Add inventory frontend support for Killing Floor

System

@@ -0,0 +1,118 @@
+[Editor.EditorEngine]
+EditPackages=Core
+EditPackages=Engine
+EditPackages=Fire
+EditPackages=Editor
+EditPackages=UnrealEd
+EditPackages=IpDrv
+EditPackages=UWeb
+EditPackages=GamePlay
+EditPackages=UnrealGame
+EditPackages=XGame
+EditPackages=XInterface
+EditPackages=XAdmin
+EditPackages=XWebAdmin
+EditPackages=GUI2K4
+EditPackages=xVoting
+EditPackages=UTV2004c
+EditPackages=UTV2004s
+EditPackages=ROEffects
+EditPackages=ROEngine
+EditPackages=ROInterface
+EditPackages=Old2k4
+EditPackages=KFMod
+EditPackages=KFChar
+EditPackages=KFGui
+EditPackages=GoodKarma
+EditPackages=KFMutators
+EditPackages=KFStoryGame
+EditPackages=KFStoryUI
+EditPackages=SideShowScript
+EditPackages=FrightScript
+CutdownPackages=Core
+CutdownPackages=Editor
+CutdownPackages=Engine
+CutdownPackages=Fire
+CutdownPackages=GamePlay
+CutdownPackages=GUI2K4
+CutdownPackages=IpDrv
+CutdownPackages=Onslaught
+CutdownPackages=UnrealEd
+CutdownPackages=UnrealGame
+CutdownPackages=UWeb
+CutdownPackages=XAdmin
+CutdownPackages=XEffects
+CutdownPackages=XInterface
+CutdownPackages=XPickups
+CutdownPackages=XWebAdmin
+CutdownPackages=XVoting
+
+
+[Engine.Engine]
+RenderDevice=D3D9Drv.D3D9RenderDevice
+AudioDevice=ALAudio.ALAudioSubsystem
+NetworkDevice=IpDrv.TcpNetDriver
+DemoRecordingDevice=Engine.DemoRecDriver
+Console=KFMod.KFConsole
+GUIController=KFGUI.KFGUIController
+StreamPlayer=Engine.StreamInteraction
+Language=int
+Product=KillingFloor
+GameEngine=Engine.GameEngine
+EditorEngine=Editor.EditorEngine
+DefaultGame=KFMod.KFGameType
+DefaultServerGame=KFMod.KFGameType
+ViewportManager=WinDrv.WindowsClient
+Render=Render.Render
+Input=Engine.Input
+Canvas=Engine.Canvas
+DetectedVideoMemory=0
+ServerReadsStdin=False
+
+
+[Core.System]
+PurgeCacheDays=30
+SavePath=..\Save
+CachePath=../Cache
+CacheExt=.uxx
+CacheRecordPath=../System/*.ucl
+MusicPath=../Music
+SpeechPath=../Speech
+Paths=../System/*.u
+Paths=../Maps/*.rom
+Paths=../TestMaps/*.rom
+Paths=../Textures/*.utx
+Paths=../Sounds/*.uax
+Paths=../Music/*.umx
+Paths=../StaticMeshes/*.usx
+Paths=../Animations/*.ukx
+Paths=../Saves/*.uvx
+Paths=../Textures/Old2k4/*.utx
+Paths=../Sounds/Old2k4/*.uax../Music/Old2k4/*.umx
+Paths=../StaticMeshes/Old2k4/*.usx
+Paths=../Animations/Old2k4/*.ukx
+Paths=../KarmaData/Old2k4/*.ka
+Suppress=DevLoad
+Suppress=DevSave
+Suppress=DevNetTraffic
+Suppress=DevGarbage
+Suppress=DevKill
+Suppress=DevReplace
+Suppress=DevCompile
+Suppress=DevBind
+Suppress=DevBsp
+Suppress=DevNet
+Suppress=DevLIPSinc
+Suppress=DevKarma
+Suppress=RecordCache
+Suppress=MapVoteDebug
+Suppress=Init
+Suppress=MapVote
+Suppress=VoiceChat
+Suppress=ChatManager
+Suppress=Time
+
+
+[ROFirstRun]
+ROFirstRun=1094
+

config/AcediaSystem_KF1Frontend.ini

@@ -0,0 +1,12 @@
+;   Every single option in this config should be considered [ADVANCED]
+[AcediaCore.KFDualiesTool]
+;   This array defines what weapons Acedia's Killing Floor frontend considers as
+; pairs of single - dual versions.
+;   If you are adding some custom dual weapons to your server, then they should
+; also be added here until a better way is implemented.
+dualiesClasses=(single=class'KFMod.SinglePickup',dual=class'KFMod.DualiesPickup')
+dualiesClasses=(single=class'KFMod.Magnum44Pickup',dual=class'KFMod.Dual44MagnumPickup')
+dualiesClasses=(single=class'KFMod.MK23Pickup',dual=class'KFMod.DualMK23Pickup')
+dualiesClasses=(single=class'KFMod.DeaglePickup',dual=class'KFMod.DualDeaglePickup')
+dualiesClasses=(single=class'KFMod.GoldenDeaglePickup',dual=class'KFMod.GoldenDualDeaglePickup')
+dualiesClasses=(single=class'KFMod.FlareRevolverPickup',dual=class'KFMod.DualFlareRevolverPickup')

sources/Gameplay/BaseClasses/Frontend/BaseFrontend.uc

@@ -21,6 +21,23 @@
  class BaseFrontend extends AcediaObject
     abstract;
 
+var private config class<ATemplatesComponent>   templatesClass;
+var public ATemplatesComponent                  templates;
+
+protected function Constructor()
+{
+    if (templatesClass != none) {
+        templates = ATemplatesComponent(_.memory.Allocate(templatesClass));
+    }
+}
+
+protected function Finalizer()
+{
+    _.memory.Free(templates);
+    templates = none;
+}
+
 defaultproperties
 {
+    templatesClass = none
 }

sources/Gameplay/BaseClasses/Frontend/EInterface.uc

@@ -8,7 +8,7 @@
  *  once (including those of the same type). Deallocating one such reference
  *  should not affect referred entity in any way and should be treated as simply
  *  getting rid of one of the references.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021 - 2022 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -42,6 +42,20 @@ public function EInterface Copy()
     return none;
 }
 
+/**
+ *  Checks if entity, referred to by the caller `EInterface` supports
+ *  `newInterfaceClass` interface class.
+ *
+ *  @param  newInterfaceClass   Class of the `EInterface`, for which method
+ *      should check support by entity, referred to by the caller `EInterface`.
+ *  @return `true` if referred entity supports `newInterfaceClass` and
+ *      `false` otherwise.
+ */
+public function bool Supports(class<EInterface> newInterfaceClass)
+{
+    return false;
+}
+
 /**
  *  Provides `EInterface` reference of given class `newInterfaceClass` to
  *  the entity, referred to by the caller `EInterface` (if supported).

sources/Gameplay/BaseClasses/Frontend/Templates/ATemplatesComponent.uc

@@ -0,0 +1,82 @@
+/**
+ *  Subset of functionality for dealing with everything related to templates.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class ATemplatesComponent extends AcediaObject
+    abstract;
+
+/**
+ *  Returns `true` if list of items named `listName` exists and
+ *  `false` otherwise.
+ *
+ *  This method is necessary, since `GetItemList()` does not allow to
+ *  distinguish between empty and non-existing item list.
+ *
+ *  @param  listName    Name of the list to check for whether it exists.
+ *  @return `true` if list named `listName` exists and `false` otherwise.
+ *      Always returns `false` if `listName` equals `none`.
+ */
+public function bool ItemListExists(Text listName)
+{
+    return false;
+}
+
+/**
+ *  Returns array with templates of items belonging to the `listName` list.
+ *
+ *  All implementations must support:
+ *      1. "all weapons" / "weapons" (both names
+ *          should refer to the same list) list with templates of all weapons in
+ *          the game;
+ *      2. "trading weapons" list with names of all weapons available for trade
+ *          in one way or another (even if they are not all tradable in
+ *          all shops / for all players).
+ *
+ *  @param  listName    Name of the list to return templates for.
+ *      In case a name of inexistent list is specified - method does nothing.
+ *  @return Array of templates in the list, specified with `listName`.
+ *      All of the `Text`s in the returned array are guaranteed to be `none`.
+ *      When incorrect `listName` is specified - empty array is returned
+ *      (which can also happen if specified list is empty).
+ */
+public function array<Text> GetItemList(Text listName)
+{
+    local array<Text> emptyArray;
+    return emptyArray;
+}
+
+/**
+ *  Returns array that is listing all available lists of item templates.
+ *
+ *  All implementations must include "all weapons" and "trading weapons" lists.
+ *
+ *  @return Array with names of all available lists.
+ *      All of the `Text`s in the returned array are guaranteed to be `none`.
+ *      If a certain list has several names (like "all weapons" / "weapons"),
+ *      only one of these names (guaranteed to always be the same between calls)
+ *      will be included.
+ */
+public function array<Text> GetAvailableLists()
+{
+    local array<Text> emptyArray;
+    return emptyArray;
+}
+
+defaultproperties
+{
+}

sources/Gameplay/BaseClasses/KillingFloor/Frontend/KFFrontend.uc

@@ -25,6 +25,7 @@ var public ATradingComponent                trading;
 
 protected function Constructor()
 {
+    super.Constructor();
     if (tradingClass != none) {
         trading = ATradingComponent(_.memory.Allocate(tradingClass));
     }

