Turn left when user inputs the left command. Update robots position.

lib/direction.rb

@@ -1,22 +1,36 @@
 # Direction
 class Direction
-  def initialize
-    @options_array = %w[WEST NORTH EAST SOUTH]
-  end
+  OPTIONS = %w[WEST NORTH EAST SOUTH].freeze
 
   def turn_right(direction)
-    # Return if unless the direction exists
-    return unless @options_array.include?(direction)
+    # Return unless the direction exists
+    return unless OPTIONS.include?(direction)
 
-    i = @options_array.index { |e| e == direction }
+    i = OPTIONS.index { |e| e == direction }
 
     # Find next value in array
-    unless direction == @options_array.last
+    unless direction == OPTIONS.last
       i += 1
 
-      return @options_array.fetch(i)
+      return OPTIONS.fetch(i)
+    end
+
+    OPTIONS.first
+  end
+
+  def turn_left(direction)
+    # Return if unless the direction exists
+    return unless OPTIONS.include?(direction)
+
+    i = OPTIONS.index { |e| e == direction }
+
+    # Find next value in array
+    unless direction == OPTIONS.first
+      i -= 1
+
+      return OPTIONS.fetch(i)
     end
 
-    @options_array.first
+    OPTIONS.last
   end
 end

lib/handle_input.rb

@@ -20,6 +20,7 @@ def interpret(command)
     right = /^RIGHT$/
     report = /^REPORT$/
 
+    # PLACE
     if place.match?(command)
       command, x, y, f = command.tr(',', ' ').split
 
@@ -37,10 +38,17 @@ def interpret(command)
     # PLACE is the only valid command unless robot is in place
     return if robot.not_in_place?
 
-    puts 'moving' if move.match?(command)
+    # LEFT
+    if left.match?(command)
+      # Turn left and update the robots direction
+      robot.position.f = Direction.new.turn_left(robot.position.f)
 
-    puts 'turn left' if left.match?(command)
+      robot.update_robot(robot.position)
 
+      puts "New position #{robot.position.x},#{robot.position.y},#{robot.position.f}"
+    end
+
+    # RIGHT
     if right.match?(command)
       # Turn right and update the robots direction
       robot.position.f = Direction.new.turn_right(robot.position.f)
@@ -50,6 +58,8 @@ def interpret(command)
       puts "New position #{robot.position.x},#{robot.position.y},#{robot.position.f}"
     end
 
+    puts 'moving' if move.match?(command)
+
     puts 'reporting' if report.match?(command)
   end
 end

spec/direction_spec.rb

@@ -4,7 +4,7 @@
 
 describe Direction do
   describe '#turn_right' do
-    it 'should return the next value in the directions array' do
+    it 'should return the next value in the OPTIONS array' do
       instance = Direction.new
       direction = 'NORTH'
 
@@ -19,4 +19,21 @@
       expect(instance.turn_right(direction)).to be_nil
     end
   end
+
+  describe '#turn_left' do
+    it 'should return the previous value in the OPTIONS array' do
+      instance = Direction.new
+      direction = 'NORTH'
+
+      expect(instance.turn_left(direction)).to be_a String
+      expect(instance.turn_left(direction)).to eq 'WEST'
+    end
+
+    it 'should return nil if the direction is empty' do
+      instance = Direction.new
+      direction = ''
+
+      expect(instance.turn_left(direction)).to be_nil
+    end
+  end
 end