refactor: use Linq and other code style improvements (#75)

BotWrapper/BotWrapper.cs

-using System;
-using System.IO;
-using System.Collections.Generic;
-using System.Text;
-using System.Text.RegularExpressions;
-using System.Diagnostics;
-using System.Runtime.InteropServices;
-using System.Linq;
-
-namespace BotWrapper
-{
-    class BotWrapper
-    {
-        [DllImport("User32.dll", CharSet = CharSet.Unicode)]
-        public static extern int MessageBox(IntPtr hWnd, string lpText, string lpCaption, int uType);
-
-        const int MB_ICONERROR = 0x00000010;
-
-        static void Main(string[] args)
-        {
-            ProcessStartInfo startInfo = new ProcessStartInfo();
-            startInfo.UseShellExecute = false;
-            startInfo.WorkingDirectory = Path.GetFullPath("WindBot");
-            startInfo.FileName = startInfo.WorkingDirectory + "\\WindBot.exe";
-
-            if (args.Length == 3)
-            {
-                startInfo.CreateNoWindow = true;
-                startInfo.WindowStyle = ProcessWindowStyle.Hidden;
-
-                string arg = args[0];
-                Match match = Regex.Match(arg, "Random=(.*)");
+using System;
+using System.IO;
+using System.Collections.Generic;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using System.Linq;
+
+namespace BotWrapper
+{
+    class BotWrapper
+    {
+        [DllImport("User32.dll", CharSet = CharSet.Unicode)]
+        public static extern int MessageBox(IntPtr hWnd, string lpText, string lpCaption, int uType);
+
+        const int MB_ICONERROR = 0x00000010;
+
+        static void Main(string[] args)
+        {
+            ProcessStartInfo startInfo = new ProcessStartInfo();
+            startInfo.UseShellExecute = false;
+            startInfo.WorkingDirectory = Path.GetFullPath("WindBot");
+            startInfo.FileName = startInfo.WorkingDirectory + "\\WindBot.exe";
+
+            if (args.Length == 3)
+            {
+                startInfo.CreateNoWindow = true;
+                startInfo.WindowStyle = ProcessWindowStyle.Hidden;
+
+                string arg = args[0];
+                Match match = Regex.Match(arg, "Random=(.*)");
                 if (match.Success)
                 {
                     string randomFlag = match.Groups[1].Value;
@@ -39,42 +39,42 @@ namespace BotWrapper
                     {
                         MessageBox((IntPtr)0, "Can't find random bot with this flag!\n\nA totally random bot will appear instead.", "WindBot", MB_ICONERROR);
                     }
-                }
-                arg = arg.Replace("'", "\"");
-                if (int.Parse(args[1]) == 1)
-                {
-                    arg += " Hand=1";
-                }
-                arg += " Port=" + args[2];
-                startInfo.Arguments = arg;
-            }
-
-            try
-            {
-                Process.Start(startInfo);
-            }
-            catch
-            {
-                MessageBox((IntPtr)0, "WindBot can't be started!", "WindBot", MB_ICONERROR);
-            }
-        }
-
+                }
+                arg = arg.Replace("'", "\"");
+                if (int.Parse(args[1]) == 1)
+                {
+                    arg += " Hand=1";
+                }
+                arg += " Port=" + args[2];
+                startInfo.Arguments = arg;
+            }
+
+            try
+            {
+                Process.Start(startInfo);
+            }
+            catch
+            {
+                MessageBox((IntPtr)0, "WindBot can't be started!", "WindBot", MB_ICONERROR);
+            }
+        }
+
         public class BotInfo
         {
             public string name;
             public string command;
             public string desc;
             public string[] flags;
-        }
-
-        static public IList<BotInfo> Bots = new List<BotInfo>();
-
+        }
+
+        static public IList<BotInfo> Bots = new List<BotInfo>();
+
         static void ReadBots()
         {
-            using (StreamReader reader = new StreamReader("bot.conf"))
-            {
-                while (!reader.EndOfStream)
-                {
+            using (StreamReader reader = new StreamReader("bot.conf"))
+            {
+                while (!reader.EndOfStream)
+                {
                     string line = reader.ReadLine().Trim();
                     if (line.Length > 0 && line[0] == '!')
                     {
@@ -88,8 +88,8 @@ namespace BotWrapper
                     }
                 }
             }
-        }
-
+        }
+
         static string GetRandomBot(string flag)
         {
             IList<BotInfo> foundBots = Bots.Where(bot => bot.flags.Contains(flag)).ToList();
@@ -100,6 +100,6 @@ namespace BotWrapper
                 return bot.command;
             }
             return "";
-        }
-    }
-}
+        }
+    }
+}

