Module: ActsAsRankedList::ActiveRecord::RankColumn

Defined in:

lib/acts_as_ranked_list/active_record/rank_column.rb

Class Method Summary

• .call(caller_class, rank_column, touch_on_update, step_increment, avoid_collisions, new_item_at, scopes) ⇒ Object

  Sets the methods to rank ::ActiveRecord objects.

Class Method Details

.call(caller_class, rank_column, touch_on_update, step_increment, avoid_collisions, new_item_at, scopes) ⇒ Object

Sets the methods to rank ::ActiveRecord objects. Please refer to the README file for usage and examples.

# File 'lib/acts_as_ranked_list/active_record/rank_column.rb', line 8

def self.call(caller_class, rank_column, touch_on_update, step_increment, avoid_collisions, new_item_at, scopes)
  caller_class.class_eval do

    private

    define_singleton_method :scope_query do
      @scope_query ||= 
        begin
          @named_scopes = []
          scopes.map do |key, value|
            case value
            when ::Symbol
              if respond_to?(value)
                @named_scopes << value
                next
              end
              "#{caller_class.quoted_table_name}.#{connection.quote_column_name(key)} = \"#{value}\""
            when ::String, ::Integer, ::TrueClass, ::FalseClass, ::Float
              "#{caller_class.quoted_table_name}.#{connection.quote_column_name(key)} = \"#{value}\""
            when nil
              casted_key = key.to_s
              key_column_name = column_names.include?(casted_key) ? casted_key : "#{casted_key}_id"

              @grouped_scopes ||= []
              @grouped_scopes << key_column_name.to_sym
              next
            when ::Proc
              called_value = value.call
              if called_value.is_a?(::String)
                next called_value
              else
                @anonymous_scopes ||= all
                @anonymous_scopes.merge!(called_value)
                next
              end
            end
          end.compact.join(" AND ") || "1 = 1"
        end
    end
    scope_query # initializes variables

    define_singleton_method :new_item_at do
      new_item_at
    end

    define_singleton_method :step_increment do
      step_increment
    end

    define_singleton_method :avoid_collisions= do |avoid_collisions_input|
      @avoid_collisions = avoid_collisions_input
    end
    @avoid_collisions = avoid_collisions

    define_singleton_method :avoid_collisions do
      @avoid_collisions
    end

    define_singleton_method :acts_as_ranked_list_query do
      @acts_as_ranked_list_query ||= 
        begin
          query = @named_scopes.inject(default_scoped.unscope(:select, :where).where("#{scope_query}")) do |chain, scope|
            chain.send(*scope)
          end
          query.merge!(@anonymous_scopes) if @anonymous_scopes.present?
          @named_scopes = nil
          @anonymous_scopes = nil

          query
        end
    end

    define_singleton_method :quoted_rank_column do
      @_quoted_rank_column ||= connection.quote_column_name(rank_column)
    end

    define_singleton_method :quoted_rank_column_with_table_name do
      @_quoted_rank_column_with_table_name ||= "#{caller_class.quoted_table_name}.#{quoted_rank_column}"
    end

