2 files changed, 455 insertions, 174 deletions

diff --git a/primedev/core/filesystem/rpakfilesystem.cpp b/primedev/core/filesystem/rpakfilesystem.cpp
index da72646b..ebb9085a 100644
--- a/primedev/core/filesystem/rpakfilesystem.cpp
+++ b/primedev/core/filesystem/rpakfilesystem.cpp
@@ -2,206 +2,447 @@
 #include "mods/modmanager.h"
 #include "dedicated/dedicated.h"
 #include "core/tier0.h"
+#include "util/utils.h"
 
-AUTOHOOK_INIT()
-
-// there are more i'm just too lazy to add
+#pragma pack(push, 1)
 struct PakLoadFuncs
 {
-	void* unk0[3];
-	int (*LoadPakAsync)(const char* pPath, void* unknownSingleton, int flags, void* callback0, void* callback1);
-	void* unk1[2];
-	void* (*UnloadPak)(int iPakHandle, void* callback);
-	void* unk2[6];
-	void* (*LoadFile)(const char* path); // unsure
-	void* unk3[10];
-	void* (*ReadFileAsync)(const char* pPath, void* a2);
+	void (*InitRpakSystem)();
+	void (*AddAssetLoaderWithJobDetails)(/*assetTypeHeader*/ void*, uint32_t, int);
+	void (*AddAssetLoader)(/*assetTypeHeader*/ void*);
+	PakHandle (*LoadRpakFileAsync)(const char* pPath, void* allocator, int flags);
+	void (*LoadRpakFile)(const char*, __int64(__fastcall*)(), __int64, void(__cdecl*)());
+	__int64 qword28;
+	void (*UnloadPak)(PakHandle iPakHandle, void* callback);
+	__int64 qword38;
+	__int64 qword40;
+	__int64 qword48;
+	__int64 qword50;
+	FARPROC (*GetDllCallback)(__int16 a1, const CHAR* a2);
+	__int64 (*GetAssetByHash)(__int64 hash);
+	__int64 (*GetAssetByName)(const char* a1);
+	__int64 qword70;
+	__int64 qword78;
+	__int64 qword80;
+	__int64 qword88;
+	__int64 qword90;
+	__int64 qword98;
+	__int64 qwordA0;
+	__int64 qwordA8;
+	__int64 qwordB0;
+	__int64 qwordBB;
+	void* (*OpenFile)(const char* pPath);
+	__int64 CloseFile;
+	__int64 qwordD0;
+	__int64 FileReadAsync;
+	__int64 ComplexFileReadAsync;
+	__int64 GetReadJobState;
+	__int64 WaitForFileReadJobComplete;
+	__int64 CancelFileReadJob;
+	__int64 CancelFileReadJobAsync;
+	__int64 qword108;
 };
+static_assert(sizeof(PakLoadFuncs) == 0x110);
+#pragma pack(pop)
 
 PakLoadFuncs* g_pakLoadApi;
-
 PakLoadManager* g_pPakLoadManager;
-void** pUnknownPakLoadSingleton;
 
-int PakLoadManager::LoadPakAsync(const char* pPath, const ePakLoadSource nLoadSource)
+static char* pszCurrentMapRpakPath = nullptr;
+static PakHandle* piCurrentMapRpakHandle = nullptr;
+static PakHandle* piCurrentMapPatchRpakHandle = nullptr;
+static /*CModelLoader*/ void** ppModelLoader = nullptr;
+static void** rpakMemoryAllocator = nullptr;
+
+static __int64 (*o_pLoadGametypeSpecificRpaks)(const char* levelName) = nullptr;
+static __int64 (**o_pCleanMaterialSystemStuff)() = nullptr;
+static __int64 (**o_pCModelLoader_UnreferenceAllModels)(/*CModelLoader*/ void* a1) = nullptr;
+static char* (*o_pLoadlevelLoadscreen)(const char* levelName) = nullptr;
+static unsigned int (*o_pGetPakPatchNumber)(const char* pPakPath) = nullptr;
+
+// Marks all mod Paks to be unloaded on next map load.
+// Also cleans up any mod Paks that are already unloaded.
+void PakLoadManager::UnloadAllModPaks()
 {
-	int nHandle = g_pakLoadApi->LoadPakAsync(pPath, *pUnknownPakLoadSingleton, 2, nullptr, nullptr);
-
-	// set the load source of the pak we just loaded
-	if (nHandle != -1)
-		GetPakInfo(nHandle)->m_nLoadSource = nLoadSource;
-
-	return nHandle;
+	NS::log::rpak->info("Reloading RPaks on next map load...");
+	for (auto& modPak : m_modPaks)
+	{
+		modPak.m_markedForDelete = true;
+	}
+	// clean up any paks that are both marked for unload and already unloaded
+	CleanUpUnloadedPaks();
+	SetForceReloadOnMapLoad(true);
 }
 
