From 3fb8be385bf9d84343b0f7bd8ad707edce991441 Mon Sep 17 00:00:00 2001
From: Anders Jenbo <anders@jenbo.dk>
Date: Sun, 20 Apr 2025 04:49:39 +0200
Subject: [PATCH] Add support for MPQ packed mods and turn Hellfire into one

---
 CMake/Assets.cmake                |  1 +
 Source/CMakeLists.txt             |  1 +
 Source/DiabloUI/selstart.cpp      |  1 +
 Source/DiabloUI/settingsmenu.cpp  |  2 --
 Source/diablo.cpp                 | 18 +++++++++++-----
 Source/discord/discord.cpp        |  6 +++---
 Source/engine/assets.cpp          | 35 ++++++++++++++++++++++---------
 Source/engine/assets.hpp          |  3 +++
 Source/game_mode.cpp              | 16 --------------
 Source/game_mode.hpp              |  5 -----
 Source/lua/lua.cpp                | 21 ++++++++++++++++++-
 Source/lua/lua.hpp                |  4 ++++
 Source/lua/modules/audio.cpp      |  2 +-
 Source/lua/modules/hellfire.cpp   | 18 ++++++++++++++++
 Source/lua/modules/hellfire.hpp   |  9 ++++++++
 Source/options.cpp                | 18 ++++++++++++++--
 Source/options.h                  |  5 ++---
 assets/lua/mods/Hellfire/init.lua |  4 ++++
 18 files changed, 121 insertions(+), 48 deletions(-)
 create mode 100644 Source/lua/modules/hellfire.cpp
 create mode 100644 Source/lua/modules/hellfire.hpp
 create mode 100644 assets/lua/mods/Hellfire/init.lua

diff --git a/CMake/Assets.cmake b/CMake/Assets.cmake
index d2e1b0e72..43919f68c 100644
--- a/CMake/Assets.cmake
+++ b/CMake/Assets.cmake
@@ -151,6 +151,7 @@ set(devilutionx_assets
   lua/devilutionx/events.lua
   lua/inspect.lua
   lua/mods/clock/init.lua
+  lua/mods/Hellfire/init.lua
   lua/repl_prelude.lua
   nlevels/cutl5w.clx
   nlevels/cutl6w.clx
diff --git a/Source/CMakeLists.txt b/Source/CMakeLists.txt
index f0aa29904..4d4620972 100644
--- a/Source/CMakeLists.txt
+++ b/Source/CMakeLists.txt
@@ -107,6 +107,7 @@ set(libdevilutionx_SRCS
   lua/autocomplete.cpp
   lua/lua.cpp
   lua/modules/audio.cpp
+  lua/modules/hellfire.cpp
   lua/modules/dev.cpp
   lua/modules/dev/display.cpp
   lua/modules/dev/items.cpp
diff --git a/Source/DiabloUI/selstart.cpp b/Source/DiabloUI/selstart.cpp
index 2d468f6be..0e755a1df 100644
--- a/Source/DiabloUI/selstart.cpp
+++ b/Source/DiabloUI/selstart.cpp
@@ -19,6 +19,7 @@ void ItemSelected(size_t value)
 {
 	auto option = static_cast<StartUpGameMode>(vecDialogItems[value]->m_value);
 	GetOptions().GameMode.gameMode.SetValue(option);
+	GetOptions().Mods.SetHellfireEnabled(option == StartUpGameMode::Hellfire);
 	SaveOptions();
 	endMenu = true;
 }
diff --git a/Source/DiabloUI/settingsmenu.cpp b/Source/DiabloUI/settingsmenu.cpp
index a21d8900d..ef1c33f28 100644
--- a/Source/DiabloUI/settingsmenu.cpp
+++ b/Source/DiabloUI/settingsmenu.cpp
@@ -68,8 +68,6 @@ bool IsValidEntry(OptionEntryBase *pOptionEntry)
 	auto flags = pOptionEntry->GetFlags();
 	if (HasAnyOf(flags, OptionEntryFlags::NeedDiabloMpq) && !HaveIntro())
 		return false;
-	if (HasAnyOf(flags, OptionEntryFlags::NeedHellfireMpq) && !HaveHellfire())
-		return false;
 	return HasNoneOf(flags, OptionEntryFlags::Invisible | (gbIsHellfire ? OptionEntryFlags::OnlyDiablo : OptionEntryFlags::OnlyHellfire));
 }
 
