Cstrike: Add CS_OnGetItemPrice forward to get/alter an item price on purchase

modules/cstrike/cstrike/CstrikeHacks.cpp

@@ -23,6 +23,7 @@ void CtrlDetours_Natives(bool set);
 int ForwardInternalCommand = -1;
 int ForwardOnBuy           = -1;
 int ForwardOnBuyAttempt    = -1;
+int ForwardOnGetItemPrice  = -1;
 
 int *UseBotArgs;
 const char **BotArgs;
@@ -258,6 +259,18 @@ DETOUR_DECL_MEMBER2(AddAccount, void, int, amount, bool, bTrackChange) // void C
 		{
 			return;
 		}
+		else if (ForwardOnGetItemPrice != -1)
+		{
+			int client = G_HL_TypeConversion.cbase_to_id(this);
+
+			cell price[1]; *price = -amount;
+			cell preparedCell = MF_PrepareCellArrayA(price, sizeof(price), true);
+
+			if (MF_IsPlayerAlive(client) && MF_ExecuteForward(ForwardOnGetItemPrice, client, CurrentItemId, preparedCell) > 0)
+			{
+				amount = -*price;
+			}
+		}
 	}
 
 	DETOUR_MEMBER_CALL(AddAccount)(amount, bTrackChange);

modules/cstrike/cstrike/CstrikeHacks.h

@@ -34,6 +34,7 @@ extern IGameConfig *CommonConfig;
 extern int ForwardInternalCommand;
 extern int ForwardOnBuy;
 extern int ForwardOnBuyAttempt;
+extern int ForwardOnGetItemPrice;
 
 typedef edict_t* (*CreateNamedEntityFunc)(string_t iszClassname);
 typedef void*    (*UTIL_FindEntityByStringFunc)(void* pStartEntity, const char *szKeyword, const char *szValue);

modules/cstrike/cstrike/CstrikeMain.cpp

@@ -65,16 +65,18 @@ void OnPluginsLoaded()
 	ForwardInternalCommand = MF_RegisterForward("CS_InternalCommand", ET_STOP, FP_CELL, FP_STRING, FP_DONE);
 	ForwardOnBuy           = MF_RegisterForward("CS_OnBuy"          , ET_STOP, FP_CELL, FP_CELL, FP_DONE);
 	ForwardOnBuyAttempt    = MF_RegisterForward("CS_OnBuyAttempt"   , ET_STOP, FP_CELL, FP_CELL, FP_DONE);
+	ForwardOnGetItemPrice  = MF_RegisterForward("CS_OnGetItemPrice" , ET_STOP, FP_CELL, FP_CELL, FP_ARRAY, FP_DONE);
 
 	// Checking whether such public forwards are used in plugins.
 	// Resetting variable to -1 to avoid running unnecessary code in ClientCommand.
 	if (!UTIL_CheckForPublic("CS_InternalCommand"))   { ForwardInternalCommand = -1; }
 	if (!UTIL_CheckForPublic("CS_OnBuy"))             { ForwardOnBuy = -1; }
 	if (!UTIL_CheckForPublic("CS_OnBuyAttempt"))      { ForwardOnBuyAttempt = -1; }
+	if (!UTIL_CheckForPublic("CS_OnGetItemPrice"))    { ForwardOnGetItemPrice = -1; }
 
 	// And enable/disable detours when necessary.
-	ToggleDetour_ClientCommands(ForwardInternalCommand != -1 || ForwardOnBuy != -1 || ForwardOnBuyAttempt != -1);
+	ToggleDetour_ClientCommands(ForwardInternalCommand != -1 || ForwardOnBuy != -1 || ForwardOnBuyAttempt != -1 || ForwardOnGetItemPrice != -1);
-	ToggleDetour_BuyCommands(ForwardOnBuy != -1);
+	ToggleDetour_BuyCommands(ForwardOnBuy != -1 || ForwardOnGetItemPrice != -1);
 
 	// Search pev/vtable offset automatically.
 	TypeConversion.init();

plugins/include/cstrike.inc

@@ -1104,4 +1104,20 @@ forward CS_OnBuyAttempt(index, item);
  * @return          PLUGIN_CONTINUE to let the buy continue
  *                  PLUGIN_HANDLED to block the buy
  */
-forward CS_OnBuy(index, item);
+forward CS_OnBuy(index, item, &price);
+
+/**
+ * Called when a client purchased an item and game is about to apply item's price.
+ *
+ * @note This is called right after the user received the item and before the
+ *       money is deducted from their cash reserves.
+ * @note For a list of possible item ids see the CSI_* constants.
+ *
+ * @param index     Client index
+ * @param item      Item id
+ * @param price     Item price or buffer to store a newly price to
+ *
+ * @return          PLUGIN_CONTINUE to use the default price
+ *                  PLUGIN_HANDLED or higher to use a newly-set price
+ */
+forward CS_OnGetItemPrice(index, item, &price);