Moved filter/compute to separate module

Converting it to model independent code, WIP

app/models/measurement.rb

@@ -45,92 +45,4 @@ class Measurement < ActiveRecord::Base
   def taken_at_time=(value)
     self.taken_at = Time.parse(value, self.taken_at)
   end
-
-  def self.filter(filters, requested_q = Quantity.none)
-    measurements = all.where(filters[:scope])
-
-    if filters[:name].present?
-      measurements = measurements.where("name LIKE ?", "%#{filters[:name]}%")
-    end
-
-    project = proxy_association.owner
-    formula_q = if filters[:readouts].present?
-                  project.quantities.new(name: '__internal_q',
-                                         formula: filters[:readouts],
-                                         domain: :measurement)
-                end
-    apply_formula = formula_q.present? && formula_q.valid?
-
-    result =
-      if !requested_q.empty? || apply_formula
-        computed = measurements.compute_nutrients(requested_q, apply_formula && formula_q)
-        requested_q.present? ? computed : [computed[0]]
-      else
-        [measurements]
-      end
-    result.push(formula_q)
-  end
-
-  def self.compute_nutrients(requested_q, filter_q = nil)
-    ingredients = all
-    unchecked_q = requested_q.map { |q| [q, nil] }
-    unchecked_q << [filter_q, nil] if filter_q
-
-    nutrients = Hash.new { |h,k| h[k] = {} }
-    Nutrient.where(ingredient: ingredients).includes(:quantity, :unit)
-      .order('quantities.lft')
-      .pluck('quantities.name', :ingredient_id, :amount, 'units.shortname')
-      .each { |q_name, i_id, a, u_id| nutrients[q_name][i_id] = [a, u_id] }
-
-    extra_q = nutrients.keys - requested_q.pluck(:name)
-
-    completed_q = {}
-    # FIXME: loop should finish unless there is circular dependency in formulas
-    # for now we don't guard against that
-    while !unchecked_q.empty?
-      q, deps = unchecked_q.shift
-
-      # quantity not computable (no formula) or not requiring calculation/computed
-      if q.formula.blank? || (nutrients[q.name].length == ingredients.count)
-        completed_q[q.name] = nutrients.delete(q.name) { {} }
-        next
-      end
-
-      # quantity with formula requires refresh of dependencies availability
-      if deps.nil? || !deps.empty?
-        deps ||= q.formula_quantities
-        deps.reject! { |q| completed_q.has_key?(q.name) }
-        deps.each { |q| unchecked_q << [q, nil] unless unchecked_q.index { |u| u[0] == q } }
-      end
-
-      # quantity with formula has all dependencies satisfied, requires calculation
-      if deps.empty?
-        input_q = q.formula_quantities
-        inputs = ingredients.select { |i| nutrients[q.name][i.id].nil? }.map do |i|
-          [
-            i,
-            input_q.map do |i_q|
-              nutrient_data = completed_q[i_q.name][i.id] || [nil, nil]
-              [i_q.name, nutrient_data[0]]
-            end.to_h
-          ]
-        end
-        q.calculate(inputs).each { |i, result| nutrients[q.name][i.id] = result }
-        unchecked_q.unshift([q, deps])
-        next
-      end
-
-      # quantity still has unsatisfied dependencies, move to the end of queue
-      unchecked_q << [q, deps]
-    end
-
-    all_q = nutrients.merge(completed_q)
-    [
-      filter_q ? ingredients.to_a.keep_if { |i| all_q[filter_q.name][i.id][0] } : ingredients,
-      ingredients.map { |i| requested_q.map { |q| [q.name, all_q[q.name][i.id]] } },
-      ingredients.map do |i|
-        extra_q.map { |q_name| [q_name, all_q[q_name][i.id]] if all_q[q_name][i.id] }
-      end
-    ]
-  end
 end