module Neighbor::Utils

def self.order(adapter, type, operator, quoted_attribute, query)
  case adapter
  when :sqlite
    case type
    when :int8
      "#{operator}(vec_int8(#{quoted_attribute}), vec_int8(#{query}))"
    when :bit
      "#{operator}(vec_bit(#{quoted_attribute}), vec_bit(#{query}))"
    else
      "#{operator}(#{quoted_attribute}, #{query})"
    end
  when :mariadb
    if operator == "BIT_COUNT"
      "BIT_COUNT(#{quoted_attribute} ^ #{query})"
    else
      "#{operator}(#{quoted_attribute}, #{query})"
    end
  when :mysql
    if operator == "BIT_COUNT"
      "BIT_COUNT(#{quoted_attribute} ^ #{query})"
    elsif operator == "COSINE"
      "DISTANCE(#{quoted_attribute}, #{query}, 'COSINE')"
    else
      "DISTANCE(#{quoted_attribute}, #{query}, 'EUCLIDEAN')"
    end
  else
    if operator == "#"
      "bit_count(#{quoted_attribute} # #{query})"
    else
      "#{quoted_attribute} #{operator} #{query}"
    end
  end
end