-void PakLoadManager::UnloadPak(const int nPakHandle)
+// Tracks all Paks related to a mod.
+void PakLoadManager::TrackModPaks(Mod& mod)
 {
-	g_pakLoadApi->UnloadPak(nPakHandle, nullptr);
+	const fs::path modPakPath("./" / mod.m_ModDirectory / "paks");
+
+	for (auto& modRpakEntry : mod.Rpaks)
+	{
+		ModPak_t pak;
+		pak.m_modName = mod.Name;
+		pak.m_path = (modPakPath / modRpakEntry.m_pakName).string();
+		pak.m_pathHash = STR_HASH(pak.m_path);
+
+		pak.m_preload = modRpakEntry.m_preload;
+		pak.m_dependentPakHash = modRpakEntry.m_dependentPakHash;
+		pak.m_mapRegex = modRpakEntry.m_loadRegex;
+
+		m_modPaks.push_back(pak);
+	}
 }
 
-void PakLoadManager::UnloadMapPaks()
+// Untracks all paks that aren't currently loaded and are marked for unload.
+void PakLoadManager::CleanUpUnloadedPaks()
 {
-	for (auto& pair : m_vLoadedPaks)
-		if (pair.second.m_nLoadSource == ePakLoadSource::MAP)
-			UnloadPak(pair.first);
+	auto fnRemovePredicate = [](ModPak_t& pak) -> bool { return pak.m_markedForDelete && pak.m_handle == PakHandle::INVALID; };
+
+	m_modPaks.erase(std::remove_if(m_modPaks.begin(), m_modPaks.end(), fnRemovePredicate), m_modPaks.end());
 }
 
-LoadedPak* PakLoadManager::TrackLoadedPak(ePakLoadSource nLoadSource, int nPakHandle, size_t nPakNameHash)
+// Unloads all paks that are marked for unload.
+void PakLoadManager::UnloadMarkedPaks()
 {
-	LoadedPak pak;
-	pak.m_nLoadSource = nLoadSource;
-	pak.m_nPakHandle = nPakHandle;
-	pak.m_nPakNameHash = nPakNameHash;
+	++m_reentranceCounter;
+	const ScopeGuard guard([&]() { --m_reentranceCounter; });
 
-	m_vLoadedPaks.insert(std::make_pair(nPakHandle, pak));
-	return &m_vLoadedPaks.at(nPakHandle);
+	(*o_pCModelLoader_UnreferenceAllModels)(*ppModelLoader);
+	(*o_pCleanMaterialSystemStuff)();
+
+	for (auto& modPak : m_modPaks)
+	{
+		if (modPak.m_handle == PakHandle::INVALID || !modPak.m_markedForDelete)
+			continue;
+
+		g_pakLoadApi->UnloadPak(modPak.m_handle, *o_pCleanMaterialSystemStuff);
+		modPak.m_handle = PakHandle::INVALID;
+	}
 }
 
-void PakLoadManager::RemoveLoadedPak(int nPakHandle)
+// Loads all modded paks for the given map.
+void PakLoadManager::LoadModPaksForMap(const char* mapName)
 {
-	m_vLoadedPaks.erase(nPakHandle);
+	++m_reentranceCounter;
+	const ScopeGuard guard([&]() { --m_reentranceCounter; });
+
+	for (auto& modPak : m_modPaks)
+	{
+		// don't load paks that are already loaded
+		if (modPak.m_handle != PakHandle::INVALID)
+			continue;
+		std::cmatch matches;
+		if (!std::regex_match(mapName, matches, modPak.m_mapRegex))
+			continue;
+
+		modPak.m_handle = g_pakLoadApi->LoadRpakFileAsync(modPak.m_path.c_str(), *rpakMemoryAllocator, 7);
+		m_mapPaks.push_back(modPak.m_pathHash);
+	}
 }
 
