Transition game between players and achieve game win

lib/islands_engine/rules.ex

@@ -66,6 +66,26 @@ defmodule IslandEngine.Rules do
     end
   end
 
+  def check(%Rules{state: :player1_turn} = rules, {:guess_coordinate, :player1}),
+    do: {:ok, %Rules{rules | state: :player2_turn}}
+
+  def check(%Rules{state: :player1_turn} = rules, {:win_check, win_or_not}) do
+    case win_or_not do
+      :no_win -> {:ok, rules}
+      :win -> {:ok, %Rules{rules | state: :game_over}}
+    end
+  end
+
+  def check(%Rules{state: :player2_turn} = rules, {:guess_coordinate, :player2}),
+    do: {:ok, %Rules{rules | state: :player1_turn}}
+
+  def check(%Rules{state: :player2_turn} = rules, {:win_check, win_or_not}) do
+    case win_or_not do
+      :no_win -> {:ok, rules}
+      :win -> {:ok, %Rules{rules | state: :game_over}}
+    end
+  end
+
   def check(_state, _action), do: :error
 
   defp both_players_islands_set?(rules),