foreign_key => 'account_id', :conditions => ['groups.context_type = ? and groups.context_id = #{id}', 'Account']
  has_many :enrollment_terms, :foreign_key => 'root_account_id'
  has_many :enrollments, :foreign_key => 'root_account_id'
  has_many :sub_accounts, :class_name => 'Account', :foreign_key => 'parent_account_id', :conditions => ['workflow_state != ?', 'deleted']
  has_many :all_accounts, :class_name => 'Account', :foreign_key => 'root_account_id'
  has_many :account_users, :dependent => :destroy
  has_many :course_sections, :foreign_key => 'root_account_id'
  has_many :learning_outcomes, :as => :context
  has_many :sis_batches
  has_many :department_abstract_courses, :class_name => 'AbstractCourse', :foreign_key => 'department_id'
  has_many :college_abstract_courses, :class_name => 'AbstractCourse', :foreign_key => 'college_id'
  has_many :root_abstract_courses, :class_name => 'AbstractCourse', :foreign_key => 'root_account_id'
  has_many :authorization_codes, :dependent => :destroy
  has_many :users, :through => :account_users
  has_many :pseudonyms, :include => :user
  has_many :role_overrides, :as => :context
  has_many :rubrics, :as => :context
  has_many :rubric_associations, :as => :context, :include => :rubric, :dependent => :destroy
  has_many :course_account_associations
  has_many :associated_courses, :through => :course_account_associations, :source => :course
  has_many :child_courses, :through => :course_account_associations, :source => :course, :conditions => ['course_account_associations.depth = 0']
  has_many :attachments, :as => :context, :dependent => :destroy
  has_many :active_attachments, :as => :context, :class_name => 'Attachment', :conditions => ['attachments.file_state != ?', 'deleted'], :order => 'attachments.display_name'
  has_many :active_assignments, :as => :context, :class_name => 'Assignment', :conditions => ['assignments.workflow_state != ?', 'deleted']
  has_many :folders, :as => :context, :dependent => :destroy, :order => 'folders.name'
  has_many :active_folders, :class_name => 'Folder', :as => :context, :conditions => ['folders.workflow_state != ?', 'deleted'], :order => 'folders.name'
  has_many :active_folders_with_sub_folders, :class_name => 'Folder', :as => :context, :include => [:active_sub_folders], :conditions => ['folders.workflow_state != ?', 'deleted'], :order => 'folders.name'
  has_many :active_folders_detailed, :class_name => 'Folder', :as => :context, :include => [:active_sub_folders, :active_file_attachments], :conditions => ['folders.workflow_state != ?', 'deleted'], :order => 'folders.name'
  has_one :account_authorization_config
  has_many :account_reports
  
  has_many :context_external_tools, :as => :context, :dependent => :destroy, :order => 'name'
  has_many :learning_outcomes, :as => :context
  has_many :learning_outcome_groups, :as => :context
  has_many :created_learning_outcomes, :class_name => 'LearningOutcome', :as => :context
  has_many :learning_outcome_tags, :class_name => 'ContentTag', :as => :context, :conditions => ['content_tags.tag_type = ? AND workflow_state != ?', 'learning_outcome_association', 'deleted']
  has_many :associated_learning_outcomes, :through => :learning_outcome_tags, :source => :learning_outcome
  has_many :page_views
  has_many :error_reports
  has_many :account_notifications

  before_save :ensure_defaults
  before_save :set_update_account_associations_if_changed
  after_save :update_account_associations_if_changed
  after_create :default_enrollment_term
  
  serialize :settings, Hash

  scopes_custom_fields

  cattr_accessor :account_settings_options
  self.account_settings_options = {}
  
  # I figure we're probably going to be adding more account-level
  # settings in the future (and moving some of the column attributes
  # to the settings hash), so it makes sense to have a general way
  # of defining what settings are allowed when.  Somebody please tell
  # me if I'm overarchitecting...
  def self.add_setting(setting, opts=nil)
    self.account_settings_options[setting.to_sym] = opts || {}
  end
  