sources/Gameplay/KF1Frontend/BaseImplementation/EKFAmmo.uc

@@ -0,0 +1,464 @@
+/**
+ *  Implementation of `EAmmo` for classic Killing Floor weapons that changes
+ *  as little as possible and only on request from another mod, otherwise not
+ *  altering gameplay at all.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class EKFAmmo extends EAmmo;
+
+var private NativeActorRef ammunitionReference;
+
+protected function Finalizer()
+{
+    _.memory.Free(ammunitionReference);
+    ammunitionReference = none;
+}
+
+/**
+ *  Creates new `EKFAmmo` that refers to the `ammunitionInstance` ammunition.
+ *
+ *  @param  ammunitionInstance  Native ammunition instance that new `EKFAmmo`
+ *      will represent.
+ *  @return New `EKFAmmo` that represents given `ammunitionInstance`.
+ *      `none` iff `ammunitionInstance` is either `none` or
+ *      is an unused flash light ammunition
+ *      (has `class'KFMod.FlashlightAmmo'` class).
+ */
+public final static /*unreal*/ function EKFAmmo Wrap(
+    Ammunition ammunitionInstance)
+{
+    local EKFAmmo newReference;
+    if (ammunitionInstance == none)                                 return none;
+    //  This one is not actually used for anything, so it is not real
+    if (ammunitionInstance.class == class'KFMod.FlashlightAmmo')    return none;
+
+    newReference = EKFAmmo(__().memory.Allocate(class'EKFAmmo'));
+    newReference.ammunitionReference = __().unreal.ActorRef(ammunitionInstance);
+    return newReference;
+}
+
+public function EInterface Copy()
+{
+    local Ammunition ammunitionInstance;
+    ammunitionInstance = GetNativeInstance();
+    return Wrap(ammunitionInstance);
+}
+
+public function bool Supports(class<EInterface> newInterfaceClass)
+{
+    if (newInterfaceClass == none)              return false;
+    if (newInterfaceClass == class'EItem')      return true;
+    if (newInterfaceClass == class'EAmmo')      return true;
+    if (newInterfaceClass == class'EKFAmmo')    return true;
+
+    return false;
+}
+
+public function EInterface As(class<EInterface> newInterfaceClass)
+{
+    if (!IsExistent()) {
+        return none;
+    }
+    if (    newInterfaceClass == class'EItem'
+        ||  newInterfaceClass == class'EAmmo'
+        ||  newInterfaceClass == class'EKFAmmo')
+    {
+        return Copy();
+    }
+    return none;
+}
+
+public function bool IsExistent()
+{
+    return (GetNativeInstance() != none);
+}
+
+public function bool SameAs(EInterface other)
+{
+    local EKFAmmo otherAmmo;
+    otherAmmo = EKFAmmo(other);
+    if (otherAmmo == none) {
+        return false;
+    }
+    return (GetNativeInstance() == otherAmmo.GetNativeInstance());
+}
+
+/**
+ *  Returns `Ammunition` instance represented by the caller `EKFAmmo`.
+ *
+ *  @return `Ammunition` instance represented by the caller `EKFAmmo`.
+ */
+public final /*unreal*/ function Ammunition GetNativeInstance()
+{
+    if (ammunitionReference != none) {
+        return Ammunition(ammunitionReference.Get());
+    }
+    return none;
+}
+
+public function array<Text> GetTags()
+{
+    local array<Text> tagArray;
+    if (ammunitionReference == none)        return tagArray;
+    if (ammunitionReference.Get() == none)  return tagArray;
+
+    tagArray[0] = P("ammo").Copy();
+    return tagArray;
+}
+
+public function bool HasTag(Text tagToCheck)
+{
+    if (tagToCheck == none)             return false;
+    if (tagToCheck.Compare(P("ammo")))  return true;
+
+    return false;
+}
+
+public function Text GetTemplate()
+{
+    local Ammunition ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) {
+        return none;
+    }
+    return _.text.FromString(string(ammunition.class));
+}
+
+public function Text GetName()
+{
+    local Ammunition ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) {
+        return none;
+    }
+    return _.text.FromString(ammunition.GetHumanReadableName());
+}
+
+public function bool IsRemovable()
+{
+    return false;
+}
+
+public function bool IsSellable()
+{
+    return false;
+}
+
+private function class<KFWeaponPickup> GetOwnerWeaponPickupClass()
+{
+    local KFWeapon      ownerWeapon;
+    local Ammunition    ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) {
+        return none;
+    }
+    ownerWeapon = GetOwnerWeapon();
+    if (ownerWeapon != none) {
+        return class<KFWeaponPickup>(ownerWeapon.pickupClass);
+    }
+    return none;
+}
+
+//      Finds a weapons that is corresponding to our ammo.
+//      We can limit ourselves to returning a single instance, since one weapon
+//  per ammo type is how Killing Floor does things.
+private function KFWeapon GetOwnerWeapon()
+{
+    local Pawn          myOwner;
+    local KFWeapon      nextWeapon;
+    local Inventory     nextInventory;
+    local Ammunition    ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) return none;
+    myOwner = Pawn(ammunition.owner);
+    if (myOwner == none)    return none;
+
+    nextInventory = myOwner.inventory;
+    while (nextInventory != none)
+    {
+        nextWeapon = KFWeapon(nextInventory);
+        nextInventory = nextInventory.inventory;
+        if (_.unreal.inventory.GetAmmoClass(nextWeapon, 0) == ammunition.class)
+        {
+            return nextWeapon;
+        }
+        else if (   _.unreal.inventory.GetAmmoClass(nextWeapon, 1)
+                ==  ammunition.class) {
+            return nextWeapon;
+        }
+    }
+    return none;
+}
+
+/**
+ *  In Killing Floor ammo object itself does not actually have a price,
+ *  instead it is defined inside weapon's `Pickup` class and, therefore,
+ *  cannot be changed for an individual item. Only calculated.
+ */
+public function bool SetPrice(int newPrice)
+{
+    return false;
+}
+
+public function int GetPrice()
+{
+    return GetPriceOf(GetAmount());
+}
+
+public function int GetTotalPrice()
+{
+    return GetPriceOf(GetTotalAmount());
+}
+
+public function int GetPriceOf(int ammoAmount)
+{
+    local Pawn                      myOwner;
+    local int                       clipSize;
+    local float                     clipPrice;
+    local KFWeapon                  ownerWeapon;
+    local KFPlayerReplicationInfo   ownerKFPRI;
+    local class<KFWeaponPickup>     ownerWeaponPickupClass;
+    local Ammunition                ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none)             return 0;
+    ownerWeapon = GetOwnerWeapon();
+    if (ownerWeapon == none)            return 0;
+    ownerWeaponPickupClass = class<KFWeaponPickup>(ownerWeapon.pickupClass);
+    if (ownerWeaponPickupClass == none) return 0;
+
+    //  Calculate clip price
+    if (    ownerWeapon.bHasSecondaryAmmo
+        &&  ammunition.class != ownerWeapon.fireModeClass[0].default.ammoClass)
+    {
+        //  Amon Killing Floor's weapons, only M4 203 has a real secondary ammo
+        clipSize = 1;
+    }
+    else {
+        clipSize = ownerWeapon.default.magCapacity;
+    }
+    if( ownerWeapon.PickupClass == class'HuskGunPickup' ) {
+        clipSize = ownerWeaponPickupClass.default.buyClipSize;
+    }
+    clipPrice = ownerWeaponPickupClass.default.ammoCost;
+    //  Calculate clip size
+    myOwner = Pawn(ammunition.owner);
+    if (myOwner != none) {
+        ownerKFPRI = KFPlayerReplicationInfo(myOwner.playerReplicationInfo);
+    }
+    if (ownerKFPRI != none)
+    {
+        clipPrice *= ownerKFPRI.clientVeteranSkill.static
+            .GetAmmoCostScaling(ownerKFPRI, ownerWeaponPickupClass);
+    }
+    //  Calculate price of total ammo
+    return int(ammoAmount * clipPrice / clipSize);
+}
+
+public function bool SetWeight(int newWeight)
+{
+    return false;
+}
+
+public function int GetWeight()
+{
+    return 0;
+}
+
+//      Killing Floor weapons do not reduce ammunition when it is loaded it into
+//  the weapons. This is because each ammo type is only ever used by one weapon,
+//  so the can simply treat it as part of the weapon and only record how much
+//  of it is currently in the weapon's magazine.
+//      This method goes through inventory weapons to find how much ammo was
+//  already loaded into the weapons.
+private function int GetLoadedAmmo()
+{
+    local KFWeapon      ownerWeapon;
+    local Ammunition    ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none)                         return 0;
+    ownerWeapon = GetOwnerWeapon();
+    if (ownerWeapon == none)                        return 0;
+    //  Husk gun does not load ammo at all
+    if (ownerWeapon.class == class'KFMod.HuskGun')  return 0;
+
+    //      Most of the Killing Floor weapons do not have a proper separate
+    //  secondary ammo: they either reuse primary ammo (like zed guns or
+    //  hunting shotgun), or they use some pseudo-ammo (like medic guns).
+    //      They only exception is M4 203 that loads itself as soon as
+    //  it fires. Some modded weapons might also be exceptions and/or use
+    //  secondary ammo differently, but we have no way of knowing how
+    //  exactly they are doing it and cannot implement this interface
+    //  for them.
+    //      That is why we only bother with the first fire mode and count
+    //  one loaded ammo for the secondary, just assuming it is M4 203.
+    //      We can also quit as soon as we have found a single weapon that
+    //  uses our ammo, since one weapon per ammo type is how Killing Floor
+    //  does things.
+    if (_.unreal.inventory.GetAmmoClass(ownerWeapon, 0) == ammunition.class) {
+        return ownerWeapon.magAmmoRemaining;
+    }
+    else if (   _.unreal.inventory.GetAmmoClass(ownerWeapon, 1)
+            ==  ammunition.class)
+    {
+        return 1; // M4 203
+    }
+    return 0;
+}
+
+public function Add(int amount, optional bool forceAddition)
+{
+    local Ammunition ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) {
+        return;
+    }
+    if (forceAddition) {
+        ammunition.ammoAmount += amount;
+    }
+    else
+    {
+        ammunition.ammoAmount =
+            Min(ammunition.maxAmmo, ammunition.ammoAmount + amount);
+    }
+    //  Correct possible negative values
+    if (ammunition.ammoAmount < 0) {
+        ammunition.ammoAmount = 0;
+    }
+    ammunition.netUpdateTime = ammunition.level.timeSeconds - 1;
+}
+
+public function int GetAmount()
+{
+    local Ammunition ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) {
+        return 0;
+    }
+    return Max(0, ammunition.ammoAmount - GetLoadedAmmo());
+}
+
+public function int GetTotalAmount()
+{
+    local Ammunition ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) {
+        return 0;
+    }
+    return Max(0, ammunition.ammoAmount);
+}
+
+public function SetAmount(int amount, optional bool forceAddition)
+{
+    local Ammunition ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) {
+        return;
+    }
+    if (forceAddition) {
+        ammunition.ammoAmount = amount;
+    }
+    else {
+        ammunition.ammoAmount = Min(ammunition.maxAmmo, amount);
+    }
+    //  Correct possible negative values
+    if (ammunition.ammoAmount < 0) {
+        ammunition.ammoAmount = 0;
+    }
+    ammunition.netUpdateTime = ammunition.level.timeSeconds - 1;
+}
+
+public function int GetMaxAmount()
+{
+    local Ammunition ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) {
+        return 0;
+    }
+    //  `Ammunition` does not really support infinite ammo, so return `0` if
+    //  the value is messed up.
+    return Max(0, ammunition.maxAmmo - GetLoadedAmmo());
+}
+
+public function int GetMaxTotalAmount()
+{
+    local Ammunition ammunition;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) {
+        return 0;
+    }
+    //  `Ammunition` does not really support infinite ammo, so return `0` if
+    //  the value is messed up.
+    return Max(0, ammunition.maxAmmo);
+}
+
+/**
+ *  Supports any non-negative ammo value.
+ */
+public function bool SetMaxAmount(
+    int             newMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    local Ammunition ammunition;
+    //  We do not support unlimited ammo values
+    if (newMaxAmmo < 0)     return false;
+    ammunition = GetNativeInstance();
+    if (ammunition == none) return false;
+
+    ammunition.maxAmmo = newMaxAmmo + GetLoadedAmmo();
+    if (!leaveCurrentAmmo) {
+        ammunition.ammoAmount = Min(ammunition.maxAmmo, ammunition.ammoAmount);
+    }
+    ammunition.netUpdateTime = ammunition.level.timeSeconds - 1;
+    return true;
+}
+
+public function bool SetMaxTotalAmount(
+    int             newTotalMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    local Ammunition ammunition;
+    //  We do not support unlimited ammo values
+    if (newTotalMaxAmmo < 0)    return false;
+    ammunition = GetNativeInstance();
+    if (ammunition == none)     return false;
+
+    ammunition.maxAmmo = newTotalMaxAmmo;
+    if (!leaveCurrentAmmo) {
+        ammunition.ammoAmount = Min(ammunition.maxAmmo, ammunition.ammoAmount);
+    }
+    ammunition.netUpdateTime = ammunition.level.timeSeconds - 1;
+    return true;
+}
+
+public function bool HasWeapon()
+{
+    return (GetOwnerWeapon() != none);
+}
+
+//  Killing Floor's ammo should also count ammo already loaded into the magazine
+public function Fill()
+{
+    if (GetMaxTotalAmount() < 0)            return;
+    if (GetAmount() >= GetMaxTotalAmount()) return;
+
+    SetAmount(GetMaxTotalAmount());
+}
+
+defaultproperties
+{
+}

sources/Gameplay/KF1Frontend/BaseImplementation/EKFFlashlightAmmo.uc

@@ -0,0 +1,298 @@
+/**
+ *  Implementation of `EAmmo` for Killing Floor's flashlight charge that changes
+ *  as little as possible and only on request from another mod, otherwise not
+ *  altering gameplay at all.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class EKFFlashlightAmmo extends EAmmo;
+
+var private NativeActorRef pawnReference;
+
+protected function Finalizer()
+{
+    _.memory.Free(pawnReference);
+    pawnReference = none;
+}
+
+/**
+ *  Creates new `EKFFlashlightAmmo` that refers to the `medicWeaponInstance`'s
+ *  medic ammunition.
+ *
+ *  @param  kfHumanPawn Pawn class with flashlight ammo.
+ *      In Killing Floor, "flashlight ammo" is basically just a variable
+ *      inside `KFHumanPawn` instance.
+ *  @return New `EKFFlashlightAmmo` that represents medic ammunition of given
+ *      `kfHumanPawn`. `none` iff `kfHumanPawn` is `none`.
+ */
+public final static /*unreal*/ function EKFFlashlightAmmo Wrap(
+    KFHumanPawn kfHumanPawn)
+{
+    local EKFFlashlightAmmo newReference;
+    if (kfHumanPawn == none) {
+        return none;
+    }
+    newReference =
+        EKFFlashlightAmmo(__().memory.Allocate(class'EKFFlashlightAmmo'));
+    newReference.pawnReference = __().unreal.ActorRef(kfHumanPawn);
+    return newReference;
+}
+
+public function EInterface Copy()
+{
+    local KFHumanPawn pawnInstance;
+    pawnInstance = GetNativeInstance();
+    return Wrap(pawnInstance);
+}
+
+public function bool Supports(class<EInterface> newInterfaceClass)
+{
+    if (newInterfaceClass == none)                      return false;
+    if (newInterfaceClass == class'EItem')              return true;
+    if (newInterfaceClass == class'EAmmo')              return true;
+    if (newInterfaceClass == class'EKFFlashlightAmmo')  return true;
+
+    return false;
+}
+
+public function EInterface As(class<EInterface> newInterfaceClass)
+{
+    if (!IsExistent()) {
+        return none;
+    }
+    if (    newInterfaceClass == class'EItem'
+        ||  newInterfaceClass == class'EAmmo'
+        ||  newInterfaceClass == class'EKFFlashlightAmmo')
+    {
+        return Copy();
+    }
+    return none;
+}
+
+public function bool IsExistent()
+{
+    return (GetNativeInstance() != none);
+}
+
+public function bool SameAs(EInterface other)
+{
+    local EKFFlashlightAmmo otherAmmo;
+    otherAmmo = EKFFlashlightAmmo(other);
+    if (otherAmmo == none) {
+        return false;
+    }
+    return (GetNativeInstance() == otherAmmo.GetNativeInstance());
+}
+
+/**
+ *  Returns `KFAmmunition` instance represented by the caller `EKFAmmo`.
+ *
+ *  @return `KFAmmunition` instance represented by the caller `EKFAmmo`.
+ */
+public final /*unreal*/ function KFHumanPawn GetNativeInstance()
+{
+    if (pawnReference != none) {
+        return KFHumanPawn(pawnReference.Get());
+    }
+    return none;
+}
+
+public function array<Text> GetTags()
+{
+    local array<Text> tagArray;
+    if (pawnReference == none)       return tagArray;
+    if (pawnReference.Get() == none) return tagArray;
+
+    tagArray[0] = P("ammo").Copy();
+    return tagArray;
+}
+
+public function bool HasTag(Text tagToCheck)
+{
+    if (tagToCheck == none)             return false;
+    if (tagToCheck.Compare(P("ammo")))  return true;
+
+    return false;
+}
+
+public function Text GetTemplate()
+{
+    if (IsExistent()) {
+        return P("flashlight:ammo").Copy();
+    }
+    return none;
+}
+
+public function Text GetName()
+{
+    if (IsExistent()) {
+        return P("Flashlight's ammo").Copy();
+    }
+    return none;
+}
+
+public function bool IsRemovable()
+{
+    return false;
+}
+
+public function bool IsSellable()
+{
+    return false;
+}
+
+/**
+ *  Medic ammo is free and does not have a price in Killing Floor.
+ */
+public function bool SetPrice(int newPrice)
+{
+    return false;
+}
+
+public function int GetPrice()
+{
+    return 0;
+}
+
+public function int GetTotalPrice()
+{
+    return 0;
+}
+
+public function int GetPriceOf(int ammoAmount)
+{
+    return 0;
+}
+
+public function bool SetWeight(int newWeight)
+{
+    return false;
+}
+
+public function int GetWeight()
+{
+    return 0;
+}
+
+public function Add(int amount, optional bool forceAddition)
+{
+    local KFHumanPawn kfHumanPawn;
+    kfHumanPawn = GetNativeInstance();
+    if (kfHumanPawn == none) {
+        return;
+    }
+    if (forceAddition) {
+        kfHumanPawn.torchBatteryLife += amount;
+    }
+    else
+    {
+        kfHumanPawn.torchBatteryLife =
+            Min(    kfHumanPawn.default.torchBatteryLife,
+                    kfHumanPawn.torchBatteryLife + amount);
+    }
+    //  Correct possible negative values
+    if (kfHumanPawn.torchBatteryLife < 0) {
+        kfHumanPawn.torchBatteryLife = 0;
+    }
+}
+
+public function int GetAmount()
+{
+    local KFHumanPawn kfHumanPawn;
+    kfHumanPawn = GetNativeInstance();
+    if (kfHumanPawn == none) {
+        return 0;
+    }
+    return Max(0, kfHumanPawn.torchBatteryLife);
+}
+
+public function int GetTotalAmount()
+{
+    return GetAmount();
+}
+
+public function SetAmount(int amount, optional bool forceAddition)
+{
+    local KFHumanPawn kfHumanPawn;
+    kfHumanPawn = GetNativeInstance();
+    if (kfHumanPawn == none) {
+        return;
+    }
+    if (forceAddition) {
+        kfHumanPawn.torchBatteryLife = amount;
+    }
+    else
+    {
+        kfHumanPawn.torchBatteryLife =
+            Min(kfHumanPawn.default.torchBatteryLife, amount);
+    }
+    //  Correct possible negative values
+    if (kfHumanPawn.torchBatteryLife < 0) {
+        kfHumanPawn.torchBatteryLife = 0;
+    }
+}
+
+public function int GetMaxAmount()
+{
+    local KFHumanPawn kfHumanPawn;
+    kfHumanPawn = GetNativeInstance();
+    if (kfHumanPawn == none) {
+        return 0;
+    }
+    return Max(0, kfHumanPawn.default.torchBatteryLife);
+}
+
+public function int GetMaxTotalAmount()
+{
+    return GetMaxAmount();
+}
+
+public function bool SetMaxAmount(
+    int             newMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    local KFHumanPawn kfHumanPawn;
+    //  We do not support unlimited ammo values
+    if (newMaxAmmo < 0)         return false;
+    kfHumanPawn = GetNativeInstance();
+    if (kfHumanPawn == none)    return false;
+
+    kfHumanPawn.default.torchBatteryLife = newMaxAmmo;
+    if (!leaveCurrentAmmo)
+    {
+        kfHumanPawn.torchBatteryLife =
+            Min(    kfHumanPawn.default.torchBatteryLife,
+                    kfHumanPawn.torchBatteryLife);
+    }
+    return true;
+}
+
+public function bool SetMaxTotalAmount(
+    int             newTotalMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    return SetMaxAmount(newTotalMaxAmmo, leaveCurrentAmmo);
+}
+
+public function bool HasWeapon()
+{
+    return (GetNativeInstance() != none);
+}
+
+defaultproperties
+{
+}

