canvas-lms/app/models/account.rb

#
# Copyright (C) 2011 - 2012 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, :turnitin_account_id,
    :turnitin_shared_secret, :turnitin_comments, :turnitin_pledge,
    :default_time_zone, :parent_account, :settings, :default_storage_quota,
    :default_storage_quota_mb, :storage_quota, :ip_filters, :default_locale,
    :default_user_storage_quota_mb

  include Workflow
  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 :group_categories, :as => :context, :conditions => ['deleted_at IS NULL']
  has_many :all_group_categories, :class_name => 'GroupCategory', :as => :context
  has_many :groups, :as => :context
  has_many :all_groups, :class_name => 'Group', :foreign_key => 'root_account_id'
  has_many :enrollment_terms, :foreign_key => 'root_account_id'
  has_many :enrollments, :foreign_key => 'root_account_id', :conditions => ["enrollments.type != 'StudentViewEnrollment'"]
  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', :order => 'name'
  has_many :account_users, :dependent => :destroy
  has_many :course_sections, :foreign_key => 'root_account_id'
  has_many :sis_batches
  has_many :abstract_courses, :class_name => 'AbstractCourse', :foreign_key => 'account_id'
  has_many :root_abstract_courses, :class_name => 'AbstractCourse', :foreign_key => 'root_account_id'
  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, :select => 'DISTINCT courses.*'
  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_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_many :account_authorization_configs, :order => "position"
  has_many :account_reports
  has_many :grading_standards, :as => :context, :conditions => ['workflow_state != ?', 'deleted']
  has_many :assessment_questions, :through => :assessment_question_banks
  has_many :assessment_question_banks, :as => :context, :include => [:assessment_questions, :assessment_question_bank_users]
  has_many :roles
  has_many :all_roles, :class_name => 'Role', :foreign_key => 'root_account_id'
  def inherited_assessment_question_banks(include_self = false, *additional_contexts)
    sql = []
    conds = []
    contexts = additional_contexts + account_chain
    contexts.delete(self) unless include_self
    contexts.each { |c|
      sql << "context_type = ? AND context_id = ?"
      conds += [c.class.to_s, c.id]
    }
    conds.unshift(sql.join(" OR "))
    AssessmentQuestionBank.scoped :conditions => conds
  end
  
  include LearningOutcomeContext

  has_many :context_external_tools, :as => :context, :dependent => :destroy, :order => 'name'
  has_many :error_reports
  has_many :announcements, :class_name => 'AccountNotification'
  has_many :alerts, :as => :context, :include => :criteria
  has_many :associated_alerts, :through => :associated_courses, :source => :alerts, :include => :criteria
  has_many :user_account_associations
  has_many :report_snapshots

  before_validation :verify_unique_sis_source_id
  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

  validates_locale :default_locale, :allow_nil => true
  validate :account_chain_loop, :if => :parent_account_id_changed?
  validate :validate_auth_discovery_url

  include StickySisFields
  are_sis_sticky :name

  def default_locale(recurse = false)
    read_attribute(:default_locale) ||
    (recurse && parent_account ? parent_account.default_locale(true) : nil)
  end

  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 || {}
    if (opts && opts[:boolean] && opts.has_key?(:default))
      if opts[:default]
        self.class_eval "def #{setting}?; settings[:#{setting}] != false; end"
      else
        self.class_eval "def #{setting}?; !!settings[:#{setting}]; end"
      end
    end
  end
  