    define_singleton_method :order_by_columns do |order = "ASC"|
      @order_by_columns ||= {}
      @order_by_columns[order] ||= "        \#{\n          [ *@grouped_scopes,\n            quoted_rank_column,\n            *quoted_timestamp_attributes_for_update_in_model,\n            primary_key\n          ].compact.join(\" \#{order}, \")\n        } \#{order}\n      ORDER_BY_COLUMNS\n    end\n\n    define_singleton_method :spread_ranks do\n      @spread_ranks_sql ||= \n        begin\n          scope_query_presence = scope_query.present? ? \"AND \#{scope_query}\" : \"\"\n          <<~SQL.squish\n            WITH ORDERED_ROW_NUMBER_CTE AS (\n              SELECT \#{caller_class.primary_key}, \n                ROW_NUMBER() OVER (ORDER BY \#{order_by_columns(\"ASC\")}) AS rn\n              FROM \#{caller_class.quoted_table_name}\n            )\n            UPDATE \#{caller_class.quoted_table_name}\n            SET \#{quoted_rank_column} = ORDERED_ROW_NUMBER_CTE.rn * \#{step_increment} \#{with_touch}\n            FROM ORDERED_ROW_NUMBER_CTE\n            WHERE \#{caller_class.quoted_table_name}.\#{caller_class.primary_key} = ORDERED_ROW_NUMBER_CTE.\#{caller_class.primary_key}\n            AND \#{quoted_rank_column_with_table_name} IS NOT NULL \#{scope_query_presence}\n          SQL\n        end\n\n      connection.execute(@spread_ranks_sql)\n    end\n\n    define_singleton_method :with_touch do\n      touch_record if touch_on_update\n    end\n\n    define_singleton_method :quoted_timestamp_attributes_for_update_in_model do\n      @_quoted_timestamp_attributes_for_update_in_model ||= timestamp_attributes_for_update_in_model.map do |attribute|\n        connection.quote_column_name(attribute)\n      end\n    end\n\n    define_singleton_method :touch_record do\n      cached_quoted_now = quoted_current_time_from_proper_timezone\n\n      quoted_timestamp_attributes_for_update_in_model.map do |attribute|\n        \", \#{attribute} = \#{cached_quoted_now}\"\n      end.join\n    end\n\n    define_singleton_method :quoted_current_time_from_proper_timezone do\n      connection.quote(connection.quoted_date(current_time_from_proper_timezone))\n    end\n\n    define_singleton_method :get_highest_items do |limit = 0|\n      @get_highest_items_query ||= acts_as_ranked_list_query\n        .where(\"\#{quoted_rank_column} IS NOT NULL\")\n        .order(order_by_columns)\n\n      return @get_highest_items_query if limit == 0\n\n      @get_highest_items_query.limit(limit)\n    end\n\n    define_singleton_method :get_lowest_items do |limit = 0|\n      @get_lowest_items_query ||= acts_as_ranked_list_query\n        .where(\"\#{quoted_rank_column} IS NOT NULL\")\n        .order(order_by_columns(\"DESC\"))\n\n      return @get_lowest_items_query if limit == 0\n\n      @get_lowest_items_query.limit(limit)\n    end\n  end\n\n  caller_class.class_eval do\n    define_method :rank_column do\n      rank_column\n    end\n\n    define_method :\"\#{rank_column}=\" do |rank|\n      self[rank_column] = rank\n      @rank_changed = true\n    end\n\n    define_method :current_rank do\n      self[rank_column]\n    end\n\n    define_method :rank_changed? do\n      @rank_changed\n    end\n\n    define_method :is_ranked? do\n      self[rank_column].present?\n    end\n\n    define_method :swap_rank_with do |item|\n      temp_rank = current_rank\n      with_persistence([self, item]) do\n        self[rank_column] = item.current_rank\n        item[rank_column] = temp_rank\n      end\n    end\n\n    define_method :set_rank_between do |item_a, item_b|\n      set_rank_below(item_a)\n    end\n\n    define_method :set_rank_above do |item|\n      higher_items = get_higher_items(2, \"DESC\", item.current_rank, true, true)\n      # TODO: Why is higher_items and lower_items sometimes need to be converted to array.