has_many_association.rb

module ActiveRecord
  module Associations
    class HasManyAssociation < AssociationCollection #:nodoc:
      def initialize(owner, reflection)
        super
        @conditions = sanitize_sql(reflection.options[:conditions])
        construct_sql
      end

      def build(attributes = {})
        if attributes.is_a?(Array)
          attributes.collect { |attr| build(attr) }
        else
          load_target
          record = @reflection.klass.new(attributes)
          record[@reflection.primary_key_name] = @owner.id unless @owner.new_record?
          @target << record
          record
        end
      end

      # DEPRECATED.
      def find_all(runtime_conditions = nil, orderings = nil, limit = nil, joins = nil)
        if @reflection.options[:finder_sql]
          @reflection.klass.find_by_sql(@finder_sql)
        else
          conditions = @finder_sql
          conditions += " AND (#{sanitize_sql(runtime_conditions)})" if runtime_conditions
          orderings ||= @reflection.options[:order]
          @reflection.klass.find_all(conditions, orderings, limit, joins)
        end
      end

      # DEPRECATED. Find the first associated record.  All arguments are optional.
      def find_first(conditions = nil, orderings = nil)
        find_all(conditions, orderings, 1).first
      end

      # Count the number of associated records. All arguments are optional.
      def count(runtime_conditions = nil)
        if @reflection.options[:counter_sql]
          @reflection.klass.count_by_sql(@counter_sql)
        elsif @reflection.options[:finder_sql]
          @reflection.klass.count_by_sql(@finder_sql)
        else
          sql = @finder_sql
          sql += " AND (#{sanitize_sql(runtime_conditions)})" if runtime_conditions
          @reflection.klass.count(sql)
        end
      end

      def find(*args)
        options = Base.send(:extract_options_from_args!, args)

        # If using a custom finder_sql, scan the entire collection.
        if @reflection.options[:finder_sql]
          expects_array = args.first.kind_of?(Array)
          ids = args.flatten.compact.uniq

          if ids.size == 1
            id = ids.first
            record = load_target.detect { |record| id == record.id }
            expects_array? ? [record] : record
          else
            load_target.select { |record| ids.include?(record.id) }
          end
        else
          conditions = "#{@finder_sql}"
          if sanitized_conditions = sanitize_sql(options[:conditions])
            conditions << " AND (#{sanitized_conditions})"
          end
          options[:conditions] = conditions

          if options[:order] && @reflection.options[:order]
            options[:order] = "#{options[:order]}, #{@reflection.options[:order]}"
          elsif @reflection.options[:order]
            options[:order] = @reflection.options[:order]
          end

          merge_options_from_reflection!(options)

          # Pass through args exactly as we received them.
          args << options
          @reflection.klass.find(*args)
        end
      end
      
      protected
        def method_missing(method, *args, &block)
          if @target.respond_to?(method) || (!@reflection.klass.respond_to?(method) && Class.respond_to?(method))
            super
          else
            @reflection.klass.with_scope(
              :find => {
                :conditions => @finder_sql, 
                :joins      => @join_sql, 
                :readonly   => false
              },
              :create => {
                @reflection.primary_key_name => @owner.id
              }
            ) do
              @reflection.klass.send(method, *args, &block)
            end
          end
        end
            
        def find_target
          if @reflection.options[:finder_sql]
            @reflection.klass.find_by_sql(@finder_sql)
          else
            find(:all)
          end
        end

        def count_records
          count = if has_cached_counter?
            @owner.send(:read_attribute, cached_counter_attribute_name)
          elsif @reflection.options[:counter_sql]
            @reflection.klass.count_by_sql(@counter_sql)
          else
            @reflection.klass.count(@counter_sql)
          end
          
          @target = [] and loaded if count == 0
          
          if @reflection.options[:limit]
            count = [ @reflection.options[:limit], count ].min
          end
          
          return count
        end

        def has_cached_counter?
          @owner.attribute_present?(cached_counter_attribute_name)
        end

        def cached_counter_attribute_name
          "#{@reflection.name}_count"
        end

        def insert_record(record)
          record[@reflection.primary_key_name] = @owner.id
          record.save
        end

        def delete_records(records)
          if @reflection.options[:dependent]
            records.each { |r| r.destroy }
          else
            ids = quoted_record_ids(records)
            @reflection.klass.update_all(
              "#{@reflection.primary_key_name} = NULL", 
              "#{@reflection.primary_key_name} = #{@owner.quoted_id} AND #{@reflection.klass.primary_key} IN (#{ids})"
            )
          end
        end

        def target_obsolete?
          false
        end

        def construct_sql
          case
            when @reflection.options[:finder_sql]
              @finder_sql = interpolate_sql(@reflection.options[:finder_sql])

            when @reflection.options[:as]
              @finder_sql = 
                "#{@reflection.klass.table_name}.#{@reflection.options[:as]}_id = #{@owner.quoted_id} AND " + 
                "#{@reflection.klass.table_name}.#{@reflection.options[:as]}_type = '#{ActiveRecord::Base.send(:class_name_of_active_record_descendant, @owner.class).to_s}'"
              @finder_sql << " AND (#{interpolate_sql(@conditions)})" if @conditions
            
            else
              @finder_sql = "#{@reflection.klass.table_name}.#{@reflection.primary_key_name} = #{@owner.quoted_id}"
              @finder_sql << " AND (#{interpolate_sql(@conditions)})" if @conditions
          end

          if @reflection.options[:counter_sql]
            @counter_sql = interpolate_sql(@reflection.options[:counter_sql])
          elsif @reflection.options[:finder_sql]
            # replace the SELECT clause with COUNT(*), preserving any hints within /* ... */
            @reflection.options[:counter_sql] = @reflection.options[:finder_sql].sub(/SELECT (\/\*.*?\*\/ )?(.*)\bFROM\b/im) { "SELECT #{$1}COUNT(*) FROM" }
            @counter_sql = interpolate_sql(@reflection.options[:counter_sql])
          else
            @counter_sql = @finder_sql
          end
        end
    end
  end
end