#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#include <TlHelp32.h>
#include <filesystem>
#include <sstream>
#include <fstream>
#include <Shlwapi.h>
#include <iostream>

namespace fs = std::filesystem;

extern "C"
{
	__declspec(dllexport) DWORD AmdPowerXpressRequestHighPerformance = 0x00000001;
	__declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;
}

HMODULE hLauncherModule;
HMODULE hHookModule;
HMODULE hTier0Module;

wchar_t exePath[4096];
wchar_t buffer[8192];

bool noLoadPlugins = false;

DWORD GetProcessByName(std::wstring processName)
{
	HANDLE snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);

	PROCESSENTRY32 processSnapshotEntry = {0};
	processSnapshotEntry.dwSize = sizeof(PROCESSENTRY32);

	if (snapshot == INVALID_HANDLE_VALUE)
		return 0;

	if (!Process32First(snapshot, &processSnapshotEntry))
		return 0;

	while (Process32Next(snapshot, &processSnapshotEntry))
	{
		if (!wcscmp(processSnapshotEntry.szExeFile, processName.c_str()))
		{
			CloseHandle(snapshot);
			return processSnapshotEntry.th32ProcessID;
		}
	}

	CloseHandle(snapshot);
	return 0;
}

bool GetExePathWide(wchar_t* dest, DWORD destSize)
{
	if (!dest)
		return NULL;
	if (destSize < MAX_PATH)
		return NULL;

	DWORD length = GetModuleFileNameW(NULL, dest, destSize);
	return length && PathRemoveFileSpecW(dest);
}

FARPROC GetLauncherMain()
{
	static FARPROC Launcher_LauncherMain;
	if (!Launcher_LauncherMain)
		Launcher_LauncherMain = GetProcAddress(hLauncherModule, "LauncherMain");
	return Launcher_LauncherMain;
}

void LibraryLoadError(DWORD dwMessageId, const wchar_t* libName, const wchar_t* location)
{
	char text[8192];
	std::string message = std::system_category().message(dwMessageId);

	sprintf_s(
		text,
		"Failed to load the %ls at \"%ls\" (%lu):\n\n%hs\n\nMake sure you followed the Northstar installation instructions carefully "
		"before reaching out for help.",
		libName, location, dwMessageId, message.c_str());

	if (dwMessageId == 126 && std::filesystem::exists(location))
	{
		sprintf_s(
			text,
			"%s\n\nThe file at the specified location DOES exist, so this error indicates that one of its *dependencies* failed to be "
			"found.\n\nTry the following steps:\n1. Install Visual C++ 2022 Redistributable: "
			"https://aka.ms/vs/17/release/vc_redist.x64.exe\n2. Repair game files",
			text);
	}
	else if (!fs::exists("Titanfall2.exe") && (fs::exists("..\\Titanfall2.exe") || fs::exists("..\\..\\Titanfall2.exe")))
	{
		auto curDir = std::filesystem::current_path().filename().string();
		auto aboveDir = std::filesystem::current_path().parent_path().filename().string();
		sprintf_s(
			text,
			"%s\n\nWe detected that in your case you have extracted the files into a *subdirectory* of your Titanfall 2 "
			"installation.\nPlease move all the files and folders from current folder (\"%s\") into the Titanfall 2 installation directory "
			"just above (\"%s\").\n\nPlease try out the above steps by yourself before reaching out to the community for support.",
			text, curDir.c_str(), aboveDir.c_str());
	}
	else if (!fs::exists("Titanfall2.exe"))
	{
		sprintf_s(
			text,
			"%s\n\nRemember: you need to unpack the contents of this archive into your Titanfall 2 game installation directory, not just "
			"to any random folder.",
			text);
	}
	else if (fs::exists("Titanfall2.exe"))
	{
		sprintf_s(
			text,
			"%s\n\nTitanfall2.exe has been found in the current directory: is the game installation corrupted or did you not unpack all "
			"Northstar files here?",
			text);
	}

	MessageBoxA(GetForegroundWindow(), text, "Northstar Launcher Error", 0);
}

void EnsureOriginStarted()
{
	if (GetProcessByName(L"Origin.exe") || GetProcessByName(L"EADesktop.exe"))
		return; // already started

	// unpacked exe will crash if origin isn't open on launch, so launch it
	// get origin path from registry, code here is reversed from OriginSDK.dll
	HKEY key;
	if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, "SOFTWARE\\WOW6432Node\\Origin", 0, KEY_READ, &key) != ERROR_SUCCESS)
	{
		MessageBoxA(0, "Error: failed reading Origin path!", "Northstar Launcher Error", MB_OK);
		return;
	}

	char originPath[520];
	DWORD originPathLength = 520;
	if (RegQueryValueExA(key, "ClientPath", 0, 0, (LPBYTE)&originPath, &originPathLength) != ERROR_SUCCESS)
	{
		MessageBoxA(0, "Error: failed reading Origin path!", "Northstar Launcher Error", MB_OK);
		return;
	}