Game/AI/Decks/BlueEyesExecutor.cs

 using YGOSharp.OCGWrapper.Enums;
 using System.Collections.Generic;
+using System.Linq;
 using WindBot;
 using WindBot.Game;
 using WindBot.Game.AI;
@@ -140,25 +141,9 @@ namespace WindBot.Game.AI.Decks
                 Logger.DebugWriteLine("OnSelectCard MelodyOfAwakeningDragon");
                 IList<ClientCard> result = new List<ClientCard>();
                 if (!Bot.HasInHand(CardId.WhiteDragon))
-                {
-                    foreach (ClientCard card in cards)
-                    {
-                        if (card.Id == CardId.WhiteDragon)
-                        {
-                            result.Add(card);
-                            break;
-                        }
-                    }
-                }
-                foreach (ClientCard card in cards)
-                {
-                    if (card.Id == CardId.AlternativeWhiteDragon && result.Count < max)
-                    {
-                        result.Add(card);
-                    }
-                }
-                AI.Utils.CheckSelectCount(result, cards, min, max);
-                return result;
+                    result.Add(cards.FirstOrDefault(card => card.Id == CardId.WhiteDragon));
+                result = result.Concat(cards.Where(card => card.Id == CardId.AlternativeWhiteDragon)).ToList();
+                return AI.Utils.CheckSelectCount(result, cards, min, max);
             }
             Logger.DebugWriteLine("Use default.");
             return null;
@@ -167,10 +152,8 @@ namespace WindBot.Game.AI.Decks
         public override IList<ClientCard> OnSelectXyzMaterial(IList<ClientCard> cards, int min, int max)
         {
             Logger.DebugWriteLine("OnSelectXyzMaterial " + cards.Count + " " + min + " " + max);
-            IList<ClientCard> result = new List<ClientCard>();
-            AI.Utils.SelectPreferredCards(result, UsedAlternativeWhiteDragon, cards, min, max);
-            AI.Utils.CheckSelectCount(result, cards, min, max);
-            return result;
+            IList<ClientCard> result = AI.Utils.SelectPreferredCards(UsedAlternativeWhiteDragon, cards, min, max);
+            return AI.Utils.CheckSelectCount(result, cards, min, max);
         }
 
         public override IList<ClientCard> OnSelectSynchroMaterial(IList<ClientCard> cards, int sum, int min, int max)

Game/AI/Decks/LightswornExecutor.cs

@@ -114,8 +114,8 @@ namespace WindBot.Game.AI.Decks
                 if (result.Count >= max)
                     break;
             }
-            AI.Utils.CheckSelectCount(result, cards, min, max);
-            return result;
+            
+            return AI.Utils.CheckSelectCount(result, cards, min, max);
         }
 
         private bool ReinforcementOfTheArmyEffect()

Game/AI/Decks/LightswornShaddoldinosourExecutor.cs

@@ -353,13 +353,13 @@ namespace WindBot.Game.AI.Decks
             }
             return false;    
             