  # these settings either are or could be easily added to
  # the account settings page
  add_setting :global_javascript, :condition => :global_includes, :root_only => true
  add_setting :global_stylesheet, :condition => :global_includes, :root_only => true
  add_setting :error_reporting, :hash => true, :values => [:action, :email, :url, :subject_param, :body_param], :root_only => true
  add_setting :prevent_course_renaming_by_teachers, :boolean => true, :root_only => true
  add_setting :teachers_can_create_courses, :boolean => true, :root_only => true
  add_setting :students_can_create_courses, :boolean => true, :root_only => true
  add_setting :no_enrollments_can_create_courses, :boolean => true, :root_only => true
  add_setting :allow_sending_scores_in_emails, :boolean => true, :root_only => true
  add_setting :support_url, :root_only => true
  add_setting :self_enrollment
  add_setting :equella_endpoint
  add_setting :equella_teaser
  
  def settings=(hash)
    if hash.is_a?(Hash)
      hash.each do |key, val|
        if account_settings_options && account_settings_options[key.to_sym]
          opts = account_settings_options[key.to_sym]
          if (opts[:root_only] && root_account_id) || (opts[:condition] && !settings[opts[:condition].to_sym])
            settings.delete key.to_sym
          elsif opts[:boolean]
            settings[key.to_sym] = (val == true || val == 'true' || val == '1' || val == 'on')
          elsif opts[:hash]
            new_hash = {}
            if val.is_a?(Hash)
              val.each do |inner_key, inner_val|
                if opts[:values].include?(inner_key.to_sym)
                  new_hash[inner_key.to_sym] = inner_val.to_s
                end
              end
            end
            settings[key.to_sym] = new_hash.empty? ? nil : new_hash
          else
            settings[key.to_sym] = val.to_s
          end
        end
      end
    end
    settings
  end
  
  def ip_filters=(params)
    filters = {}
    require 'ipaddr'
    params.each do |key, str|
      ips = []
      vals = str.split(/,/)
      vals.each do |val|
        ip = IPAddr.new(val) rescue nil
        # right now the ip_filter column on quizzes is just a string,
        # so it has a max length.  I figure whatever we set it to this
        # setter should at the very least limit stored values to that
        # length.
        ips << val if ip && val.length <= 255 
      end
      filters[key] = ips.join(',') unless ips.empty?
    end
    settings[:ip_filters] = filters
  end
  
  def ensure_defaults
    self.uuid ||= AutoHandle.generate_securish_uuid
  end
  
  def set_update_account_associations_if_changed
    self.root_account_id ||= self.parent_account.root_account_id if self.parent_account
    self.root_account_id ||= self.parent_account_id
    self.parent_account_id ||= self.root_account_id
    Account.invalidate_cache(self.id) if self.id
    @should_update_account_associations = self.parent_account_id_changed? || self.root_account_id_changed?
    true
  end
  
  def update_account_associations_if_changed
    send_later_if_production(:update_account_associations) if @should_update_account_associations
  end
  
  def equella_settings
    endpoint = self.settings[:equella_endpoint] || self.equella_endpoint
    if !endpoint.blank?
      OpenObject.new({
        :endpoint => endpoint,
        :default_action => self.settings[:equella_action] || 'selectOrAdd',
        :teaser => self.settings[:equella_teaser]
      })
    else
      nil
    end
  end
  
  def settings
    self.read_attribute(:settings) || self.write_attribute(:settings, {})
  end
  
  def domain
    HostUrl.context_host(self)
  end
  
  def sub_accounts_as_options(indent=0)
    res = [[("&nbsp;&nbsp;" * indent).html_safe + self.name, self.id]]
    self.sub_accounts.each do |account|
      res += account.sub_accounts_as_options(indent + 1)
    end
    res
  end
  
  def users_name_like(query="")
    @cached_users_name_like ||= {}
    @cached_users_name_like[query] ||= self.fast_all_users.name_like(query)
  end
  