  # these settings either are or could be easily added to
  # the account settings page
  add_setting :global_includes, :root_only => true, :boolean => true, :default => false
  add_setting :global_javascript, :condition => :allow_global_includes
  add_setting :global_stylesheet, :condition => :allow_global_includes
  add_setting :sub_account_includes, :condition => :allow_global_includes, :boolean => true, :default => false
  add_setting :error_reporting, :hash => true, :values => [:action, :email, :url, :subject_param, :body_param], :root_only => true
  add_setting :custom_help_links, :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, :default => false
  add_setting :students_can_create_courses, :boolean => true, :root_only => true, :default => false
  add_setting :no_enrollments_can_create_courses, :boolean => true, :root_only => true, :default => false
  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
  add_setting :enable_alerts, :boolean => true, :root_only => true
  add_setting :enable_eportfolios, :boolean => true, :root_only => true
  add_setting :users_can_edit_name, :boolean => true, :root_only => true
  add_setting :open_registration, :boolean => true, :root_only => true
  add_setting :enable_scheduler, :boolean => true, :root_only => true, :default => false
  add_setting :calendar2_only, :boolean => true, :root_only => true, :default => false
  add_setting :show_scheduler, :boolean => true, :root_only => true, :default => false
  add_setting :enable_profiles, :boolean => true, :root_only => true, :default => false
  add_setting :mfa_settings, :root_only => true
  add_setting :canvas_authentication, :boolean => true, :root_only => true
  add_setting :admins_can_change_passwords, :boolean => true, :root_only => true, :default => false
  add_setting :outgoing_email_default_name
  add_setting :external_notification_warning, :boolean => true, :default => false
  # 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.
  add_setting :allow_invitation_previews, :boolean => true, :root_only => true, :default => false

  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] && !self.root_account?) || (opts[:condition] && !self.send("#{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 allow_global_includes?
    self.global_includes? || self.parent_account.try(:sub_account_includes?)
  end

  def global_includes_hash
    includes = {}
    if allow_global_includes?
      includes = {}
      includes[:js] = settings[:global_javascript] if settings[:global_javascript].present?
      includes[:css] = settings[:global_stylesheet] if settings[:global_stylesheet].present?
    end
    includes.present? ? includes : nil
  end

  def mfa_settings
    settings[:mfa_settings].try(:to_sym) || :disabled
  end

  def canvas_authentication?
    settings[:canvas_authentication] != false || !self.account_authorization_config
  end

  def open_registration?
    !!settings[:open_registration] && canvas_authentication?
  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 verify_unique_sis_source_id
    return true unless self.sis_source_id
    if self.root_account?
      self.errors.add(:sis_source_id, t('#account.root_account_cant_have_sis_id', "SIS IDs cannot be set on root accounts"))
      return false
    end

    root = self.root_account
    existing_account = Account.find_by_root_account_id_and_sis_source_id(root.id, self.sis_source_id)
    
    return true if !existing_account || existing_account.id == self.id

    self.errors.add(:sis_source_id, t('#account.sis_id_in_use', "SIS ID \"%{sis_id}\" is already in use", :sis_id => self.sis_source_id))
    false
  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
    result = self.read_attribute(:settings)
    return result if result
    return self.write_attribute(:settings, {}) unless frozen?
    {}.freeze
  end
  
  def domain
    HostUrl.context_host(self)
  end
  
  def root_account?
    !self.root_account_id
  end

  def root_account_with_self
    return self if self.root_account?
    root_account_without_self
  end
  alias_method_chain :root_account, :self

  def sub_accounts_as_options(indent = 0, preloaded_accounts = nil)
    unless preloaded_accounts
      preloaded_accounts = {}
      self.root_account.all_accounts.active.each do |account|
        (preloaded_accounts[account.parent_account_id] ||= []) << account
      end
    end
    res = [[("&nbsp;&nbsp;" * indent).html_safe + self.name, self.id]]
    if preloaded_accounts[self.id]
      preloaded_accounts[self.id].each do |account|
        res += account.sub_accounts_as_options(indent + 1, preloaded_accounts)
      end
    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_course_base(opts)
    columns = "courses.id, courses.name, courses.workflow_state, courses.course_code, courses.sis_source_id, courses.enrollment_term_id"
    associated_courses = self.associated_courses.active
    associated_courses = associated_courses.with_enrollments if opts[:hide_enrollmentless_courses]
    associated_courses = associated_courses.for_term(opts[:term]) if opts[:term].present?
    associated_courses = yield associated_courses if block_given?
    associated_courses.limit(opts[:limit]).active_first.find(:all, :select => columns, :group => columns)
  end

