finds of-a-kind and flushes

lib/dojo/hand.ex

@@ -2,7 +2,55 @@ defmodule Dojo.Hand do
   alias Dojo.Card
 
   def score(cards) do
-    evaluate(cards)
+    check_of_a_kind(cards)
+  end
+
+  defp check_of_a_kind(cards) do
+    cards
+    |> Enum.uniq_by(&(&1.rank))
+    |> Enum.count
+    |> case do
+      3 -> :three_of_a_kind
+      2 -> check_full_house(cards)
+      _ -> check_flush(cards)
+    end
+  end
+
+  defp check_full_house(cards) do
+    :four_of_a_kind
+  end
+
+  defp check_flush(cards) do
+    cards
+    |> Enum.uniq_by(&(&1.suit))
+    |> Enum.count
+    |> case do
+      1 -> get_flush_type(cards)
+      _ -> evaluate(cards)
+    end
+  end
+
+  def get_flush_type(cards) do
+    sorted_cards =
+    cards
+    |> Enum.map(&(&1.rank))
+    |> Enum.sort
+
+    sorted_cards
+    |> is_straight_or_royal
+    |> case do
+      true ->
+        Enum.sum(sorted_cards)
+          |> case do
+            60 -> :royal_flush
+            _ -> :straight_flush
+          end
+      false -> :flush
+    end
+  end
+
+  def is_straight_or_royal(cards) do
+    cards == Enum.to_list(Enum.at(cards, 0)..Enum.at(cards, length(cards) - 1))
   end
 
   defp evaluate(_), do: :high_card

test/dojo/hand_test.exs

@@ -5,6 +5,18 @@ defmodule Dojo.HandTest do
   doctest Dojo.Hand
 
   test "evaluates a straight flush" do
+    cards = [
+      %Card{rank: 4, suit: :hearts},
+      %Card{rank: 5, suit: :hearts},
+      %Card{rank: 6, suit: :hearts},
+      %Card{rank: 7, suit: :hearts},
+      %Card{rank: 8, suit: :hearts}
+    ]
+
+    assert Hand.score(cards) == :straight_flush
+  end
+
+  test "evaluates a royal flush" do
     cards = [
       %Card{rank: 10, suit: :hearts},
       %Card{rank: 11, suit: :hearts},
@@ -13,7 +25,7 @@ defmodule Dojo.HandTest do
       %Card{rank: 14, suit: :hearts}
     ]
 
-    assert Hand.score(cards) == :straight_flush
+    assert Hand.score(cards) == :royal_flush
   end
 
   test "evaluates flush of hearts" do
@@ -63,4 +75,40 @@ defmodule Dojo.HandTest do
 
     assert Hand.score(cards) == :high_card
   end
+
+  test "evaluates four of a kind" do
+    cards = [
+      %Card{rank: 2, suit: :spades},
+      %Card{rank: 2, suit: :hearts},
+      %Card{rank: 2, suit: :diamonds},
+      %Card{rank: 2, suit: :clubs},
+      %Card{rank: 11, suit: :spades}
+    ]
+
+    assert Hand.score(cards) == :four_of_a_kind
+  end
+
+  test "evaluates three of a kind" do
+    cards = [
+      %Card{rank: 2, suit: :spades},
+      %Card{rank: 2, suit: :hearts},
+      %Card{rank: 2, suit: :diamonds},
+      %Card{rank: 6, suit: :clubs},
+      %Card{rank: 11, suit: :spades}
+    ]
+
+    assert Hand.score(cards) == :three_of_a_kind
+  end
+
+  test "evaluates full house" do
+    cards = [
+      %Card{rank: 2, suit: :spades},
+      %Card{rank: 2, suit: :hearts},
+      %Card{rank: 2, suit: :diamonds},
+      %Card{rank: 6, suit: :clubs},
+      %Card{rank: 6, suit: :spades}
+    ]
+
+    assert Hand.score(cards) == :full_house
+  end
 end