-LoadedPak* PakLoadManager::GetPakInfo(const int nPakHandle)
+// Unloads all modded map paks.
+void PakLoadManager::UnloadModPaks()
 {
-	return &m_vLoadedPaks.at(nPakHandle);
+	++m_reentranceCounter;
+	const ScopeGuard guard([&]() { --m_reentranceCounter; });
+
+	(*o_pCModelLoader_UnreferenceAllModels)(*ppModelLoader);
+	(*o_pCleanMaterialSystemStuff)();
+
+	for (auto& modPak : m_modPaks)
+	{
+		for (auto it = m_mapPaks.begin(); it != m_mapPaks.end(); ++it)
+		{
+			if (*it != modPak.m_pathHash)
+				continue;
+
+			m_mapPaks.erase(it, it + 1);
+			g_pakLoadApi->UnloadPak(modPak.m_handle, *o_pCleanMaterialSystemStuff);
+			modPak.m_handle = PakHandle::INVALID;
+			break;
+		}
+	}
+
+	// If this has happened, we may have leaked a pak?
+	// It basically means that none of the entries in m_modPaks matched the hash in m_mapPaks so we didn't end up unloading it
+	assert_msg(m_mapPaks.size() == 0, "Not all map paks were unloaded?");
 }
 
-int PakLoadManager::GetPakHandle(const size_t nPakNameHash)
+// Called after a Pak was loaded.
+void PakLoadManager::OnPakLoaded(std::string& originalPath, std::string& resultingPath, PakHandle resultingHandle)
 {
-	for (auto& pair : m_vLoadedPaks)
-		if (pair.second.m_nPakNameHash == nPakNameHash)
-			return pair.first;
+	if (IsVanillaCall())
+	{
+		// add entry to loaded vanilla rpaks
+		m_vanillaPaks.emplace_back(originalPath, resultingHandle);
+	}
 
-	return -1;
+	LoadDependentPaks(resultingPath, resultingHandle);
 }
 
-int PakLoadManager::GetPakHandle(const char* pPath)
+// Called before a Pak was unloaded.
+void PakLoadManager::OnPakUnloading(PakHandle handle)
 {
-	return GetPakHandle(STR_HASH(pPath));
+	UnloadDependentPaks(handle);
+
+	if (IsVanillaCall())
+	{
+		// remove entry from loaded vanilla rpaks
+		auto fnRemovePredicate = [handle](std::pair<std::string, PakHandle>& pair) -> bool { return pair.second == handle; };
+
+		m_vanillaPaks.erase(std::remove_if(m_vanillaPaks.begin(), m_vanillaPaks.end(), fnRemovePredicate), m_vanillaPaks.end());
+
+		// no need to handle aliasing here, if vanilla wants it gone, it's gone
+	}
+	else
+	{
+		// note: aliasing is handled the old way, long term todo: move it over to the PakLoadManager
+		// handle the potential unloading of an aliased vanilla rpak (we aliased it, and we are now unloading the alias, so we should load
+		// the vanilla one again)
+		// for (auto& [path, resultingHandle] : m_vanillaPaks)
+		//{
+		//	if (resultingHandle != handle)
+		//		continue;
+
+		//	// load vanilla rpak
+		//}
+	}
+
+	// set handle of the mod pak (if any) that has this handle for proper tracking
+	for (auto& modPak : m_modPaks)
+	{
+		if (modPak.m_handle == handle)
+			modPak.m_handle = PakHandle::INVALID;
+	}
 }
 
-void* PakLoadManager::LoadFile(const char* path)
+// Whether the vanilla game has this rpak
+static bool VanillaHasPak(const char* pakName)
 {
-	return g_pakLoadApi->LoadFile(path);
+	fs::path originalPath = fs::path("./r2/paks/Win64") / pakName;
+	unsigned int highestPatch = o_pGetPakPatchNumber(pakName);
+	if (highestPatch)
+	{
+		// add the patch path to the extension
+		char buf[16];
+		snprintf(buf, sizeof(buf), "(%02u).rpak", highestPatch);
+		// remove the .rpak and add the new suffix
+		originalPath = originalPath.replace_extension().string() + buf;
+	}
+	else
+	{
+		originalPath /= pakName;
+	}
+
+	return fs::exists(originalPath);
 }
 
-void HandlePakAliases(char** map)
+// If vanilla doesn't have an rpak for this path, tries to map it to a modded rpak of the same name.
+void PakLoadManager::FixupPakPath(std::string& pakPath)
 {
-	// convert the pak being loaded to it's aliased one, e.g. aliasing mp_hub_timeshift => sp_hub_timeshift
-	for (int64_t i = g_pModManager->m_LoadedMods.size() - 1; i > -1; i--)
+	if (VanillaHasPak(pakPath.c_str()))
+		return;
+
+	for (ModPak_t& modPak : m_modPaks)
 	{
-		Mod* mod = &g_pModManager->m_LoadedMods[i];
-		if (!mod->m_bEnabled)
+		if (modPak.m_markedForDelete)
 			continue;
 
-		if (mod->RpakAliases.find(*map) != mod->RpakAliases.end())
+		fs::path modPakFilename = fs::path(modPak.m_path).filename();
+		if (pakPath == modPakFilename.string())
 		{
-			*map = &mod->RpakAliases[*map][0];
+			pakPath = modPak.m_path;
 			return;
 		}
 	}
 }
 