-        }
-
-        private bool GamecieltheSeaTurtleKaijusp()
-        {
-            if (!Bot.HasInMonstersZone(CardId.UltimateConductorTytanno))
-                return DefaultKaijuSpsummon();
-            return false;
+        }
+
+        private bool GamecieltheSeaTurtleKaijusp()
+        {
+            if (!Bot.HasInMonstersZone(CardId.UltimateConductorTytanno))
+                return DefaultKaijuSpsummon();
+            return false;
         }
 
         private bool RadiantheMultidimensionalKaijusp()
@@ -409,9 +409,9 @@ namespace WindBot.Game.AI.Decks
         }
 
         private bool MonsterRepos()
-        {
+        {
             if (Card.Id == CardId.UltimateConductorTytanno && Card.IsFacedown()) return true;
-            if (Card.Id == CardId.ElShaddollConstruct && Card.IsFacedown()) return true;
+            if (Card.Id == CardId.ElShaddollConstruct && Card.IsFacedown()) return true;
             if (Card.Id == CardId.ElShaddollConstruct && Card.IsAttack()) return false;
             if (Card.Id == CardId.GlowUpBulb && Card.IsDefense()) return false;
             if (Card.Id == CardId.ShaddollDragon && Card.IsFacedown() && Enemy.GetMonsterCount() >= 0) return true;
@@ -526,8 +526,8 @@ namespace WindBot.Game.AI.Decks
 
         
         private bool FairyTailSnowsummon()
-        {
-            ClientCard target = AI.Utils.GetBestEnemyMonster(true, true);
+        {
+            ClientCard target = AI.Utils.GetBestEnemyMonster(true, true);
             if(target != null)
             {
                 return true;
@@ -549,13 +549,13 @@ namespace WindBot.Game.AI.Decks
                
                 int spell_count = 0;
                 IList<ClientCard> grave = Bot.Graveyard;               
-                IList<ClientCard> all = new List<ClientCard>();
-                foreach (ClientCard check in grave)
-                {
-                    if (check.Id == CardId.GiantRex)
-                    {
-                        all.Add(check);
-                    }
+                IList<ClientCard> all = new List<ClientCard>();
+                foreach (ClientCard check in grave)
+                {
+                    if (check.Id == CardId.GiantRex)
+                    {
+                        all.Add(check);
+                    }
                 }
                 foreach (ClientCard check in grave)
                     {
@@ -572,8 +572,8 @@ namespace WindBot.Game.AI.Decks
                         all.Add(check);
                     }
                 }
-                if (AI.Utils.ChainContainsCard(CardId.FairyTailSnow)) return false;
-
+                if (AI.Utils.ChainContainsCard(CardId.FairyTailSnow)) return false;
+
                 if ( Duel.Player == 1  && Duel.Phase == DuelPhase.BattleStart && Bot.BattlingMonster == null && Enemy_atk >=Bot.LifePoints ||
                     Duel.Player == 0 && Duel.Phase==DuelPhase.BattleStart && Enemy.BattlingMonster == null && Enemy.LifePoints<=1850
                     )
@@ -590,9 +590,9 @@ namespace WindBot.Game.AI.Decks
         private bool SouleatingOviraptoreff()
         {
             if (!OvertexCoatlseff_used && Bot.GetRemainingCount(CardId.OvertexCoatls, 3) > 0)
-            {
-                AI.SelectCard(CardId.OvertexCoatls);
-                AI.SelectOption(0);
+            {
+                AI.SelectCard(CardId.OvertexCoatls);
+                AI.SelectOption(0);
             }
             else
             {
@@ -992,7 +992,7 @@ namespace WindBot.Game.AI.Decks
         
         private bool LostWindeff()
         {
-            if (Card.Location == CardLocation.Grave)
+            if (Card.Location == CardLocation.Grave)
                 return true;
             List<ClientCard> check = Enemy.GetMonsters();
             foreach (ClientCard m in check)

Game/AI/Decks/RainbowExecutor.cs

@@ -172,8 +172,8 @@ namespace WindBot.Game.AI.Decks
                 if (result.Count > 0)
                     break;
             }
-            AI.Utils.CheckSelectCount(result, cards, min, max);
-            return result;
+            
+            return AI.Utils.CheckSelectCount(result, cards, min, max);
         }
 
         private bool UnexpectedDaiEffect()

