1 files changed, 33 insertions, 3 deletions

diff --git a/CLI/ruby/lib/game_of_life/universe.rb b/CLI/ruby/lib/game_of_life/universe.rb
index ccaf0cd..5b6e29a 100644
--- a/CLI/ruby/lib/game_of_life/universe.rb
+++ b/CLI/ruby/lib/game_of_life/universe.rb
@@ -6,6 +6,7 @@ module GameOfLife
   class Universe
     extend Forwardable
     delegate :[] => :@current
+    delegate :[]= => :@current
 
     # Initialize the empty initial universe 2D plane (circular arrays)
     # @param width [Integer] the width of the universe array
@@ -17,19 +18,48 @@ module GameOfLife
 
     # Representation of the game of life universe
     # @return [String] representing the current state
-    # @see ::GameOfLife::Cell#to_s
+    # @see GameOfLife::Cell#to_s
     def to_s
       @current.map(&:join).join("\n")
     end
 
+    # Update the current state of the universe (according to the game of life laws) and
+    # set the current state to the next future generation
+    #
+    # This have computational order O(width*height)
+    # It loops over all the universe cells and evolves them to the next generation
+    # @see #neighbors
     def evolve!
       @current.each do |row|
         row.each do |cell|
-          @future[cell.pos_y][cell.pos_x] = cell.evolve!(@current)
-          # @future[cell.pos_y][cell.pos_x] = cell.send(:living_neighbors, @current)
+          @future[cell.y][cell.x] = cell.evolve!(neighbors(cell))
         end
       end
       @current = @future
     end
+
+    # Return the array of all the neighboring cells using the circular universe array
+    # @param universe [Array<GameOfLife::Cell>] the {GameOfLife::Universe#current} state of universe
+    # @return [Array<GameOfLife::Cell>] of all the immediate neighboring cells
+    # @example given a cell "C" in a universe of cells "." the immediate neighbors would be "x" as in
+    # the following different examples
+    #
+    #     .....  |  .xxx.  |  .xCx.  |  xCx..  |  Cx..x  |  xx..x  |
+    #     .xxx.  |  .xCx.  |  .xxx.  |  xxx..  |  xx..x  |  Cx..x  |
+    #     .xCx.  |  .xxx.  |  .....  |  .....  |  .....  |  xx..x  |
+    #     .xxx.  |  .....  |  .....  |  .....  |  .....  |  .....  |
+    #     .....  |  .....  |  .xxx.  |  xxx..  |  xx..x  |  .....  |
+    #
+    # @smell AbcSize higher than configuration, but needed to return the neighboring cells array
+    # rubocop:disable Metrics/AbcSize
+    private def neighbors(cell)
+      x, y = cell.x, cell.y # rubocop:disable Style/ParallelAssignment
+      [
+        @current[y - 1][x - 1], @current[y - 1][x], @current[y - 1][x + 1],
+        @current[y][x - 1], @current[y][x + 1],
+        @current[y + 1][x - 1], @current[y + 1][x], @current[y + 1][x + 1]
+      ]
+    end
+    # rubocop:enable Metrics/AbcSize
   end
 end