  def fast_all_courses(opts = {})
    columns =  "courses.id, courses.name, courses.section, courses.workflow_state, courses.course_code, courses.sis_source_id"
    @cached_fast_all_courses ||= {}
    @cached_fast_all_courses[opts] ||= self.associated_courses.active.for_term(opts[:term]).active_first.limit(opts[:limit]).find(:all, :select => columns, :group => columns)
  end
  
  def all_users(limit=250)
    @cached_all_users ||= {}
    @cached_all_users[limit] ||= User.of_account(self).scoped(:limit=>limit)
  end
  
  def fast_all_users(limit=nil)
    @cached_fast_all_users ||= {}
    @cached_fast_all_users[limit] ||= self.all_users(limit).active.order_by_sortable_name.scoped(:select => "users.id, users.name")
  end
  
  def paginate_users_not_in_groups(groups, page, per_page = 15)
    User.paginate_by_sql(["SELECT u.id, u.name 
                             FROM users u
                            INNER JOIN user_account_associations uaa on uaa.user_id = u.id
                            WHERE uaa.account_id = ? AND u.workflow_state != 'deleted'
                                  #{"AND NOT EXISTS (SELECT *
                                                       FROM group_memberships gm
                                                      WHERE gm.user_id = u.id AND
                                                            gm.group_id IN (#{groups.map(&:id).join ','}))" unless groups.empty?}
                            ORDER BY u.sortable_name ASC", self.id], :page => page, :per_page => per_page)
  end
  
  def courses_name_like(query="")
    columns =  "courses.id, name, courses.workflow_state, courses.course_code, courses.sis_source_id"
    self.associated_courses.active.active_first.name_like(query).limit(200).find(:all, :select => columns, :group => columns)
  end
  memoize :courses_name_like

  def file_namespace
    root = self.root_account || self
    "account_#{root.id}"
  end
  
  def self.account_lookup_cache_key(id)
    ['_account_lookup', id].cache_key
  end
  
  def find_user_by_unique_id(unique_id)
    self.pseudonyms.find_by_unique_id(unique_id_or_email).user rescue nil
  end
  
  def clear_cache_keys!
    Rails.cache.delete(self.id)
    true
  end
  
  def self.invalidate_cache(id)
    Rails.cache.delete(account_lookup_cache_key(id)) if id
  rescue 
    nil
  end
  
  def quota
    # in megabytes
    Rails.cache.fetch(['current_quota', self].cache_key) do
      return read_attribute(:storage_quota) || (self.parent_account.default_storage_quota rescue nil) || 500
    end
  end
  
  def default_storage_quota
    read_attribute(:default_storage_quota) || 
    (self.parent_account.default_storage_quota rescue nil) ||
    500
  end
  
  def default_storage_quota=(val)
    val = val.to_f
    val = nil if val <= 0
    # If the value is the same as the inherited value, then go
    # ahead and blank it so it keeps using the inherited value
    if parent_account && parent_account.default_storage_quota == val
      val = nil
    end
    write_attribute(:default_storage_quota, val)
  end
  
  def has_outcomes?
    self.learning_outcomes.count > 0
  end
  
  def turnitin_shared_secret=(secret)
    return if secret.blank?
    self.turnitin_crypted_secret, self.turnitin_salt = Canvas::Security.encrypt_password(secret, 'instructure_turnitin_secret_shared')
  end
  
  def turnitin_shared_secret
    return nil unless self.turnitin_salt && self.turnitin_crypted_secret
    Canvas::Security.decrypt_password(self.turnitin_crypted_secret, self.turnitin_salt, 'instructure_turnitin_secret_shared')
  end
  
  def account_chain
    res = [self]
    account = self
    while account.parent_account
      account = account.parent_account
      res << account
    end
    res << self.root_account
    res.uniq.compact
  end
  
  def all_page_views
    PageView.of_account(self)
  end
  
  def membership_for_user(user)
    self.account_users.find_by_user_id(user && user.id)
  end
  
  def page_views_by_day(*args)
    dates = (!args.empty? && args) || [1.year.ago, Time.now ]
    PageView.count(
      :group => "date(created_at)", 
      :order => "date(created_at)",
      :conditions => {
        :account_id, self_and_all_sub_accounts,
        :created_at, (dates.first)..(dates.last)
      }
    )
  end
  memoize :page_views_by_day
  