Game/AI/Decks/Rank5Executor.cs

@@ -120,15 +120,13 @@ namespace WindBot.Game.AI.Decks
 
         public override IList<ClientCard> OnSelectXyzMaterial(IList<ClientCard> cards, int min, int max)
         {
-            IList<ClientCard> result = new List<ClientCard>();
-            AI.Utils.SelectPreferredCards(result, new[] {
+            IList<ClientCard> result = AI.Utils.SelectPreferredCards(new[] {
                 CardId.MistArchfiend,
                 CardId.PanzerDragon,
                 CardId.SolarWindJammer,
                 CardId.StarDrawing
             }, cards, min, max);
-            AI.Utils.CheckSelectCount(result, cards, min, max);
-            return result;
+            return AI.Utils.CheckSelectCount(result, cards, min, max);
         }
 
         private bool NormalSummon()

Game/AI/Decks/YosenjuExecutor.cs

@@ -181,10 +181,8 @@ namespace WindBot.Game.AI.Decks
 
         public override IList<ClientCard> OnSelectXyzMaterial(IList<ClientCard> cards, int min, int max)
         {
-            IList<ClientCard> result = new List<ClientCard>();
-            AI.Utils.SelectPreferredCards(result, CardId.YosenjuTsujik, cards, min, max);
-            AI.Utils.CheckSelectCount(result, cards, min, max);
-            return result;
+            IList<ClientCard> result = AI.Utils.SelectPreferredCards(CardId.YosenjuTsujik, cards, min, max);
+            return AI.Utils.CheckSelectCount(result, cards, min, max);
         }
 
         private bool PotOfDualityEffect()

Game/AI/Decks/ZexalWeaponsExecutor.cs

@@ -138,14 +138,12 @@ namespace WindBot.Game.AI.Decks
 
         public override IList<ClientCard> OnSelectXyzMaterial(IList<ClientCard> cards, int min, int max)
         {
-            IList<ClientCard> result = new List<ClientCard>();
-            AI.Utils.SelectPreferredCards(result, new[] {
+            IList<ClientCard> result = AI.Utils.SelectPreferredCards(new[] {
                 CardId.StarDrawing,
                 CardId.SolarWindJammer,
                 CardId.Goblindbergh
             }, cards, min, max);
-            AI.Utils.CheckSelectCount(result, cards, min, max);
-            return result;
+            return AI.Utils.CheckSelectCount(result, cards, min, max);
         }
 
         private bool Number39Utopia()

Game/AI/Dialogs.cs

@@ -127,7 +127,7 @@ namespace WindBot.Game.AI
 
         public void SendOnDirectAttack(string attacker)
         {
-            if (attacker == "" || attacker == null)
+            if (string.IsNullOrEmpty(attacker))
             {
                 attacker = _facedownmonstername;
             }

Game/AI/Executor.cs

 using System;
 using System.Collections.Generic;
+using System.Linq;
 using YGOSharp.OCGWrapper.Enums;
 using WindBot;
 using WindBot.Game;
@@ -82,12 +83,12 @@ namespace WindBot.Game.AI
 
         public virtual void OnChaining(int player, ClientCard card)
         {
-            
+            // For overriding
         }
 
         public virtual void OnChainEnd()
         {
-            
+            // For overriding
         }
         public virtual void OnNewPhase()
         {
@@ -239,12 +240,7 @@ namespace WindBot.Game.AI
 
         private bool DefaultNoExecutor()
         {
-            foreach (CardExecutor exec in Executors)
-            {
-                if (exec.Type == Type && exec.CardId == Card.Id)
-                    return false;
-            }
-            return true;
+            return Executors.All(exec => exec.Type != Type || exec.CardId != Card.Id);
         }
     }
 }
\ No newline at end of file