\n      # Is it related to if items are not found? Otherwise it returns an error\n      padded_array = pad_array(higher_items.to_a.pluck(rank_column), 0)\n      new_rank = padded_array.sum / 2\n\n      with_persistence do\n        self[rank_column] = new_rank\n      end\n    end\n\n    define_method :set_rank_below do |item|\n      # effectively the same as, without the padding of arrays\n      # sql = <<~SQL.squish\n      #   with CTE AS (\n      #     SELECT DISTINCT \#{self.class.quoted_rank_column_with_table_name} AS dis\n      #     FROM \#{caller_class.quoted_table_name}\n      #     WHERE (\#{self.class.quoted_rank_column_with_table_name} >= \#{item.current_rank}::numeric)\n      #     GROUP BY \#{self.class.quoted_rank_column_with_table_name}\n      #     ORDER BY \#{self.class.quoted_rank_column_with_table_name}\n      #     LIMIT 2\n      #   )\n      #   SELECT AVG(CTE.dis)\n      #   FROM CTE\n      # SQL\n      # new_rank = ::ActiveRecord::Base.connection.execute(sql).to_a.first.values.first\n\n      lower_items = get_lower_items(2, \"ASC\", item.current_rank, true, true)\n      padded_array = pad_array(lower_items.to_a.pluck(rank_column))\n      new_rank = padded_array.sum / 2\n\n      with_persistence do\n        self[rank_column] = new_rank\n      end\n    end\n\n    define_method :increase_rank do |count = 1|\n      higher_items = get_higher_items(count + 1, \"DESC\")\n      return if higher_items.blank?\n\n      padded_array = pad_array(higher_items.pluck(rank_column), 0)\n      new_rank = padded_array.sum / 2\n\n      with_persistence do\n        self[rank_column] = new_rank\n      end\n    end\n\n    define_method :decrease_rank do |count = 1|\n      lower_items = get_lower_items(count + 1, \"ASC\")\n      return if lower_items.blank?\n\n      padded_array = pad_array(lower_items.pluck(rank_column))\n      new_rank = padded_array.sum / 2\n\n      with_persistence do\n        self[rank_column] = new_rank\n      end\n    end\n\n    define_method :get_higher_items do |limit = 0, order = \"DESC\", rank = nil, distinct = false, include_self_rank = false|\n      return if current_rank.nil?\n\n      operator = include_self_rank ? \"<=\" : \"<\"\n      rank ||= current_rank\n\n      query = self.class.acts_as_ranked_list_query\n        .where(\"\#{self.class.quoted_rank_column} \#{operator} \#{rank}\")\n\n      self.class.instance_variable_get(:@grouped_scopes)&.each do |grouped_scope|\n        query = query.where(grouped_scope => self.send(grouped_scope))\n      end\n\n      query = query.order(self.class.order_by_columns(order))\n\n      query = query.distinct(self.class.quoted_rank_column) if distinct\n\n      return query if limit == 0\n\n      query.limit(limit)\n    end\n\n    define_method :get_lower_items do |limit = 0, order = \"ASC\", rank = nil, distinct = false, include_self_rank = false|\n      return if current_rank.nil?\n\n      operator = include_self_rank ? \">=\" : \">\"\n      rank ||= current_rank\n\n      query = self.class.acts_as_ranked_list_query\n        .where(\"\#{self.class.quoted_rank_column} \#{operator} \#{rank}\")\n\n      self.class.instance_variable_get(:@grouped_scopes)&.each do |grouped_scope|\n        query = query.where(grouped_scope => self.send(grouped_scope))\n      end\n\n      query = query.order(self.class.order_by_columns(order))\n\n      query = query.distinct(self.class.quoted_rank_column) if distinct\n\n      return query if limit == 0\n\n      query.limit(limit)\n    end\n\n    define_method :highest_item? do\n      !get_higher_items.exists?\n    end\n\n    define_method :lowest_item? do\n      !get_lower_items.exists?\n    end\n\n    private\n\n    define_method :with_persistence do |items = [self], &blk|\n      blk.call\n\n      item_record_timestamps = items.map do |i|\n        i.record_timestamps?\n      end\n\n      items.each { |i| i.record_timestamps = touch_on_update }\n\n      items.each(&:save!) unless skip_persistence?\n\n      items.each_with_index do |i, idx|\n        i.record_timestamps = item_record_timestamps[idx]\n      end\n    end\n\n    define_method :pad_array do |array, value = nil, size = 2|\n      current_array_value = array[0] || self.class.step_increment\n      value ||= current_array_value + self.class.step_increment\n      array + ::Array.new(size - array.size, value)\n    end\n  end\nend\n".squish