	PROCESS_INFORMATION pi;
	memset(&pi, 0, sizeof(pi));
	STARTUPINFO si;
	memset(&si, 0, sizeof(si));
	CreateProcessA(
		originPath, (char*)"", NULL, NULL, false, CREATE_DEFAULT_ERROR_MODE | CREATE_NEW_PROCESS_GROUP, NULL, NULL, (LPSTARTUPINFOA)&si,
		&pi);

	printf("[*] Waiting for Origin...\n");

	// wait for origin to be ready, this process is created when origin is ready enough to launch game without any errors
	while (!GetProcessByName(L"OriginClientService.exe") && !GetProcessByName(L"EADesktop.exe"))
		Sleep(200);

	CloseHandle(pi.hProcess);
	CloseHandle(pi.hThread);
}

void PrependPath()
{
	wchar_t* pPath;
	size_t len;
	errno_t err = _wdupenv_s(&pPath, &len, L"PATH");
	if (!err)
	{
		swprintf_s(buffer, L"PATH=%s\\bin\\x64_retail\\;%s", exePath, pPath);
		auto result = _wputenv(buffer);
		if (result == -1)
		{
			MessageBoxW(
				GetForegroundWindow(),
				L"Warning: could not prepend the current directory to app's PATH environment variable. Something may break because of "
				L"that.",
				L"Northstar Launcher Warning", 0);
		}
		free(pPath);
	}
	else
	{
		MessageBoxW(
			GetForegroundWindow(),
			L"Warning: could not get current PATH environment variable in order to prepend the current directory to it. Something may "
			L"break because of that.",
			L"Northstar Launcher Warning", 0);
	}
}

bool ShouldLoadNorthstar(int argc, char* argv[])
{
	bool loadNorthstar = true;
	for (int i = 0; i < argc; i++)
		if (!strcmp(argv[i], "-vanilla"))
			loadNorthstar = false;

	if (!loadNorthstar)
		return loadNorthstar;

	auto runNorthstarFile = std::ifstream("run_northstar.txt");
	if (runNorthstarFile)
	{
		std::stringstream runNorthstarFileBuffer;
		runNorthstarFileBuffer << runNorthstarFile.rdbuf();
		runNorthstarFile.close();
		if (runNorthstarFileBuffer.str()._Starts_with("0"))
			loadNorthstar = false;
	}
	return loadNorthstar;
}

bool LoadNorthstar()
{
	FARPROC Hook_Init = nullptr;
	{
		swprintf_s(buffer, L"%s\\Northstar.dll", exePath);
		hHookModule = LoadLibraryExW(buffer, 0i64, 8u);
		if (hHookModule)
			Hook_Init = GetProcAddress(hHookModule, "InitialiseNorthstar");
		if (!hHookModule || Hook_Init == nullptr)
		{
			LibraryLoadError(GetLastError(), L"Northstar.dll", buffer);
			return false;
		}
	}
	((bool (*)())Hook_Init)();

	FARPROC LoadPlugins = nullptr;
	if (!noLoadPlugins)
	{
		LoadPlugins = GetProcAddress(hHookModule, "LoadPlugins");
		if (!hHookModule || LoadPlugins == nullptr)
		{
			printf("Failed to get function pointer to LoadPlugins of Northstar.dll\n");
			LibraryLoadError(GetLastError(), L"Northstar.dll", buffer);
			return false;
		}
		((bool (*)())LoadPlugins)();
	}

	return true;
}

HMODULE LoadDediStub(const char* name)
{
	// this works because materialsystem_dx11.dll uses relative imports, and even a DLL loaded with an absolute path will take precedence
	printf("[*]   Loading %s\n", name);
	swprintf_s(buffer, L"%s\\bin\\x64_dedi\\%hs", exePath, name);
	HMODULE h = LoadLibraryExW(buffer, 0, LOAD_WITH_ALTERED_SEARCH_PATH);
	if (!h)
	{
		wprintf(L"[*] Failed to load stub %hs from \"%ls\": %hs\n", name, buffer, std::system_category().message(GetLastError()).c_str());
	}
	return h;
}

int main(int argc, char* argv[])
{

	if (!GetExePathWide(exePath, sizeof(exePath)))
	{
		MessageBoxA(
			GetForegroundWindow(), "Failed getting game directory.\nThe game cannot continue and has to exit.", "Northstar Launcher Error",
			0);
		return 1;
	}