  def fast_all_courses(opts={})
    @cached_fast_all_courses ||= {}
    @cached_fast_all_courses[opts] ||= self.fast_course_base(opts)
  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, users.sortable_name")
  end

  def users_not_in_groups_sql(groups, opts={})
    ["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 #{opts[:order_by]}" if opts[:order_by].present?}", self.id]
  end

  def users_not_in_groups(groups)
    User.find_by_sql(users_not_in_groups_sql(groups))
  end
  
  def paginate_users_not_in_groups(groups, page, per_page = 15)
    User.paginate_by_sql(users_not_in_groups_sql(groups, :order_by => "#{User.sortable_name_order_by_clause('u')} ASC"),
                         :page => page, :per_page => per_page)
  end

  def courses_name_like(query="", opts={})
    opts[:limit] ||= 200
    @cached_courses_name_like ||= {}
    @cached_courses_name_like[[query, opts]] ||= self.fast_course_base(opts) {|q| q.name_like(query)}
  end

  def self_enrollment_course_for(code)
    all_courses.
      where(:self_enrollment => true, :self_enrollment_code => code).
      first
  end

  def file_namespace
    Shard.default.activate { "account_#{self.root_account.id}" }
  end
  
  def self.account_lookup_cache_key(id)
    ['_account_lookup2', id].cache_key
  end
  
  def self.invalidate_cache(id)
    Rails.cache.delete(account_lookup_cache_key(id)) if id
  rescue 
    nil
  end
  
  def quota
    Rails.cache.fetch(['current_quota', self].cache_key) do
      read_attribute(:storage_quota) ||
        (self.parent_account.default_storage_quota rescue nil) ||
        Setting.get_cached('account_default_quota', 500.megabytes.to_s).to_i
    end
  end
  
  def default_storage_quota
    read_attribute(:default_storage_quota) || 
      (self.parent_account.default_storage_quota rescue nil) ||
      Setting.get_cached('account_default_quota', 500.megabytes.to_s).to_i
  end
  
  def default_storage_quota_mb
    default_storage_quota / 1.megabyte
  end
  
  def default_storage_quota_mb=(val)
    self.default_storage_quota = val.try(:to_i).try(:megabytes)
  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 default_user_storage_quota
    read_attribute(:default_user_storage_quota) ||
    User.default_storage_quota
  end

  def default_user_storage_quota=(val)
    val = val.to_i
    val = nil if val == User.default_storage_quota || val <= 0
    write_attribute(:default_user_storage_quota, val)
  end

  def default_user_storage_quota_mb
    default_user_storage_quota / 1.megabyte
  end
  
  def default_user_storage_quota_mb=(val)
    self.default_user_storage_quota = val.try(:to_i).try(:megabytes)
  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(opts = {})
    res = [self]

    if ActiveRecord::Base.configurations[RAILS_ENV]['adapter'] == 'postgresql'
      res.concat Account.find_by_sql(<<-SQL) if self.parent_account_id
          WITH RECURSIVE t AS (
            SELECT * FROM accounts WHERE id=#{self.parent_account_id}
            UNION
            SELECT accounts.* FROM accounts INNER JOIN t ON accounts.id=t.parent_account_id
          )
          SELECT * FROM t
        SQL
    else
      account = self
      while account.parent_account
        account = account.parent_account
        res << account
      end
    end
    res << self.root_account unless res.map(&:id).include?(self.root_account_id)
    res << Account.site_admin if opts[:include_site_admin] && !self.site_admin?
    res.compact
  end

  def account_chain_loop
    # this record hasn't been saved to the db yet, so if the the chain includes
    # this account, it won't point to the new parent yet, and should still be
    # valid
    if self.parent_account.account_chain_ids.include?(self.id)
      errors.add(:parent_account_id,
                 "Setting account #{self.sis_source_id || self.id}'s parent to #{self.parent_account.sis_source_id || self.parent_account_id} would create a loop")
    end
  end

  def associated_accounts
    self.account_chain
  end
  
  def account_chain_ids(opts={})
    account_chain(opts).map(&:id)
  end
  memoize :account_chain_ids

