Implements switching Pokemon and fleeing from battle

PkmnLib.Dynamic/Libraries/MiscLibrary.cs

@@ -19,4 +19,6 @@ public interface IMiscLibrary
     /// Gets the current time of day for the battle.
     /// </summary>
     TimeOfDay GetTimeOfDay();
+
+    bool CanFlee(IBattle battle, IFleeChoice fleeChoice);
 }

PkmnLib.Dynamic/Models/BattleFlow/TurnRunner.cs

@@ -84,7 +84,75 @@ public static class TurnRunner
             case IMoveChoice moveChoice:
                 MoveTurnExecutor.ExecuteMoveChoice(battle, moveChoice);
                 break;
-            // TODO: Implement other choice types
+            case ISwitchChoice switchChoice:
+                ExecuteSwitchChoice(battle, switchChoice);
+                break;
+            case IFleeChoice fleeChoice:
+                ExecuteFleeChoice(battle, fleeChoice);
+                break;
+            // TODO: Implement item choice types
         }
     }
+
+    private static void ExecuteSwitchChoice(IBattle battle, ISwitchChoice fleeChoice)
+    {
+        var user = fleeChoice.User;
+        var battleData = user.BattleData;
+        if (battleData == null)
+            return;
+        var preventSwitch = false;
+        fleeChoice.RunScriptHook(script => script.PreventSelfSwitch(fleeChoice, ref preventSwitch));
+        if (preventSwitch)
+            return;
+        foreach (var side in battle.Sides)
+        {
+            if (side.Index == battleData.SideIndex)
+                continue;
+            foreach (var pokemon in side.Pokemon.WhereNotNull())
+            {
+                pokemon.RunScriptHook(script => script.PreventOpponentSwitch(fleeChoice, ref preventSwitch));
+                if (preventSwitch)
+                    return;
+            }
+        }
+        user.Volatile.Clear();
+        var userSide = battle.Sides[battleData.SideIndex];
+        userSide.SwapPokemon(battleData.Position, fleeChoice.SwitchTo);
+    }
+
+
+    private static void ExecuteFleeChoice(IBattle battle, IFleeChoice fleeChoice)
+    {
+        var user = fleeChoice.User;
+        var battleData = user.BattleData;
+        if (battleData == null)
+            return;
+        if (!battle.CanFlee)
+            return;
+        
+        var preventFlee = false;
+        fleeChoice.RunScriptHook(script => script.PreventSelfRunAway(fleeChoice, ref preventFlee));
+        if (preventFlee)
+            return;
+
+        foreach (var side in battle.Sides)
+        {
+            if (side.Index == battleData.SideIndex)
+                continue;
+            foreach (var pokemon in side.Pokemon.WhereNotNull())
+            {
+                pokemon.RunScriptHook(script => script.PreventOpponentRunAway(fleeChoice, ref preventFlee));
+                if (preventFlee)
+                    return;
+            }
+        }
+        
+        if (!battle.Library.MiscLibrary.CanFlee(battle, fleeChoice))
+            return;
+        
+        var userSide = battle.Sides[battleData.SideIndex];
+        userSide.MarkAsFled();
+        battle.ValidateBattleState();
+    }
+
 }

PkmnLib.Dynamic/Models/BattleSide.cs

@@ -111,6 +111,16 @@ public interface IBattleSide : IScriptSource, IDeepCloneable
     /// </summary>
     bool IsDefeated();
     
+    /// <summary>
+    /// The number of times this side has attempted to flee.
+    /// </summary>
+    uint FleeAttempts { get; }
+    
+    /// <summary>
+    /// Registers a flee attempt for this side.
+    /// </summary>
+    void RegisterFleeAttempt();
+
     /// <summary>
     /// Mark the side as fled.
     /// </summary>
@@ -267,6 +277,15 @@ public class BattleSideImpl : ScriptSource, IBattleSide
         return _fillablePositions.All(fillable => !fillable);
     }
 
+    /// <inheritdoc />
+    public uint FleeAttempts { get; private set; }
+
+    /// <inheritdoc />
+    public void RegisterFleeAttempt()
+    {
+        FleeAttempts++;
+    }
+
     /// <inheritdoc />
     public void MarkAsFled() => HasFledBattle = true;
 

PkmnLib.Dynamic/Models/Choices/SwitchChoice.cs

@@ -7,7 +7,10 @@ namespace PkmnLib.Dynamic.Models.Choices;
 /// </summary>
 public interface ISwitchChoice : ITurnChoice
 {
-    
+    /// <summary>
+    /// The Pokémon to switch to.
+    /// </summary>
+    IPokemon SwitchTo { get; }
 }
 
 /// <inheritdoc cref="ISwitchChoice"/>
@@ -18,6 +21,7 @@ public class SwitchChoice : TurnChoice, ISwitchChoice
         SwitchTo = switchTo;
     }
 
+    /// <inheritdoc />
     public IPokemon SwitchTo { get; }
 
     /// <inheritdoc />

Plugins/PkmnLib.Plugin.Gen7/Libraries/Gen7MiscLibrary.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 using PkmnLib.Dynamic;
 using PkmnLib.Dynamic.Libraries;
 using PkmnLib.Dynamic.Models;
@@ -35,4 +36,31 @@ public class Gen7MiscLibrary : IMiscLibrary
             _ => TimeOfDay.Night,
         };
     }
+
+    /// <inheritdoc />
+    public bool CanFlee(IBattle battle, IFleeChoice fleeChoice)
+    {
+        var user = fleeChoice.User;
+        var battleData = user.BattleData;
+        if (battleData == null)
+            return false;
+        var opponentSide = battle.Sides[battleData.SideIndex == 0 ? 1 : 0];
+        var opponent = opponentSide.Pokemon.FirstOrDefault(x => x is not null);
+        if (opponent == null)
+            return true;
+        
+        var userSpeed = user.FlatStats.Speed;
+        var opponentSpeed = opponent.FlatStats.Speed;
+        // If the player's active Pokémon's Speed is greater than or equal to the wild Pokémon's Speed, fleeing will
+        // always succeed
+        if (userSpeed >= opponentSpeed)
+            return true;
+        
+        var userSide = battle.Sides[battleData.SideIndex];
+        
+        userSide.RegisterFleeAttempt();
+        var fleeChance = ((userSpeed * 32) / (opponentSpeed / 4) + (30 * userSide.FleeAttempts)) / 256;
+        var random = battle.Random.GetInt(0, 100);
+        return random < fleeChance;
+    }
 }