-void LoadPreloadPaks()
+// Loads all "Preload" Paks. todo: deprecate Preload.
+void PakLoadManager::LoadPreloadPaks()
 {
-	// note, loading from ./ is necessary otherwise paks will load from gamedir/r2/paks
-	for (Mod& mod : g_pModManager->m_LoadedMods)
+	++m_reentranceCounter;
+	const ScopeGuard guard([&]() { --m_reentranceCounter; });
+
+	for (auto& modPak : m_modPaks)
 	{
-		if (!mod.m_bEnabled)
+		if (modPak.m_markedForDelete || modPak.m_handle != PakHandle::INVALID || !modPak.m_preload)
 			continue;
 
-		// need to get a relative path of mod to mod folder
-		fs::path modPakPath("./" / mod.m_ModDirectory / "paks");
+		modPak.m_handle = g_pakLoadApi->LoadRpakFileAsync(modPak.m_path.c_str(), *rpakMemoryAllocator, 7);
+	}
+}
 
-		for (ModRpakEntry& pak : mod.Rpaks)
-			if (pak.m_bAutoLoad)
-				g_pPakLoadManager->LoadPakAsync((modPakPath / pak.m_sPakName).string().c_str(), ePakLoadSource::CONSTANT);
+// Causes all "Postload" paks to be loaded again.
+void PakLoadManager::ReloadPostloadPaks()
+{
+	++m_reentranceCounter;
+	const ScopeGuard guard([&]() { --m_reentranceCounter; });
+
+	// pretend that we just loaded all of these vanilla paks
+	for (auto& [path, handle] : m_vanillaPaks)
+	{
+		LoadDependentPaks(path, handle);
 	}
 }
 
-void LoadPostloadPaks(const char* pPath)
+// Wrapper for Pak load API.
+void* PakLoadManager::OpenFile(const char* path)
 {
-	// note, loading from ./ is necessary otherwise paks will load from gamedir/r2/paks
-	for (Mod& mod : g_pModManager->m_LoadedMods)
+	return g_pakLoadApi->OpenFile(path);
+}
+
+// Loads Paks that depend on this Pak.
+void PakLoadManager::LoadDependentPaks(std::string& path, PakHandle handle)
+{
+	++m_reentranceCounter;
+	const ScopeGuard guard([&]() { --m_reentranceCounter; });
+
+	const size_t hash = STR_HASH(path);
+	for (auto& modPak : m_modPaks)
 	{
-		if (!mod.m_bEnabled)
+		if (modPak.m_handle != PakHandle::INVALID)
+			continue;
+		if (modPak.m_dependentPakHash != hash)
 			continue;
 
-		// need to get a relative path of mod to mod folder
-		fs::path modPakPath("./" / mod.m_ModDirectory / "paks");
-
-		for (ModRpakEntry& pak : mod.Rpaks)
-			if (pak.m_sLoadAfterPak == pPath)
-				g_pPakLoadManager->LoadPakAsync((modPakPath / pak.m_sPakName).string().c_str(), ePakLoadSource::CONSTANT);
+		// load pak
+		modPak.m_handle = g_pakLoadApi->LoadRpakFileAsync(modPak.m_path.c_str(), *rpakMemoryAllocator, 7);
+		m_dependentPaks.emplace_back(handle, hash);
 	}
 }
 
-void LoadCustomMapPaks(char** pakName, bool* bNeedToFreePakName)
+// Unloads Paks that depend on this Pak.
+void PakLoadManager::UnloadDependentPaks(PakHandle handle)
 {
-	// whether the vanilla game has this rpak
-	bool bHasOriginalPak = fs::exists(fs::path("r2/paks/Win64/") / *pakName);
+	++m_reentranceCounter;
+	const ScopeGuard guard([&]() { --m_reentranceCounter; });
 
-	// note, loading from ./ is necessary otherwise paks will load from gamedir/r2/paks
-	for (Mod& mod : g_pModManager->m_LoadedMods)
+	auto fnRemovePredicate = [&](std::pair<PakHandle, size_t>& pair) -> bool
 	{
-		if (!mod.m_bEnabled)
-			continue;
+		if (pair.first != handle)
+			return false;
 
-		// need to get a relative path of mod to mod folder
-		fs::path modPakPath("./" / mod.m_ModDirectory / "paks");
+		for (auto& modPak : m_modPaks)
+		{
+			if (modPak.m_pathHash != pair.second || modPak.m_handle == PakHandle::INVALID)
+				continue;
 