  def membership_for_user(user)
    self.account_users.find_by_user_id(user && user.id)
  end

  def available_account_roles
    account_roles = roles.for_accounts.active.map(&:name)
    account_roles |= ['AccountAdmin']
    account_roles |= self.parent_account.available_account_roles if self.parent_account
    account_roles
  end

  def available_course_roles
    course_roles = roles.for_courses.active.map(&:name)
    course_roles |= parent_account.available_course_roles if parent_account
    course_roles
  end

  def available_course_roles_by_name
    role_map = {}
    roles.for_courses.active.each { |role| role_map[role.name] = role }
    role_map.reverse_merge!(parent_account.available_course_roles_by_name) if parent_account
    role_map
  end

  def get_course_role(role_name)
    course_role = self.roles.for_courses.find_by_name(role_name)
    course_role ||= self.parent_account.get_course_role(role_name) if self.parent_account
    course_role
  end

  def has_role?(role_name)
    roles.not_deleted.scoped(:conditions => ["roles.name = ?", role_name]).any?
  end

  def find_role(role_name)
    roles.not_deleted.find_by_name(role_name) || (parent_account && parent_account.find_role(role_name))
  end

  def account_authorization_config
    # We support multiple auth configs per account, but several places we assume there is only one.
    # This is for compatibility with those areas. TODO: migrate everything to supporting multiple
    # auth configs
    self.account_authorization_configs.first
  end
  
  def login_handle_name_is_customized?
    self.account_authorization_config && self.account_authorization_config.login_handle_name.present?
  end
  
  def login_handle_name
    login_handle_name_is_customized? ? self.account_authorization_config.login_handle_name :
        (self.delegated_authentication? ? AccountAuthorizationConfig.default_delegated_login_handle_name :
            AccountAuthorizationConfig.default_login_handle_name)
  end
  
  def self_and_all_sub_accounts
    @self_and_all_sub_accounts ||= Account.connection.select_all("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]
  end
  
  def default_time_zone
    read_attribute(:default_time_zone) || "Mountain Time (US & Canada)"
  end
  
  workflow do
    state :active
    state :deleted
  end

  def account_users_for(user)
    return [] unless user
    @account_users_cache ||= {}
    if self == Account.site_admin
      @account_users_cache[user] ||= Rails.cache.fetch('all_site_admin_account_users', :expires_in => 30.minutes) do
        self.account_users.all
      end.select { |au| au.user_id == user.id }.each { |au| au.account = self }
    else
      @account_chain_ids ||= self.account_chain(:include_site_admin => true).map { |a| a.active? ? a.id : nil }.compact
      @account_users_cache[user] ||= Shard.partition_by_shard(@account_chain_ids) do |account_chain_ids|
        if account_chain_ids == [Account.site_admin.id]
          Account.site_admin.account_users_for(user)
        else
          AccountUser.find(:all, :conditions => { :account_id => account_chain_ids, :user_id => user.id })
        end
      end
    end
    @account_users_cache[user] ||= []
    @account_users_cache[user]
  end

  # returns all account users for this entire account tree
  def all_account_users_for(user)
    raise "must be a root account" unless self.root_account?
    Shard.partition_by_shard([self, Account.site_admin].uniq) do |accounts|
      ids = accounts.map(&:id)
      AccountUser.find(:all, :include => :account, :joins => :account, :conditions => ["user_id=? AND (root_account_id IN (?) OR account_id IN (?))", user.id, ids, ids])
    end
  end

  set_policy do
    enrollment_types = RoleOverride.enrollment_types.map { |role| role[:name] }
    RoleOverride.permissions.each do |permission, details|
      given { |user| self.account_users_for(user).any? { |au| au.has_permission_to?(permission) && (!details[:if] || send(details[:if])) } }
      can permission
      can :create_courses if permission == :manage_courses

