Initial commit

app/models/duration_timecode.rb

@@ -0,0 +1,48 @@
+class DurationTimecode
+  def self.parse(timecode)
+    if match = DURATION_TIMECODE_REGEX.match(timecode)
+      hours = match[1].to_i
+      minutes = match[2].to_i
+      seconds = match[3].to_i
+      new(hours, minutes, seconds)
+    else
+      raise ArgumentError.new("Must be HH:MM:SS format")
+    end
+  end
+
+  def self.from_seconds(total_seconds)
+    hours = total_seconds / 60 / 60
+    minutes = total_seconds / 60 % 60
+    seconds = total_seconds % 60
+
+    DurationTimecode.new(hours, minutes, seconds)
+  end
+
+  attr_reader :hours, :minutes, :seconds
+
+  def initialize(hours, minutes, seconds)
+    @hours = hours
+    @minutes = minutes
+    @seconds = seconds
+  end
+
+  def to_s
+    [hours, minutes, seconds].map { |t| t.to_s.rjust(2,'0') }.join(':')
+  end
+
+  def to_i
+    [
+      hours * 60 * 60,
+      minutes * 60,
+      seconds
+    ].sum
+  end
+
+  def +(other)
+    DurationTimecode.from_seconds(to_i + other.to_i)
+  end
+
+  private
+
+  DURATION_TIMECODE_REGEX = /\A(\d+):(\d+):(\d+)\z/
+end