Use gem for dice rolling

Gemfile

@@ -22,6 +22,8 @@ gem "mission_control-jobs"
 
 gem "active_storage_validations"
 
+gem "dice-roller", git: "https://github.com/Tablewarez/always_rolling"
+
 group :development, :test do
   gem "debug", platforms: %i[ mri windows ]
   gem "dotenv"

Gemfile.lock

@@ -1,3 +1,14 @@
+GIT
+  remote: https://github.com/Tablewarez/always_rolling
+  revision: 44ed421d854dc41e6021da3ab9427455d9c807ba
+  specs:
+    dice-roller (0.0.5)
+      activesupport (>= 4.2)
+      expression_parser (~> 0.9)
+      pry (~> 0.10)
+      rspec (~> 3.4)
+      simplecov (~> 0.11)
+
 GEM
   remote: https://rubygems.org/
   specs:
@@ -100,6 +111,7 @@ GEM
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
     childprocess (5.0.0)
+    coderay (1.1.3)
     concurrent-ruby (1.2.3)
     connection_pool (2.4.1)
     crass (1.0.6)
@@ -107,11 +119,14 @@ GEM
     debug (1.9.2)
       irb (~> 1.10)
       reline (>= 0.3.8)
+    diff-lcs (1.5.1)
+    docile (1.4.0)
     dotenv (3.1.2)
     drb (2.2.1)
     erubi (1.12.0)
     et-orbi (1.2.11)
       tzinfo
+    expression_parser (0.9.0)
     ffi (1.16.3)
     fugit (1.10.1)
       et-orbi (~> 1, >= 1.2.7)
@@ -151,6 +166,7 @@ GEM
       net-smtp
     marcel (1.0.4)
     matrix (0.4.2)
+    method_source (1.1.0)
     mini_magick (4.12.0)
     mini_mime (1.1.5)
     minitest (5.23.1)
@@ -193,6 +209,9 @@ GEM
       activesupport (>= 7.0.0)
       rack
       railties (>= 7.0.0)
+    pry (0.14.2)
+      coderay (~> 1.1)
+      method_source (~> 1.0)
     psych (5.1.2)
       stringio
     public_suffix (5.0.5)
@@ -246,6 +265,19 @@ GEM
       io-console (~> 0.5)
     rexml (3.2.8)
       strscan (>= 3.0.9)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
     rubocop (1.64.0)
       json (~> 2.3)
       language_server-protocol (>= 3.17.0)
@@ -284,6 +316,12 @@ GEM
       rexml (~> 3.2, >= 3.2.5)
       rubyzip (>= 1.2.2, < 3.0)
       websocket (~> 1.0)
+    simplecov (0.22.0)
+      docile (~> 1.1)
+      simplecov-html (~> 0.11)
+      simplecov_json_formatter (~> 0.1)
+    simplecov-html (0.12.3)
+    simplecov_json_formatter (0.1.4)
     solid_queue (0.3.1)
       activejob (>= 7.1)
       activerecord (>= 7.1)
@@ -331,6 +369,7 @@ DEPENDENCIES
   bootsnap
   capybara
   debug
+  dice-roller!
   dotenv
   image_processing (~> 1.2)
   importmap-rails

app/services/dice_roller.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "dice"
+
 class DiceRoller
   attr_reader :dice
   attr_reader :result
@@ -11,21 +13,8 @@ class DiceRoller
   end
 
   def roll
-    result = 0
-    operator = nil
-    roll_command_parts.each do |part|
-      case part
-      when /\A\d*d\d+\z/
-        operator.nil? ? (result += roll_dice(part)) : (result = result.send(operator, roll_dice(part)))
-      when /\A\d+\z/
-        operator.nil? ? (result += part.to_i) : (result = result.send(operator, part.to_i))
-      when "self"
-        operator.nil? ? (result += @stat) : (result = result.send(operator, @stat))
-      when /\A[+\-*\/]\z/
-        operator = part
-      end
-    end
-    result
+    @roll_command = @roll_command.sub("self", @stat.to_s) if @roll_command.include?("self")
+    Dice.roll(@roll_command)
   end
 
   def valid?
@@ -50,12 +39,6 @@ class DiceRoller
 
   private
 
-    def roll_command_parts
-      @roll_command.scan(/([+\-*\/])|(\d*d\d+)|(\d+)|(self)/xi)
-                   .flatten
-                   .compact_blank
-    end
-
     def roll_dice(command)
       parts = command.downcase.split("d").compact_blank
       die_type = parts.last

test/fixtures/stats.yml

@@ -1,14 +1,14 @@
 strength:
   name: Strength
   value: 10
-  roll_command: d20+self
+  roll_command: 1d20+self
 
 dexterity:
   name: Dexterity
   value: 10
-  roll_command: d20+self
+  roll_command: 1d20+self
 
 constitution:
   name: Constitution
   value: 10
-  roll_command: d20+self
+  roll_command: 1d20+self

test/models/stat_test.rb

@@ -27,7 +27,7 @@ class StatTest < ActiveSupport::TestCase
 
   test "rolls with roll_command" do
     stat = stats(:strength)
-    stat.roll_command = "1d6"
+    stat.update(roll_command: "1d6")
     100.times { assert (1..6).cover?(stat.roll(tables(:dnd_table))) }
   end
 end

test/services/dice_roller_test.rb

@@ -8,15 +8,15 @@ class DiceRollerTest < ActiveSupport::TestCase
       "2d6",
       "12",
       "self",
-      "d12",
-      "d20+self",
-      "8+D8-self",
+      "1d12",
+      "1d20+self",
+      "8+1D8-self",
     ]
 
     invalid_strings = [
       "+",
       "sel+10",
-      "d8++13",
+      "1d8++13",
     ]
 
     valid_strings.each do |roll_command|
@@ -30,9 +30,9 @@ class DiceRollerTest < ActiveSupport::TestCase
 
   test "rolls appropriate results" do
     100.times do
-      assert (1..6).include? DiceRoller.new("d6").roll
+      assert (1..6).include? DiceRoller.new("1d6").roll
       assert (2..12).include? DiceRoller.new("2d6").roll
-      assert (11..30).include? DiceRoller.new("d20+self", stat: stats(:strength)).roll
+      assert (11..30).include? DiceRoller.new("1d20+self", stat: stats(:strength)).roll
     end
   end
 end