sources/Gameplay/KF1Frontend/BaseImplementation/EKFItemTemplateInfo.uc

@@ -1,5 +1,5 @@
 /**
- *  Implementation of `EKFItemTemplateInfo` for classic Killing Floor items that
+ *  Implementation of `EItemTemplateInfo` for classic Killing Floor items that
  *  changes as little as possible and only on request from another mod,
  *  otherwise not altering gameplay at all.
  *      Copyright 2021 - 2022 Anton Tarasenko

sources/Gameplay/KF1Frontend/BaseImplementation/EKFMedicAmmo.uc

@@ -0,0 +1,285 @@
+/**
+ *  Implementation of `EAmmo` for Killing Floor medic weapons that changes
+ *  as little as possible and only on request from another mod, otherwise not
+ *  altering gameplay at all.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class EKFMedicAmmo extends EAmmo;
+
+var private NativeActorRef medicWeaponReference;
+
+protected function Finalizer()
+{
+    _.memory.Free(medicWeaponReference);
+    medicWeaponReference = none;
+}
+
+/**
+ *  Creates new `EKFMedicAmmo` that refers to the `medicWeaponInstance`'s
+ *  medic ammunition.
+ *
+ *  @param  medicWeaponInstance Native medic gun, whose medic ammunition
+ *      new `EKFMedicAmmo` will represent.
+ *  @return New `EKFMedicAmmo` that represents medic ammunition of given
+ *      `medicWeaponInstance`. `none` iff `medicWeaponInstance` is `none`.
+ */
+public final static /*unreal*/ function EKFMedicAmmo Wrap(
+    KFMedicGun medicWeaponInstance)
+{
+    local EKFMedicAmmo newReference;
+    if (medicWeaponInstance == none) {
+        return none;
+    }
+    newReference = EKFMedicAmmo(__().memory.Allocate(class'EKFMedicAmmo'));
+    newReference.medicWeaponReference =
+        __().unreal.ActorRef(medicWeaponInstance);
+    return newReference;
+}
+
+public function EInterface Copy()
+{
+    local KFMedicGun medicWeaponInstance;
+    medicWeaponInstance = GetNativeInstance();
+    return Wrap(medicWeaponInstance);
+}
+
+public function bool Supports(class<EInterface> newInterfaceClass)
+{
+    if (newInterfaceClass == none)                  return false;
+    if (newInterfaceClass == class'EItem')          return true;
+    if (newInterfaceClass == class'EAmmo')          return true;
+    if (newInterfaceClass == class'EKFMedicAmmo')   return true;
+
+    return false;
+}
+
+public function EInterface As(class<EInterface> newInterfaceClass)
+{
+    if (!IsExistent()) {
+        return none;
+    }
+    if (    newInterfaceClass == class'EItem'
+        ||  newInterfaceClass == class'EAmmo'
+        ||  newInterfaceClass == class'EKFMedicAmmo')
+    {
+        return Copy();
+    }
+    return none;
+}
+
+public function bool IsExistent()
+{
+    return (GetNativeInstance() != none);
+}
+
+public function bool SameAs(EInterface other)
+{
+    local EKFMedicAmmo otherAmmo;
+    otherAmmo = EKFMedicAmmo(other);
+    if (otherAmmo == none) {
+        return false;
+    }
+    return (GetNativeInstance() == otherAmmo.GetNativeInstance());
+}
+
+/**
+ *  Returns `KFAmmunition` instance represented by the caller `EKFAmmo`.
+ *
+ *  @return `KFAmmunition` instance represented by the caller `EKFAmmo`.
+ */
+public final /*unreal*/ function KFMedicGun GetNativeInstance()
+{
+    if (medicWeaponReference != none) {
+        return KFMedicGun(medicWeaponReference.Get());
+    }
+    return none;
+}
+
+public function array<Text> GetTags()
+{
+    local array<Text> tagArray;
+    if (medicWeaponReference == none)       return tagArray;
+    if (medicWeaponReference.Get() == none) return tagArray;
+
+    tagArray[0] = P("ammo").Copy();
+    return tagArray;
+}
+
+public function bool HasTag(Text tagToCheck)
+{
+    if (tagToCheck == none)             return false;
+    if (tagToCheck.Compare(P("ammo")))  return true;
+
+    return false;
+}
+
+public function Text GetTemplate()
+{
+    local KFMedicGun medicWeapon;
+    medicWeapon = GetNativeInstance();
+    if (medicWeapon == none) {
+        return none;
+    }
+    return _.text.FromString(string(medicWeapon.class) $ ":ammo");
+}
+
+public function Text GetName()
+{
+    local KFMedicGun medicWeapon;
+    medicWeapon = GetNativeInstance();
+    if (medicWeapon == none) {
+        return none;
+    }
+    return _.text.FromString(medicWeapon.GetHumanReadableName() $ "'s ammo");
+}
+
+public function bool IsRemovable()
+{
+    return false;
+}
+
+public function bool IsSellable()
+{
+    return false;
+}
+
+/**
+ *  Medic ammo is free and does not have a price in Killing Floor.
+ */
+public function bool SetPrice(int newPrice)
+{
+    return false;
+}
+
+public function int GetPrice()
+{
+    return 0;
+}
+
+public function int GetTotalPrice()
+{
+    return 0;
+}
+
+public function int GetPriceOf(int ammoAmount)
+{
+    return 0;
+}
+
+public function bool SetWeight(int newWeight)
+{
+    return false;
+}
+
+public function int GetWeight()
+{
+    return 0;
+}
+
+public function Add(int amount, optional bool forceAddition)
+{
+    local KFMedicGun medicWeapon;
+    medicWeapon = GetNativeInstance();
+    if (medicWeapon == none) {
+        return;
+    }
+    if (forceAddition) {
+        medicWeapon.healAmmoCharge += amount;
+    }
+    else
+    {
+        medicWeapon.healAmmoCharge =
+            Min(medicWeapon.maxAmmoCount, medicWeapon.healAmmoCharge + amount);
+    }
+    //  Correct possible negative values
+    if (medicWeapon.healAmmoCharge < 0) {
+        medicWeapon.healAmmoCharge = 0;
+    }
+}
+
+public function int GetAmount()
+{
+    local KFMedicGun medicWeapon;
+    medicWeapon = GetNativeInstance();
+    if (medicWeapon == none) {
+        return 0;
+    }
+    return Max(0, medicWeapon.healAmmoCharge);
+}
+
+public function int GetTotalAmount()
+{
+    return GetAmount();
+}
+
+public function SetAmount(int amount, optional bool forceAddition)
+{
+    local KFMedicGun medicWeapon;
+    medicWeapon = GetNativeInstance();
+    if (medicWeapon == none) {
+        return;
+    }
+    if (forceAddition) {
+        medicWeapon.healAmmoCharge = amount;
+    }
+    else {
+        medicWeapon.healAmmoCharge = Min(medicWeapon.maxAmmoCount, amount);
+    }
+    //  Correct possible negative values
+    if (medicWeapon.healAmmoCharge < 0) {
+        medicWeapon.healAmmoCharge = 0;
+    }
+}
+
+public function int GetMaxAmount()
+{
+    local KFMedicGun medicWeapon;
+    medicWeapon = GetNativeInstance();
+    if (medicWeapon == none) {
+        return 0;
+    }
+    return Max(0, medicWeapon.maxAmmoCount);
+}
+
+public function int GetMaxTotalAmount()
+{
+    return GetMaxAmount();
+}
+
+public function bool SetMaxAmount(
+    int             newMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    return false;
+}
+
+public function bool SetMaxTotalAmount(
+    int             newTotalMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    return false;
+}
+
+public function bool HasWeapon()
+{
+    return (GetNativeInstance() != none);
+}
+
+defaultproperties
+{
+}

sources/Gameplay/KF1Frontend/BaseImplementation/EKFSyringeAmmo.uc

@@ -0,0 +1,288 @@
+/**
+ *  Implementation of `EAmmo` for Killing Floor medical syringe that changes
+ *  as little as possible and only on request from another mod, otherwise not
+ *  altering gameplay at all.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class EKFSyringeAmmo extends EAmmo;
+
+var private NativeActorRef syringeReference;
+
+protected function Finalizer()
+{
+    _.memory.Free(syringeReference);
+    syringeReference = none;
+}
+
+/**
+ *  Creates new `EKFSyringeAmmo` that refers to the `syringeInstance`'s
+ *  ammunition.
+ *
+ *  @param  syringeInstance Native syringe instance, whose ammunition
+ *      new `EKFSyringeAmmo` will represent.
+ *  @return New `EKFSyringeAmmo` that represents ammunition of given
+ *      `syringeInstance`. `none` iff `syringeInstance` is `none`.
+ */
+public final static /*unreal*/ function EKFSyringeAmmo Wrap(
+    Syringe syringeInstance)
+{
+    local EKFSyringeAmmo newReference;
+    if (syringeInstance == none) {
+        return none;
+    }
+    newReference = EKFSyringeAmmo(__().memory.Allocate(class'EKFSyringeAmmo'));
+    newReference.syringeReference =
+        __().unreal.ActorRef(syringeInstance);
+    return newReference;
+}
+
+public function EInterface Copy()
+{
+    local Syringe syringeInstance;
+    syringeInstance = GetNativeInstance();
+    return Wrap(syringeInstance);
+}
+
+public function bool Supports(class<EInterface> newInterfaceClass)
+{
+    if (newInterfaceClass == none)                  return false;
+    if (newInterfaceClass == class'EItem')          return true;
+    if (newInterfaceClass == class'EAmmo')          return true;
+    if (newInterfaceClass == class'EKFSyringeAmmo') return true;
+
+    return false;
+}
+
+public function EInterface As(class<EInterface> newInterfaceClass)
+{
+    if (!IsExistent()) {
+        return none;
+    }
+    if (    newInterfaceClass == class'EItem'
+        ||  newInterfaceClass == class'EAmmo'
+        ||  newInterfaceClass == class'EKFSyringeAmmo')
+    {
+        return Copy();
+    }
+    return none;
+}
+
+public function bool IsExistent()
+{
+    return (GetNativeInstance() != none);
+}
+
+public function bool SameAs(EInterface other)
+{
+    local EKFSyringeAmmo otherAmmo;
+    otherAmmo = EKFSyringeAmmo(other);
+    if (otherAmmo == none) {
+        return false;
+    }
+    return (GetNativeInstance() == otherAmmo.GetNativeInstance());
+}
+
+/**
+ *  Returns `KFAmmunition` instance represented by the caller `EKFAmmo`.
+ *
+ *  @return `KFAmmunition` instance represented by the caller `EKFAmmo`.
+ */
+public final /*unreal*/ function Syringe GetNativeInstance()
+{
+    if (syringeReference != none) {
+        return Syringe(syringeReference.Get());
+    }
+    return none;
+}
+
+public function array<Text> GetTags()
+{
+    local array<Text> tagArray;
+    if (syringeReference == none)       return tagArray;
+    if (syringeReference.Get() == none) return tagArray;
+
+    tagArray[0] = P("ammo").Copy();
+    return tagArray;
+}
+
+public function bool HasTag(Text tagToCheck)
+{
+    if (tagToCheck == none)             return false;
+    if (tagToCheck.Compare(P("ammo")))  return true;
+
+    return false;
+}
+
+public function Text GetTemplate()
+{
+    local Syringe syringeInstance;
+    syringeInstance = GetNativeInstance();
+    if (syringeInstance == none) {
+        return none;
+    }
+    return _.text.FromString("kfmod.syringe:ammo");
+}
+
+public function Text GetName()
+{
+    local Syringe syringeInstance;
+    syringeInstance = GetNativeInstance();
+    if (syringeInstance == none) {
+        return none;
+    }
+    return _.text.FromString("Syringe's ammo");
+}
+
+public function bool IsRemovable()
+{
+    return false;
+}
+
+public function bool IsSellable()
+{
+    return false;
+}
+
+/**
+ *  Medic ammo is free and does not have a price in Killing Floor.
+ */
+public function bool SetPrice(int newPrice)
+{
+    return false;
+}
+
+public function int GetPrice()
+{
+    return 0;
+}
+
+public function int GetTotalPrice()
+{
+    return 0;
+}
+
+public function int GetPriceOf(int ammoAmount)
+{
+    return 0;
+}
+
+public function bool SetWeight(int newWeight)
+{
+    return false;
+}
+
+public function int GetWeight()
+{
+    return 0;
+}
+
+public function Add(int amount, optional bool forceAddition)
+{
+    local Syringe syringeInstance;
+    syringeInstance = GetNativeInstance();
+    if (syringeInstance == none) {
+        return;
+    }
+    if (forceAddition) {
+        syringeInstance.ammoCharge[0] += amount;
+    }
+    else
+    {
+        syringeInstance.ammoCharge[0] =
+            Min(syringeInstance.maxAmmoCount,
+                syringeInstance.ammoCharge[0] + amount);
+    }
+    //  Correct possible negative values
+    if (syringeInstance.ammoCharge[0] < 0) {
+        syringeInstance.ammoCharge[0] = 0;
+    }
+}
+
+public function int GetAmount()
+{
+    local Syringe syringeInstance;
+    syringeInstance = GetNativeInstance();
+    if (syringeInstance == none) {
+        return 0;
+    }
+    return Max(0, syringeInstance.ammoCharge[0]);
+}
+
+public function int GetTotalAmount()
+{
+    return GetAmount();
+}
+
+public function SetAmount(int amount, optional bool forceAddition)
+{
+    local Syringe syringeInstance;
+    syringeInstance = GetNativeInstance();
+    if (syringeInstance == none) {
+        return;
+    }
+    if (forceAddition) {
+        syringeInstance.ammoCharge[0] = amount;
+    }
+    else
+    {
+        syringeInstance.ammoCharge[0] =
+            Min(syringeInstance.maxAmmoCount, amount);
+    }
+    //  Correct possible negative values
+    if (syringeInstance.ammoCharge[0] < 0) {
+        syringeInstance.ammoCharge[0] = 0;
+    }
+}
+
+public function int GetMaxAmount()
+{
+    local Syringe syringeInstance;
+    syringeInstance = GetNativeInstance();
+    if (syringeInstance == none) {
+        return 0;
+    }
+    return Max(0, syringeInstance.maxAmmoCount);
+}
+
+public function int GetMaxTotalAmount()
+{
+    return GetMaxAmount();
+}
+
+public function bool SetMaxAmount(
+    int             newMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    return false;
+}
+
+public function bool SetMaxTotalAmount(
+    int             newTotalMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    return false;
+}
+
+public function bool HasWeapon()
+{
+    return (GetNativeInstance() != none);
+}
+
+defaultproperties
+{
+}