diff --git a/Source/diablo.cpp b/Source/diablo.cpp
index afe7e4d31..0f4f4776e 100644
--- a/Source/diablo.cpp
+++ b/Source/diablo.cpp
@@ -1192,10 +1192,18 @@ void DiabloInit()
 {
 	if (forceSpawn || *GetOptions().GameMode.shareware)
 		gbIsSpawn = true;
-	if (forceDiablo || *GetOptions().GameMode.gameMode == StartUpGameMode::Diablo)
-		gbIsHellfire = false;
-	if (forceHellfire)
-		gbIsHellfire = true;
+
+	bool wasHellfireDiscovered = false;
+	if (!forceDiablo && !forceHellfire)
+		wasHellfireDiscovered = (HaveHellfire() && *GetOptions().GameMode.gameMode == StartUpGameMode::Ask);
+	bool enableHellfire = forceHellfire || wasHellfireDiscovered;
+	if (!forceDiablo && *GetOptions().GameMode.gameMode == StartUpGameMode::Hellfire) { // Migrate legacy options
+		GetOptions().GameMode.gameMode.SetValue(StartUpGameMode::Diablo);
+		enableHellfire = true;
+	}
+	if (forceDiablo || enableHellfire) {
+		GetOptions().Mods.SetHellfireEnabled(enableHellfire);
+	}
 
 	gbIsHellfireSaveGame = gbIsHellfire;
 
@@ -1213,7 +1221,7 @@ void DiabloInit()
 	UiInitialize();
 	was_ui_init = true;
 
-	if (gbIsHellfire && !forceHellfire && *GetOptions().GameMode.gameMode == StartUpGameMode::Ask) {
+	if (wasHellfireDiscovered) {
 		UiSelStartUpGameOption();
 		if (!gbIsHellfire) {
 			// Reinitialize the UI Elements because we changed the game
diff --git a/Source/discord/discord.cpp b/Source/discord/discord.cpp
index 7ec110b1c..c4d3f5467 100644
--- a/Source/discord/discord.cpp
+++ b/Source/discord/discord.cpp
@@ -17,9 +17,9 @@
 #include <fmt/format.h>
 
 #include "config.h"
-#include "game_mode.hpp"
 #include "levels/gendung.h"
 #include "levels/setmaps.h"
+#include "lua/lua.hpp"
 #include "multi.h"
 #include "panels/charpanel.hpp"
 #include "player.h"
@@ -29,11 +29,11 @@
 
 namespace devilution {
 namespace {
-void IsHellfireChanged()
+void ModChanged()
 {
 	discord_manager::UpdateMenu(true);
 }
-const auto IsHellfireChangedHandler = (AddIsHellfireChangeHandler(IsHellfireChanged), true);
+const auto ModChangedHandler = (AddModsChangedHandler(ModChanged), true);
 } // namespace
 
 namespace discord_manager {
diff --git a/Source/engine/assets.cpp b/Source/engine/assets.cpp
index f3c5b5238..ab89442f7 100644
--- a/Source/engine/assets.cpp
+++ b/Source/engine/assets.cpp
@@ -3,7 +3,6 @@
 #include <algorithm>
 #include <cstdint>
 #include <cstring>
-#include <string_view>
 
 #include "appfat.h"
 #include "game_mode.hpp"
@@ -76,9 +75,6 @@ bool FindMpqFile(std::string_view filename, MpqArchive **archive, uint32_t *file
 
 	// Iterate over archives in reverse order to prefer files from high priority archives
 	for (auto rit = MpqArchives.rbegin(); rit != MpqArchives.rend(); ++rit) {
-		int priority = rit->first;
-		if (!gbIsHellfire && priority >= 8000 && priority < 9000)
-			continue;
 		if (rit->second->GetFileNumber(fileHash, *fileNumber)) {
 			*archive = rit->second.get();
 			return true;
@@ -423,8 +419,6 @@ void LoadGameArchives()
 		}
 	}
 	hellfire_data_path = FindUnpackedMpqData(paths, "hellfire");
-	if (hellfire_data_path)
-		gbIsHellfire = true;
 	if (forceHellfire && !hellfire_data_path)
 		InsertCDDlg("hellfire");
 #else // !UNPACKED_MPQS
@@ -442,15 +436,11 @@ void LoadGameArchives()
 		}
 	}
 
