move account settings to a separate module

so that a plugin can define settings on account before account
is fully loaded

Change-Id: I41b538d152136e3b48452e8f48046a9caa882c13
Reviewed-on: https://gerrit.instructure.com/51773
Tested-by: Jenkins
Reviewed-by: Ethan Vizitei <evizitei@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>

app/models/account.rb

@@ -148,50 +148,7 @@ class Account < ActiveRecord::Base
     result
   end
 
-  cattr_accessor :account_settings_options
-  self.account_settings_options = {}
-
-  def self.add_setting(setting, opts=nil)
-    if opts && opts[:inheritable]
-      opts[:hash] = true
-      opts[:values] = [:value, :locked]
-
-      self.class_eval "def #{setting}; calculate_inherited_setting(:#{setting}); end"
-    elsif (opts && opts[:boolean] && opts.has_key?(:default))
-      if opts[:default]
-        # if the default is true, we want a nil result to evaluate to true.
-        # this prevents us from having to backfill true values into a
-        # serialized column, which would be expensive.
-        self.class_eval "def #{setting}?; settings[:#{setting}] != false; end"
-      else
-        # if the default is not true, we can fall back to a straight boolean.
-        self.class_eval "def #{setting}?; !!settings[:#{setting}]; end"
-      end
-    end
-    self.account_settings_options[setting.to_sym] = opts || {}
-  end
-
-  # should continue down the account chain until it reaches a locked value
-  # otherwise use the last explicitly set value
-  def calculate_inherited_setting(setting)
-    inherited_hash = {:locked => false, :value => self.class.account_settings_options[setting][:default]}
-    self.account_chain.reverse.each do |acc|
-      current_hash = acc.settings[setting]
-      next if current_hash.nil?
-
-      if !current_hash.is_a?(Hash)
-        current_hash = {:locked => false, :value => current_hash}
-      end
-      current_hash[:inherited] = true if (self != acc)
-
-      if current_hash[:locked]
-        return current_hash
-      else
-        inherited_hash = current_hash
-      end
-    end
-    return inherited_hash
-  end
+  include ::Account::Settings
 
   # these settings either are or could be easily added to
   # the account settings page

app/models/account/settings.rb

@@ -0,0 +1,51 @@
+module Account::Settings
+  module ClassMethods
+    def add_setting(setting, opts=nil)
+      if opts && opts[:inheritable]
+        opts[:hash] = true
+        opts[:values] = [:value, :locked]
+
+        self.class_eval "def #{setting}; calculate_inherited_setting(:#{setting}); end"
+      elsif (opts && opts[:boolean] && opts.has_key?(:default))
+        if opts[:default]
+          # if the default is true, we want a nil result to evaluate to true.
+          # this prevents us from having to backfill true values into a
+          # serialized column, which would be expensive.
+          self.class_eval "def #{setting}?; settings[:#{setting}] != false; end"
+        else
+          # if the default is not true, we can fall back to a straight boolean.
+          self.class_eval "def #{setting}?; !!settings[:#{setting}]; end"
+        end
+      end
+      self.account_settings_options[setting.to_sym] = opts || {}
+    end
+  end
+
+  def self.included(klass)
+    klass.extend(ClassMethods)
+    klass.send(:cattr_accessor, :account_settings_options)
+    klass.account_settings_options ||= {}
+  end
+
+  # should continue down the account chain until it reaches a locked value
+  # otherwise use the last explicitly set value
+  def calculate_inherited_setting(setting)
+    inherited_hash = {:locked => false, :value => self.class.account_settings_options[setting][:default]}
+    self.account_chain.reverse.each do |acc|
+      current_hash = acc.settings[setting]
+      next if current_hash.nil?
+
+      if !current_hash.is_a?(Hash)
+        current_hash = {:locked => false, :value => current_hash}
+      end
+      current_hash[:inherited] = true if (self != acc)
+
+      if current_hash[:locked]
+        return current_hash
+      else
+        inherited_hash = current_hash
+      end
+    end
+    return inherited_hash
+  end
+end