Game/ClientCard.cs

@@ -151,27 +151,27 @@ namespace WindBot.Game
 
         public bool HasLinkMarker(int dir)
         {
-            return ((LinkMarker & dir) != 0);
+            return (LinkMarker & dir) != 0;
         }
 
         public bool HasLinkMarker(LinkMarker dir)
         {
-            return ((LinkMarker & (int)dir) != 0);
+            return (LinkMarker & (int)dir) != 0;
         }
 
         public bool HasType(CardType type)
         {
-            return ((Type & (int)type) != 0);
+            return (Type & (int)type) != 0;
         }
 
         public bool HasPosition(CardPosition position)
         {
-            return ((Position & (int)position) != 0);
+            return (Position & (int)position) != 0;
         }
 
         public bool HasAttribute(CardAttribute attribute)
         {
-            return ((Attribute & (int)attribute) != 0);
+            return (Attribute & (int)attribute) != 0;
         }
 
         public bool IsMonster()
@@ -221,7 +221,7 @@ namespace WindBot.Game
 
         public bool IsDisabled()
         {
-            return (Disabled != 0);
+            return Disabled != 0;
         }
 
         public bool HasXyzMaterial()

Game/ClientField.cs

 using System.Collections.Generic;
+using System.Linq;
+using WindBot.Game.AI;
 using YGOSharp.OCGWrapper.Enums;
 
 namespace WindBot.Game
@@ -94,20 +96,18 @@ namespace WindBot.Game
             }
             return count;
         }
-                
+
 
         public int GetFieldCount()
         {
             return GetSpellCount() + GetMonsterCount();
         }
 
-
         public int GetFieldHandCount()
         {
             return GetSpellCount() + GetMonsterCount() + GetHandCount();
         }
 
-
         public bool IsFieldEmpty()
         {
             return GetMonsters().Count == 0 && GetSpells().Count == 0;
@@ -117,7 +117,6 @@ namespace WindBot.Game
         {
             return GetCards(MonsterZone);
         }
-        
 
         public List<ClientCard> GetGraveyardMonsters()
         {
@@ -141,23 +140,12 @@ namespace WindBot.Game
 
         public List<ClientCard> GetMonstersInExtraZone()
         {
-            List<ClientCard> cards = new List<ClientCard>();
-            if (MonsterZone[5] != null)
-                cards.Add(MonsterZone[5]);
-            if (MonsterZone[6] != null)
-                cards.Add(MonsterZone[6]);
-            return cards;
+            return GetMonsters().Where((card, i) => i >= 5).ToList();
         }
 
         public List<ClientCard> GetMonstersInMainZone()
         {
-            List<ClientCard> cards = new List<ClientCard>();
-            for (int i = 0; i < 5; i++)
-            {
-                if (MonsterZone[i] != null)
-                    cards.Add(MonsterZone[i]);
-            }
-            return cards;
+            return GetMonsters().Where((card, i) => i < 5).ToList();
         }
 
         public bool HasInHand(int cardId)
@@ -202,24 +190,12 @@ namespace WindBot.Game
 
         public bool HasAttackingMonster()
         {
-            IList<ClientCard> monsters = GetMonsters();
-            foreach (ClientCard card in monsters)
-            {
-                if (card.IsAttack())
-                    return true;
-            }
-            return false;
+            return GetMonsters().Any(card => card.IsAttack());
         }
 
         public bool HasDefendingMonster()
         {
-            IList<ClientCard> monsters = GetMonsters();
-            foreach (ClientCard card in monsters)
-            {
-                if (card.IsDefense())
-                    return true;
-            }
-            return false;
+            return GetMonsters().Any(card => card.IsDefense());
         }
 
         public bool HasInMonstersZone(int cardId, bool notDisabled = false, bool hasXyzMaterial = false)
@@ -315,94 +291,46 @@ namespace WindBot.Game
         public int GetRemainingCount(int cardId, int initialCount)
         {
             int remaining = initialCount;
-            foreach (ClientCard card in Hand)
-                if (card != null && card.Id == cardId)
-                    remaining--;
-            foreach (ClientCard card in SpellZone)
-                if (card != null && card.Id == cardId)
-                    remaining--;
-            foreach (ClientCard card in Graveyard)
-                if (card != null && card.Id == cardId)
-                    remaining--;
-            foreach (ClientCard card in Banished)
-                if (card != null && card.Id == cardId)
-                    remaining--;
+            remaining = remaining - Hand.Count(card => card != null && card.Id == cardId);
+            remaining = remaining - SpellZone.Count(card => card != null && card.Id == cardId);
+            remaining = remaining - Graveyard.Count(card => card != null && card.Id == cardId);
+            remaining = remaining - Banished.Count(card => card != null && card.Id == cardId);
             return (remaining < 0) ? 0 : remaining;
         }
 