sources/Gameplay/KF1Frontend/BaseImplementation/EKFUnknownItem.uc

@@ -0,0 +1,168 @@
+/**
+ *  Dummy implementation for `EItem` interface that can wrap around `Inventory`
+ *  instances that Acedia does not know about - including any non-weapons and
+ *  non-ammo items added by any other mods.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class EKFUnknownItem extends EItem;
+
+var private NativeActorRef inventoryReference;
+
+protected function Finalizer()
+{
+    _.memory.Free(inventoryReference);
+    inventoryReference = none;
+}
+
+/**
+ *  Creates new `EKFUnknownItem` that refers to the `inventoryInstance`.
+ *
+ *  @param  inventoryInstance   Native inventory instance that new
+ *      `EKFUnknownItem` will represent.
+ *  @return New `EKFUnknownItem` that represents given `inventoryInstance`.
+ *      `none` iff `inventoryInstance` is either `none`.
+ */
+public final static /*unreal*/ function EKFUnknownItem Wrap(
+    Inventory inventoryInstance)
+{
+    local EKFUnknownItem newReference;
+    if (inventoryInstance == none)                              return none;
+    if (Ammunition(inventoryInstance) != none)                  return none;
+    //  This one is not actually used for anything, so it is not real
+    if (inventoryInstance.class == class'KFMod.FlashlightAmmo') return none;
+
+    newReference = EKFUnknownItem(__().memory.Allocate(class'EKFUnknownItem'));
+    newReference.inventoryReference = __().unreal.ActorRef(inventoryInstance);
+    return newReference;
+}
+
+/**
+ *  Returns `Inventory` instance represented by the caller `EKFUnknownItem`.
+ *
+ *  @return `Inventory` instance represented by the caller `EKFUnknownItem`.
+ */
+public final /*unreal*/ function Inventory GetNativeInstance()
+{
+    if (inventoryReference != none) {
+        return Inventory(inventoryReference.Get());
+    }
+    return none;
+}
+
+public function EInterface Copy()
+{
+    local Inventory inventoryInstance;
+    inventoryInstance = GetNativeInstance();
+    return Wrap(inventoryInstance);
+}
+
+public function bool Supports(class<EInterface> newInterfaceClass)
+{
+    if (newInterfaceClass == none)              return false;
+    if (newInterfaceClass == class'EItem')      return true;
+
+    return false;
+}
+
+public function EInterface As(class<EInterface> newInterfaceClass)
+{
+    if (!IsExistent()) {
+        return none;
+    }
+    if (newInterfaceClass == class'EItem') {
+        return Copy();
+    }
+    return none;
+}
+
+public function bool IsExistent()
+{
+    return (GetNativeInstance() != none);
+}
+
+public function bool SameAs(EInterface other)
+{
+    local EKFUnknownItem otherItem;
+    otherItem = EKFUnknownItem(other);
+    if (otherItem == none) {
+        return false;
+    }
+    return (GetNativeInstance() == otherItem.GetNativeInstance());
+}
+
+public function array<Text> GetTags()
+{
+    local array<Text> emptyArray;
+    return emptyArray;
+}
+
+public function bool HasTag(Text tagToCheck)
+{
+    return false;
+}
+
+public function Text GetTemplate()
+{
+    local Inventory inventory;
+    inventory = GetNativeInstance();
+    if (inventory == none) {
+        return none;
+    }
+    return _.text.FromString(string(inventory.class));
+}
+
+public function Text GetName()
+{
+    local Inventory inventory;
+    inventory = GetNativeInstance();
+    if (inventory == none) {
+        return none;
+    }
+    return _.text.FromString(inventory.GetHumanReadableName());
+}
+
+public function bool IsRemovable()
+{
+    return true;
+}
+
+public function bool IsSellable()
+{
+    return false;
+}
+
+public function bool SetPrice(int newPrice)
+{
+    return false;
+}
+
+public function int GetPrice() { return 0; }
+
+public function bool SetWeight(int newWeight)
+{
+    return false;
+}
+
+public function int GetWeight()
+{
+    return 0;
+}
+
+defaultproperties
+{
+}

sources/Gameplay/KF1Frontend/BaseImplementation/EKFWeapon.uc

@@ -1,5 +1,5 @@
 /**
- *  Implementation of `EItem` for classic Killing Floor weapons that changes
+ *  Implementation of `EWeapon` for classic Killing Floor weapons that changes
  *  as little as possible and only on request from another mod, otherwise not
  *  altering gameplay at all.
  *      Copyright 2021 - 2022 Anton Tarasenko
@@ -19,11 +19,12 @@
  * You should have received a copy of the GNU General Public License
  * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
  */
-class EKFWeapon extends EItem
-    abstract;
+class EKFWeapon extends EWeapon;
 
 var private NativeActorRef weaponReference;
 
+var private config array< class<KFWeapon> > weaponsWithFlashlight;
+
 protected function Finalizer()
 {
     _.memory.Free(weaponReference);
@@ -40,11 +41,59 @@ protected function Finalizer()
 public final static /*unreal*/ function EKFWeapon Wrap(KFWeapon weaponInstance)
 {
     local EKFWeapon newReference;
+    if (weaponInstance == none) {
+        return none;
+    }
     newReference = EKFWeapon(__().memory.Allocate(class'EKFWeapon'));
     newReference.weaponReference = __().unreal.ActorRef(weaponInstance);
     return newReference;
 }
 
+public function EInterface Copy()
+{
+    local KFWeapon weaponInstance;
+    weaponInstance = GetNativeInstance();
+    return Wrap(weaponInstance);
+}
+
+public function bool Supports(class<EInterface> newInterfaceClass)
+{
+    if (newInterfaceClass == none)              return false;
+    if (newInterfaceClass == class'EWeapon')    return true;
+    if (newInterfaceClass == class'EKFWeapon')  return true;
+
+    return false;
+}
+
+public function EInterface As(class<EInterface> newInterfaceClass)
+{
+    if (!IsExistent()) {
+        return none;
+    }
+    if (    newInterfaceClass == class'EItem'
+        ||  newInterfaceClass == class'EWeapon'
+        ||  newInterfaceClass == class'EKFWeapon')
+    {
+        return Copy();
+    }
+    return none;
+}
+
+public function bool IsExistent()
+{
+    return (GetNativeInstance() != none);
+}
+
+public function bool SameAs(EInterface other)
+{
+    local EKFWeapon otherWeapon;
+    otherWeapon = EKFWeapon(other);
+    if (otherWeapon == none) {
+        return false;
+    }
+    return (GetNativeInstance() == otherWeapon.GetNativeInstance());
+}
+
 /**
  *  Returns `KFWeapon` instance represented by the caller `EKFWeapon`.
  *
@@ -65,9 +114,19 @@ public function array<Text> GetTags()
     if (weaponReference.Get() == none)  return tagArray;
 
     tagArray[0] = P("weapon").Copy();
+    tagArray[1] = P("visible").Copy();
     return tagArray;
 }
 
+public function bool HasTag(Text tagToCheck)
+{
+    if (tagToCheck == none)                 return false;
+    if (tagToCheck.Compare(P("weapon")))    return true;
+    if (tagToCheck.Compare(P("visible")))   return true;
+
+    return false;
+}
+
 public function Text GetTemplate()
 {
     local Weapon weapon;
@@ -85,7 +144,7 @@ public function Text GetName()
     weapon = Weapon(weaponReference.Get());
     if (weapon == none)             return none;
 
-    return _.text.FromString(Locs(weapon.itemName));
+    return _.text.FromString(weapon.GetHumanReadableName());
 }
 
 public function bool IsRemovable()
@@ -145,6 +204,97 @@ public function int GetWeight()
     return int(kfWeapon.weight);
 }
 
+public function array<EAmmo> GetAvailableAmmo()
+{
+    local EAmmo                 nextAmmo;
+    local KFWeapon              kfWeapon;
+    local Inventory             nextInventory;
+    local array<EAmmo>          result;
+    local class<Ammunition>     ammoClass1, ammoClass2;
+    if (weaponReference == none)    return result;
+    kfWeapon = KFWeapon(weaponReference.Get());
+    if (kfWeapon == none)           return result;
+    if (kfWeapon.owner == none)     return result;
+
+    ammoClass1 = _.unreal.inventory.GetAmmoClass(kfWeapon, 0);
+    ammoClass2 = _.unreal.inventory.GetAmmoClass(kfWeapon, 1);
+    nextInventory = kfWeapon.owner.inventory;
+    while (nextInventory != none)
+    {
+        if (    nextInventory.class == ammoClass1
+            ||  nextInventory.class == ammoClass2)
+        {
+            nextAmmo = class'EKFAmmo'.static.Wrap(Ammunition(nextInventory));
+            if (nextAmmo != none) {
+                result[result.length] = nextAmmo;
+            }
+            //  Reset temporary variable to avoid adding same `EKFAmmo` twice
+            nextAmmo = none;
+        }
+        nextInventory = nextInventory.inventory;
+    }
+    result = AddSpecialAmmo(kfWeapon, result);
+    return result;
+}
+
+private function array<EAmmo> AddSpecialAmmo(
+    KFWeapon        kfWeapon,
+    array<EAmmo>    ammoCollection)
+{
+    local EAmmo         nextAmmo;
+    local KFMedicGun    kfMedicWeapon;
+    if (kfWeapon == none) {
+        return ammoCollection;
+    }
+    kfMedicWeapon = KFMedicGun(kfWeapon);
+    if (kfMedicWeapon != none)
+    {
+        nextAmmo = class'EKFMedicAmmo'.static.Wrap(kfMedicWeapon);
+        if (nextAmmo != none) {
+            ammoCollection[ammoCollection.length] = nextAmmo;
+        }
+    }
+    if (HasFlashlight(kfWeapon))
+    {
+        nextAmmo =
+            class'EKFFlashlightAmmo'.static.Wrap(KFHumanPawn(kfWeapon.owner));
+        if (nextAmmo != none) {
+            ammoCollection[ammoCollection.length] = nextAmmo;
+        }
+    }
+    if (kfWeapon.class == class'KFMod.Syringe')
+    {
+        nextAmmo =
+            class'EKFSyringeAmmo'.static.Wrap(Syringe(kfWeapon));
+        if (nextAmmo != none) {
+            ammoCollection[ammoCollection.length] = nextAmmo;
+        }
+    }
+    return ammoCollection;
+}
+
+private function bool HasFlashlight(KFWeapon weapon)
+{
+    local int i;
+    if (weapon == none) {
+        return false;
+    }
+    for (i = 0; i < weaponsWithFlashlight.length; i += 1)
+    {
+        if (weapon.class == weaponsWithFlashlight[i]) {
+            return true;
+        }
+    }
+    return false;
+}
+
 defaultproperties
 {
+    weaponsWithFlashlight(0) = class'Single'
+    weaponsWithFlashlight(1) = class'Dualies'
+    weaponsWithFlashlight(2) = class'Shotgun'
+    weaponsWithFlashlight(3) = class'CamoShotgun'
+    weaponsWithFlashlight(4) = class'NailGun'
+    weaponsWithFlashlight(5) = class'BenelliShotgun'
+    weaponsWithFlashlight(6) = class'GoldenBenelliShotgun'
 }

sources/Gameplay/KF1Frontend/KF1_Frontend.uc

@@ -33,5 +33,6 @@ public function EItemTemplateInfo GetItemTemplateInfo(Text templateName)
 
 defaultproperties
 {
-    tradingClass = class'KF1_TradingComponent'
+    templatesClass  = class'KF1_TemplatesComponent'
+    tradingClass    = class'KF1_TradingComponent'
 }

sources/Gameplay/KF1Frontend/Trading/KF1_TemplatesComponent.uc

@@ -0,0 +1,215 @@
+/**
+ *  `ATemplatesComponent`'s implementation for `KF1_Frontend`.
+ *  Lists weapons available at the trader, provides support for per-perk lists,
+ *  derived from the `KFLevelRules`.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class KF1_TemplatesComponent extends ATemplatesComponent;
+
+var private bool listsAreReady;
+// TODO: add tools
+var private array<Text> availableWeaponLists;
+var private array<Text> allWeaponsList;
+var private array<Text> medicWeaponsList;
+var private array<Text> supportWeaponsList;
+var private array<Text> sharpshooterWeaponsList;
+var private array<Text> commandoWeaponsList;
+var private array<Text> berserkerWeaponsList;
+var private array<Text> firebugWeaponsList;
+var private array<Text> demolitionWeaponsList;
+var private array<Text> neutralWeaponsList;
+
+protected function Finalizer()
+{
+    _.memory.FreeMany(allWeaponsList);
+    _.memory.FreeMany(medicWeaponsList);
+    _.memory.FreeMany(supportWeaponsList);
+    _.memory.FreeMany(sharpshooterWeaponsList);
+    _.memory.FreeMany(commandoWeaponsList);
+    _.memory.FreeMany(berserkerWeaponsList);
+    _.memory.FreeMany(firebugWeaponsList);
+    _.memory.FreeMany(demolitionWeaponsList);
+    _.memory.FreeMany(neutralWeaponsList);
+    _.memory.FreeMany(availableWeaponLists);
+    if (allWeaponsList.length > 0) {
+        allWeaponsList.length = 0;
+    }
+    if (medicWeaponsList.length > 0) {
+        medicWeaponsList.length = 0;
+    }
+    if (supportWeaponsList.length > 0) {
+        supportWeaponsList.length = 0;
+    }
+    if (sharpshooterWeaponsList.length > 0) {
+        sharpshooterWeaponsList.length = 0;
+    }
+    if (commandoWeaponsList.length > 0) {
+        commandoWeaponsList.length = 0;
+    }
+    if (berserkerWeaponsList.length > 0) {
+        berserkerWeaponsList.length = 0;
+    }
+    if (firebugWeaponsList.length > 0) {
+        firebugWeaponsList.length = 0;
+    }
+    if (demolitionWeaponsList.length > 0) {
+        demolitionWeaponsList.length = 0;
+    }
+    if (neutralWeaponsList.length > 0) {
+        neutralWeaponsList.length = 0;
+    }
+    if (availableWeaponLists.length > 0) {
+        availableWeaponLists.length = 0;
+    }
+    listsAreReady = false;
+}
+
+private function BuildKFWeaponLists()
+{
+    local LevelInfo     level;
+    local KFLevelRules  kfLevelRules;
+    if (listsAreReady)          return;
+    level = _.unreal.GetLevel();
+    if (level == none)          return;
+    foreach level.DynamicActors(class'KFMod.KFLevelRules', kfLevelRules) break;
+    if (kfLevelRules == none)   return;
+
+    medicWeaponsList        = MakeWeaponList(kfLevelRules.mediItemForSale);
+    supportWeaponsList      = MakeWeaponList(kfLevelRules.suppItemForSale);
+    sharpshooterWeaponsList = MakeWeaponList(kfLevelRules.shrpItemForSale);
+    commandoWeaponsList     = MakeWeaponList(kfLevelRules.commItemForSale);
+    berserkerWeaponsList    = MakeWeaponList(kfLevelRules.bersItemForSale);
+    firebugWeaponsList      = MakeWeaponList(kfLevelRules.fireItemForSale);
+    demolitionWeaponsList   = MakeWeaponList(kfLevelRules.demoItemForSale);
+    neutralWeaponsList      = MakeWeaponList(kfLevelRules.neutItemForSale);
+    availableWeaponLists[0] = _.text.FromString("all weapons");
+    availableWeaponLists[1] = _.text.FromString("trading weapons");
+    availableWeaponLists[2] = _.text.FromString("medic weapons");
+    availableWeaponLists[3] = _.text.FromString("support weapons");
+    availableWeaponLists[4] = _.text.FromString("sharpshooter weapons");
+    availableWeaponLists[5] = _.text.FromString("commando weapons");
+    availableWeaponLists[6] = _.text.FromString("firebug weapons");
+    availableWeaponLists[7] = _.text.FromString("demolition weapons");
+    availableWeaponLists[8] = _.text.FromString("neutral weapons");
+    listsAreReady = true;
+}
+
+private function array<Text> MakeWeaponList(array< class<Pickup> > shopList)
+{
+    local int           i;
+    local Text          nextTemplate;
+    local class<Weapon> nextWeaponClass;
+    local array<Text>   resultArray;
+    if (listsAreReady) {
+        return resultArray;
+    }
+    for (i = 0; i < shopList.length; i += 1)
+    {
+        if (shopList[i] == none)        continue;
+        nextWeaponClass = class<Weapon>(shopList[i].default.inventoryType);
+        if (nextWeaponClass == none)    continue;
+    
+        nextTemplate = _.text.FromString(string(nextWeaponClass));
+        resultArray[resultArray.length] = nextTemplate.Copy();
+        allWeaponsList[allWeaponsList.length] = nextTemplate;
+    }
+    return resultArray;
+}
+
+private function array<Text> CopyList(array<Text> inputList)
+{
+    local int i;
+    local array<Text> outputList;
+    //  `inputList` is guaranteed to not contain invalid `Text` objects
+    for (i = 0; i < inputList.length; i += 1) {
+        outputList[outputList.length] = inputList[i].Copy();
+    }
+    return outputList;
+}
+
+public function bool ItemListExists(Text listName)
+{
+    local string listNameAsString;
+    if (listName == none) return false;
+    listNameAsString = listName.ToString();
+    if (listNameAsString == "weapons")              return true;
+    if (listNameAsString == "all weapons")          return true;
+    if (listNameAsString == "trading weapons")      return true;
+    if (listNameAsString == "medic weapons")        return true;
+    if (listNameAsString == "support weapons")      return true;
+    if (listNameAsString == "sharpshooter weapons") return true;
+    if (listNameAsString == "commando weapons")     return true;
+    if (listNameAsString == "berserker weapons")    return true;
+    if (listNameAsString == "firebug weapons")      return true;
+    if (listNameAsString == "demolition weapons")   return true;
+    if (listNameAsString == "neutral weapons")      return true;
+
+    return false;
+}
+
+public function array<Text> GetItemList(Text listName)
+{
+    local string        listNameAsString;
+    local array<Text>   emptyArray;
+    if (listName == none) {
+        return emptyArray;
+    }
+    listNameAsString = listName.ToString();
+    BuildKFWeaponLists();
+    if (    listNameAsString == "weapons"
+        ||  listNameAsString == "all weapons"
+        ||  listNameAsString == "trading weapons")
+    {
+        return CopyList(allWeaponsList);
+    }
+    if (listNameAsString == "medic weapons") {
+        return CopyList(medicWeaponsList);
+    }
+    if (listNameAsString == "support weapons") {
+        return CopyList(supportWeaponsList);
+    }
+    if (listNameAsString == "sharpshooter weapons") {
+        return CopyList(sharpshooterWeaponsList);
+    }
+    if (listNameAsString == "commando weapons") {
+        return CopyList(commandoWeaponsList);
+    }
+    if (listNameAsString == "berserker weapons") {
+        return CopyList(berserkerWeaponsList);
+    }
+    if (listNameAsString == "firebug weapons") {
+        return CopyList(firebugWeaponsList);
+    }
+    if (listNameAsString == "demolition weapons") {
+        return CopyList(demolitionWeaponsList);
+    }
+    if (listNameAsString == "neutral weapons") {
+        return CopyList(neutralWeaponsList);
+    }
+    return emptyArray;
+}
+
+public function array<Text> GetAvailableLists()
+{
+    BuildKFWeaponLists();
+    return CopyList(availableWeaponLists);
+}
+
+defaultproperties
+{
+}