  def page_views_by_hour(*args)
    dates = (!args.empty? && args) || [1.year.ago, Time.now ]
    PageView.count(
      :group => "hour(created_at)", 
      :order => "hour(created_at)",
      :conditions => {
        :account_id, self_and_all_sub_accounts,
        :created_at, (dates.first)..(dates.last)
      }
    )
  end
  memoize :page_views_by_hour
  
  def page_view_hourly_report(*args)
    # if they dont supply a date range then use the first day returned by page_views_by_day (which should be the first day that there is pageview statistics gathered)
    hours = []
    max = page_views_by_hour(*args).map{|key, val| val}.compact.max
    24.times do |hour|
      utc_hour = ActiveSupport::TimeWithZone.new(Time.parse("#{hour}:00"), Time.zone).utc.hour
      hours << [hour, ((page_views_by_hour(*args)[utc_hour.to_s].to_f / max.to_f * 100.0).to_i rescue 0) ]
    end
    hours
  end
  
  def page_view_data(*args)
    # if they dont supply a date range then use the first day returned by page_views_by_day (which should be the first day that there is pageview statistics gathered)
    dates = args.empty? ? [page_views_by_day.sort.first.first.to_datetime, Time.now] : args 
    days = []
    dates.first.to_datetime.upto(dates.last) do |d| 
      # this * 1000 part is because the Highcharts expects something like what Date.UTC(2006, 2, 28) would give you,
      # which is MILLISECONDS from the unix epoch, ruby's to_f gives you SECONDS since then.
      days << [ (d.at_beginning_of_day.to_f * 1000).to_i , page_views_by_day[d.to_date.to_s].to_i ]
    end
    days
  rescue
    return []
  end
  memoize :page_view_data
  
  def most_popular_courses(options={})
    conditions = {
      :account_id, self_and_all_sub_accounts
    }
    if options[:dates]
      conditions.merge!({
        :created_at, (options[:dates].first)..(options[:dates].last)
      })
    end
    PageView.scoped(
      :select => 'count(*) AS page_views_count, context_type, context_id',
      :group => "context_type, context_id", 
      :conditions => conditions,
      :order => "page_views_count DESC"
    ).map do |context|
      context.attributes.merge({"page_views_count" => context.page_views_count.to_i}).with_indifferent_access
    end
  end
  memoize :most_popular_courses
  
  def popularity_of(context)
    index = most_popular_courses.index( most_popular_courses.detect { |i| 
      i[:context_type] == context.class.to_s && i[:context_id] == context.id 
    })
    index ? 
      { :rank => index, :page_views_count => most_popular_courses[index][:page_views_count] } :
      { :rank => courses.count, :page_views_count => 0 } 
  end
  memoize :popularity_of
  
  def account_membership_types
    res = ['AccountAdmin']
    res += self.parent_account.account_membership_types if self.parent_account
    res += (self.membership_types || "").split(",").select{|t| !t.empty? }
    res.uniq
  end
  
  def add_account_membership_type(type)
    types = account_membership_types
    types += type.split(",")
    self.membership_types  = types.join(',')
    self.save
  end
  
  def remove_account_membership_type(type)
    self.membership_types = self.account_membership_types.select{|t| t != type}.join(',')
    self.save
  end
  
  def membership_allows(user, permission)
    return false unless user && permission
    account_users = AccountUser.for_user(user).select{|a| a.account_id == self.id}
    result = account_users.any?{|e| e.has_permission_to?(permission) }
  end
  
  def login_handle_name
    self.account_authorization_config && self.account_authorization_config.login_handle_name ? 
      self.account_authorization_config.login_handle_name :
      AccountAuthorizationConfig.default_login_handle_name
  end
  
  def self_and_all_sub_accounts
    @self_and_all_sub_accounts ||= ActiveRecord::Base.connection.send(:select, "SELECT id FROM accounts WHERE accounts.root_account_id = #{self.id} OR accounts.parent_account_id = #{self.id}").map{|ref| ref['id'].to_i}.uniq + [self.id] #(self.all_accounts + [self]).map &:id
  end
  