      next unless details[:account_only]
      ((details[:available_to] | details[:true_for]) & enrollment_types).each do |role|
        given { |user| user && RoleOverride.permission_for(self, permission, role)[:enabled] &&
          self.course_account_associations.find(:first, :joins => 'INNER JOIN enrollments ON course_account_associations.course_id=enrollments.course_id',
            :conditions => ["enrollments.type=? AND enrollments.workflow_state IN ('active', 'completed') AND user_id=?", role, user.id]) &&
          (!details[:if] || send(details[:if])) }
        can permission
      end
    end

    given { |user| !self.account_users_for(user).empty? }
    can :read and can :manage and can :update and can :delete and can :read_outcomes

    given { |user|
      root_account = self.root_account
      result = false
      site_admin = self.site_admin?

      if !site_admin && user && root_account.teachers_can_create_courses?
        count = user.enrollments.scoped(:select=>'id', :conditions=>"enrollments.type IN ('TeacherEnrollment', 'DesignerEnrollment') AND (enrollments.workflow_state != 'deleted') AND root_account_id = #{root_account.id}").count
        result = true if count > 0
      end
      if !site_admin && user && !result && root_account.students_can_create_courses?
        count = user.enrollments.scoped(:select=>'id', :conditions=>"enrollments.type IN ('StudentEnrollment', 'ObserverEnrollment') AND (enrollments.workflow_state != 'deleted') AND root_account_id = #{root_account.id}").count
        result = true if count > 0
      end
      if !site_admin && user && !result && root_account.no_enrollments_can_create_courses?
        count = user.enrollments.scoped(:select=>'id', :conditions=>"enrollments.workflow_state != 'deleted' AND root_account_id = #{root_account.id}").count
        result = true if count == 0
      end

      result
    }
    can :create_courses

    # any logged in user can read global outcomes, but must be checked against the site admin
    given{ |user,session| self.site_admin? && user }
    can :read_global_outcomes

    # any user with an association to this account can read the outcomes in the account
    given{ |user,session| user && self.user_account_associations.find_by_user_id(user.id) }
    can :read_outcomes
  end

  alias_method :destroy!, :destroy
  def destroy
    self.workflow_state = 'deleted'
    self.deleted_at = Time.now
    save!
  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
    if self.root_account?
      @default_enrollment_term = self.enrollment_terms.active.find_or_create_by_name(EnrollmentTerm::DEFAULT_TERM_NAME)
    end
  end
  
  def add_user(user, membership_type = nil)
    return nil unless user && user.is_a?(User)
    membership_type ||= 'AccountAdmin'
    au = self.account_users.find_by_user_id_and_membership_type(user.id, membership_type)
    au ||= self.account_users.create(:user => user, :membership_type => membership_type)
  end
  
  def context_code
    raise "DONT USE THIS, use .short_name instead" unless ENV['RAILS_ENV'] == "production"
  end
  
  def short_name
    name
  end

  # can be set/overridden by plugin to enforce email pseudonyms
  attr_accessor :email_pseudonyms
  
  def password_authentication?
    !!(!self.account_authorization_config || self.account_authorization_config.password_authentication?)
  end

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

  def forgot_password_external_url
    account_authorization_config.try(:change_password_url)
  end

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

  def ldap_authentication?
    self.account_authorization_configs.any? { |aac| aac.ldap_authentication? }
  end

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

  def multi_auth?
    self.account_authorization_configs.count > 1
  end

  def auth_discovery_url=(url)
    self.settings[:auth_discovery_url] = url
  end

  def auth_discovery_url
    self.settings[:auth_discovery_url]
  end

  def validate_auth_discovery_url
    return if self.settings[:auth_discovery_url].blank?

    begin
      value, uri = CustomValidations.validate_url(self.settings[:auth_discovery_url])
      self.auth_discovery_url = value
    rescue URI::InvalidURIError, ArgumentError
      errors.add(:discovery_url, t('errors.invalid_discovery_url', "The discovery URL is not valid" ))
    end
  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.clear_special_account_cache!
    @special_accounts = {}
  end

