addons/roller: A capable die roller

lib/addons/roller.rb

@@ -0,0 +1,108 @@
+# frozen_string_literal: true
+
+module Chronicle
+  module Matrix
+    # Roll dice and get the results
+    #
+    # @param message [hash] The message data from Matrix
+    def handle_roll(client, message)
+      msgstr = message.content[:body]
+                      .gsub(/!roll\s*/, '')
+                      .strip
+
+      room = client.ensure_room(message.room_id)
+
+      res = Roller.roll(msgstr)
+
+      final_msg = res.reduce("") { |x,y| x+y+"\n" }
+
+      room.send_notice(final_msg)
+    end
+
+    module Roller
+      # Solve an arithmatic forumla from a string
+      #
+      # @param string [String] The string representation of the formula
+      # @return Integer of the solution
+      def self.solve(string)
+        formatted = string.gsub(/\s+/, '')
+        formatted = formatted.gsub(/\[[\d,]*\]/) do |a|
+          a.scan(/\d*/).reduce(0) { |x, y| x + y.to_i }
+        end
+
+        if formatted.match(/\(.*\)/)
+          formatted = formatted.sub(/\(.*\)/) do |m|
+            solve(m[1..-2])
+          end
+
+          solve(formatted)
+
+        elsif formatted.match(/\d+\*\d+/)
+          formatted = formatted.sub(/\d+\*\d+/) do |m|
+            m.split('*').reduce(1) { |x, y| x * y.to_i }
+          end
+
+          solve(formatted)
+
+        elsif formatted.match(/\d+\/\d+/)
+          formatted = formatted.sub(/\d*\/\d*/) do |m|
+            m.split('/').reduce { |x, y| x.to_i / y.to_i }
+          end
+
+          solve(formatted)
+
+        elsif formatted.match(/\d+\+\d+/)
+          formatted = formatted.sub(/\d+\+\d+/) do |m|
+            m.split('+').reduce(0) { |x, y| x + y.to_i }
+          end
+
+          solve(formatted)
+
+        elsif formatted.match(/\d+\-\d+/)
+          formatted = formatted.sub(/\d+\-\d+/) do |m|
+            m.split('-').reduce { |x, y| x.to_i + -(y.to_i) }
+          end
+
+          solve(formatted)
+
+        else
+          formatted.to_i
+        end
+      end
+
+      # Pretty-print a result
+      #
+      # @param func [String] The name of the function
+      # @param orig [String] The original request
+      # @param string [String] The processed request
+      # @param res [String] The result of the process
+      # @return String re-formatted
+      def self.pretty(func, orig, string, res)
+        orig.gsub!(/[\+\-*\/]/) { |s| " #{s} " }
+        string.gsub!(/[\+\-*\/]/) { |s| " #{s} " }
+        "#{func.capitalize}: #{orig} (#{string}) ==> #{res}"
+      end
+
+      # Roll dice
+      #
+      # @param string [String] The string representation of the dice roll
+      #        example: 2d4+6
+      # @return Array of the message and the result
+      def self.roll(string)
+        results = []
+        string.gsub(/\s+/,'').split(',').each do |roll|
+          orig = roll
+          res = roll.gsub(/[0-9]*d[0-9]*/) do |d|
+            num,sides = d.split('d')
+            num = num.empty? ? '1' : num
+            Array.new(num.to_i.abs) { Random.new.rand(sides.to_i) + 1 }
+          end
+
+          results << pretty("Roll", orig, res, solve(res))
+        end
+
+        results
+      end
+    end
+  end
+end