Module: Preferences::ClassMethods

Defined in:
lib/preferences.rb

Overview

:nodoc:

Instance Method Summary collapse

Instance Method Details

#build_preference_scope(preferences, inverse = false) ⇒ Object

Generates the scope for looking under records with a specific set of preferences associated with them.

Note thate this is a bit more complicated than usual since the preference definitions aren’t in the database for joins, defaults need to be accounted for, and querying for the the presence of multiple preferences requires multiple joins.



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# File 'lib/preferences.rb', line 235

def build_preference_scope(preferences, inverse = false)
  joins = []
  statements = []
  values = []
  
  # Flatten the preferences for easier processing
  preferences = preferences.inject({}) do |result, (group, value)|
    if value.is_a?(Hash)
      value.each {|preference, value| result[[group, preference]] = value}
    else
      result[[nil, group]] = value
    end
    result
  end
  
  preferences.each do |(group, preference), value|
    group_id, group_type = Preference.split_group(group)
    preference = preference.to_s
    definition = preference_definitions[preference.to_s]
    value = definition.type_cast(value)
    is_default = definition.default_value(group_type) == value
    
    table = "preferences_#{group_id}_#{group_type}_#{preference}"
    
    # Since each preference is a different record, they need their own
    # join so that the proper conditions can be set
    joins << "LEFT JOIN preferences AS #{table} ON #{table}.owner_id = #{table_name}.#{primary_key} AND " + sanitize_sql(
      "#{table}.owner_type" => base_class.name.to_s,
      "#{table}.group_id" => group_id,
      "#{table}.group_type" => group_type,
      "#{table}.name" => preference
    )
    
    if inverse
      statements << "#{table}.id IS NOT NULL AND #{table}.value " + (value.nil? ? ' IS NOT NULL' : ' != ?') + (!is_default ? " OR #{table}.id IS NULL" : '')
    else
      statements << "#{table}.id IS NOT NULL AND #{table}.value " + (value.nil? ? ' IS NULL' : ' = ?') + (is_default ? " OR #{table}.id IS NULL" : '')
    end
    values << value unless value.nil?
  end
  
  sql = statements.map! {|statement| "(#{statement})"} * ' AND '
  {:joins => joins, :conditions => values.unshift(sql)}
end