feat: event on usable activating effects

EXILED/Exiled.Events/EventArgs/Player/ConsumableActivatingEffectsEventArgs.cs

@@ -0,0 +1,46 @@
+// -----------------------------------------------------------------------
+// <copyright file="ConsumableActivatingEffectsEventArgs.cs" company="ExMod Team">
+// Copyright (c) ExMod Team. All rights reserved.
+// Licensed under the CC BY-SA 3.0 license.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Exiled.Events.EventArgs.Player
+{
+    using Exiled.API.Features.Items;
+    using Exiled.Events.EventArgs.Interfaces;
+
+    using BaseConsumable = InventorySystem.Items.Usables.Consumable;
+
+    /// <summary>
+    /// Interesting.
+    /// </summary>
+    public class ConsumableActivatingEffectsEventArgs : IPlayerEvent, IDeniableEvent
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ConsumableActivatingEffectsEventArgs"/> class.
+        /// </summary>
+        /// <param name="referenceHub"><inheritdoc cref="ReferenceHub"/></param>
+        /// <param name="consumable"><inheritdoc cref="BaseConsumable" /></param>
+        /// <param name="isAllowed"><inheritdoc cref="bool" /></param>
+        public ConsumableActivatingEffectsEventArgs(ReferenceHub referenceHub, BaseConsumable consumable, bool isAllowed = true)
+        {
+            Player = API.Features.Player.Get(referenceHub);
+            IsAllowed = isAllowed;
+            Consumable = (Consumable)Item.Get(consumable);
+        }
+
+        /// <summary>
+        /// Gets the player that consumed the <see cref="Consumable"/>.
+        /// </summary>
+        public API.Features.Player Player { get; }
+
+        /// <inheritdoc />
+        public bool IsAllowed { get; set; }
+
+        /// <summary>
+        /// Gets the <see cref="API.Features.Items.Consumable"/> that was consumed.
+        /// </summary>
+        public Consumable Consumable { get; }
+    }
+}

EXILED/Exiled.Events/Handlers/Player.cs

@@ -651,6 +651,11 @@ public class Player
         /// </summary>
         public static Event<Scp1576TransmissionEndedEventArgs> Scp1576TransmissionEnded { get; set; } = new();
 
+        /// <summary>
+        /// Invoked before <see cref="API.Features.Player"/>'s consumable activates effects.
+        /// </summary>
+        public static Event<ConsumableActivatingEffectsEventArgs> ConsumableActivatingEffects { get; set; } = new();
+
         /// <summary>
         /// Called before a player's emotion changed.
         /// </summary>
@@ -1434,5 +1439,11 @@ public static void OnItemRemoved(ReferenceHub referenceHub, InventorySystem.Item
         /// </summary>
         /// <param name="ev">The <see cref="Scp1576TransmissionEndedEventArgs"/> instance.</param>
         public static void OnScp1576TransmissionEnded(Scp1576TransmissionEndedEventArgs ev) => Scp1576TransmissionEnded.InvokeSafely(ev);
+
+        /// <summary>
+        /// Called before <see cref="API.Features.Player"/>'s consumable activates its effects.
+        /// </summary>
+        /// <param name="ev">The <see cref="ConsumableActivatingEffectsEventArgs"/> instance.</param>
+        public static void OnConsumableActivatingEffects(ConsumableActivatingEffectsEventArgs ev) => ConsumableActivatingEffects.InvokeSafely(ev);
     }
 }

EXILED/Exiled.Events/Patches/Events/Player/ConsumableActivatingEffects.cs

@@ -0,0 +1,76 @@
+// -----------------------------------------------------------------------
+// <copyright file="ConsumableActivatingEffects.cs" company="ExMod Team">
+// Copyright (c) ExMod Team. All rights reserved.
+// Licensed under the CC BY-SA 3.0 license.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Exiled.Events.Patches.Events.Player
+{
+    using System.Collections.Generic;
+    using System.Reflection.Emit;
+
+    using Exiled.API.Features.Pools;
+    using Exiled.Events.Attributes;
+    using Exiled.Events.EventArgs.Player;
+    using HarmonyLib;
+    using InventorySystem.Items.Usables;
+
+    using static HarmonyLib.AccessTools;
+
+    /// <summary>
+    /// Patches <see cref="Consumable.ActivateEffects"/> and adds <see cref="Handlers.Player.ConsumableActivatingEffects"/> event.
+    /// </summary>
+    [HarmonyPatch(typeof(Consumable), nameof(Consumable.ActivateEffects))]
+    [EventPatch(typeof(Handlers.Player), nameof(Handlers.Player.ConsumableActivatingEffects))]
+    internal static class ConsumableActivatingEffects
+    {
+        private static IEnumerable<CodeInstruction> Transpiler(IEnumerable<CodeInstruction> instructions, ILGenerator generator)
+        {
+            List<CodeInstruction> newInstructions = ListPool<CodeInstruction>.Pool.Get(instructions);
+
+            Label continueLabel = generator.DefineLabel();
+
+            int secondOffset = 1;
+            int secondIndex = newInstructions.FindIndex(i => i.opcode == OpCodes.Ldarg_0) + secondOffset;
+
+            int firstOffset = -1;
+            int firstIndex = newInstructions.FindIndex(i => i.opcode == OpCodes.Callvirt) + firstOffset;
+            newInstructions[firstIndex].WithLabels(continueLabel);
+            newInstructions.InsertRange(firstIndex, new List<CodeInstruction>()
+            {
+                new(OpCodes.Ldarg_0),
+            });
+
+            newInstructions.InsertRange(secondIndex, new List<CodeInstruction>()
+            {
+                // this.Owner
+                new(OpCodes.Callvirt, PropertyGetter(typeof(Consumable), nameof(Consumable.Owner))),
+
+                // this
+                new(OpCodes.Ldarg_0),
+
+                // true
+                new(OpCodes.Ldc_I4_1),
+
+                // ConsumableActivatingEffectsEventArgs ev = new(this.Owner, this, true)
+                new(OpCodes.Newobj, GetDeclaredConstructors(typeof(ConsumableActivatingEffectsEventArgs))[0]),
+                new(OpCodes.Dup),
+
+                // OnConsumableActivatingEffects(ev)
+                new(OpCodes.Call, Method(typeof(Handlers.Player), nameof(Handlers.Player.OnConsumableActivatingEffects))),
+
+                // if (!ev.IsAllowed)
+                //      return;
+                new(OpCodes.Callvirt, PropertyGetter(typeof(ConsumableActivatingEffectsEventArgs), nameof(ConsumableActivatingEffectsEventArgs.IsAllowed))),
+                new(OpCodes.Brtrue_S, continueLabel),
+                new(OpCodes.Ret),
+            });
+
+            for (int z = 0; z < newInstructions.Count; z++)
+                yield return newInstructions[z];
+
+            ListPool<CodeInstruction>.Pool.Return(newInstructions);
+        }
+    }
+}