sources/Players/EPlayer.uc

@@ -134,7 +134,7 @@ public function bool SameAs(EInterface other)
     if (other == none)              return false;
     if (controller == none)         return false;
     asPlayer = EPlayer(other);
-    if (asPlayer != none)           return false;
+    if (asPlayer == none)           return false;
     otherController = asPlayer.controller;
     if (otherController == none)    return false;
     

sources/Players/Inventory/EAmmo.uc

@@ -0,0 +1,259 @@
+/**
+ *      Abstract interface that represents ammunition of a certain type.
+ *      Ammunition methods make distinction between "amount" and "total amount":
+ *          * "Amount" is how much of this ammo is stored in this
+ *              inventory item, "max amount" is how much it can store at once.
+ *              These values can be affected by other items in the inventory.
+ *          * "Total amount" is how much ammo of this type player has in his
+ *              inventory in total.
+ *  Neither amounts can ever be negative.
+ *  For Killing Floor "total ammo" corresponds to the amount of ammunition
+ *  associated with a weapon, while "ammo" would correspond to the amount of
+ *  ammo still unleaded into the weapon. This means that "max ammo" becomes
+ *  quite a bizarre value that depends on how full your magazine is.
+ *  For example, if you bought lever action rifle, filled it
+ *  with ammo (80 bullets) and then shot out 6, you will have:
+ *          * "Ammo" == 70 - since you will have that much still unloaded;
+ *          * "Max ammo" == 76 - since with 4 loaded bullets you can only
+ *              have 76 unloaded ones;
+ *          * "Total ammo" == 74 - amount of bullets you can still shoot;
+ *          * "Max total ammo" = 80 - since that is the limit of LAR bullets you
+ *              can carry in total.
+ *      When one loads ammo into the weapon, its "amount" decreases, but its
+ *  "total amount" stays the same. Unless specified otherwise, all the methods
+ *  deal with a regular "amount".
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class EAmmo extends EItem
+    abstract;
+
+/**
+ *  Changes amount of ammo inside referred ammunition item by given `amount`.
+ *
+ *  Negative argument values will decrease it ("adding" a negative amount).
+ *
+ *      New value cannot go below zero and can only exceed maximum amount
+ *  (@see `GetMaxAmount()` and @see `GetMaxTotalAmount()`) if `forceAddition`
+ *  is also set to `true`.
+ *      If resulting value is to go over the limits - it will be clamped inside
+ *  allowed range.
+ *
+ *  @param  amount          How much ammo to add. `0` does nothing, negative
+ *      values decrease the total ammo count. Cannot force total ammo to go into
+ *      negative values.
+ *  @param  forceAddition   This parameter is only relevant when changing ammo
+ *      amount by `amount` will go over maximum (total) amount that referred
+ *      ammo item can store. Setting this parameter to `true` will allow you to
+ *      add more ammo than caller `EAmmo` normally supports.
+ *      Cannot force total amount below zero.
+ */
+public function Add(int amount, optional bool forceAddition) {}
+
+/**
+ *  Returns current price of total ammo inside inventory of the owner of
+ *  referred ammunition item.
+ *
+ *  In comparison, `EItem`'s method `GetPrice()` returns the price of only
+ *  the ammo inside the referred item.
+ *  @return Current price of total ammo inside inventory of the owner of
+ *      referred ammunition item.
+ */
+public function int GetTotalPrice()
+{
+    return 0;
+}
+
+/**
+ *  Returns how much would `ammoAmount` amount of referred ammo item would cost.
+ *
+ *  @return Price of `ammoAmount` amount of referred ammo item.
+ */
+public function int GetPriceOf(int ammoAmount)
+{
+    return 0;
+}
+
+/**
+ *  Returns current amount of ammo inside referred ammunition item.
+ *
+ *  Guaranteed to not be negative, but can exceed maximum value
+ *  (@see `GetMaxAmount()`).
+ *
+ *  @return Current amount of ammo inside referred ammunition item.
+ */
+public function int GetAmount()
+{
+    return 0;
+}
+
+/**
+ *  Returns current total amount of ammo inside inventory of the owner of
+ *  referred ammunition item.
+ *
+ *  Guaranteed to not be negative, but can exceed maximum value
+ *  (@see `GetMaxTotalAmount()`).
+ *
+ *  @return Current amount of ammo inside referred ammunition item.
+ */
+public function int GetTotalAmount()
+{
+    return 0;
+}
+
+/**
+ *  Changes amount of ammo inside referred ammunition item.
+ *
+ *      Negative values will be treated as `0`. Values that exceed
+ *  maximum (total) amount will be automatically reduced to said maximum amount
+ *  (@see `GetMaxAmount()` and @see `GetMaxTotalAmount()`), unless
+ *  `forceAddition` is also set to `true`.
+ *      If resulting value is to go over the limits - it will be clamped inside
+ *  allowed range.
+ *
+ *  @param  amount          How much ammo should referred ammunition item have.
+ *      Negative values are treated like `0`.
+ *  @param  forceAddition   This parameter is only relevant when `amount` is
+ *      higher than maximum (total) amount that referred ammo item can store.
+ *      Setting this parameter to `true` will allow you to add more ammo than
+ *      caller `EAmmo` normally supports. Cannot force total amount below zero.
+ */
+public function SetAmount(int amount, optional bool forceAddition) {}
+
+/**
+ *  Returns maximum amount of ammo referred ammunition item supports.
+ *
+ *      This is not a hard limit and can be bypassed by `SetAmount()` and
+ *  `Add()` methods, meaning that it is possible that
+ *  `GetAmount() > GetMaxAmount()`.
+ *      Treat this value like a limit obtainable through "normal means", that
+ *  can only be exceeded through cheats or special powerups of some kind.
+ *
+ *  @return Current "soft" max ammo limit of the referred ammunition item.
+ *      Returning negative value means that there is no upper limit.
+ *      Zero is considered a valid value.
+ */
+public function int GetMaxAmount()
+{
+    return 0;
+}
+
+/**
+ *  Returns maximum total amount of ammo owner of the referred ammunition item
+ *  can hold.
+ *
+ *      This is not a hard limit and can be bypassed by `SetAmount()` and
+ *  `Add()` methods, meaning that it is possible that
+ *  `GetTotalAmount() > GetMaxTotalAmount()`.
+ *      Treat this value like a limit obtainable through "normal means", that
+ *  can only be exceeded through cheats or special powerups of some kind.
+ *
+ *  @return Current "soft" max total ammo limit of the referred ammunition item.
+ *      Returning negative value means that there is no upper limit.
+ *      Zero is considered a valid value.
+ */
+public function int GetMaxTotalAmount()
+{
+    return 0;
+}
+
+/**
+ *  Changes maximum amount of ammo referred ammunition item supports.
+ *
+ *      This is not a hard limit and can be bypassed by `SetAmount()` and
+ *  `Add()` methods, meaning that it is possible that
+ *  `GetAmount() > GetMaxAmount()`.
+ *      Treat this value like a limit obtainable through "normal means", that
+ *  can only be exceeded through cheats or special powerups of some kind.
+ *
+ *  Referred ammunition item does not have to support this method and is
+ *  allowed to refuse changing maximum ammo value. It can also only support
+ *  certain ranges of values.
+ *
+ *  @param  newMaxAmmo          New maximum ammo referred ammunition
+ *      should support. Negative values mean unlimited maximum value.
+ *  @param  leaveCurrentAmmo    Default value of `false` will result in current
+ *      ammo being updated to not exceed `newMaxAmmo`, while setting this to
+ *      `true` will leave it unchanged.
+ *
+ *  @return `true` if maximum value was changed and `false` otherwise.
+ */
+public function bool SetMaxAmount(
+    int             newMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    return false;
+}
+
+/**
+ *  Changes maximum total amount of ammo that owner of the referred
+ *  ammunition item supports.
+ *
+ *      This is not a hard limit and can be bypassed by `SetAmount()` and
+ *  `Add()` methods, meaning that it is possible that
+ *  `GetTotalAmount() > GetMaxTotalAmount()`.
+ *      Treat this value like a limit obtainable through "normal means", that
+ *  can only be exceeded through cheats or special powerups of some kind.
+ *
+ *  Referred ammunition item does not have to support this method is allowed to
+ *  refuse changing maximum ammo value. It can also only support certain ranges
+ *  of values.
+ *
+ *  @param  newTotalMaxAmmo     New maximum total ammo owner of the referred
+ *      ammunition can have. Negative values mean unlimited maximum value.
+ *  @param  leaveCurrentAmmo    Default value of `false` will result in current
+ *      total ammo being updated to not exceed `newTotalMaxAmmo`, while setting
+ *      this to `true` will leave it unchanged.
+ *
+ *  @return `true` if maximum value was changed and `false` otherwise.
+ */
+public function bool SetMaxTotalAmount(
+    int             newTotalMaxAmmo,
+    optional bool   leaveCurrentAmmo)
+{
+    return false;
+}
+
+/**
+ *  Checks whether the owner of the referred ammo item also has a weapon that
+ *  can be loaded with that ammo.
+ *
+ *  @return `true` if owner of the referred ammo has a weapon that can be
+ *      loaded with that ammo and `false` otherwise.
+ */
+public function bool HasWeapon()
+{
+    return false;
+}
+
+/**
+ *  Maxes out amount of ammo of the referred ammunition item.
+ *
+ *  Does nothing if current ammo is already at (or higher) than maximum value 
+ *  (@see `GetMaxAmount()`).
+ */
+public function Fill()
+{
+    if (GetMaxAmount() < 0)             return;
+    if (GetAmount() >= GetMaxAmount())  return;
+
+    SetAmount(GetMaxAmount());
+}
+
+defaultproperties
+{
+}

sources/Players/Inventory/EInventory.uc

@@ -21,7 +21,7 @@
  * You should have received a copy of the GNU General Public License
  * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
  */
-class EInventory extends AcediaObject
+class EInventory extends EInterface
     abstract;
 
 /**
@@ -30,7 +30,7 @@ class EInventory extends AcediaObject
  *  This method should not be called manually, unless you implement your own
  *  game interface.
  *
- *  Cannot fail for any connected player and can assume it will not be called
+ *  Cannot fail for any connected player and will assume it will not be called
  *  for not connected ones.
  *
  *  @param  player  `EPlayer` for which to initialize this inventory.
@@ -44,17 +44,23 @@ public function Initialize(EPlayer player) {}
  *  inventory system - it can refuse it.
  *
  *  @param  newItem         New item to add to the caller inventory system.
+ *      Can be destroyed as a result of this call, if it gets merged with
+ *      another weapon inside the inventory.
  *  @param  forceAddition   This parameter is only relevant when `newItem`
  *      cannot be added in the caller inventory system. If it cannot be added
  *      because of the conflict with other items - setting this flag to `true`
  *      allows caller inventory system to get rid of such items to make room for
  *      `newItem`. Removing items is only allowed if it will actually let us add
  *      `newItem`. How removal will be done is up to the implementation.
- *  @return `true` if `newItem` was added and `false` otherwise.
+ *  @return `EItem` added as a result. Can be different from `newItem` in case
+ *      inventory made it "merge" with another weapon. This can happen,
+ *      for example, if we add a single pistol when inventory already contains
+ *      pistol of the same type.
+ *      `none` if we have failed to add `newItem` to the inventory.
  */
-public function bool Add(EItem newItem, optional bool forceAddition)
+public function EItem Add(EItem newItem, optional bool forceAddition)
 {
-    return false;
+    return none;
 }
 
 /**
@@ -72,19 +78,22 @@ public function bool Add(EItem newItem, optional bool forceAddition)
  *      allows caller inventory system to get rid of such items to make room for
  *      new item. Removing items is only allowed if it will actually let us add
  *      new item. How removal will be done is up to the implementation.
- *  @return `true` if new item was added and `false` otherwise.
+ *  @return Reference to `EItem` interface to the added item entity,
+ *      `none` iff adding item has failed.
  */
-public function bool AddTemplate(
+public function EItem AddTemplate(
     Text            newItemTemplate,
     optional bool   forceAddition)
 {
-    return false;
+    return none;
 }
 
