diff --git a/adventofcode.tests/adventofcode.com/2015/Testing2015day0022.cs b/adventofcode.tests/adventofcode.com/2015/Testing2015day0022.cs
new file mode 100644
index 0000000..7821f81
--- /dev/null
+++ b/adventofcode.tests/adventofcode.com/2015/Testing2015day0022.cs
@@ -0,0 +1,19 @@
+
+using adventofcode.adventofcode.com._2015;
+
+namespace adventofcode.tests.adventofcode.com._2015;
+
+public class Testing2015day0022
+{
+    [TestCase]
+    public void TestWhoWins()
+    {
+        var result = Solution2015day0022.WhoWins(
+            new Solution2015day0022.Player(10, 250),
+            new int[] { 3, 0 },
+            new Solution2015day0022.Player(13, 0, 8));
+        result.Winner.Should().Be(0);
+    }
+
+    private const string MainInput = @"{input}";
+}
diff --git a/adventofcode/adventofcode.com/2015/Solution2015day0022.cs b/adventofcode/adventofcode.com/2015/Solution2015day0022.cs
new file mode 100644
index 0000000..2a8ca34
--- /dev/null
+++ b/adventofcode/adventofcode.com/2015/Solution2015day0022.cs
@@ -0,0 +1,46 @@
+
+namespace adventofcode.adventofcode.com._2015;
+
+public static class Solution2015day0022
+{
+    public record Effect(int Turns, int Armor, int Damage, int Mana, int Heal);
+
+    private record Spell(int ManaCost, int Damage, int Heal, Effect? Effect = null);
+
+    public record Player(int HitPoints, int Mana = 0, int Damage = 0)
+    {
+        public List<Effect> Effects { get; init; } = new List<Effect>();
+    }
+    
+    private static Spell[] Spells = new Spell[] {
+        new Spell(53, 4, 0),                                                            // 0. Magic Missle
+        new Spell(73, 2, 2),                                                            // 1. Drain
+        new Spell(113, 0, 0, new Effect(6, 7, 0, 0, 0)), // 2. Shield
+        new Spell(173, 0, 0, new Effect(6, 0, 3, 0, 0)), // 3. Poison
+        new Spell(113, 0, 0, new Effect(5, 0, 0, 101, 0))// 4. Recharge
+    };
+
+    public static (int Winner, int Mana) WhoWins(Player player, int[] spellsToCast, Player boss)
+        => Enumerable.Range(0, Math.Max(player.HitPoints, boss.HitPoints))
+            .TakeWhile(round =>
+            {
+                (player, boss) = round % 2 == 0 ? PlayerMove(round, player, spellsToCast, boss) : BossMove(player, boss);
+                return player.HitPoints > 0 && boss.HitPoints > 0;
+            }).ToList()
+            .And(rounds =>
+            (
+                Winner: player.HitPoints > 0 ? 0 : 1,
+                Mana: rounds.Append(rounds.Last() + 1)
+                    .Select(idx => idx < spellsToCast.Length ? Spells[spellsToCast[idx]].ManaCost : 0).Sum()
+            ));
+
+    private static (Player player, Player boss) BossMove(Player player, Player boss)
+        => (player with {
+            HitPoints = player.HitPoints - boss.Damage
+        }, boss);
+
+    private static (Player player, Player boss) PlayerMove(int round, Player player, int[] spellsToCast, Player boss)
+    {
+        throw new NotImplementedException();
+    }
+}
diff --git a/prepare_solution/Program.cs b/prepare_solution/Program.cs
index 9131f77..0d23236 100644
--- a/prepare_solution/Program.cs
+++ b/prepare_solution/Program.cs
@@ -2,7 +2,7 @@
 
 using System.Reflection;
 
-var url = "https://adventofcode.com/2015/day/22";
+var url = "https://adventofcode.com/2015/day/23";
 var year = "2015";
 var solutionFolder = GetSolutionFolder();
 var libFolder = Path.Combine(solutionFolder, "adventofcode");