-		for (ModRpakEntry& pak : mod.Rpaks)
+			// unload pak
+			g_pakLoadApi->UnloadPak(modPak.m_handle, *o_pCleanMaterialSystemStuff);
+			modPak.m_handle = PakHandle::INVALID;
+		}
+
+		return true;
+	};
+	m_dependentPaks.erase(std::remove_if(m_dependentPaks.begin(), m_dependentPaks.end(), fnRemovePredicate), m_dependentPaks.end());
+}
+
+// Handles aliases for rpaks defined in rpak.json, effectively redirecting an rpak load to a different path.
+static void HandlePakAliases(std::string& originalPath)
+{
+	// convert the pak being loaded to its aliased one, e.g. aliasing mp_hub_timeshift => sp_hub_timeshift
+	for (int64_t i = g_pModManager->m_LoadedMods.size() - 1; i > PakHandle::INVALID; i--)
+	{
+		Mod* mod = &g_pModManager->m_LoadedMods[i];
+		if (!mod->m_bEnabled)
+			continue;
+
+		if (mod->RpakAliases.find(originalPath) != mod->RpakAliases.end())
 		{
-			if (!pak.m_bAutoLoad && !pak.m_sPakName.compare(*pakName))
-			{
-				// if the game doesn't have the original pak, let it handle loading this one as if it was the one it was loading originally
-				if (!bHasOriginalPak)
-				{
-					std::string path = (modPakPath / pak.m_sPakName).string();
-					*pakName = new char[path.size() + 1];
-					strcpy(*pakName, &path[0]);
-					(*pakName)[path.size()] = '\0';
-
-					bHasOriginalPak = true;
-					*bNeedToFreePakName =
-						true; // we can't free this memory until we're done with the pak, so let whatever's calling this deal with it
-				}
-				else
-					g_pPakLoadManager->LoadPakAsync((modPakPath / pak.m_sPakName).string().c_str(), ePakLoadSource::MAP);
-			}
+			originalPath = (mod->m_ModDirectory / "paks" / mod->RpakAliases[originalPath]).string();
+			return;
 		}
 	}
 }
 
-// clang-format off
-HOOK(LoadPakAsyncHook, LoadPakAsync,
-int, __fastcall, (char* pPath, void* unknownSingleton, int flags, void* pCallback0, void* pCallback1))
-// clang-format on
+/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+static bool (*o_pLoadMapRpaks)(char* mapPath) = nullptr;
+static bool h_LoadMapRpaks(char* mapPath)
 {
-	HandlePakAliases(&pPath);
+	// unload all mod rpaks that are marked for unload
+	g_pPakLoadManager->UnloadMarkedPaks();
+	g_pPakLoadManager->CleanUpUnloadedPaks();
 
-	// dont load the pak if it's currently loaded already
-	size_t nPathHash = STR_HASH(pPath);
-	if (g_pPakLoadManager->GetPakHandle(nPathHash) != -1)
-		return -1;
+	// strip file extension
+	const std::string mapName = fs::path(mapPath).replace_extension().string();
 
-	bool bNeedToFreePakName = false;
+	// load mp_common, sp_common etc.
+	o_pLoadGametypeSpecificRpaks(mapName.c_str());
 
-	static bool bShouldLoadPaks = true;
-	if (bShouldLoadPaks)
+	// unload old modded map paks
+	g_pPakLoadManager->UnloadModPaks();
+	// load modded map paks
+	g_pPakLoadManager->LoadModPaksForMap(mapName.c_str());
+
+	// don't load/unload anything when going to the lobby, presumably to save load times when going back to the same map
+	if (!g_pPakLoadManager->GetForceReloadOnMapLoad() && !strcmp("mp_lobby", mapName.c_str()))
+		return false;
+
+	if (g_pPakLoadManager->GetForceReloadOnMapLoad())
 	{
-		// make a copy of the path for comparing to determine whether we should load this pak on dedi, before it could get overwritten by
-		// LoadCustomMapPaks
-		std::string originalPath(pPath);
+		g_pPakLoadManager->LoadPreloadPaks();
+		g_pPakLoadManager->ReloadPostloadPaks();
+	}
 
-		// disable preloading while we're doing this
-		bShouldLoadPaks = false;
+	char mapRpakStr[272];
+	snprintf(mapRpakStr, 272, "%s.rpak", mapName.c_str());
 
-		LoadPreloadPaks();
-		LoadCustomMapPaks(&pPath, &bNeedToFreePakName);
+	// if level being loaded is the same as current level, do nothing
+	if (!g_pPakLoadManager->GetForceReloadOnMapLoad() && !strcmp(mapRpakStr, pszCurrentMapRpakPath))
+		return true;
 