  # an opportunity for plugins to load some other stuff up before caching the account
  def precache
  end

  def self.find_cached(id)
    account = Rails.cache.fetch(account_lookup_cache_key(id), :expires_in => 1.hour) do
      account = Account.find_by_id(id)
      account.precache if account
      account || :nil
    end
    account = nil if account == :nil
    account
  end

  def self.get_special_account(special_account_type, default_account_name)
    Shard.default.activate do
      @special_account_ids ||= {}
      @special_accounts ||= {}

      account = @special_accounts[special_account_type]
      unless account
        special_account_id = @special_account_ids[special_account_type] ||= Setting.get("#{special_account_type}_account_id", nil)
        account = @special_accounts[special_account_type] = Account.find_cached(special_account_id) if special_account_id
      end
      # another process (i.e. selenium spec) may have changed the setting
      unless account
        special_account_id = Setting.get("#{special_account_type}_account_id", nil)
        if special_account_id && special_account_id != @special_account_ids[special_account_type]
          @special_account_ids[special_account_type] = special_account_id
          account = @special_accounts[special_account_type] = Account.find_by_id(special_account_id)
        end
      end
      unless account
        # TODO i18n
        t '#account.default_site_administrator_account_name', 'Site Admin'
        t '#account.default_account_name', 'Default Account'
        account = @special_accounts[special_account_type] = Account.create!(:name => default_account_name)
        Setting.set("#{special_account_type}_account_id", account.id)
        @special_account_ids[special_account_type] = account.id
      end
      account
    end
  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
    account_chain_cache = {}
    all_user_ids = []
    all_user_ids += Course.update_account_associations(self.associated_courses, :skip_user_account_associations => true, :account_chain_cache => account_chain_cache)

    # 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 => self.id }).map(&:user_id)

    # Update the users' associations as well
    User.update_account_associations(all_user_ids.uniq, :account_chain_cache => account_chain_cache)
  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
      sub_account.save!
    end
    account.parent_account = self
    account.root_account = self.root_account
    account.save!
    account.pseudonyms.each do |pseudonym|
      pseudonym.account = self.root_account
      pseudonym.save!
    end
  end

  def course_count
    self.child_courses.not_deleted.count('DISTINCT course_id')
  end
  memoize :course_count
  
  def sub_account_count
    self.sub_accounts.active.count
  end
  memoize :sub_account_count

  def user_count
    self.user_account_associations.count
  end
  memoize :user_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.parent_account.turnitin_pledge
      res ||= t('#account.turnitin_pledge', "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
  TAB_GRADING_STANDARDS = 12
  TAB_QUESTION_BANKS = 13
  # site admin tabs
  TAB_PLUGINS = 14
  TAB_JOBS = 15
  TAB_DEVELOPER_KEYS = 16

  def external_tool_tabs(opts)
    tools = ContextExternalTool.active.find_all_for(self, :account_navigation)
    tools.sort_by(&:id).map do |tool|
     {
        :id => tool.asset_string,
        :label => tool.label_for(:account_navigation, opts[:language]),
        :css_class => tool.asset_string,
        :href => :account_external_tool_path,
        :external => true,
        :args => [self.id, tool.id]
     }
    end
  end
  