 /**
  *  Checks whether given item `itemToCheck` can be added to the caller
  *  inventory system.
  *
+ *  See also `CanAddExplain()`.
+ *
  *  @param  itemToCheck     Item to check for whether we can add it to
  *      the caller `EInventory`.
  *  @param  forceAddition   New items can be added with or without
@@ -93,15 +102,24 @@ public function bool AddTemplate(
  *  @return `true` if given `itemToCheck` can be added to the caller
  *      inventory system with given flag `forceAddition` and `false` otherwise.
  */
-public function bool CanAdd(EItem itemToCheck, optional bool forceAddition)
+public final function bool CanAdd(
+    EItem           itemToCheck,
+    optional bool   forceAddition)
 {
-    return false;
+    local bool success;
+    local Text explanation;
+    explanation = CanAddExplain(itemToCheck, forceAddition);
+    success = (explanation == none);
+    _.memory.Free(explanation);
+    return success;
 }
 
 /**
  *  Checks whether item with given template `itemToCheck` can be added to
  *  the caller inventory system.
  *
+ *  See also `CanAddTemplateExplain()`.
+ *
  *  @param  itemTemplateToCheck Template of the item to check for whether we can
  *      add it to the caller `EInventory`.
  *  @param  forceAddition       New items can be added with or without
@@ -115,7 +133,58 @@ public function bool CanAddTemplate(
     Text            itemTemplateToCheck,
     optional bool   forceAddition)
 {
-    return false;
+    local bool success;
+    local Text explanation;
+    explanation = CanAddTemplateExplain(itemTemplateToCheck, forceAddition);
+    success = (explanation == none);
+    _.memory.Free(explanation);
+    return success;
+}
+
+/**
+ *  Checks whether given item `itemToCheck` can be added to the caller
+ *  inventory system and provides short explanation (dependent on
+ *  implementation) if item cannot be added.
+ *
+ *  See also `CanAdd()`.
+ *
+ *  @param  itemToCheck     Item to check for whether we can add it to
+ *      the caller `EInventory`.
+ *  @param  forceAddition   New items can be added with or without
+ *      `forceAddition` flag. This parameter allows you to check whether we
+ *      test for addition with or without it.
+ *  @return `none` if given `itemToCheck` can be added to the caller
+ *      inventory system with given flag `forceAddition` and `Text` with
+ *      description of reason why not otherwise.
+ */
+public function Text CanAddExplain(
+    EItem           itemToCheck,
+    optional bool   forceAddition)
+{
+    return none;
+}
+
+/**
+ *  Checks whether item with given template `itemToCheck` can be added to
+ *  the caller inventory system and provides short explanation (dependent on
+ *  implementation) if item cannot be added.
+ *
+ *  See also `CanAddTemplate()`.
+ *
+ *  @param  itemTemplateToCheck Template of the item to check for whether we can
+ *      add it to the caller `EInventory`.
+ *  @param  forceAddition       New items can be added with or without
+ *      `forceAddition` flag. This parameter allows you to check whether we
+ *      test for addition with or without it.
+ *  @return `none` if given `itemToCheck` can be added to the caller
+ *      inventory system with given flag `forceAddition` and `Text` with
+ *      description of reason why not otherwise.
+ */
+public function Text CanAddTemplateExplain(
+    Text            itemTemplateToCheck,
+    optional bool   forceAddition)
+{
+    return none;
 }
 
 /**
@@ -137,15 +206,16 @@ public function bool CanAddTemplate(
  *      `EInventory` in the first place).
  */
 public function bool Remove(
-    EItem itemToRemove,
-    optional bool keepItem,
-    optional bool forceRemoval)
+    EItem           itemToRemove,
+    optional bool   keepItem,
+    optional bool   forceRemoval)
 {
     return false;
 }
 
 /**
- *  Removes item of type `itemTemplateToRemove` from the caller `EInventory`.
+ *  Removes item with given template `itemTemplateToRemove` from the caller
+ *  `EInventory`.
  *
  *  By default removes one arbitrary (can be based on simple convenience of
  *  implementation) item, but optional parameter can make it remove all items
@@ -194,13 +264,18 @@ public function bool RemoveTemplate(
  *  @param  forceRemoval    Set this to `true` if item must be removed
  *      no matter what. Otherwise inventory system can refuse removal of items,
  *      whose `IsRemovable()` returns `false`.
+ *  @param  forceRemoval    Set this to `true` if even invisible to the player
+ *      items have to be removed. In Killing Floor only weapons are visible to
+ *      the player (ammunition items are considered to be just
+ *      their parameters).
  *  @return `true` if any `EItem` was removed and `false` otherwise
  *      (including the case where no `EItem`s were kept in the caller
  *      `EInventory` in the first place).
  */
 public function bool RemoveAll(
     optional bool keepItems,
-    optional bool forceRemoval)
+    optional bool forceRemoval,
+    optional bool includeHidden)
 {
     return false;
 }
@@ -217,6 +292,20 @@ public function bool Contains(EItem itemToCheck)
     return false;
 }
 
+/**
+ *  Checks whether caller `EInventory` contains item with given template
+ *  `itemTemplateToCheck`.
+ *
+ *  @param  itemTemplateToCheck Template we want to check for belonging to
+ *      the caller `EInventory`.
+ *  @result `true` if item with a given template does belong to the inventory
+ *      and `false` otherwise.
+ */
+public function bool ContainsTemplate(Text itemTemplateToCheck)
+{
+    return false;
+}
+
 /**
  *  Returns array with all `EItem`s contained inside the caller `EInventory`.
  *
@@ -228,6 +317,21 @@ public function array<EItem> GetAllItems()
     return emptyArray;
 }
 
+/**
+ *  Returns array with all `EItem`s contained inside the caller `EInventory`
+ *  that support interface of class `interfaceClass`.
+ *
+ *  @return Array with all `EItem`s that support interface of
+ *      class `interfaceClass` contained inside the caller `EInventory`.
+ *      Guaranteed to not contain `none` references of interfaces to
+ *      inexistent entities.
+ */
+public function array<EItem> GetItemsSupporting(class<EItem> interfaceClass)
+{
+    local array<EItem> emptyArray;
+    return emptyArray;
+}
+
 /**
  *  Returns array with all `EItem`s contained inside the caller `EInventory`
  *  that has specified tag `tag`.
@@ -235,6 +339,8 @@ public function array<EItem> GetAllItems()
  *  @param  tag Tag, which items we want to get.
  *  @return Array with all `EItem`s contained inside the caller `EInventory`
  *      that has specified tag `tag`.
+ *      Guaranteed to not contain `none` references of interfaces to
+ *      inexistent entities.
  */
 public function array<EItem> GetTagItems(Text tag)
 {
@@ -254,6 +360,7 @@ public function array<EItem> GetTagItems(Text tag)
  *  @param  tag   Tag, which item we want to get.
  *  @return `EItem` contained inside the caller `EInventory` that belongs to
  *      the specified tag `tag`.
+ *      Guaranteed to not be `none` or refer to non-existent entity.
  */
 public function EItem GetTagItem(Text tag) { return none; }
 
@@ -264,6 +371,8 @@ public function EItem GetTagItem(Text tag) { return none; }
  *  @param  template    Template, that items we want to get originated from.
  *  @return Array with all `EItem`s contained inside the caller `EInventory`
  *      that originated from the specified template `template`.
+ *      Guaranteed to not contain `none` references or interfaces to
+ *      inexistent entities.
  */
 public function array<EItem> GetTemplateItems(Text template)
 {
@@ -272,7 +381,7 @@ public function array<EItem> GetTemplateItems(Text template)
 }
 
 /**
- *  Returns array with all `EItem`s contained inside the caller `EInventory`
+ *  Returns `EItem`s contained inside the caller `EInventory`
  *  that originated from the specified template `template`.
  *
  *  If several `EItem`s inside caller `EInventory` originated from
@@ -283,9 +392,27 @@ public function array<EItem> GetTemplateItems(Text template)
  *  @param  template    Template, that item we want to get originated from.
  *  @return `EItem`s contained inside the caller `EInventory` that originated
  *      from the specified template `template`.
+ *      Guaranteed to not be `none` or refer to non-existent entity.
  */
 public function EItem GetTemplateItem(Text template) { return none; }
 
+/**
+ *  Returns array of caller `EInventory`'s items that are currently equipped by
+ *  its owner player.
+ *
+ *  @return Array with all `EItem`s contained inside the caller `EInventory`
+ *      that are equipped by its owner.
+ *      Guaranteed to not contain `none` references or interfaces to
+ *      inexistent entities.
+ */
+public function array<EItem> GetEquippedItems()
+{
+    local array<EItem> emptyArray;
+    return emptyArray;
+}
+
+public function EItem GetEquippedItem() { return none; }
+
 defaultproperties
 {
 }

sources/Players/Inventory/EItem.uc

@@ -30,7 +30,7 @@
  *      2.  Weight. Accessed by `SetWeight()` / `GetWeight()`.
  *      All of these parameters can be ignored if they are not applicable to
  *  a certain type of item.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021 - 2022 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -47,7 +47,7 @@
  * You should have received a copy of the GNU General Public License
  * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
  */
-class EItem extends AcediaObject
+class EItem extends EInterface
     abstract;
 
 /**
@@ -63,6 +63,12 @@ public function array<Text> GetTags()
     return emptyArray;
 }
 
+// TODO: document this
+public function bool HasTag(Text tagToCheck)
+{
+    return false;
+}
+
 /**
  *  Returns template caller `EItem` was created from.
  *

sources/Players/Inventory/EWeapon.uc

@@ -0,0 +1,57 @@
+/**
+ *      Abstract interface that represents any kind of weapon.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class EWeapon extends EItem
+    abstract;
+
+/**
+ *  Returns `EAmmo` for every ammo item that can be used with the caller's
+ *  referred weapon. Method looks for that ammo in the weapon's owner's
+ *  inventory.
+ *
+ *  @return Array of `EAmmo`s that refer to ammo items suitable for use with
+ *      referred weapon. Every item of the returned array is guaranteed to not
+ *      be `none` and refer to an existent item.
+ */
+public function array<EAmmo> GetAvailableAmmo()
+{
+    local array<EAmmo> emptyArray;
+    return emptyArray;
+}
+
+/**
+ *  Fills (@see `EAmmo.Fill()` method) `EAmmo` for every ammo item that can be
+ *  used with the caller's referred weapon. Method looks for that ammo in
+ *  the weapon's owner's inventory.
+ */
+public final function FillAmmo()
+{
+    local int           i;
+    local array<EAmmo>  myAmmo;
+    myAmmo = GetAvailableAmmo();
+    for (i = 0; i < myAmmo.length; i += 1) {
+        myAmmo[i].Fill();
+    }
+    _.memory.FreeMany(myAmmo);
+}
+
+
+defaultproperties
+{
+}

sources/Text/MutableText.uc

@@ -100,6 +100,17 @@ public final function MutableText AppendCharacter(Text.Character newCharacter)
     return MutableText(AppendCodePoint(newCharacter.codePoint));
 }
 
+/**
+ *  Adds new line character to the end of the caller `MutableText`.
+ *
+ *  @return Caller `MutableText` to allow for method chaining.
+ */
+public final function MutableText AppendNewLine()
+{
+    AppendCodePoint(CODEPOINT_NEWLINE);
+    return self;
+}
+
 /**
  *  Converts caller `MutableText` instance into lower case.
  */

sources/Types/AcediaActor.uc

@@ -397,4 +397,9 @@ public static function _cleanup()
 
 defaultproperties
 {
+    RemoteRole      = ROLE_None
+    drawType        = DT_None
+    bCollideActors  = false
+    bCollideWorld   = false
+    bBlockActors    = false
 }