         private static int GetCount(IEnumerable<ClientCard> cards)
         {
-            int count = 0;
-            foreach (ClientCard card in cards)
-            {
-                if (card != null)
-                    count++;
-            }
-            return count;
+            return cards.Count(card => card != null);
         }
 
         public int GetCountCardInZone(IEnumerable<ClientCard> cards, int cardId)
         {
-            int count = 0;
-            foreach (ClientCard card in cards)
-            {
-                if (card != null && card.Id == cardId)
-                    count++;
-            }
-            return count;
+            return cards.Count(card => card != null && card.Id == cardId);
         }
 
         public int GetCountCardInZone(IEnumerable<ClientCard> cards, List<int> cardId)
         {
-            int count = 0;
-            foreach (ClientCard card in cards)
-            {
-                if (card != null && cardId.Contains(card.Id))
-                    count++;
-            }
-            return count;
+            return cards.Count(card => card != null && cardId.Contains(card.Id));
         }
 
         private static List<ClientCard> GetCards(IEnumerable<ClientCard> cards, CardType type)
         {
-            List<ClientCard> nCards = new List<ClientCard>();
-            foreach (ClientCard card in cards)
-            {
-                if (card != null && card.HasType(type))
-                    nCards.Add(card);
-            }
-            return nCards;
+            return cards.Where(card => card != null && card.HasType(type)).ToList();
         }
 
         private static List<ClientCard> GetCards(IEnumerable<ClientCard> cards)
         {
-            List<ClientCard> nCards = new List<ClientCard>();
-            foreach (ClientCard card in cards)
-            {
-                if (card != null)
-                    nCards.Add(card);
-            }
-            return nCards;
+            return cards.Where(card => card != null).ToList();
         }
 
         private static bool HasInCards(IEnumerable<ClientCard> cards, int cardId, bool notDisabled = false, bool hasXyzMaterial = false)
         {
-            foreach (ClientCard card in cards)
-            {
-                if (card != null && card.Id == cardId && !(notDisabled && card.IsDisabled()) && !(hasXyzMaterial && !card.HasXyzMaterial()))
-                    return true;
-            }
-            return false;
+            return cards.Any(card => card != null && card.Id == cardId && !(notDisabled && card.IsDisabled()) && !(hasXyzMaterial && !card.HasXyzMaterial()));
         }
 
         private static bool HasInCards(IEnumerable<ClientCard> cards, IList<int> cardId, bool notDisabled = false, bool hasXyzMaterial = false)
         {
-            foreach (ClientCard card in cards)
-            {
-                if (card != null && cardId.Contains(card.Id) && !(notDisabled && card.IsDisabled()) && !(hasXyzMaterial && !card.HasXyzMaterial()))
-                    return true;
-            }
-            return false;
+            return cards.Any(card => card != null && cardId.Contains(card.Id) && !(notDisabled && card.IsDisabled()) && !(hasXyzMaterial && !card.HasXyzMaterial()));
         }
     }
 }
\ No newline at end of file

Game/Deck.cs

@@ -83,8 +83,7 @@ namespace WindBot.Game
             }
             catch (Exception)
             {
-                if (reader != null)
-                    reader.Close();
+                reader?.Close();
                 return null;
             }
         }

Game/GameAI.cs

@@ -360,10 +360,7 @@ namespace WindBot.Game
                 return result;
             result = new List<ClientCard>();
             // TODO: use selector
-            for (int i = 0; i < cards.Count; i++)
-            {
-                result.Add(cards[i]);
-            }
+            result = cards.ToList();
             return result;
         }
 
