Remove influence of sorting configuration on applied sort

lib/sift/filtrator.rb

@@ -17,7 +17,7 @@ def initialize(collection, params, _sort, filters = [])
     end
 
     def filter
-      active_filters.reduce(collection) do |col, filter|
+      ordered_active_filters.reduce(collection) do |col, filter|
         apply(col, filter)
       end
     end
@@ -33,21 +33,31 @@ def filter_params
     end
 
     def active_sorts_hash
-      active_sorts_hash = {}
-      Array(sort).each do |s|
-        if s.starts_with?("-")
-          active_sorts_hash[s[1..-1].to_sym] = :desc
-        else
-          active_sorts_hash[s.to_sym] = :asc
+      @active_sorts_hash ||= begin
+        active_sorts_hash = {}
+        Array(sort).each do |s|
+          if s.starts_with?("-")
+            active_sorts_hash[s[1..-1].to_sym] = :desc
+          else
+            active_sorts_hash[s.to_sym] = :asc
+          end
         end
+        active_sorts_hash
       end
-      active_sorts_hash
     end
 
     def active_filters
       filters.select do |filter|
         filter_params[filter.param].present? || filter.default || filter.always_active?
       end
     end
+
+    def ordered_active_filters
+      active_filters.sort_by { |filter| sorts_by_index.fetch(filter.param, Float::INFINITY) }
+    end
+
+    def sorts_by_index
+      @sorts_by_index ||= active_sorts_hash.keys.each_with_index.to_h
+    end
   end
 end

test/controller_test.rb

@@ -183,6 +183,21 @@ class PostsControllerTest < ActionDispatch::IntegrationTest
     assert_equal [nil, 10, 1, nil], json.map(&:priority)
   end
 
+  test "it can do multiple sorts contrary to the order in which sorts are configured" do
+    Post.create!(title: "a", priority: 1)
+    Post.create!(title: "b", visible: true)
+    Post.create!(title: "f", priority: 10, visible: true)
+    Post.create!(title: "c", priority: 10, visible: false)
+    Post.create!(title: "d", priority: 10)
+
+    get("/posts", params: { sort: "priority,-visible,title" })
+
+    json = JSON.parse(@response.body, object_class: OpenStruct)
+    assert_equal ["b", "a", "f", "c", "d"], json.map(&:title)
+    assert_equal [nil, 1, 10, 10, 10], json.map(&:priority)
+    assert_equal [true, nil, true, false, nil], json.map(&:visible)
+  end
+
   test "it errors on unknown fields" do
     expected_json = { "errors" => { "sort" => ["is not included in the list"] } }
 

test/dummy/app/controllers/posts_controller.rb

@@ -43,6 +43,7 @@ class PostsController < ApplicationController
 
   before_action :render_filter_errors, unless: :filters_valid?
 
+  sort_on :visible, type: :int
   sort_on :title, type: :string
   sort_on :priority, type: :string
   sort_on :foobar, type: :string, internal_name: :title