  def abstract_courses
    if self.is_a?(Department)
      self.department_abstract_courses
    elsif self.is_a?(College)
      self.college_abstract_courses
    else
      self.root_abstract_courses
    end
  end
  
  def default_time_zone
    read_attribute(:default_time_zone) || "Mountain Time (US & Canada)"
  end
  
  workflow do
    state :active
    state :deleted
  end
  
  set_policy do
    RoleOverride.permissions.each do |permission, params|
      given {|user, session| self.membership_allows(user, permission) }
      set { can permission }
      
      given {|user, session| self.parent_account && self.parent_account.grants_right?(user, session, permission) }
      set { can permission }

      given {|user, session| !site_admin? && Account.site_admin_user?(user) }
      set { can permission }
    end

    given { |user| self.active? && self.users.include?(user) }
    set { can :read and can :read_roster and can :manage and can :update and can :delete }
    
    given { |user| self.root_account && self.root_account.grants_right?(user, nil, :manage) }
    set { can :read and can :read_roster and can :manage and can :update and can :delete }
    
    given { |user| self.parent_account && self.parent_account.grants_right?(user, nil, :manage) }
    set { can :read and can :read_roster and can :manage and can :update and can :delete }
    
    given { |user| !site_admin? && Account.site_admin_user?(user) }
    set { can :read and can :read_roster and can :manage and can :update and can :delete }
  end

  alias_method :destroy!, :destroy
  def destroy
    self.workflow_state = 'deleted'
    self.deleted_at = Time.now
    save!
  end
  
  def self.site_admin_user?(user, permission = :site_admin)
    !!(user && Account.site_admin.grants_right?(user, permission))
  end
  
  def to_atom
    Atom::Entry.new do |entry|
      entry.title     = self.name
      entry.updated   = self.updated_at
      entry.published = self.created_at
      entry.links    << Atom::Link.new(:rel => 'alternate', 
                                    :href => "/accounts/#{self.id}")
    end
  end
  
  def default_enrollment_term
    return @default_enrollment_term if @default_enrollment_term
    unless self.root_account_id
      @default_enrollment_term = self.enrollment_terms.active.find_or_create_by_name("Default Term")
    end
  end
  
  def add_admin(args)
    email = args[:email]
    membership_type = args[:membership_type] || 'AccountAdmin'
    user = User.find_by_email(email)
    data = {}
    if !user && true # check if can add password-based users
      data = User.assert_by_email(email)
      user = data[:user]
    end
    if user
      account_user = self.account_users.find_or_initialize_by_user_id(user.id)
      account_user.membership_type = membership_type
      account_user.save
      if data[:new]
        account_user.account_user_registration!
      else
        account_user.account_user_notification!
      end
      account_user
    else
      nil
    end
  end
  
  def add_user(user, membership_type = nil)
    return nil unless user && user.is_a?(User)
    membership_type ||= 'AccountAdmin'
    self.account_users.find_or_create_by_user_id_and_membership_type(user.id, membership_type) rescue nil
  end
  
  def context_code
    raise "DONT USE THIS, use .short_name instead" unless ENV['RAILS_ENV'] == "production"
  end
  
  def short_name
    name
  end

  def email_pseudonyms
    false
  end
  
  def password_authentication?
    !!(!self.account_authorization_config || self.account_authorization_config.password_authentication?)
  end

  def delegated_authentication?
    !!(self.account_authorization_config && self.account_authorization_config.delegated_authentication?)
  end

  def cas_authentication?
    !!(self.account_authorization_config && self.account_authorization_config.cas_authentication?)
  end
  
  def ldap_authentication?
    !!(self.account_authorization_config && self.account_authorization_config.ldap_authentication?)
  end
  
  def saml_authentication?
    !!(self.account_authorization_config && self.account_authorization_config.saml_authentication?)
  end
  
