class ActiveRecord::Associations::ClassMethods::JoinDependency::JoinAssociation

def aliased_table_name_for(name, suffix = nil)
  if !parent.table_joins.blank? && parent.table_joins.to_s.downcase =~ %r{join(\s+\w+)?\s+#{active_record.connection.quote_table_name name.downcase}\son}
    @join_dependency.table_aliases[name] += 1
  end
  unless @join_dependency.table_aliases[name].zero?
    # if the table name has been used, then use an alias
    name = active_record.connection.table_alias_for "#{pluralize(reflection.name)}_#{parent_table_name}#{suffix}"
    table_index = @join_dependency.table_aliases[name]
    @join_dependency.table_aliases[name] += 1
    name = name[0..active_record.connection.table_alias_length-3] + "_#{table_index+1}" if table_index > 0
  else
    @join_dependency.table_aliases[name] += 1
  end
  name
end

def association_join
  connection = reflection.active_record.connection
  join = case reflection.macro
    when :has_and_belongs_to_many
      " #{join_type} %s ON %s.%s = %s.%s " % [
         table_alias_for(options[:join_table], aliased_join_table_name),
         connection.quote_table_name(aliased_join_table_name),
         options[:foreign_key] || reflection.active_record.to_s.foreign_key,
         connection.quote_table_name(parent.aliased_table_name),
         reflection.active_record.primary_key] +
      " #{join_type} %s ON %s.%s = %s.%s " % [
         table_name_and_alias,
         connection.quote_table_name(aliased_table_name),
         klass.primary_key,
         connection.quote_table_name(aliased_join_table_name),
         options[:association_foreign_key] || klass.to_s.foreign_key
         ]
    when :has_many, :has_one
      case
        when reflection.options[:through]
          through_conditions = through_reflection.options[:conditions] ? "AND #{interpolate_sql(sanitize_sql(through_reflection.options[:conditions]))}" : ''
          jt_foreign_key = jt_as_extra = jt_source_extra = jt_sti_extra = nil
          first_key = second_key = as_extra = nil
          if through_reflection.options[:as] # has_many :through against a polymorphic join
            jt_foreign_key = through_reflection.options[:as].to_s + '_id'
            jt_as_extra = " AND %s.%s = %s" % [
              connection.quote_table_name(aliased_join_table_name),
              connection.quote_column_name(through_reflection.options[:as].to_s + '_type'),
              klass.quote_value(parent.active_record.base_class.name)
            ]
          else
            jt_foreign_key = through_reflection.primary_key_name
          end
          case source_reflection.macro
          when :has_many
            if source_reflection.options[:as]
              first_key   = "#{source_reflection.options[:as]}_id"
              second_key  = options[:foreign_key] || primary_key
              as_extra    = " AND %s.%s = %s" % [
                connection.quote_table_name(aliased_table_name),
                connection.quote_column_name("#{source_reflection.options[:as]}_type"),
                klass.quote_value(source_reflection.active_record.base_class.name)
              ]
            else
              first_key   = through_reflection.klass.base_class.to_s.foreign_key
              second_key  = options[:foreign_key] || primary_key
            end
            unless through_reflection.klass.descends_from_active_record?
              jt_sti_extra = " AND %s.%s = %s" % [
                connection.quote_table_name(aliased_join_table_name),
                connection.quote_column_name(through_reflection.active_record.inheritance_column),
                through_reflection.klass.quote_value(through_reflection.klass.sti_name)]
            end
          when :belongs_to
            first_key = primary_key
            if reflection.options[:source_type]
              second_key = source_reflection.association_foreign_key
              jt_source_extra = " AND %s.%s = %s" % [
                connection.quote_table_name(aliased_join_table_name),
                connection.quote_column_name(reflection.source_reflection.options[:foreign_type]),
                klass.quote_value(reflection.options[:source_type])
              ]
            else
              second_key = source_reflection.primary_key_name
            end
          end
          " #{join_type} %s ON (%s.%s = %s.%s%s%s%s) " % [
            table_alias_for(through_reflection.klass.table_name, aliased_join_table_name),
            connection.quote_table_name(parent.aliased_table_name),
            connection.quote_column_name(parent.primary_key),
            connection.quote_table_name(aliased_join_table_name),
            connection.quote_column_name(jt_foreign_key),
            jt_as_extra, jt_source_extra, jt_sti_extra
          ] +
          " #{join_type} %s ON (%s.%s = %s.%s%s) " % [
            table_name_and_alias,
            connection.quote_table_name(aliased_table_name),
            connection.quote_column_name(first_key),
            connection.quote_table_name(aliased_join_table_name),
            connection.quote_column_name(second_key),
            as_extra
          ]
        when reflection.options[:as] && [:has_many, :has_one].include?(reflection.macro)
          " #{join_type} %s ON %s.%s = %s.%s AND %s.%s = %s" % [
            table_name_and_alias,
            connection.quote_table_name(aliased_table_name),
            "#{reflection.options[:as]}_id",
            connection.quote_table_name(parent.aliased_table_name),
            parent.primary_key,
            connection.quote_table_name(aliased_table_name),
            "#{reflection.options[:as]}_type",
            klass.quote_value(parent.active_record.base_class.name)
          ]
        else
          foreign_key = options[:foreign_key] || reflection.active_record.name.foreign_key
          " #{join_type} %s ON %s.%s = %s.%s " % [
            table_name_and_alias,
            aliased_table_name,
            foreign_key,
            parent.aliased_table_name,
            reflection.options[:primary_key] || parent.primary_key
          ]
      end
    when :belongs_to
      " #{join_type} %s ON %s.%s = %s.%s " % [
         table_name_and_alias,
         connection.quote_table_name(aliased_table_name),
         reflection.options[:primary_key] || reflection.klass.primary_key,
         connection.quote_table_name(parent.aliased_table_name),
         options[:foreign_key] || reflection.primary_key_name
        ]
    else
      ""
  end || ''
  join << %(AND %s) % [
    klass.send(:type_condition, aliased_table_name)] unless klass.descends_from_active_record?
  [through_reflection, reflection].each do |ref|
    join << "AND #{interpolate_sql(sanitize_sql(ref.options[:conditions], aliased_table_name))} " if ref && ref.options[:conditions]
  end
  join
end

def initialize(reflection, join_dependency, parent = nil)
  reflection.check_validity!
  if reflection.options[:polymorphic]
    raise EagerLoadPolymorphicError.new(reflection)
  end
  super(reflection.klass)
  @join_dependency    = join_dependency
  @parent             = parent
  @reflection         = reflection
  @aliased_prefix     = "t#{ join_dependency.joins.size }"
  @parent_table_name  = parent.active_record.table_name
  @aliased_table_name = aliased_table_name_for(table_name)
  if reflection.macro == :has_and_belongs_to_many
    @aliased_join_table_name = aliased_table_name_for(reflection.options[:join_table], "_join")
  end
  if [:has_many, :has_one].include?(reflection.macro) && reflection.options[:through]
    @aliased_join_table_name = aliased_table_name_for(reflection.through_reflection.klass.table_name, "_join")
  end
end

def interpolate_sql(sql)
  instance_eval("%@#{sql.gsub('@', '\@')}@")
end

def join_type
  "LEFT OUTER JOIN"
end

def pluralize(table_name)
  ActiveRecord::Base.pluralize_table_names ? table_name.to_s.pluralize : table_name
end

def table_alias_for(table_name, table_alias)
   "#{reflection.active_record.connection.quote_table_name(table_name)} #{table_alias if table_name != table_alias}".strip
end

def table_name_and_alias
  table_alias_for table_name, @aliased_table_name
end