Dice lib

3 files changed, 75 insertions, 0 deletions

diff --git a/app/lib/dice.rb b/app/lib/dice.rb
new file mode 100644
index 0000000..3b6df48
--- /dev/null
+++ b/app/lib/dice.rb
@@ -0,0 +1,29 @@
+module Dice
+  # @param sides [Integer]
+  # @return [Dice::Result]
+  def self.roll(sides)
+    result = Dice::Result.new
+    result.add_roll Dice::Roll.new(sides)
+    result
+  end
+
+  # @param formula [String]
+  def self.roll_formula(formula)
+    # Will add other delimiters later.
+    parts = formula.split("d")
+
+    if parts.length < 2
+      raise "Invalid formula: #{formula}"
+    end
+
+    num_dice = parts[0].empty? ? 1 : parts[0].to_i
+    sides = parts[1].to_i
+
+    result = Dice::Result.new
+    num_dice.times do
+      result.add_roll Dice::Roll.new(sides)
+    end
+
+    result
+  end
+end
diff --git a/app/lib/dice/result.rb b/app/lib/dice/result.rb
new file mode 100644
index 0000000..103a282
--- /dev/null
+++ b/app/lib/dice/result.rb
@@ -0,0 +1,32 @@
+class Dice::Result
+  attr_reader :rolls
+
+  def initialize
+    @rolls = []
+  end
+
+  # @param other [Dice::Result]
+  def ==(other)
+    sides == other.sides && face == other.face
+  end
+
+  # @param roll [Dice::Roll]
+  def add_roll(roll)
+    @rolls << roll
+  end
+
+  # @return [Integer]
+  def total
+    @rolls.sum(&:face)
+  end
+
+  def increase_sides_below_max(max_value, increase_by)
+    @rolls.each do |roll|
+      roll.increase_side_below_max(max_value, increase_by)
+    end
+  end
+
+  def to_s
+    "#{total} (#{@rolls.map(&:face).join(', ')})"
+  end
+end
diff --git a/app/lib/dice/roll.rb b/app/lib/dice/roll.rb
new file mode 100644
index 0000000..dd4788b
--- /dev/null
+++ b/app/lib/dice/roll.rb
@@ -0,0 +1,14 @@
+class Dice::Roll
+  attr_reader :sides, :face
+
+  # @param sides [Integer]
+  # @param face [Integer] (Optional) Rolled if not provided.
+  def initialize(sides, face = nil)
+    @sides = sides
+    @face = face || rand(1..sides)
+  end
+
+  def increase_side_below_max(max_value, increase_by)
+    @face += increase_by if @face < max_value
+  end
+end