-	if (HasHellfireMpq)
-		gbIsHellfire = true;
 	if (forceHellfire && !HasHellfireMpq)
 		InsertCDDlg("hellfire.mpq");
 	LoadMPQ(paths, "hfbard.mpq", 8110);
 	LoadMPQ(paths, "hfbarb.mpq", 8120);
 #endif
-	if (gbIsHellfire)
-		LoadHellfireArchives();
 }
 
 void LoadHellfireArchives()
@@ -473,4 +463,29 @@ void LoadHellfireArchives()
 		DisplayFatalErrorAndExit(_("Some Hellfire MPQs are missing"), _("Not all Hellfire MPQs were found.\nPlease copy all the hf*.mpq files."));
 }
 
+void UnloadModArchives()
+{
+#ifndef UNPACKED_MPQS
+	for (auto it = MpqArchives.begin(); it != MpqArchives.end();) {
+		if ((it->first >= 8000 && it->first < 9000) || it->first >= 10000) {
+			it = MpqArchives.erase(it); // erase returns the next valid iterator
+		} else {
+			++it;
+		}
+	}
+#endif
+}
+
+void LoadModArchives(std::span<const std::string_view> modnames)
+{
+#ifndef UNPACKED_MPQS
+	int priority = 10000;
+	const std::string modsPath = StrCat(paths::PrefPath(), "mods/");
+	for (std::string_view modname : modnames) {
+		LoadMPQ({ modsPath }, StrCat(modname, ".mpq"), priority);
+		priority++;
+	}
+#endif
+}
+
 } // namespace devilution
diff --git a/Source/engine/assets.hpp b/Source/engine/assets.hpp
index bba39b86e..f466ce770 100644
--- a/Source/engine/assets.hpp
+++ b/Source/engine/assets.hpp
@@ -5,6 +5,7 @@
 #include <cstdio>
 #include <map>
 #include <optional>
+#include <span>
 #include <string>
 #include <string_view>
 
@@ -297,6 +298,8 @@ void LoadCoreArchives();
 void LoadLanguageArchive();
 void LoadGameArchives();
 void LoadHellfireArchives();
+void UnloadModArchives();
+void LoadModArchives(std::span<const std::string_view> modnames);
 
 #ifdef UNPACKED_MPQS
 #ifdef BUILD_TESTING
diff --git a/Source/game_mode.cpp b/Source/game_mode.cpp
index 7830961b1..53bd4be96 100644
--- a/Source/game_mode.cpp
+++ b/Source/game_mode.cpp
@@ -6,17 +6,6 @@
 
 namespace devilution {
 namespace {
-std::vector<tl::function_ref<void()>> IsHellfireChangeHandlers;
-
-void OptionGameModeChanged()
-{
-	gbIsHellfire = *GetOptions().GameMode.gameMode == StartUpGameMode::Hellfire;
-	for (tl::function_ref<void()> handler : IsHellfireChangeHandlers) {
-		handler();
-	}
-}
-const auto OptionChangeHandlerGameMode = (GetOptions().GameMode.gameMode.SetValueChangedCallback(OptionGameModeChanged), true);
-
 void OptionSharewareChanged()
 {
 	gbIsSpawn = *GetOptions().GameMode.shareware;
@@ -29,9 +18,4 @@ bool gbIsHellfire;
 bool gbVanilla;
 bool forceHellfire;
 
-void AddIsHellfireChangeHandler(tl::function_ref<void()> callback)
-{
-	IsHellfireChangeHandlers.push_back(callback);
-}
-
 } // namespace devilution
diff --git a/Source/game_mode.hpp b/Source/game_mode.hpp
index 0be30d72e..60ac5e8f0 100644
--- a/Source/game_mode.hpp
+++ b/Source/game_mode.hpp
@@ -1,7 +1,5 @@
 #pragma once
 
-#include <function_ref.hpp>
-
 #include "utils/attributes.h"
 
 namespace devilution {
@@ -15,7 +13,4 @@ extern DVL_API_FOR_TEST bool gbVanilla;
 /** Whether the Hellfire mode is required (forced). */
 extern bool forceHellfire;
 
-/** Adds a handler to be called then `gbIsHellfire` changes after the initial startup. */
-void AddIsHellfireChangeHandler(tl::function_ref<void()> callback);
-
 } // namespace devilution
diff --git a/Source/lua/lua.cpp b/Source/lua/lua.cpp
index abfa386df..f4d6958ac 100644
--- a/Source/lua/lua.cpp
+++ b/Source/lua/lua.cpp
@@ -11,6 +11,7 @@
 #include "appfat.h"
 #include "engine/assets.hpp"
 #include "lua/modules/audio.hpp"
+#include "lua/modules/hellfire.hpp"
 #include "lua/modules/i18n.hpp"
 #include "lua/modules/items.hpp"
 #include "lua/modules/log.hpp"
@@ -42,6 +43,8 @@ struct LuaState {
 
 std::optional<LuaState> CurrentLuaState;
 