@@ -550,10 +547,15 @@ namespace WindBot.Game
                 }
                 else
                 {
-                    if (hint == HINTMSG_SMATERIAL)
-                        selected = Executor.OnSelectSynchroMaterial(cards, sum, min, max);
-                    if (hint == HINTMSG_RELEASE)
-                        selected = Executor.OnSelectRitualTribute(cards, sum, min, max);
+                    switch (hint)
+                    {
+                        case HINTMSG_SMATERIAL:
+                            selected = Executor.OnSelectSynchroMaterial(cards, sum, min, max);
+                            break;
+                        case HINTMSG_RELEASE:
+                            selected = Executor.OnSelectRitualTribute(cards, sum, min, max);
+                            break;
+                    }
                 }
                 if (selected != null)
                 {
@@ -1017,12 +1019,7 @@ namespace WindBot.Game
         /// <returns>A list of the selected attributes.</returns>
         public virtual IList<CardAttribute> OnAnnounceAttrib(int count, IList<CardAttribute> attributes)
         {
-            IList<CardAttribute> foundAttributes = new List<CardAttribute>();
-            foreach (CardAttribute attribute in m_attributes)
-            {
-                if(attributes.Contains(attribute))
-                    foundAttributes.Add(attribute);
-            }
+            IList<CardAttribute> foundAttributes = m_attributes.Where(attributes.Contains).ToList();
             if (foundAttributes.Count > 0)
                 return foundAttributes;
 
@@ -1037,12 +1034,7 @@ namespace WindBot.Game
         /// <returns>A list of the selected races.</returns>
         public virtual IList<CardRace> OnAnnounceRace(int count, IList<CardRace> races)
         {
-            IList<CardRace> foundRaces = new List<CardRace>();
-            foreach (CardRace race in m_races)
-            {
-                if (races.Contains(race))
-                    foundRaces.Add(race);
-            }
+            IList<CardRace> foundRaces = m_races.Where(races.Contains).ToList();
             if (foundRaces.Count > 0)
                 return foundRaces;
 
@@ -1080,12 +1072,10 @@ namespace WindBot.Game
         private bool ShouldExecute(CardExecutor exec, ClientCard card, ExecutorType type, int desc = -1)
         {
             Executor.SetCard(type, card, desc);
-            if (card != null &&
-                exec.Type == type &&
-                (exec.CardId == -1 || exec.CardId == card.Id) &&
-                (exec.Func == null || exec.Func()))
-                return true;
-            return false;
+            return card != null &&
+                   exec.Type == type &&
+                   (exec.CardId == -1 || exec.CardId == card.Id) &&
+                   (exec.Func == null || exec.Func());
         }
     }
 }

Game/GameBehavior.cs

@@ -619,7 +619,7 @@ namespace WindBot.Game
             _duel.Fields[attackcard.Controller].BattlingMonster = attackcard;
             _duel.Fields[1 - attackcard.Controller].BattlingMonster = defendcard;
 
-            if (ld == 0 && (attackcard != null) && (ca != 0))
+            if (ld == 0 && ca != 0)
             {
                 _ai.OnDirectAttack(attackcard);
             }
@@ -732,9 +732,8 @@ namespace WindBot.Game
             packet.ReadInt32(); // ???
 
             ClientCard card = _duel.GetCard(player, (CardLocation)loc, seq);
-            if (card == null) return;
 
-            card.Update(packet, _duel);
+            card?.Update(packet, _duel);
         }
 
         private void OnUpdateData(BinaryReader packet)
@@ -1448,11 +1447,7 @@ namespace WindBot.Game
             ClientCard equipCard = _duel.GetCard(equipCardControler, (CardLocation)equipCardLocation, equipCardSequence);
             ClientCard targetCard = _duel.GetCard(targetCardControler, (CardLocation)targetCardLocation, targetCardSequence);
             if (equipCard == null || targetCard == null) return;
-            if (equipCard.EquipTarget != null)
-            {
-                equipCard.EquipTarget.EquipCards.Remove(equipCard);
-            }
-
+            equipCard.EquipTarget?.EquipCards.Remove(equipCard);
             equipCard.EquipTarget = targetCard;
             targetCard.EquipCards.Add(equipCard);
         }