sources/Unreal/InventoryAPI/InventoryAPI.uc

@@ -0,0 +1,530 @@
+/**
+ *      Low-level API that provides set of utility methods for working with
+ *  unreal script inventory classes, including some Killing Floor specific
+ *  methods that depend on how its weapons work.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class InventoryAPI extends AcediaObject
+    config(AcediaSystem);
+
+/**
+ *  Describes a single-dual weapons class pair.
+ *  For example,    `single = class'MK23Pickup'` and
+ *                  `dual = class'DualMK23Pickup'`.
+ */
+struct DualiesPair
+{
+    var class<KFWeaponPickup>   single;
+    var class<KFWeaponPickup>   dual;
+};
+//  All dual pairs that Acedia will recognize
+var private const config array<DualiesPair> dualiesClasses;
+
+/**
+ *  Describe the role of the weapon regarding a dual wielding.
+ *  All weapons have a dual wielding role, although for most it
+ *  is simply `DWR_None`.
+ */
+enum DualWieldingRole
+{
+    //  Not a dual weapons and cannot be dual wielded;
+    //  Most weapons are in this category (e.g. lar, ak47, husk cannon, etc.)
+    DWR_None,
+    //  Not a dual weapon, but can be dual wielded (e.g. single pistols)
+    DWR_Single,
+    //  A dual weapon, consisted of two single ones (e.g. dual pistols)
+    DWR_Dual
+};
+
+/**
+ *      Returns array of single - dual pairs (`DualiesPair`) that defines which
+ *  single weapon class corresponds to which dual class.
+ *      For example, `KFMod.GoldenDeaglePickup` is a single class corresponding
+ *  to the `KFMod.GoldenDualDeaglePickup` dual class.
+ */
+public function array<DualiesPair> GetDualiesPairs()
+{
+    return dualiesClasses;
+}
+
+/**
+ *  Returns dual wielding role of the given class of weapon `weaponClass`.
+ *  See `DualWieldingRole` enum for more details.
+ *
+ *  @param  weaponClass Weapon class to check the role for.
+ *  @return Dual wielding role of the weapon of given class `weaponClass`.
+ *      `DWR_None` in case given `weaponClass` is `none`.
+ */
+public function DualWieldingRole GetDualWieldingRole(
+    class<KFWeapon> weaponClass)
+{
+    local int                   i;
+    local class<KFWeaponPickup> pickupClass;
+    if (weaponClass == none) return DWR_None;
+    pickupClass = class<KFWeaponPickup>(weaponClass.default.pickupClass);
+    if (pickupClass == none) return DWR_None;
+
+    for (i = 0; i < dualiesClasses.length; i += 1)
+    {
+        if (dualiesClasses[i].single == pickupClass) {
+            return DWR_Single;
+        }
+        if (dualiesClasses[i].dual == pickupClass) {
+            return DWR_Dual;
+        }
+    }
+    return DWR_None;
+}
+
+/**
+ *  For "dual" weapons (`DWR_Dual`), corresponding of two "single" version
+ *  returns class of corresponding single version, for any other
+ *  (including single weapons themselves) returns `none`.
+ *
+ *  @param  weaponClass Weapon class for which to find matching single class.
+ *  @return Single class that corresponds to the given `weaponClass`, if it is
+ *      classified as `DWR_Dual`. `none` for every other class.
+ */
+public function class<KFWeapon> GetSingleClass(class<KFWeapon> weapon)
+{
+    local int                   i;
+    local class<KFWeaponPickup> pickupClass;
+    local class<KFWeaponPickup> singlePickupClass;
+    if (weapon == none)         return none;
+    pickupClass = class<KFWeaponPickup>(weapon.default.pickupClass);
+    if (pickupClass == none)    return none;
+
+    for (i = 0; i < dualiesClasses.length; i += 1)
+    {
+        if (dualiesClasses[i].dual == pickupClass)
+        {
+            singlePickupClass = dualiesClasses[i].single;
+            if (singlePickupClass != none) {
+                return class<KFWeapon>(singlePickupClass.default.inventoryType);
+            }
+        }
+    }
+    return none;
+}
+
+/**
+ *  For "single" weapons (`DWR_Single`) that can have a "dual" version returns
+ *  class of corresponding dual version, for any other (including dual weapons
+ *  themselves) returns `none`.
+ *
+ *  @param  weaponClass Weapon class for which to find matching dual class.
+ *  @return Dual class that corresponds to the given `weaponClass`, if it is
+ *      classified as `DWR_Single`. `none` for every other class.
+ */
+public function class<KFWeapon> GetDualClass(class<KFWeapon> weaponClass)
+{
+    local int                   i;
+    local class<KFWeaponPickup> pickupClass;
+    local class<KFWeaponPickup> dualPickupClass;
+    if (weaponClass == none)    return none;
+    pickupClass = class<KFWeaponPickup>(weaponClass.default.pickupClass);
+    if (pickupClass == none)    return none;
+
+    for (i = 0; i < dualiesClasses.length; i += 1)
+    {
+        if (dualiesClasses[i].single == pickupClass)
+        {
+            dualPickupClass = dualiesClasses[i].dual;
+            if (dualPickupClass != none) {
+                return class<KFWeapon>(dualPickupClass.default.inventoryType);
+            }
+        }
+    }
+    return none;
+}
+
+/**
+ *  Convenience method for finding a first inventory entry of the given
+ *  class `inventoryClass` in the given inventory chain `inventoryChain`.
+ *
+ *  Inventory is stored as a linked list, where next inventory item is available
+ *  through the `inventory` reference. This method follows this list, starting
+ *  from `inventoryChain` until it finds `Inventory` of the appropriate class
+ *  or reaches the end of the list.
+ *
+ *  @param  inventoryClass      Class of the inventory we are interested in.
+ *  @param  inventoryChain      Inventory chain in which we should search for
+ *      the given class.
+ *  @param  acceptChildClass    `true` if method should also return any
+ *      `Inventory` of class derived from `inventoryClass` and `false` if
+ *      we want given class specifically (default).
+ *  @return First inventory from `inventoryChain` that matches given
+ *      `inventoryClass` class (whether exactly or as a child class,
+ *      in case `acceptChildClass == true`).
+ */
+public final function Inventory Get(
+    class<Inventory>    inventoryClass,
+    Inventory           inventoryChain,
+    optional bool       acceptChildClass)
+{
+    if (inventoryClass == none) {
+        return none;
+    }
+    while (inventoryChain != none)
+    {
+        if (inventoryChain.class == inventoryClass) {
+            return inventoryChain;
+        }
+        if (    acceptChildClass
+            &&  ClassIsChildOf(inventoryChain.class, inventoryClass))
+        {
+            return inventoryChain;
+        }
+        inventoryChain = inventoryChain.inventory;
+    }
+    return none;
+}
+
+/**
+ *  Convenience method for finding all inventory entries of the given
+ *  class `inventoryClass` in the given inventory chain `inventoryChain`.
+ *
+ *  Inventory is stored as a linked list, where next inventory item is available
+ *  through the `inventory` reference. This method follows this list, starting
+ *  from `inventoryChain` until the end of the list.
+ *
+ *  @param  inventoryClass      Class of the inventory we are interested in.
+ *  @param  inventoryChain      Inventory chain in which we should search for
+ *      the given class.
+ *  @param  acceptChildClass    `true` if method should also return any
+ *      `Inventory` of class derived from `inventoryClass` and `false` if
+ *      we want given class specifically (default).
+ *  @return Array of inventory items from `inventoryChain` that match given
+ *      `inventoryClass` class (whether exactly or as a child class,
+ *      in case `acceptChildClass == true`).
+ */
+public final function array<Inventory> GetAll(
+    class<Inventory>    inventoryClass,
+    Inventory           inventoryChain,
+    optional bool       acceptChildClass)
+{
+    local bool              shouldAdd;
+    local array<Inventory>  result;
+    if (inventoryClass == none) {
+        return result;
+    }
+    while (inventoryChain != none)
+    {
+        shouldAdd = false;
+        if (inventoryChain.class == inventoryClass) {
+            shouldAdd = true;
+        }
+        else if (acceptChildClass) {
+            shouldAdd = ClassIsChildOf(inventoryChain.class, inventoryClass);
+        }
+        if (shouldAdd) {
+            result[result.length] = inventoryChain;
+        }
+        inventoryChain = inventoryChain.inventory;
+    }
+    return result;
+}
+
+/**
+ *  Checks whether `inventory` is contained in the inventory given by
+ *  `inventoryChain`.
+ *
+ *  @param  inventory       Item we are searching for.
+ *  @param  inventoryChain  Inventory chain in which we should search for
+ *      the given item.
+ *  @return `true` if `inventoryChain` contains `inventory` and
+ *      `false` otherwise.
+ */
+public final function bool Contains(
+    Inventory inventory,
+    Inventory inventoryChain)
+{
+    while (inventoryChain != none)
+    {
+        if (inventoryChain == inventory) {
+            return true;
+        }
+        inventoryChain = inventoryChain.inventory;
+    }
+    return false;
+}
+
+/**
+ *      Returns a root pickup class.
+ *  For non-dual weapons, root class is defined as either:
+ *      1. The first variant (reskin), if there are variants for that weapon;
+ *      2. And as the class itself, if there are no variants.
+ *          For dual weapons (all dual pistols) root class is defined as
+ *          a root of their single version.
+ *
+ *  This definition is useful because:
+ *      1. Vanilla game rules are such that player can only have two weapons
+ *          in the inventory if they have different roots;
+ *      2. Root is easy to find.
+ *
+ *  @param  weaponClass Weapon class for which we must find root class.
+ *  @return Root class for the provided `weaponClass` class.
+ *      If `weaponClass` is `none`, method will also return `none`.
+*/
+public final function class<KFWeaponPickup> GetRootPickupClass(
+    class<KFWeapon> weaponClass)
+{
+    local int                   i;
+    local class<KFWeaponPickup> root;
+    if (weaponClass == none)    return none;
+    //  Start with a pickup of the given weapons
+    root = class<KFWeaponPickup>(weaponClass.default.pickupClass);
+    if (root == none)           return none;
+
+    //      In case it's a dual version - find corresponding single pickup class
+    //  (it's root would be the same).
+    for (i = 0; i < dualiesClasses.length; i += 1)
+    {
+        if (dualiesClasses[i].dual == root)
+        {
+            root = dualiesClasses[i].single;
+            break;
+        }
+    }
+    //      Take either first variant class or the class itself -
+    //  it's going to be root by definition
+    if (root != none && root.default.variantClasses.length > 0) {
+        root = class<KFWeaponPickup>(root.default.variantClasses[0]);
+    }
+    return root;
+}
+
+/**
+ *  Convenience method for finding a first inventory entry with the same root as
+ *  class `inventoryClass` in the given inventory chain `inventoryChain`.
+ *  For information of what a "root" is, see `GetRootPickupClass()`.
+ *
+ *  Inventory is stored as a linked list, where next inventory item is available
+ *  through the `inventory` reference. This method follows this list, starting
+ *  from `inventoryChain` until it finds `Inventory` of the appropriate class
+ *  or reaches the end of the list.
+ *
+ *  @param  inventoryClass  Class of the inventory we are interested in.
+ *  @param  inventoryChain  Inventory chain in which we should search for
+ *      the given class.
+ *  @return First inventory from `inventoryChain` that has the same root as
+ *      given `inventoryClass` class.
+ */
+public function KFWeapon GetByRoot(
+    class<KFWeapon> inventoryClass,
+    Inventory       inventoryChain)
+{
+    local class<KFWeapon>       nextWeaponClass;
+    local class<KFWeaponPickup> itemRoot, nextRoot;
+    itemRoot = GetRootPickupClass(inventoryClass);
+    if (itemRoot == none) {
+        return none;
+    }
+    while (inventoryChain != none)
+    {
+        nextWeaponClass = class<KFWeapon>(inventoryChain.class);
+        nextRoot = GetRootPickupClass(nextWeaponClass);
+        if (itemRoot == nextRoot) {
+            return KFWeapon(inventoryChain);
+        }
+        inventoryChain = inventoryChain.inventory;
+    }
+    return none;
+}
+
+/**
+ *  Convenience method for finding all inventory entries with the same root as
+ *  class `inventoryClass` in the given inventory chain `inventoryChain`.
+ *  For information of what a "root" is, see `GetRootPickupClass()`.
+ *
+ *  Inventory is stored as a linked list, where next inventory item is available
+ *  through the `inventory` reference. This method follows this list, starting
+ *  from `inventoryChain` until the end of the list.
+ *
+ *  @param  inventoryClass  Class of the inventory we are interested in.
+ *  @param  inventoryChain  Inventory chain in which we should search for
+ *      the given class.
+ *  @return Array of inventory items from `inventoryChain` that have the same
+ *      root as given `inventoryClass` class.
+ */
+public function array<KFWeapon> GetAllByRoot(
+    class<KFWeapon> inventoryClass,
+    Inventory       inventoryChain)
+{
+    local array<KFWeapon>       result;
+    local KFWeapon              nextWeapon;
+    local class<KFWeapon>       nextWeaponClass;
+    local class<KFWeaponPickup> itemRoot, nextRoot;
+    itemRoot = GetRootPickupClass(inventoryClass);
+    if (itemRoot == none) {
+        return result;
+    }
+    while (inventoryChain != none)
+    {
+        nextWeaponClass = class<KFWeapon>(inventoryChain.class);
+        nextRoot = GetRootPickupClass(nextWeaponClass);
+        if (itemRoot == nextRoot) {
+            nextWeapon = KFWeapon(inventoryChain);
+        }
+        if (nextWeapon != none)
+        {
+            result[result.length] = nextWeapon;
+            nextWeapon = none;
+        }
+        inventoryChain = inventoryChain.inventory;
+    }
+    return result;
+}
+
+/**
+ *  Returns ammunition class for the given `weapon` weapon, that it uses for
+ *  fire mode numbered `modeNumber`.
+ *
+ *  @param  weapon      Weapon for which ammunition class should be found.
+ *  @param  modeNumber  Fire mode for which ammunition class should be found.
+ *  @return Class of ammunition used for `weapon`'s fire mode,
+ *      numbered `modeNumber`.
+ *      `none` if `weapon` is `none`, fire mode does not exist or
+ *      it is not associated with inventory ammo class.
+ */
+public function class<Ammunition> GetAmmoClass(Weapon weapon, int modeNumber)
+{
+    local WeaponFire relevantWeaponFire;
+    if (weapon == none) {
+        return none;
+    }
+    //  Just use majestic rjp's hack method `GetFireMode()` to get ammo class
+    //  through a weapon fire
+    relevantWeaponFire = weapon.GetFireMode(modeNumber);
+    if (relevantWeaponFire != none) {
+        return relevantWeaponFire.ammoClass;
+    }
+    return none;
+}
+
+/**
+ *  Removes all ammo from the given `weapon`. Assumes weapons has no more than
+ *  two fire modes.
+ *
+ *  In case given weapon is a child class of `KFWeapon`, also clears its
+ *  magazine counter.
+ *
+ *  @param  weapon  Weapon to remove all ammo from. If `none`,
+ *      method does nothing.
+ */
+public final function ClearAmmo(Weapon weapon)
+{
+    local InventoryService service;
+    service = InventoryService(class'InventoryService'.static.Require());
+    if (service != none) {
+        service.ClearAmmo(weapon);
+    }
+}
+
+/**
+ *  Creates and adds a weapons of the given class to the `pawn` with specified
+ *  amount of ammunition.
+ *
+ *  @param  pawn                `Pawn` to which we should add new weapon.
+ *      If `none` - method does nothing.
+ *  @param  weaponClassToAdd    Class of the weapon we need to add.
+ *      If `none` - method does nothing.
+ *  @param  totalAmmoPrimary    Ammo to add to the primary fire.
+ *  @param  totalAmmoSecondary  Ammo to add to the secondary fire.
+ *  @param  magazineAmmo        Ammo to add to the new weapon's magazine count.
+ *      Only relevant if `weaponClassToAdd` is a child class of `KFWeapon` and
+ *      otherwise ignored.
+ *  @param  clearStarterAmmo    Newly created weapons usually come with some
+ *      default amount of ammo. Setting this flag to `true` will remove it
+ *      before adding `totalAmmoPrimary`, `totalAmmoSecondary` and
+ *      `magazineAmmo`.
+ *  @return Instance of the newly created weapon. `none` in case of failure or
+ *      if created weapon was destroyed in the process of adding it to
+ *      the `pawn` (can happen as a result of interaction with preexisting
+ *      weapons - e.g. pistol can merge with another one of the same type and
+ *      produce a new weapon).
+ */
+public function Weapon AddWeaponWithAmmo(
+    Pawn            pawn,
+    class<Weapon>   weaponClassToAdd,
+    optional int    totalAmmoPrimary,
+    optional int    totalAmmoSecondary,
+    optional int    magazineAmmo,
+    optional bool   clearStarterAmmo)
+{
+    local InventoryService service;
+    service = InventoryService(class'InventoryService'.static.Require());
+    if (service == none) {
+        return none;
+    }
+    return service.AddWeaponWithAmmo(   pawn, weaponClassToAdd,
+                                        totalAmmoPrimary, totalAmmoSecondary,
+                                        magazineAmmo, clearStarterAmmo);
+}
+
+/**
+ *  Auxiliary method for "merging" weapons. Basically acts as
+ *  a `AddWeaponWithAmmo()` - creates and adds a weapons of the given class to
+ *  the `pawn`. But instead of taking numeric parameters to specify starter
+ *  ammunition, copies ammunition counts (adding them together) from two weapons
+ *  (`weaponToMerge1` and `weaponToMerge2`) specified for "merging"
+ *
+ *  @param  pawn            `Pawn` to which we should add new merged weapon.
+ *      If `none` - method does nothing.
+ *  @param  mergedClass     Class of the weapon we need to add as a result
+ *      of "merging". If `none` - method does nothing.
+ *  @param  weaponToMerge1  First weapon from which to copy ammunition counts.
+ *      In case it is of a child class of `KFWeapon`, also copies magazine size.
+ *      If `none` - assumes all ammo counts to be zero. 
+ *  @param  weaponToMerge2  Second weapon from which to copy ammunition counts.
+ *      Completely interchangeable with `weaponToMerge1`.
+ *  @param  clearStarterAmmo    Newly created weapons usually come with some
+ *      default amount of ammo. Setting this flag to `true` will remove it
+ *      before adding ammunition counts from `weaponToMerge1` and
+ *      `weaponToMerge2`.
+ *  @return Instance of the newly created weapon. `none` in case of failure or
+ *      if created weapon was destroyed in the process of adding it to
+ *      the `pawn` (can happen as a result of interaction with preexisting
+ *      weapons - e.g. pistol can merge with another one of the same type and
+ *      produce a new weapon).
+ */
+public function Weapon MergeWeapons(
+    Pawn            ownerPawn,
+    class<Weapon>   mergedClass,
+    optional Weapon weaponToMerge1,
+    optional Weapon weaponToMerge2,
+    optional bool   clearStarterAmmo)
+{
+    local InventoryService service;
+    service = InventoryService(class'InventoryService'.static.Require());
+    if (service == none) {
+        return none;
+    }
+    return service.MergeWeapons(ownerPawn, mergedClass,
+                                weaponToMerge1, weaponToMerge2);
+}
+
+defaultproperties
+{
+    dualiesClasses(0)=(single=class'KFMod.SinglePickup',dual=class'KFMod.DualiesPickup')
+    dualiesClasses(1)=(single=class'KFMod.Magnum44Pickup',dual=class'KFMod.Dual44MagnumPickup')
+    dualiesClasses(2)=(single=class'KFMod.MK23Pickup',dual=class'KFMod.DualMK23Pickup')
+    dualiesClasses(3)=(single=class'KFMod.DeaglePickup',dual=class'KFMod.DualDeaglePickup')
+    dualiesClasses(4)=(single=class'KFMod.GoldenDeaglePickup',dual=class'KFMod.GoldenDualDeaglePickup')
+    dualiesClasses(5)=(single=class'KFMod.FlareRevolverPickup',dual=class'KFMod.DualFlareRevolverPickup')
+}

