From a0ced5c34e86ca271bbeafd0b57566a04f788461 Mon Sep 17 00:00:00 2001
From: hispidence <squidshirehimself@gmail.com>
Date: Tue, 13 Jul 2021 13:21:13 +0100
Subject: [PATCH] Make GameLogicScript use kInventorySlots. Make InvItem a
 read-only table. This means we do not need to write an enum directly in the
 Lua source.

---
 TR5Main/Scripting/GameLogicScript.cpp | 36 +++++++++++++++++++++------
 TR5Main/Scripting/GameLogicScript.h   |  8 +++---
 2 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/TR5Main/Scripting/GameLogicScript.cpp b/TR5Main/Scripting/GameLogicScript.cpp
index e499eb3da..5682f002d 100644
--- a/TR5Main/Scripting/GameLogicScript.cpp
+++ b/TR5Main/Scripting/GameLogicScript.cpp
@@ -13,6 +13,7 @@
 #include "pickup.h"
 #include "newinv2.h"
 #include <iostream>
+#include "InventorySlots.h"
 
 extern GameFlow* g_GameFlow;
 GameScript* g_GameScript;
@@ -29,6 +30,26 @@ GameScript::GameScript(sol::state* lua) : LuaHandler{ lua }
 	m_lua->set_function("GetInvItemCount", &GameScript::InventoryGetCount);
 	m_lua->set_function("SetInvItemCount", &GameScript::InventorySetCount);
 
+	// Put all the data in InvItem's metatable	
+	m_lua->set("InvItemMeta", sol::as_table(kInventorySlots));
+
+	// Make the metatable's __index refer to itself so that requests
+	// to InvItem will go through to the metatable (and thus the
+	// kInventorySlot members)
+	m_lua->safe_script("InvItemMeta.__index = InvItemMeta");
+
+	// Don't allow InvItem to have new elements put into it
+	m_lua->safe_script("InvItemMeta.__newindex = function() error('InvItem is read-only') end");
+
+	// Protect the metatable
+	m_lua->safe_script("InvItemMeta.__metatable = 'metatable is protected'");
+
+	auto tab = m_lua->create_named_table("InvItem");
+	m_lua->safe_script("setmetatable(InvItem, InvItemMeta)");
+
+	// point InvItemMeta array from the table
+	m_lua->safe_script("InvItemMeta = nil");
+
 	GameScriptItemInfo::Register(m_lua);
 	GameScriptPosition::Register(m_lua);
 	GameScriptRotation::Register(m_lua);
@@ -311,26 +332,25 @@ void GameScript::Earthquake(int strength)
 }
 
 // Inventory
-void GameScript::InventoryAdd(int slot, sol::optional<int> count)
+void GameScript::InventoryAdd(GAME_OBJECT_ID slot, sol::optional<int> count)
 {
-	PickedUpObject(static_cast<GAME_OBJECT_ID>(inventry_objects_list[slot].object_number), count.value_or(0));
+	PickedUpObject(slot, count.value_or(0));
 }
 
-void GameScript::InventoryRemove(int slot, sol::optional<int> count)
+void GameScript::InventoryRemove(GAME_OBJECT_ID slot, sol::optional<int> count)
 {
 	RemoveObjectFromInventory(static_cast<GAME_OBJECT_ID>(inventry_objects_list[slot].object_number), count.value_or(0));
 }
 
-int GameScript::InventoryGetCount(int slot)
+int GameScript::InventoryGetCount(GAME_OBJECT_ID slot)
 {
-	return GetInventoryCount(static_cast<GAME_OBJECT_ID>( inventry_objects_list[slot].object_number));
+	return GetInventoryCount(slot);
 }
 
-void GameScript::InventorySetCount(int slot, int count)
+void GameScript::InventorySetCount(GAME_OBJECT_ID slot, int count)
 {
-	auto result = static_cast<GAME_OBJECT_ID>( inventry_objects_list[slot].object_number );
 	// add the amount we'd need to add to get to count
-	int currAmt = GetInventoryCount(result);
+	int currAmt = GetInventoryCount(slot);
 	InventoryAdd(slot, count - currAmt);
 }
 
diff --git a/TR5Main/Scripting/GameLogicScript.h b/TR5Main/Scripting/GameLogicScript.h
index 8d232e7bb..42b4b7c37 100644
--- a/TR5Main/Scripting/GameLogicScript.h
+++ b/TR5Main/Scripting/GameLogicScript.h
@@ -96,10 +96,10 @@ public:
 	void								Earthquake(int strength);
 
 	// Inventory
-	static void							InventoryAdd(int slot, sol::optional<int> count);
-	static void							InventoryRemove(int slot, sol::optional<int> count);
-	static int							InventoryGetCount(int slot);
-	static void							InventorySetCount(int slot, int count);
+	static void							InventoryAdd(GAME_OBJECT_ID slot, sol::optional<int> count);
+	static void							InventoryRemove(GAME_OBJECT_ID slot, sol::optional<int> count);
+	static int							InventoryGetCount(GAME_OBJECT_ID slot);
+	static void							InventorySetCount(GAME_OBJECT_ID slot, int count);
 	void								InventoryCombine(int slot1, int slot2);
 	void								InventorySeparate(int slot);