-		bShouldLoadPaks = true;
+	strcpy(pszCurrentMapRpakPath, mapRpakStr);
+
+	(*o_pCleanMaterialSystemStuff)();
+	o_pLoadlevelLoadscreen(mapName.c_str());
+
+	// unload old map rpaks
+	PakHandle curHandle = *piCurrentMapRpakHandle;
+	PakHandle curPatchHandle = *piCurrentMapPatchRpakHandle;
+	if (curHandle != PakHandle::INVALID)
+	{
+		(*o_pCModelLoader_UnreferenceAllModels)(*ppModelLoader);
+		(*o_pCleanMaterialSystemStuff)();
+		g_pakLoadApi->UnloadPak(curHandle, *o_pCleanMaterialSystemStuff);
+		*piCurrentMapRpakHandle = PakHandle::INVALID;
+	}
+	if (curPatchHandle != PakHandle::INVALID)
+	{
+		(*o_pCModelLoader_UnreferenceAllModels)(*ppModelLoader);
+		(*o_pCleanMaterialSystemStuff)();
+		g_pakLoadApi->UnloadPak(curPatchHandle, *o_pCleanMaterialSystemStuff);
+		*piCurrentMapPatchRpakHandle = PakHandle::INVALID;
+	}
+
+	*piCurrentMapRpakHandle = g_pakLoadApi->LoadRpakFileAsync(mapRpakStr, *rpakMemoryAllocator, 7);
+
+	// load special _patch rpak (seemingly used for dev things?)
+	char levelPatchRpakStr[272];
+	snprintf(levelPatchRpakStr, 272, "%s_patch.rpak", mapName.c_str());
+	*piCurrentMapPatchRpakHandle = g_pakLoadApi->LoadRpakFileAsync(levelPatchRpakStr, *rpakMemoryAllocator, 7);
+
+	// we just reloaded the paks, so we don't need to force it again
+	g_pPakLoadManager->SetForceReloadOnMapLoad(false);
+	return true;
+}
+
+// clang-format off
+HOOK(LoadPakAsyncHook, LoadPakAsync,
+PakHandle, __fastcall, (const char* pPath, void* memoryAllocator, int flags))
+// clang-format on
+{
+	// make a copy of the path for comparing to determine whether we should load this pak on dedi, before it could get overwritten
+	std::string svOriginalPath(pPath);
+
+	std::string resultingPath(pPath);
+	HandlePakAliases(resultingPath);
+
+	if (g_pPakLoadManager->IsVanillaCall())
+	{
+		g_pPakLoadManager->LoadPreloadPaks();
+		g_pPakLoadManager->FixupPakPath(resultingPath);
 
 		// do this after custom paks load and in bShouldLoadPaks so we only ever call this on the root pakload call
 		// todo: could probably add some way to flag custom paks to not be loaded on dedicated servers in rpak.json
@@ -210,44 +451,27 @@ int, __fastcall, (char* pPath, void* unknownSingleton, int flags, void* pCallbac
 		// sp_<map> rpaks contain tutorial ghost data
 		// sucks to have to load the entire rpak for that but sp was never meant to be done on dedi
 		if (IsDedicatedServer() &&
-			(CommandLine()->CheckParm("-nopakdedi") || strncmp(&originalPath[0], "common", 6) && strncmp(&originalPath[0], "sp_", 3)))
+			(CommandLine()->CheckParm("-nopakdedi") || strncmp(&svOriginalPath[0], "common", 6) && strncmp(&svOriginalPath[0], "sp_", 3)))
 		{
-			if (bNeedToFreePakName)
-				delete[] pPath;
-
-			NS::log::rpak->info("Not loading pak {} for dedicated server", originalPath);
-			return -1;
+			NS::log::rpak->info("Not loading pak {} for dedicated server", svOriginalPath);
+			return PakHandle::INVALID;
 		}
 	}
 
-	int iPakHandle = LoadPakAsync(pPath, unknownSingleton, flags, pCallback0, pCallback1);
-	NS::log::rpak->info("LoadPakAsync {} {}", pPath, iPakHandle);
-
-	// trak the pak
-	g_pPakLoadManager->TrackLoadedPak(ePakLoadSource::UNTRACKED, iPakHandle, nPathHash);
-	LoadPostloadPaks(pPath);
+	PakHandle iPakHandle = LoadPakAsync(resultingPath.c_str(), memoryAllocator, flags);
+	NS::log::rpak->info("LoadPakAsync {} {}", resultingPath, iPakHandle);
 