  def tabs_available(user=nil, opts={})
    manage_settings = user && self.grants_right?(user, nil, :manage_account_settings)
    if site_admin?
      tabs = []
      tabs << { :id => TAB_USERS, :label => t('#account.tab_users', "Users"), :css_class => 'users', :href => :account_users_path } if user && self.grants_right?(user, nil, :read_roster)
      tabs << { :id => TAB_PERMISSIONS, :label => t('#account.tab_permissions', "Permissions"), :css_class => 'permissions', :href => :account_permissions_path } if user && self.grants_right?(user, nil, :manage_role_overrides)
      tabs << { :id => TAB_AUTHENTICATION, :label => t('#account.tab_authentication', "Authentication"), :css_class => 'authentication', :href => :account_account_authorization_configs_path } if manage_settings
      tabs << { :id => TAB_PLUGINS, :label => t("#account.tab_plugins", "Plugins"), :css_class => "plugins", :href => :plugins_path, :no_args => true } if self.grants_right?(user, nil, :manage_site_settings)
      tabs << { :id => TAB_JOBS, :label => t("#account.tab_jobs", "Jobs"), :css_class => "jobs", :href => :jobs_path, :no_args => true } if self.grants_right?(user, nil, :manage_jobs)
      tabs << { :id => TAB_DEVELOPER_KEYS, :label => t("#account.tab_developer_keys", "Developer Keys"), :css_class => "developer_keys", :href => :developer_keys_path, :no_args => true } if self.grants_right?(user, nil, :manage_developer_keys)
    else
      tabs = []
      tabs << { :id => TAB_COURSES, :label => t('#account.tab_courses', "Courses"), :css_class => 'courses', :href => :account_path } if user && self.grants_right?(user, nil, :read_course_list)
      tabs << { :id => TAB_USERS, :label => t('#account.tab_users', "Users"), :css_class => 'users', :href => :account_users_path } if user && self.grants_right?(user, nil, :read_roster)
      tabs << { :id => TAB_STATISTICS, :label => t('#account.tab_statistics', "Statistics"), :css_class => 'statistics', :href => :statistics_account_path } if user && self.grants_right?(user, nil, :view_statistics)
      tabs << { :id => TAB_PERMISSIONS, :label => t('#account.tab_permissions', "Permissions"), :css_class => 'permissions', :href => :account_permissions_path } if user && self.grants_right?(user, nil, :manage_role_overrides)
      if user && self.grants_right?(user, nil, :manage_outcomes)
        tabs << { :id => TAB_OUTCOMES, :label => t('#account.tab_outcomes', "Outcomes"), :css_class => 'outcomes', :href => :account_outcomes_path }
        tabs << { :id => TAB_RUBRICS, :label => t('#account.tab_rubrics', "Rubrics"), :css_class => 'rubrics', :href => :account_rubrics_path }
      end
      tabs << { :id => TAB_GRADING_STANDARDS, :label => t('#account.tab_grading_standards', "Grading Schemes"), :css_class => 'grading_standards', :href => :account_grading_standards_path } if user && self.grants_right?(user, nil, :manage_grades)
      tabs << { :id => TAB_QUESTION_BANKS, :label => t('#account.tab_question_banks', "Question Banks"), :css_class => 'question_banks', :href => :account_question_banks_path } if user && self.grants_right?(user, nil, :manage_grades)
      tabs << { :id => TAB_SUB_ACCOUNTS, :label => t('#account.tab_sub_accounts', "Sub-Accounts"), :css_class => 'sub_accounts', :href => :account_sub_accounts_path } if manage_settings
      tabs << { :id => TAB_FACULTY_JOURNAL, :label => t('#account.tab_faculty_journal', "Faculty Journal"), :css_class => 'faculty_journal', :href => :account_user_notes_path} if self.enable_user_notes && user && self.grants_right?(user, nil, :manage_user_notes)
      tabs << { :id => TAB_TERMS, :label => t('#account.tab_terms', "Terms"), :css_class => 'terms', :href => :account_terms_path } if self.root_account? && manage_settings
      tabs << { :id => TAB_AUTHENTICATION, :label => t('#account.tab_authentication', "Authentication"), :css_class => 'authentication', :href => :account_account_authorization_configs_path } if self.root_account? && manage_settings
      tabs << { :id => TAB_SIS_IMPORT, :label => t('#account.tab_sis_import', "SIS Import"), :css_class => 'sis_import', :href => :account_sis_import_path } if self.root_account? && self.allow_sis_import && user && self.grants_right?(user, nil, :manage_sis)
    end
    tabs += external_tool_tabs(opts)
    tabs << { :id => TAB_SETTINGS, :label => t('#account.tab_settings', "Settings"), :css_class => 'settings', :href => :account_settings_path }
    tabs
  end