+std::vector<tl::function_ref<void()>> IsModChangeHandlers;
+
 // A Lua function that we use to generate a `require` implementation.
 constexpr std::string_view RequireGenSrc = R"lua(
 function requireGen(env, loaded, loadFn)
@@ -198,17 +201,32 @@ sol::environment CreateLuaSandbox()
 	return sandbox;
 }
 
+void AddModsChangedHandler(tl::function_ref<void()> callback)
+{
+	IsModChangeHandlers.push_back(callback);
+}
+
 void LuaReloadActiveMods()
 {
 	// Loaded without a sandbox.
 	CurrentLuaState->events = RunScript(/*env=*/std::nullopt, "devilutionx.events", /*optional=*/false);
 	CurrentLuaState->commonPackages["devilutionx.events"] = CurrentLuaState->events;
 
-	for (std::string_view modname : GetOptions().Mods.GetActiveModList()) {
+	gbIsHellfire = false;
+	UnloadModArchives();
+
+	std::vector<std::string_view> modnames = GetOptions().Mods.GetActiveModList();
+	LoadModArchives(modnames);
+
+	for (std::string_view modname : modnames) {
 		std::string packageName = StrCat("mods.", modname, ".init");
 		RunScript(CreateLuaSandbox(), packageName, /*optional=*/true);
 	}
 
+	for (tl::function_ref<void()> handler : IsModChangeHandlers) {
+		handler();
+	}
+
 	LuaEvent("LoadModsComplete");
 }
 
@@ -243,6 +261,7 @@ void LuaInitialize()
 	    "devilutionx.player", LuaPlayerModule(lua),
 	    "devilutionx.render", LuaRenderModule(lua),
 	    "devilutionx.towners", LuaTownersModule(lua),
+	    "devilutionx.hellfire", LuaHellfireModule(lua),
 	    "devilutionx.message", [](std::string_view text) { EventPlrMsg(text, UiFlags::ColorRed); },
 	    // This package is loaded without a sandbox:
 	    "inspect", RunScript(/*env=*/std::nullopt, "inspect", /*optional=*/false));
diff --git a/Source/lua/lua.hpp b/Source/lua/lua.hpp
index afe360f31..80fbb1211 100644
--- a/Source/lua/lua.hpp
+++ b/Source/lua/lua.hpp
@@ -3,6 +3,7 @@
 #include <string_view>
 
 #include <expected.hpp>
+#include <function_ref.hpp>
 #include <sol/forward.hpp>
 
 namespace devilution {
@@ -15,4 +16,7 @@ sol::state &GetLuaState();
 sol::environment CreateLuaSandbox();
 sol::object SafeCallResult(sol::protected_function_result result, bool optional);
 
+/** Adds a handler to be called when mods status changes after the initial startup. */
+void AddModsChangedHandler(tl::function_ref<void()> callback);
+
 } // namespace devilution
diff --git a/Source/lua/modules/audio.cpp b/Source/lua/modules/audio.cpp
index e090ded05..8e486fcd5 100644
--- a/Source/lua/modules/audio.cpp
+++ b/Source/lua/modules/audio.cpp
@@ -1,4 +1,4 @@
-#include "lua/modules/render.hpp"
+#include "lua/modules/audio.hpp"
 
 #include <sol/sol.hpp>
 
diff --git a/Source/lua/modules/hellfire.cpp b/Source/lua/modules/hellfire.cpp
new file mode 100644
index 000000000..20c64f5db
--- /dev/null
+++ b/Source/lua/modules/hellfire.cpp
@@ -0,0 +1,18 @@
+#include "lua/modules/hellfire.hpp"
+
+#include <sol/sol.hpp>
+
+#include "engine/assets.hpp"
+#include "lua/metadoc.hpp"
+
+namespace devilution {
+
+sol::table LuaHellfireModule(sol::state_view &lua)
+{
+	sol::table table = lua.create_table();
+	SetWithSignature(table, "loadData", "()", []() { LoadHellfireArchives(); });
+	SetWithSignature(table, "enable", "()", []() { gbIsHellfire = true; });
+	return table;
+}
+
+} // namespace devilution
diff --git a/Source/lua/modules/hellfire.hpp b/Source/lua/modules/hellfire.hpp
new file mode 100644
index 000000000..b2a62a580
--- /dev/null
+++ b/Source/lua/modules/hellfire.hpp
@@ -0,0 +1,9 @@
+#pragma once
+
+#include <sol/sol.hpp>
+
+namespace devilution {
+
+sol::table LuaHellfireModule(sol::state_view &lua);
+
+} // namespace devilution
diff --git a/Source/options.cpp b/Source/options.cpp
index 8c6f44198..edbd11d69 100644
--- a/Source/options.cpp
+++ b/Source/options.cpp
@@ -65,6 +65,10 @@ void DiscoverMods()
 	// Add mods available by default:
 	std::unordered_set<std::string> modNames = { "clock" };
 