	bool noOriginStartup = false;
	bool dedicated = false;
	bool nostubs = false;

	for (int i = 0; i < argc; i++)
		if (!strcmp(argv[i], "-noOriginStartup"))
			noOriginStartup = true;
		else if (!strcmp(argv[i], "-dedicated")) // also checked by Northstar.dll
			dedicated = true;
		else if (!strcmp(argv[i], "-nostubs"))
			nostubs = true;
		else if (!strcmp(argv[i], "-noplugins"))
			noLoadPlugins = true;

	if (!noOriginStartup && !dedicated)
	{
		EnsureOriginStarted();
	}

	if (dedicated && !nostubs)
	{
		// clang-format keeps messing with the easy-to-read if statements, so
		// clang-format off
		printf("[*] Loading stubs\n");
		HMODULE gssao, gtxaa, d3d11;
		if (!(gssao = GetModuleHandleA("GFSDK_SSAO.win64.dll")) &&
			!(gtxaa = GetModuleHandleA("GFSDK_TXAA.win64.dll")) &&
			!(d3d11 = GetModuleHandleA("d3d11.dll")))
		{
			if (!(gssao = LoadDediStub("GFSDK_SSAO.win64.dll")) ||
				!(gtxaa = LoadDediStub("GFSDK_TXAA.win64.dll")) ||
				!(d3d11 = LoadDediStub("d3d11.dll")))
			{
				if ((!gssao || FreeLibrary(gssao)) &&
					(!gtxaa || FreeLibrary(gtxaa)) &&
					(!d3d11 || FreeLibrary(d3d11)))
				{
					printf(
						"[*] WARNING: Failed to load d3d11/gfsdk stubs from bin/x64_dedi. "
						"The stubs have been unloaded and the original libraries will be used instead.\n");
				}
				else
				{
					// this is highly unlikely
					MessageBoxA(
						GetForegroundWindow(),
						"Failed to load one or more stubs, but could not unload them either.\n"
						"The game cannot continue and has to exit.",
						"Northstar Launcher Error", 0);
					return 1;
				}
			}
		}
		else
		{
			// this should never happen
			printf(
				"[*] WARNING: Failed to load stubs because conflicting modules are already loaded, so those will be used instead "
				"(did Northstar initialize too late?).\n");
		}
		// clang-format on
	}

	{
		PrependPath();

		if (!fs::exists("ns_startup_args.txt"))
		{
			std::ofstream file("ns_startup_args.txt");
			std::string defaultArgs = "-multiple";
			file.write(defaultArgs.c_str(), defaultArgs.length());
			file.close();
		}
		if (!fs::exists("ns_startup_args_dedi.txt"))
		{
			std::ofstream file("ns_startup_args_dedi.txt");
			std::string defaultArgs = "+setplaylist private_match";
			file.write(defaultArgs.c_str(), defaultArgs.length());
			file.close();
		}

		printf("[*] Loading tier0.dll\n");
		swprintf_s(buffer, L"%s\\bin\\x64_retail\\tier0.dll", exePath);
		hTier0Module = LoadLibraryExW(buffer, 0, LOAD_WITH_ALTERED_SEARCH_PATH);
		if (!hTier0Module)
		{
			LibraryLoadError(GetLastError(), L"tier0.dll", buffer);
			return 1;
		}

		bool loadNorthstar = ShouldLoadNorthstar(argc, argv);
		if (loadNorthstar)
		{
			printf("[*] Loading Northstar\n");
			if (!LoadNorthstar())
				return 1;
		}
		else
			printf("[*] Going to load the vanilla game\n");

		printf("[*] Loading launcher.dll\n");
		swprintf_s(buffer, L"%s\\bin\\x64_retail\\launcher.dll", exePath);
		hLauncherModule = LoadLibraryExW(buffer, 0, LOAD_WITH_ALTERED_SEARCH_PATH);
		if (!hLauncherModule)
		{
			LibraryLoadError(GetLastError(), L"launcher.dll", buffer);
			return 1;
		}
	}

	printf("[*] Launching the game...\n");
	auto LauncherMain = GetLauncherMain();
	if (!LauncherMain)
		MessageBoxA(
			GetForegroundWindow(), "Failed loading launcher.dll.\nThe game cannot continue and has to exit.", "Northstar Launcher Error",
			0);
	// auto result = ((__int64(__fastcall*)())LauncherMain)();
	// auto result = ((signed __int64(__fastcall*)(__int64))LauncherMain)(0i64);

	return ((int(/*__fastcall*/*)(HINSTANCE, HINSTANCE, LPSTR, int))LauncherMain)(
		NULL, NULL, NULL, 0); // the parameters aren't really used anyways
}