Module: Scopes::Dynamic

Included in:
ProductScope
Defined in:
lib/scopes/dynamic.rb

Class Method Summary collapse

Class Method Details

.price_scopes_for(products, scope_limit = 5) ⇒ Object

Sample dynamic scope generating from set of products generates 0 or (2..scope_limit) scopes for prices, based on number of products (uses Math.log, to guess number of scopes)



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# File 'lib/scopes/dynamic.rb', line 7

def price_scopes_for(products, scope_limit=5)
  scopes = []

  # Price based scopes
  all_prices = products.map(&:price).sort
  ranges = [Math.log(products.length).floor, scope_limit].max
  if ranges >= 2
    l = all_prices.length / ranges
    scopes << ProductScope.new({
        :name => "master_price_lte",
        :arguments => [all_prices[l]]
      })
    (ranges - 2).times do |x|
      scopes << ProductScope.new({
          :name => "price_between",
          :arguments => [
            all_prices[l*(x+1)+1],
            all_prices[l*(x+2)]
          ]
        })
    end
    scopes << ProductScope.new({
        :name => "master_price_gte",
        :arguments => [all_prices[l*(ranges-1)+1]]
      })
  end

  scopes
end