Module: Card::Query::Sorting

Included in:
Card::Query
Defined in:
lib/card/query/sorting.rb

Constant Summary collapse

SORT_BY_ITEM_JOIN_MAP = 
{ left: "left_id", right: "right_id" }.freeze

Instance Method Summary collapse

Instance Method Details

#sort(val) ⇒ Object 



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# File 'lib/card/query/sorting.rb', line 6

def sort val
  return nil unless full?
  sort_field = val[:return] || "db_content"
  val = val.clone
  item = val.delete(:item) || "left"
  if sort_field == "count"
    sort_by_count val, item
  else
    sort_by_item_join val, item, sort_field
  end
end

#sort_by_count(val, item) ⇒ Object

EXPERIMENTAL!



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# File 'lib/card/query/sorting.rb', line 31

def sort_by_count val, item
  method_name = "sort_by_count_#{item}"
  sort_by_count_not_implemented :count, item unless respond_to? method_name
  send method_name, val
end

#sort_by_count_referred_to(val) ⇒ Object 



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# File 'lib/card/query/sorting.rb', line 41

def sort_by_count_referred_to val
  @mods[:sort] = "coalesce(count,0)" # needed for postgres
  cs = Query.new(
    return: "coalesce(count(*), 0) as count",
    group: "sort_join_field",
    superquery: self
  )
  subselect = Query.new val.merge(return: "id", superquery: self)
  cs.add_condition "referer_id in (#{subselect.sql})"
  # FIXME: - SQL generated before SQL phase
  cs.joins << Join.new(
    from: cs,
    to: %w(card_references wr referee_id)
  )
  cs.mods[:sort_join_field] = "#{cs.table_alias}.id as sort_join_field"
  # HACK!

  joins << Join.new(
    from: self,
    to: [cs, "srtbl", "sort_join_field"]
  )
end

#sort_by_item_join(val, item, sort_field) ⇒ Object 



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# File 'lib/card/query/sorting.rb', line 18

def sort_by_item_join val, item, sort_field
  join_field = sort_by_item_join_field item
  join = join_cards val, to_field: join_field,
                         side: "LEFT",
                         conditions_on_join: true
  @mods[:sort] ||= "#{join.table_alias}.#{sort_field}"
end

#sort_by_item_join_field(item) ⇒ Object 



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# File 'lib/card/query/sorting.rb', line 26

def sort_by_item_join_field item
  SORT_BY_ITEM_JOIN_MAP[item.to_sym] || sort_method_not_implemented(:join, item)
end

#sort_method_not_implemented(method, item) ⇒ Object

Raises:



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# File 'lib/card/query/sorting.rb', line 37

def sort_method_not_implemented method, item
  raise Card::Error::BadQuery, "sorting by ##{method}/#{item} not yet implemented"
end