+	if (HaveHellfire()) {
+		modNames.insert("Hellfire");
+	}
+
 	// Check if the mods directory exists.
 	const std::string modsPath = StrCat(paths::PrefPath(), "mods");
 	if (DirectoryExists(modsPath.c_str())) {
@@ -414,7 +418,7 @@ std::string_view OptionCategoryBase::GetDescription() const
 
 GameModeOptions::GameModeOptions()
     : OptionCategoryBase("GameMode", N_("Game Mode"), N_("Game Mode Settings"))
-    , gameMode("Game", OptionEntryFlags::NeedHellfireMpq | OptionEntryFlags::RecreateUI, N_("Game Mode"), N_("Play Diablo or Hellfire."), StartUpGameMode::Ask,
+    , gameMode("Game", OptionEntryFlags::Invisible, N_("Game Mode"), N_("Play Diablo or Hellfire."), StartUpGameMode::Ask,
           {
               { StartUpGameMode::Diablo, N_("Diablo") },
               // Ask is missing, because we want to hide it from UI-Settings.
@@ -1542,6 +1546,16 @@ void ModOptions::RemoveModEntry(const std::string &modName)
 	});
 }
 
+void ModOptions::SetHellfireEnabled(bool enableHellfire)
+{
+	for (auto &modEntry : GetModEntries()) {
+		if (modEntry.name == "Hellfire") {
+			modEntry.enabled.SetValue(enableHellfire);
+			break;
+		}
+	}
+}
+
 std::forward_list<ModOptions::ModEntry> &ModOptions::GetModEntries()
 {
 	if (modEntries)
@@ -1559,7 +1573,7 @@ std::forward_list<ModOptions::ModEntry> &ModOptions::GetModEntries()
 
 ModOptions::ModEntry::ModEntry(std::string_view name)
     : name(name)
-    , enabled(this->name, OptionEntryFlags::None, this->name.c_str(), "", false)
+    , enabled(this->name, OptionEntryFlags::RecreateUI, this->name.c_str(), "", false)
 {
 }
 
diff --git a/Source/options.h b/Source/options.h
index e022d97e4..62c969809 100644
--- a/Source/options.h
+++ b/Source/options.h
@@ -116,8 +116,6 @@ enum class OptionEntryFlags : uint8_t {
 	RecreateUI = 1 << 5,
 	/** @brief diablo.mpq must be present. */
 	NeedDiabloMpq = 1 << 6,
-	/** @brief hellfire.mpq must be present. */
-	NeedHellfireMpq = 1 << 7,
 };
 use_enum_as_flags(OptionEntryFlags);
 
@@ -832,6 +830,7 @@ struct ModOptions : OptionCategoryBase {
 	std::vector<OptionEntryBase *> GetEntries() override;
 	void AddModEntry(const std::string &modName);
 	void RemoveModEntry(const std::string &modName);
+	void SetHellfireEnabled(bool enableHellfire);
 
 private:
 	struct ModEntry {
@@ -868,6 +867,7 @@ struct Options {
 	{
 		return {
 			&Language,
+			&Mods,
 			&GameMode,
 			&StartUp,
 			&Graphics,
@@ -880,7 +880,6 @@ struct Options {
 			&Chat,
 			&Keymapper,
 			&Padmapper,
-			&Mods,
 		};
 	}
 };
diff --git a/assets/lua/mods/Hellfire/init.lua b/assets/lua/mods/Hellfire/init.lua
new file mode 100644
index 000000000..0b2250b30
--- /dev/null
+++ b/assets/lua/mods/Hellfire/init.lua
@@ -0,0 +1,4 @@
+local hellfire = require("devilutionx.hellfire")
+
+hellfire.loadData()
+hellfire.enable()