sources/Unreal/InventoryAPI/InventoryService.uc

@@ -0,0 +1,128 @@
+/**
+ *      Service that simply does some of the work of `InventoryService`, since
+ *  working with `Actor`s that can get destroyed in the process is much safer
+ *  inside another `Actor`.
+ *      For description of all methods see `InventoryAPI`.
+ *      Copyright 2022 Anton Tarasenko
+ *------------------------------------------------------------------------------
+ * This file is part of Acedia.
+ *
+ * Acedia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Acedia is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Acedia.  If not, see <https://www.gnu.org/licenses/>.
+ */
+class InventoryService extends Service;
+
+public function Weapon AddWeaponWithAmmo(
+    Pawn            pawn,
+    class<Weapon>   weaponClassToAdd,
+    optional int    totalAmmoPrimary,
+    optional int    totalAmmoSecondary,
+    optional int    magazineAmmo,
+    optional bool   clearStarterAmmo)
+{
+    local Weapon    newWeapon;
+    local KFWeapon  newKFWeapon;
+    if (pawn == none)       return none;
+    newWeapon = Weapon(_.memory.Allocate(weaponClassToAdd));
+    if (newWeapon == none)  return none;
+    //  It is possible that `newWeapon` can get destroyed somewhere here,
+    //  so add two more checks
+    _.unreal.GetKFGameType().WeaponSpawned(newWeapon);
+    if (newWeapon == none)  return none;
+    newWeapon.GiveTo(pawn);
+    if (newWeapon == none)  return none;
+
+    //  Update ammo & magazine (if applicable)
+    if (clearStarterAmmo) {
+        ClearAmmo(newWeapon);
+    }
+    newKFWeapon = KFWeapon(newWeapon);
+    if (newKFWeapon != none)
+    {
+        if (clearStarterAmmo) {
+            newKFWeapon.magAmmoRemaining = 0;
+        }
+        newKFWeapon.magAmmoRemaining += magazineAmmo;
+    }
+    if (totalAmmoPrimary > 0) {
+        newWeapon.AddAmmo(totalAmmoPrimary, 0); 
+    }
+    if (totalAmmoSecondary > 0) {
+        newWeapon.AddAmmo(totalAmmoSecondary, 1); 
+    }
+    return newWeapon;
+}
+
+public function Weapon MergeWeapons(
+    Pawn            pawn,
+    class<Weapon>   mergedClass,
+    optional Weapon weaponToMerge1,
+    optional Weapon weaponToMerge2,
+    optional bool   clearStarterAmmo)
+{
+    local int       totalAmmoPrimary, totalAmmoSecondary, magazineAmmo;
+    local KFWeapon  kfWeapon;
+    if (pawn == none) {
+        return none;
+    }
+    if (weaponToMerge1 != none)
+    {
+        kfWeapon = KFWeapon(weaponToMerge1);
+        if (kfWeapon != none) {
+            magazineAmmo += kfWeapon.magAmmoRemaining;
+        }
+        totalAmmoPrimary    += weaponToMerge1.AmmoAmount(0);
+        totalAmmoSecondary  += weaponToMerge1.AmmoAmount(1);
+        weaponToMerge1.Destroyed();
+        if (weaponToMerge1 != none) {
+            weaponToMerge1.Destroy();
+        }
+    }
+    if (weaponToMerge2 != none)
+    {
+        kfWeapon = KFWeapon(weaponToMerge2);
+        if (kfWeapon != none) {
+            magazineAmmo += kfWeapon.magAmmoRemaining;
+        }
+        totalAmmoPrimary    += weaponToMerge2.AmmoAmount(0);
+        totalAmmoSecondary  += weaponToMerge2.AmmoAmount(1);
+        weaponToMerge2.Destroyed();
+        if (weaponToMerge2 != none) {
+            weaponToMerge2.Destroy();
+        }
+    }
+    return AddWeaponWithAmmo(   pawn, mergedClass, totalAmmoPrimary,
+                                totalAmmoSecondary, magazineAmmo,
+                                clearStarterAmmo);
+}
+
+public final function ClearAmmo(Weapon weapon)
+{
+    local float     auxiliary, currentAmmoPrimary, currentAmmoSecondary;
+    local KFWeapon  kfWeapon;
+    if (weapon == none) {
+        return;
+    }
+    weapon.GetAmmoCount(auxiliary, currentAmmoPrimary);
+    //weapon.GetSecondaryAmmoCount(auxiliary, currentAmmoSecondary);
+    weapon.AddAmmo(-currentAmmoPrimary, 0);
+    weapon.AddAmmo(-currentAmmoSecondary, 1);
+    kfWeapon = KFWeapon(weapon);
+    if (kfWeapon != none) {
+        kfWeapon.magAmmoRemaining = 0;
+    }
+}
+
+defaultproperties
+{
+}

sources/Unreal/Tests/TEST_UnrealAPI.uc

@@ -156,43 +156,43 @@ protected static function SubTest_InventoryChainFetchingSingle(Inventory chain)
 {
     Issue("Does not find correct first entry inside the inventory chain.");
     TEST_ExpectTrue(
-            __().unreal.GetInventoryFrom(class'MockInventoryA', chain)
+            __().unreal.inventory.Get(class'MockInventoryA', chain)
         ==  chain.inventory.inventory);
     TEST_ExpectTrue(
-            __().unreal.GetInventoryFrom(class'MockInventoryB', chain)
+            __().unreal.inventory.Get(class'MockInventoryB', chain)
         ==  chain.inventory);
     TEST_ExpectTrue(
-            __().unreal.GetInventoryFrom(class'MockInventoryAChild', chain)
+            __().unreal.inventory.Get(class'MockInventoryAChild', chain)
         ==  chain);
 
     Issue("Incorrectly finds missing inventory entries.");
-    TEST_ExpectNone(__().unreal.GetInventoryFrom(none, chain));
-    TEST_ExpectNone(__().unreal.GetInventoryFrom(class'Winchester', chain));
+    TEST_ExpectNone(__().unreal.inventory.Get(none, chain));
+    TEST_ExpectNone(__().unreal.inventory.Get(class'Winchester', chain));
 
     Issue("Does not find correct first entry inside the inventory chain when" @
         "allowing for child classes.");
     TEST_ExpectTrue(
-            __().unreal.GetInventoryFrom(class'MockInventoryA', chain, true)
+            __().unreal.inventory.Get(class'MockInventoryA', chain, true)
         ==  chain);
     TEST_ExpectTrue(
-            __().unreal.GetInventoryFrom(class'MockInventoryB', chain, true)
+            __().unreal.inventory.Get(class'MockInventoryB', chain, true)
         ==  chain.inventory);
     TEST_ExpectTrue(
-        __().unreal.GetInventoryFrom(class'MockInventoryAChild', chain, true)
+        __().unreal.inventory.Get(class'MockInventoryAChild', chain, true)
         == chain);
 
     Issue("Incorrectly finds missing inventory entries when allowing for" @
         "child classes.");
-    TEST_ExpectNone(__().unreal.GetInventoryFrom(none, chain, true));
-    TEST_ExpectNone(__().unreal.GetInventoryFrom(   class'Winchester', chain,
-                                                    true));
+    TEST_ExpectNone(__().unreal.inventory.Get(none, chain, true));
+    TEST_ExpectNone(__().unreal.inventory.Get(  class'Winchester', chain,
+                                                true));
 }
 
 protected static function SubTest_InventoryChainFetchingMany(Inventory chain)
 {
     local array<Inventory> result;
     Issue("Does not find correct entries inside the inventory chain.");
-    result = __().unreal.GetAllInventoryFrom(class'MockInventoryB', chain);
+    result = __().unreal.inventory.GetAll(class'MockInventoryB', chain);
     TEST_ExpectTrue(result.length == 2);
     TEST_ExpectTrue(result[0] == chain.inventory);
     TEST_ExpectTrue(result[1] == chain.inventory.inventory.inventory.inventory);
@@ -200,12 +200,12 @@ protected static function SubTest_InventoryChainFetchingMany(Inventory chain)
     Issue("Does not find correct entries inside the inventory chain when" @
         "allowing for child classes.");
     result =
-        __().unreal.GetAllInventoryFrom(class'MockInventoryB', chain, true);
+        __().unreal.inventory.GetAll(class'MockInventoryB', chain, true);
     TEST_ExpectTrue(result.length == 2);
     TEST_ExpectTrue(result[0] == chain.inventory);
     TEST_ExpectTrue(result[1] == chain.inventory.inventory.inventory.inventory);
     result =
-        __().unreal.GetAllInventoryFrom(class'MockInventoryA', chain, true);
+        __().unreal.inventory.GetAll(class'MockInventoryA', chain, true);
     TEST_ExpectTrue(result.length == 5);
     TEST_ExpectTrue(result[0] == chain);
     TEST_ExpectTrue(result[1] == chain.inventory.inventory);
@@ -218,9 +218,9 @@ protected static function SubTest_InventoryChainFetchingMany(Inventory chain)
         ==  chain.inventory.inventory.inventory.inventory.inventory.inventory);
     
     Issue("Does not return empty array for non-existing inventory class.");
-    result = __().unreal.GetAllInventoryFrom(class'Winchester', chain);
+    result = __().unreal.inventory.GetAll(class'Winchester', chain);
     TEST_ExpectTrue(result.length == 0);
-    result = __().unreal.GetAllInventoryFrom(class'Winchester', chain, true);
+    result = __().unreal.inventory.GetAll(class'Winchester', chain, true);
     TEST_ExpectTrue(result.length == 0);
 }
 

sources/Unreal/UnrealAPI.uc

@@ -1,7 +1,7 @@
 /**
  *      Low-level API that provides set of utility methods for working with
  *  unreal script classes.
- *      Copyright 2021 Anton Tarasenko
+ *      Copyright 2021 - 2022 Anton Tarasenko
  *------------------------------------------------------------------------------
  * This file is part of Acedia.
  *
@@ -23,6 +23,7 @@ class UnrealAPI extends AcediaObject;
 var public MutatorAPI   mutator;
 var public GameRulesAPI gameRules;
 var public BroadcastAPI broadcasts;
+var public InventoryAPI inventory;
 
 var private LoggerAPI.Definition fatalNoStalker;
 
@@ -31,6 +32,7 @@ protected function Constructor()
     mutator     = MutatorAPI(_.memory.Allocate(class'MutatorAPI'));
     gameRules   = GameRulesAPI(_.memory.Allocate(class'GameRulesAPI'));
     broadcasts  = BroadcastAPI(_.memory.Allocate(class'BroadcastAPI'));
+    inventory   = InventoryAPI(_.memory.Allocate(class'InventoryAPI'));
 }
 
 public function DropAPI()
@@ -38,6 +40,7 @@ public function DropAPI()
     mutator     = none;
     gameRules   = none;
     broadcasts  = none;
+    inventory   = none;
 }
 
 /**
@@ -199,93 +202,6 @@ public final function PlayerController GetLocalPlayer()
         .GetLocalPlayerController();
 }
 
-/**
- *  Convenience method for finding a first inventory entry of the given
- *  class `inventoryClass` in the given inventory chain `inventoryChain`.
- *
- *  Inventory is stored as a linked list, where next inventory item is available
- *  through the `inventory` reference. This method follows this list, starting
- *  from `inventoryChain` until it finds `Inventory` of the appropriate class
- *  or reaches the end of the list.
- *
- *  @param  inventoryClass      Class of the inventory we are interested in.
- *  @param  inventoryChain      Inventory chain in which we should search for
- *      the given class.
- *  @param  acceptChildClass    `true` if method should also return any
- *      `Inventory` of class derived from `inventoryClass` and `false` if
- *      we want given class specifically (default).
- *  @return First inventory from `inventoryChain` that matches given
- *      `inventoryClass` class (whether exactly or as a child class,
- *      in case `acceptChildClass == true`).
- */
-public final function Inventory GetInventoryFrom(
-    class<Inventory>    inventoryClass,
-    Inventory           inventoryChain,
-    optional bool       acceptChildClass)
-{
-    if (inventoryClass == none) {
-        return none;
-    }
-    while (inventoryChain != none)
-    {
-        if (inventoryChain.class == inventoryClass) {
-            return inventoryChain;
-        }
-        if (    acceptChildClass
-            &&  ClassIsChildOf(inventoryChain.class, inventoryClass))
-        {
-            return inventoryChain;
-        }
-        inventoryChain = inventoryChain.inventory;
-    }
-    return none;
-}
-
-/**
- *  Convenience method for finding a all inventory entries of the given
- *  class `inventoryClass` in the given inventory chain `inventoryChain`.
- *
- *  Inventory is stored as a linked list, where next inventory item is available
- *  through the `inventory` reference. This method follows this list, starting
- *  from `inventoryChain` until the end of the list.
- *
- *  @param  inventoryClass      Class of the inventory we are interested in.
- *  @param  inventoryChain      Inventory chain in which we should search for
- *      the given class.
- *  @param  acceptChildClass    `true` if method should also return any
- *      `Inventory` of class derived from `inventoryClass` and `false` if
- *      we want given class specifically (default).
- *  @return Array of inventory items from `inventoryChain` that match given
- *      `inventoryClass` class (whether exactly or as a child class,
- *      in case `acceptChildClass == true`).
- */
-public final function array<Inventory> GetAllInventoryFrom(
-    class<Inventory>    inventoryClass,
-    Inventory           inventoryChain,
-    optional bool       acceptChildClass)
-{
-    local bool              shouldAdd;
-    local array<Inventory>  result;
-    if (inventoryClass == none) {
-        return result;
-    }
-    while (inventoryChain != none)
-    {
-        shouldAdd = false;
-        if (inventoryChain.class == inventoryClass) {
-            shouldAdd = true;
-        }
-        else if (acceptChildClass) {
-            shouldAdd = ClassIsChildOf(inventoryChain.class, inventoryClass);
-        }
-        if (shouldAdd) {
-            result[result.length] = inventoryChain;
-        }
-        inventoryChain = inventoryChain.inventory;
-    }
-    return result;
-}
-
 /**
  *  Creates reference object to store a `Actor` value.
  *