  def require_account_pseudonym?
    false
  end
  
  # When a user is invited to a course, do we let them see a preview of the
  # course even without registering?  This is part of the free-for-teacher
  # account perks, since anyone can invite anyone to join any course, and it'd
  # be nice to be able to see the course first if you weren't expecting the
  # invitation.
  def allow_invitation_previews?
    self == Account.default
  end
  
  def pseudonym_session_scope
    self.require_account_pseudonym? ? self.pseudonym_sessions : PseudonymSession
  end
  
  def find_courses(string)
    self.all_courses.select{|c| c.name.match(string) }
  end
  
  def find_users(string)
    self.pseudonyms.map{|p| p.user }.select{|u| u.name.match(string) }
  end

  def self.site_admin
    get_special_account('site_admin', 'Site Admin')
  end

  def self.default
    get_special_account('default', 'Default Account')
  end

  def self.get_special_account(special_account_type, default_account_name)
    @special_accounts ||= {}

    if Rails.env.test?
      # TODO: we have to do this because tests run in transactions. maybe it'd
      # be good to create some sort of of memoize_if_safe method, that only
      # memoizes when we're caching classes and not in test mode? I dunno. But
      # this stinks.
      return @special_accounts[special_account_type] = Account.find_or_create_by_parent_account_id_and_name(nil, default_account_name)
    end

    account = @special_accounts[special_account_type]
    return account if account
    if (account_id = Setting.get("#{special_account_type}_account_id", nil)) && account_id.present?
      account = Account.find_by_id(account_id)
    end
    return @special_accounts[special_account_type] = account if account
    account = Account.create!(:name => default_account_name)
    Setting.set("#{special_account_type}_account_id", account.id)
    return @special_accounts[special_account_type] = account
  end

  def site_admin?
    self == Account.site_admin
  end

  def display_name
    self.name
  end

  # Updates account associations for all the courses and users associated with this account
  def update_account_associations
    all_user_ids = []
    self.associated_courses.compact.uniq.each do |course|
      # Don't update the user associations yet, we'll do that afterwards so we only do it once per user
      course.update_account_associations(false)
      all_user_ids += course.user_ids
    end
    
    # Make sure we have all users with existing account associations.
    # (This should catch users with Pseudonyms associated with the account.)
    all_user_ids += UserAccountAssociation.scoped(:select => 'user_id', :conditions => { :account_id => id }).map(&:user_id)
    
    # Update the users' associations as well
    User.update_account_associations(all_user_ids.uniq)
  end
  
  # this will take an account and make it a sub_account of
  # itself.  Also updates all it's descendant accounts to point to
  # the correct root account, and updates the pseudonyms to
  # points to the new root account as well.
  def consume_account(account)
    account.all_accounts.each do |sub_account|
      sub_account.root_account = self.root_account || self
      sub_account.save!
    end
    account.parent_account = self
    account.root_account = self.root_account || self
    account.save!
    account.pseudonyms.each do |pseudonym|
      pseudonym.account = self.root_account || self
      pseudonym.save!
    end
  end
  
  def self.root_account_id_for(obj)
    res = nil
    if obj.respond_to?(:root_account_id)
      res = obj.root_account_id
    elsif obj.respond_to?(:context)
      res = obj.context.root_account_id rescue nil
    end
    raise "Root account ID is undiscoverable for #{obj.inspect}" unless res
  end
  
  def course_count
    self.child_courses.not_deleted.uniq.count
  end
  memoize :course_count
  
  def sub_account_count
    self.sub_accounts.active.count
  end
  memoize :sub_account_count
  
  def current_sis_batch
    if (current_sis_batch_id = self.read_attribute(:current_sis_batch_id)) && current_sis_batch_id.present?
      self.sis_batches.find_by_id(current_sis_batch_id)
    end
  end
  
  def turnitin_settings
    if self.turnitin_account_id && self.turnitin_shared_secret && !self.turnitin_account_id.empty? && !self.turnitin_shared_secret.empty?
      [self.turnitin_account_id, self.turnitin_shared_secret]
    else
      self.parent_account.turnitin_settings rescue nil
    end
  end
  