-	if (bNeedToFreePakName)
-		delete[] pPath;
+	g_pPakLoadManager->OnPakLoaded(svOriginalPath, resultingPath, iPakHandle);
 
 	return iPakHandle;
 }
 
 // clang-format off
 HOOK(UnloadPakHook, UnloadPak,
-void*, __fastcall, (int nPakHandle, void* pCallback))
+void*, __fastcall, (PakHandle nPakHandle, void* pCallback))
 // clang-format on
 {
-	// stop tracking the pak
-	g_pPakLoadManager->RemoveLoadedPak(nPakHandle);
-
-	static bool bShouldUnloadPaks = true;
-	if (bShouldUnloadPaks)
-	{
-		bShouldUnloadPaks = false;
-		g_pPakLoadManager->UnloadMapPaks();
-		bShouldUnloadPaks = true;
-	}
+	g_pPakLoadManager->OnPakUnloading(nPakHandle);
 
 	NS::log::rpak->info("UnloadPak {}", nPakHandle);
 	return UnloadPak(nPakHandle, pCallback);
@@ -256,7 +480,7 @@ void*, __fastcall, (int nPakHandle, void* pCallback))
 // we hook this exclusively for resolving stbsp paths, but seemingly it's also used for other stuff like vpk, rpak, mprj and starpak loads
 // tbh this actually might be for memory mapped files or something, would make sense i think
 // clang-format off
-HOOK(ReadFileAsyncHook, ReadFileAsync, 
+HOOK(OpenFileHook, o_pOpenFile, 
 void*, __fastcall, (const char* pPath, void* pCallback))
 // clang-format on
 {
@@ -329,19 +553,34 @@ void*, __fastcall, (const char* pPath, void* pCallback))
 		NS::log::rpak->info("LoadStreamPak: {}", filename.string());
 	}
 
-	return ReadFileAsync(pPath, pCallback);
+	return o_pOpenFile(pPath, pCallback);
 }
 
 ON_DLL_LOAD("engine.dll", RpakFilesystem, (CModule module))
 {
-	AUTOHOOK_DISPATCH();
-
 	g_pPakLoadManager = new PakLoadManager;
 
 	g_pakLoadApi = module.Offset(0x5BED78).Deref().RCast<PakLoadFuncs*>();
-	pUnknownPakLoadSingleton = module.Offset(0x7C5E20).RCast<void**>();
 
-	LoadPakAsyncHook.Dispatch((LPVOID*)g_pakLoadApi->LoadPakAsync);
+	LoadPakAsyncHook.Dispatch((LPVOID*)g_pakLoadApi->LoadRpakFileAsync);
 	UnloadPakHook.Dispatch((LPVOID*)g_pakLoadApi->UnloadPak);
-	ReadFileAsyncHook.Dispatch((LPVOID*)g_pakLoadApi->ReadFileAsync);
+	OpenFileHook.Dispatch((LPVOID*)g_pakLoadApi->OpenFile);
+
+	pszCurrentMapRpakPath = module.Offset(0x1315C3E0).RCast<decltype(pszCurrentMapRpakPath)>();
+	piCurrentMapRpakHandle = module.Offset(0x7CB5A0).RCast<decltype(piCurrentMapRpakHandle)>();
+	piCurrentMapPatchRpakHandle = module.Offset(0x7CB5A4).RCast<decltype(piCurrentMapPatchRpakHandle)>();
+	ppModelLoader = module.Offset(0x7C4AC0).RCast<decltype(ppModelLoader)>();
+	rpakMemoryAllocator = module.Offset(0x7C5E20).RCast<decltype(rpakMemoryAllocator)>();
+
+	o_pLoadGametypeSpecificRpaks = module.Offset(0x15AD20).RCast<decltype(o_pLoadGametypeSpecificRpaks)>();
+	o_pCleanMaterialSystemStuff = module.Offset(0x12A11F00).RCast<decltype(o_pCleanMaterialSystemStuff)>();
+	o_pCModelLoader_UnreferenceAllModels = module.Offset(0x5ED580).RCast<decltype(o_pCModelLoader_UnreferenceAllModels)>();
+	o_pLoadlevelLoadscreen = module.Offset(0x15A810).RCast<decltype(o_pLoadlevelLoadscreen)>();
+
+	o_pLoadMapRpaks = module.Offset(0x15A8C0).RCast<decltype(o_pLoadMapRpaks)>();
+	HookAttach(&(PVOID&)o_pLoadMapRpaks, (PVOID)h_LoadMapRpaks);
+
+	// kinda bad, doing things in rtech in an engine callback but it seems fine for now
+	CModule rtechModule(GetModuleHandleA("rtech_game.dll"));
+	o_pGetPakPatchNumber = rtechModule.Offset(0x9A00).RCast<decltype(o_pGetPakPatchNumber)>();
 }
diff --git a/primedev/core/filesystem/rpakfilesystem.h b/primedev/core/filesystem/rpakfilesystem.h
index bcd57a73..87a41e7b 100644
--- a/primedev/core/filesystem/rpakfilesystem.h
+++ b/primedev/core/filesystem/rpakfilesystem.h
@@ -1,39 +1,81 @@
 #pragma once
 
