Add exclude_card_id to decklist_resource

app/resources/decklist_resource.rb

@@ -36,6 +36,15 @@ class DecklistResource < ApplicationResource
     end
   end
 
+  # Will return decklists that do NOT contain any of the specified cards.
+  filter :exclude_card_id, :string do
+    eq do |scope, card_ids|
+      scope.left_joins(:decklist_cards)
+           .group('decklists.id')
+           .having('COUNT(CASE WHEN decklists_cards.card_id IN (?) THEN 1 END) = 0', card_ids)
+    end
+  end
+
   attribute :card_slots, :hash
   attribute :num_cards, :integer
   attribute :influence_spent, :integer

spec/acceptance/decklists_spec.rb

@@ -50,6 +50,21 @@
     end
   end
 
+  get '/api/v3/public/decklists?filter[exclude_card_id]=pennyshaver,stargate' do
+    parameter :exclude_card_id, type: :string, required: true
+
+    example_request 'Filter - Get decklists excluding all supplied Card ids' do
+      explanation <<~EXPLANATION
+        The exclude_card_id filter can accept a single card_id or a comma-separated list of card ids.
+
+        If multiple card ids are supplied, the decklist must NOT contain any of the
+        cards to be included in the results.
+      EXPLANATION
+
+      expect(status).to eq 200
+    end
+  end
+
   get '/api/v3/public/decklists?filter[faction_id]=:faction_id' do
     parameter :nsg_rules_team_verified, type: :boolean, required: true
 

spec/resources/decklist_resource_reads_spec.rb

@@ -42,6 +42,40 @@
         expect(d.map(&:id)).to eq([decklist.id])
       end
     end
+
+    context 'with exclude_card_id' do
+      let!(:corp_decklist) { Decklist.find('11111111-1111-1111-1111-111111111111') }
+      let!(:runner_decklist) { Decklist.find('22222222-2222-2222-2222-222222222222') }
+
+      it 'excludes decklists with one specified card' do
+        params[:filter] = { exclude_card_id: { eq: 'pennyshaver' } }
+
+        render
+        decklist_ids = d.map(&:id)
+
+        expect(decklist_ids).to include(corp_decklist.id)
+        expect(decklist_ids).not_to include(runner_decklist.id)
+      end
+
+      it 'excludes decklists with multiple specified cards' do
+        params[:filter] =
+          { exclude_card_id: { eq: 'pennyshaver,adonis_campaign' } }
+        render
+        decklist_ids = d.map(&:id)
+
+        expect(decklist_ids).not_to include(corp_decklist.id)
+        expect(decklist_ids).not_to include(runner_decklist.id)
+      end
+
+      it 'exludes no decklists when nonexistent card is specified' do
+        params[:filter] = { exclude_card_id: { eq: 'nonexistent_card' } }
+        render
+        decklist_ids = d.map(&:id)
+
+        expect(decklist_ids).to include(corp_decklist.id)
+        expect(decklist_ids).to include(runner_decklist.id)
+      end
+    end
   end
 
   describe 'sideloading' do