  def closest_turnitin_pledge
    if self.turnitin_pledge && !self.turnitin_pledge.empty?
      self.turnitin_pledge
    else
      res = self.account.turnitin_pledge rescue nil
      res ||= "This assignment submission is my own, original work"
    end
  end
  
  def closest_turnitin_comments
    if self.turnitin_comments && !self.turnitin_comments.empty?
      self.turnitin_comments
    else
      self.parent_account.closest_turnitin_comments rescue nil
    end
  end
  
  def self_enrollment_allowed?(course)
    if !settings[:self_enrollment].blank?
      !!(settings[:self_enrollment] == 'any' || (!course.sis_source_id && settings[:self_enrollment] == 'manually_created'))
    else
      !!(parent_account && parent_account.self_enrollment_allowed?(course))
    end
  end
  
  TAB_COURSES = 0
  TAB_STATISTICS = 1
  TAB_PERMISSIONS = 2
  TAB_SUB_ACCOUNTS = 3
  TAB_TERMS = 4
  TAB_AUTHENTICATION = 5
  TAB_USERS = 6
  TAB_OUTCOMES = 7
  TAB_RUBRICS = 8
  TAB_SETTINGS = 9
  TAB_FACULTY_JOURNAL = 10
  TAB_SIS_IMPORT = 11
  
  def tabs_available(user=nil, opts={})
    if site_admin?
      tabs = [
        { :id => TAB_PERMISSIONS, :label => "Permissions", :href => :account_role_overrides_path },
      ]
    else
      tabs = [
        { :id => TAB_COURSES, :label => "Courses", :href => :account_path },
        { :id => TAB_USERS, :label => "Users", :href => :account_users_path },
        { :id => TAB_STATISTICS, :label => "Statistics", :href => :statistics_account_path },
        { :id => TAB_PERMISSIONS, :label => "Permissions", :href => :account_role_overrides_path },
        { :id => TAB_OUTCOMES, :label => "Outcomes", :href => :account_outcomes_path },
        { :id => TAB_RUBRICS, :label => "Rubrics", :href => :account_rubrics_path },
        { :id => TAB_SUB_ACCOUNTS, :label => "Sub-Accounts", :href => :account_sub_accounts_path },
      ]
      tabs << { :id => TAB_FACULTY_JOURNAL, :label => "Faculty Journal", :href => :account_user_notes_path} if self.enable_user_notes
      tabs << { :id => TAB_TERMS, :label => "Terms", :href => :account_terms_path } if !self.root_account_id
      tabs << { :id => TAB_AUTHENTICATION, :label => "Authentication", :href => :account_account_authorization_config_path } if self.parent_account_id.nil?
      tabs << { :id => TAB_SIS_IMPORT, :label => "SIS Import", :href => :account_sis_import_path } if self.allow_sis_import
    end
    tabs << { :id => TAB_SETTINGS, :label => "Settings", :href => :account_settings_path }
    tabs
  end

  def is_a_context?
    true
  end
  
  def self.allowable_services
    {
      :google_docs => {
        :name => "Google Docs", 
        :description => "",
        :expose_to_ui => !!GoogleDocs.config
      },
      :google_docs_previews => {
        :name => "Google Docs Previews", 
        :description => "",
        :expose_to_ui => true
      },
      :facebook => {
        :name => "Facebook", 
        :description => "",
        :expose_to_ui => !!Facebook.config
      },
      :skype => {
        :name => "Skype", 
        :description => "",
        :expose_to_ui => true
      },
      :linked_in => {
        :name => "LinkedIn", 
        :description => "",
        :expose_to_ui => !!LinkedIn.config
      },
      :twitter => {
        :name => "Twitter", 
        :description => "",
        :expose_to_ui => !!Twitter.config
      },
      :delicious => {
        :name => "Delicious", 
        :description => "",
        :expose_to_ui => true
      },
      :diigo => {
        :name => "Diigo", 
        :description => "",
        :expose_to_ui => true
      },
      :avatars => {
        :name => "User Avatars",
        :description => "",
        :default => false
      }
    }.freeze
  end
  