-enum class ePakLoadSource
-{
-	UNTRACKED = -1, // not a pak we loaded, we shouldn't touch this one
+#include <regex>
 
-	CONSTANT, // should be loaded at all times
-	MAP // loaded from a map, should be unloaded when the map is unloaded
+enum PakHandle : int
+{
+	INVALID = -1,
 };
 
-struct LoadedPak
+struct ModPak_t
 {
-	ePakLoadSource m_nLoadSource;
-	int m_nPakHandle;
-	size_t m_nPakNameHash;
+	std::string m_modName;
+
+	std::string m_path;
+	size_t m_pathHash = 0;
+
+	// If the map being loaded matches this regex, this pak will be loaded.
+	std::regex m_mapRegex;
+	// If a pak with a hash matching this is loaded, this pak will be loaded.
+	size_t m_dependentPakHash = 0;
+	// If this is set, this pak will be loaded whenever any other pak is loaded.
+	bool m_preload = false;
+
+	// If this is set, the Pak will be unloaded on next map load
+	bool m_markedForDelete = false;
+	// The current rpak handle associated with this Pak
+	PakHandle m_handle = PakHandle::INVALID;
 };
 
 class PakLoadManager
 {
-private:
-	std::map<int, LoadedPak> m_vLoadedPaks {};
-	std::unordered_map<size_t, int> m_HashToPakHandle {};
-
 public:
-	int LoadPakAsync(const char* pPath, const ePakLoadSource nLoadSource);
-	void UnloadPak(const int nPakHandle);
-	void UnloadMapPaks();
-	void* LoadFile(const char* path); // this is a guess
+	void UnloadAllModPaks();
+	void TrackModPaks(Mod& mod);
+
+	void CleanUpUnloadedPaks();
+	void UnloadMarkedPaks();
+
+	void LoadModPaksForMap(const char* mapName);
+	void UnloadModPaks();
+
+	// Whether the current context is a vanilla call to a function, or a modded one
+	bool IsVanillaCall() const { return m_reentranceCounter == 0; }
+	// Whether paks will be forced to reload on the next map load
+	bool GetForceReloadOnMapLoad() const { return m_forceReloadOnMapLoad; }
+	void SetForceReloadOnMapLoad(bool value) { m_forceReloadOnMapLoad = value; }
+
+	void OnPakLoaded(std::string& originalPath, std::string& resultingPath, PakHandle resultingHandle);
+	void OnPakUnloading(PakHandle handle);
+
+	void FixupPakPath(std::string& path);
+
+	void LoadPreloadPaks();
+	void ReloadPostloadPaks();
+
+	void* OpenFile(const char* path);
+
+private:
+	void LoadDependentPaks(std::string& path, PakHandle handle);
+	void UnloadDependentPaks(PakHandle handle);
 
-	LoadedPak* TrackLoadedPak(ePakLoadSource nLoadSource, int nPakHandle, size_t nPakNameHash);
-	void RemoveLoadedPak(int nPakHandle);
+	// All paks that vanilla has attempted to load. (they may have been aliased away)
+	// Also known as a list of rpaks that the vanilla game would have loaded at this point in time.
+	std::vector<std::pair<std::string, PakHandle>> m_vanillaPaks;
 
-	LoadedPak* GetPakInfo(const int nPakHandle);
+	// All mod Paks that are currently tracked
+	std::vector<ModPak_t> m_modPaks;
+	// Hashes of the currently loaded map mod paks
+	std::vector<size_t> m_mapPaks;
+	// Currently loaded Pak path hashes that depend on a handle to remain loaded (Postload)
+	std::vector<std::pair<PakHandle, size_t>> m_dependentPaks;
 
-	int GetPakHandle(const size_t nPakNameHash);
-	int GetPakHandle(const char* pPath);
+	// Used to force rpaks to be unloaded and reloaded on the next map load.
+	// Vanilla behaviour is to not do this when loading into mp_lobby, or loading into the same map you were last in.
+	bool m_forceReloadOnMapLoad = false;
+	// Used to track if the current hook call is a vanilla call or not.
+	// When loading/unloading a mod Pak, increment this before doing so, and decrement afterwards.
+	int m_reentranceCounter = 0;
 };
 
 extern PakLoadManager* g_pPakLoadManager;