  def is_a_context?
    true
  end
  
  def help_links
    settings[:custom_help_links] || []
  end

  def self.allowable_services
    {
      :google_docs => {
        :name => "Google Docs", 
        :description => "",
        :expose_to_ui => (GoogleDocs.config ? :service : false)
      },
      :google_docs_previews => {
        :name => "Google Docs Previews", 
        :description => "",
        :expose_to_ui => :service
      },
      :facebook => {
        :name => "Facebook", 
        :description => "",
        :expose_to_ui => (Facebook.config ? :service : false)
      },
      :skype => {
        :name => "Skype", 
        :description => "",
        :expose_to_ui => :service
      },
      :linked_in => {
        :name => "LinkedIn", 
        :description => "",
        :expose_to_ui => (LinkedIn.config ? :service : false)
      },
      :twitter => {
        :name => "Twitter", 
        :description => "",
        :expose_to_ui => (Twitter.config ? :service : false)
      },
      :delicious => {
        :name => "Delicious", 
        :description => "",
        :expose_to_ui => :service
      },
      :diigo => {
        :name => "Diigo", 
        :description => "",
        :expose_to_ui => :service
      },
      # TODO: move avatars to :settings hash, it makes more sense there
      # In the meantime, we leave it as a service but expose it in the
      # "Features" (settings) portion of the account admin UI
      :avatars => {
        :name => "User Avatars",
        :description => "",
        :default => false,
        :expose_to_ui => :setting
      }
    }.merge(@plugin_services || {}).freeze
  end

  def self.register_service(service_name, info_hash)
    @plugin_services ||= {}
    @plugin_services[service_name.to_sym] = info_hash.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}$") }
      allowed_service_names << service if enable
    else
      allowed_service_names.reject! { |flag| flag.match("^[+-]?#{service}$") }
      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

  # if expose_as is nil, all services exposed in the ui are returned
  # if it's :service or :setting, then only services set to be exposed as that type are returned
  def self.services_exposed_to_ui_hash(expose_as = nil)
    if expose_as
      self.allowable_services.reject { |key, setting| setting[:expose_to_ui] != expose_as }
    else
      self.allowable_services.reject { |key, setting| !setting[:expose_to_ui] }
    end
  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.all_accounts_for(context)
    if context.respond_to?(:account)
      context.account.account_chain
    elsif context.respond_to?(:parent_account)
      context.account_chain
    else
      []
    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

  def manually_created_courses_account
    return self.root_account.manually_created_courses_account unless self.root_account?
    display_name = t('#account.manually_created_courses', "Manually-Created Courses")
    acct = manually_created_courses_account_from_settings
    if acct.blank?
      transaction do
        lock!
        acct = manually_created_courses_account_from_settings
        acct ||= self.sub_accounts.find_by_name(display_name) # for backwards compatibility
        acct ||= self.sub_accounts.create!(:name => display_name)
        if acct.id != self.settings[:manually_created_courses_account_id]
          self.settings[:manually_created_courses_account_id] = acct.id
          self.save!
        end
      end
    end
    acct
  end

  def manually_created_courses_account_from_settings
    acct_id = self.settings[:manually_created_courses_account_id]
    acct = self.sub_accounts.find_by_id(acct_id) if acct_id.present?
    acct = nil if acct.present? && acct.root_account_id != self.id
    acct
  end
  private :manually_created_courses_account_from_settings

  def trusted_account_ids
    return [] if !root_account? || self == Account.site_admin
    [ Account.site_admin.id ]
  end

  def user_list_search_mode_for(user)
    return :preferred if self.root_account.open_registration?
    return :preferred if self.root_account.grants_right?(user, :manage_user_logins)
    :closed
  end

  named_scope :root_accounts, :conditions => {:root_account_id => nil}
  named_scope :processing_sis_batch, :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, :conditions => ['accounts.workflow_state != ?', 'deleted']
  named_scope :limit, lambda {|limit|
    {:limit => limit}
  }

  def canvas_network_enabled?
    false
  end

  def import_from_migration(data, params, migration)

    LearningOutcome.process_migration(data, migration)

    migration.progress=100
    migration.workflow_state = :imported
    migration.save
  end
end