Remove limit volume tracking from order book

It is not super relevant for the current matching engine,
we are going to solve this in the server implementation

lib/rex/order_book.rb

@@ -2,10 +2,6 @@ require "rbtree"
 
 module Rex
   class OrderBook
-    attr_reader(
-      :buy_limit_volumes,
-      :sell_limit_volumes
-    )
     def initialize(matcher: Matcher.new)
       @matcher = matcher
       @sell_side = RBTree.new
@@ -13,19 +9,15 @@ module Rex
       @order_ids = {} # order_id => order
       @current_trade_id = 0
       @current_order_id = 0
-      @buy_limit_volumes = {} # price => volume
-      @sell_limit_volumes = {} # price => volume
     end
 
     def add_order(order)
       side = side_for_order(order)
-      limit_volumes = limit_volume_for_order_side(order)
       order.id = next_order_id
 
       side[order.price] ||= Limit.new(order.price)
       side[order.price].add_order(order)
-      limit_volumes[order.price] ||= 0
+
-      limit_volumes[order.price] += order.remaining_quantity
       order_ids[order.id] = order
     end
 
@@ -46,9 +38,6 @@ module Rex
         side.delete(limit.price)
       end
 
-      limit_volumes = limit_volume_for_order_side(order)
-      limit_volumes[order.price] -= order.remaining_quantity
-
       order_ids.delete(order.id)
     end
 
@@ -58,9 +47,6 @@ module Rex
       trade.buy_order.remaining_quantity -= trade.quantity
       trade.sell_order.remaining_quantity -= trade.quantity
 
-      buy_limit_volumes[trade.buy_order.price] -= trade.quantity
-      sell_limit_volumes[trade.sell_order.price] -= trade.quantity
-
       remove_order(trade.buy_order.id) if trade.buy_order.filled?
       remove_order(trade.sell_order.id) if trade.sell_order.filled?
     end
@@ -97,14 +83,6 @@ module Rex
       @current_order_id += 1
     end
 
-    def limit_volume_for_order_side(order)
-      if order.is_buy
-        @buy_limit_volumes
-      else
-        @sell_limit_volumes
-      end
-    end
-
     def side_for_order(order)
       if order.is_buy
         buy_side

spec/matcher_spec.rb

@@ -41,13 +41,6 @@ RSpec.describe Rex::Matcher do
         expect(order_book.lowest_sell_order).to eq(pricier_sell_order)
         expect(order_book.lowest_sell_order.remaining_quantity).to eq(20)
       end
-
-      it "adjusts the limit volumes" do
-        instance.match(order_book)
-
-        expect(order_book.buy_limit_volumes).to eq({100 => 0})
-        expect(order_book.sell_limit_volumes).to eq({99 => 0, 100 => 20})
-      end
     end
 
     context "when order book is empty" do

spec/order_book_spec.rb

@@ -13,13 +13,6 @@ RSpec.describe Rex::OrderBook do
       expect(instance.best_buy_price).to eq(100)
     end
 
-    it "adjusts the limit volume on the correct side" do
-      order = build(:order, is_buy: true, quantity: 100, remaining_quantity: 99)
-      instance.add_order(order)
-
-      expect(instance.buy_limit_volumes[order.price]).to eq(99)
-    end
-
     it "assigns an order id" do
       expect { instance.add_order(order_a) }.to change(order_a, :id).from(nil).to(1)
       expect { instance.add_order(order_b) }.to change(order_b, :id).from(nil).to(2)
@@ -150,13 +143,6 @@ RSpec.describe Rex::OrderBook do
         instance.add_order(sell_order)
       end
 
-      it "adjusts the limit's volume" do
-        expect do
-          instance.cancel_order(sell_order.id)
-        end.to(change { instance.sell_limit_volumes[sell_order.price] }
-          .by(-sell_order.remaining_quantity))
-      end
-
       it "does not affect the buy side" do
         instance.cancel_order(sell_order.id)