  def self.default_allowable_services
    self.allowable_services.reject {|s, info| info[:default] == false }
  end
  
  def set_service_availability(service, enable)
    service = service.to_sym
    raise "Invalid Service" unless Account.allowable_services[service]
    allowed_service_names = (self.allowed_services || "").split(",").compact
    if allowed_service_names.count > 0 and not [ '+', '-' ].member?(allowed_service_names[0][0,1])
      # This account has a hard-coded list of services, so handle accordingly
      allowed_service_names.reject! { |flag| flag.match(service.to_s) }
      allowed_service_names << service if enable
    else
      allowed_service_names.reject! { |flag| flag.match(service.to_s) }
      if enable
        # only enable if it is not enabled by default
        allowed_service_names << "+#{service}" unless Account.default_allowable_services[service]
      else
        # only disable if it is not enabled by default
        allowed_service_names << "-#{service}" if Account.default_allowable_services[service]
      end
    end
    
    @allowed_services_hash = nil
    self.allowed_services = allowed_service_names.empty? ? nil : allowed_service_names.join(",")
  end
  
  def enable_service(service)
    set_service_availability(service, true)
  end
  
  def disable_service(service)
    set_service_availability(service, false)
  end
  
  def allowed_services_hash
    return @allowed_services_hash if @allowed_services_hash
    account_allowed_services = Account.default_allowable_services
    if self.allowed_services
      allowed_service_names = self.allowed_services.split(",").compact
      
      if allowed_service_names.count > 0
        unless [ '+', '-' ].member?(allowed_service_names[0][0,1])
          # This account has a hard-coded list of services, so we clear out the defaults
          account_allowed_services = { }
        end
        
        allowed_service_names.each do |service_switch|
          if service_switch =~ /\A([+-]?)(.*)\z/
            flag = $1
            service_name = $2.to_sym
            
            if flag == '-'
              account_allowed_services.delete(service_name)
            else
              account_allowed_services[service_name] = Account.allowable_services[service_name]
            end
          end
        end
      end
    end
    @allowed_services_hash = account_allowed_services
  end
  
  def self.services_exposed_to_ui_hash
    self.allowable_services.reject { |key, setting| !setting[:expose_to_ui] }
  end
  
  def service_enabled?(service)
    service = service.to_sym
    case service
    when :none
      self.allowed_services_hash.empty?
    else
      self.allowed_services_hash.has_key?(service)
    end
  end
  
  def self.serialization_excludes; [:uuid]; end
  
  # This could be much faster if we implement a SQL tree for the account tree
  # structure.
  def find_child(child_id)
    child_id = child_id.to_i
    child_ids = self.class.connection.select_values("SELECT id FROM accounts WHERE parent_account_id = #{self.id}").map(&:to_i)
    until child_ids.empty?
      if child_ids.include?(child_id)
        return self.class.find(child_id)
      end
      child_ids = self.class.connection.select_values("SELECT id FROM accounts WHERE parent_account_id IN (#{child_ids.join(",")})").map(&:to_i)
    end
    return false
  end

  named_scope :sis_sub_accounts, lambda{|account, *sub_account_source_ids|
    {:conditions => {:root_account_id => account.id, :sis_source_id => sub_account_source_ids}, :order => :sis_source_id}
  }
  named_scope :root_accounts, lambda{
    {:conditions => {:root_account_id => nil} }
  }
  named_scope :needs_parent_account, lambda{|account, limit|
    {:conditions => {:parent_account_id => nil, :root_account_id => account.id}, :limit => limit }
  }
  named_scope :processing_sis_batch, lambda{ 
    {:conditions => ['accounts.current_sis_batch_id IS NOT NULL'], :order => :updated_at}
  }
  named_scope :name_like, lambda { |name|
    { :conditions => wildcard('accounts.name', name) }
  }
  named_scope :active, lambda {
    { :conditions => ['accounts.workflow_state != ?', 'deleted'] }
  }
  named_scope :limit, lambda {|limit|
    {:limit => limit}
  }
end