// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

#include "precomp.h"

extern "C" HRESULT Initialize(int argc, wchar_t* argv[])
{
	HRESULT hr = S_OK;

	// We're not going to do any clever parsing. This is intended to be called from
	// the standalone bundle only and there will only be two parameters:
	// 1. The path of the log file, created by the bundle.
	// 2. The dependent we're trying to clean up.
	if (argc != 3)
	{
		return HRESULT_FROM_WIN32(ERROR_INVALID_COMMAND_LINE);
	}

	LogInitialize(::GetModuleHandleW(NULL));

#ifdef _DEBUG
	LogSetLevel(REPORT_DEBUG, FALSE);
#else
	LogSetLevel(REPORT_VERBOSE, FALSE); // FALSE means don't write an additional text line to the log saying the level changed
#endif

	hr = LogOpen(NULL, argv[1], NULL, NULL, FALSE, TRUE, NULL);
	ExitOnFailure(hr, "Failed to create log file.");

	hr = RegInitialize();
	ExitOnFailure(hr, "Failed to initialize the registry.");

	hr = WiuInitialize();
	ExitOnFailure(hr, "Failed to initialize Windows Installer.");

LExit:
	return hr;
}

extern "C" HRESULT RemoveDependent(LPWSTR sczDependent, BOOL* pbRestartRequired)
{
	HRESULT hr = S_OK;
	HKEY hkInstallerDependenciesKey = NULL;
	HKEY hkProviderKey = NULL;
	HKEY hkDependentsKey = NULL;
	LPWSTR sczProviderKey = NULL;
	LPWSTR sczDependentsKey = NULL;
	LPWSTR sczProductId = NULL;
	LPWSTR sczProductName = NULL;
	DWORD cSubKeys = 0;
	DWORD dwExitCode = 0;
	WIU_RESTART restart = WIU_RESTART_NONE;

	// Optional workloads are always per-machine installs, so we don't need to check HKCU. 
	hr = RegOpen(HKEY_LOCAL_MACHINE, L"SOFTWARE\\Classes\\Installer\\Dependencies", KEY_READ, &hkInstallerDependenciesKey);
	ExitOnFailure(hr, "Failed to read installer dependencies key.");

	// This has to be an exhaustive search as we're not looking for a specific provider key, but for a specific dependent
	// that could be registered against any provider key.
	for (DWORD dwIndex = 0;; ++dwIndex)
	{
		// Get the next provider key name
		hr = RegKeyEnum(hkInstallerDependenciesKey, dwIndex, &sczProviderKey);

		if (E_NOMOREITEMS == hr)
		{
			hr = S_OK;
			break;
		}

		ExitOnFailure(hr, "Failed to enumerate installer dependency provider keys.");
		LogStringLine(REPORT_STANDARD, "Processing provider key: %ls", sczProviderKey);

		hr = RegOpen(hkInstallerDependenciesKey, sczProviderKey, KEY_READ, &hkProviderKey);
		ExitOnFailure(hr, "Unable to open provider key.");

		// Open the dependents key with write permissions so we can modify it if it matches
		// the target dependent value.
		hr = RegOpen(hkProviderKey, L"Dependents", KEY_READ | KEY_WRITE, &hkDependentsKey);
		if (E_FILENOTFOUND == hr)
		{
			// Providers can sometimes become orphaned during uninstalls. If there's no Dependents subkey, we just
			// release the handle and continue to the next provider key.
			hr = S_OK;
			ReleaseRegKey(hkProviderKey);

			continue;
		}

		ExitOnFailure(hr, "Unable to open dependents key.");

		// Enumerate over all the dependent keys
		for (DWORD dwDependentsKeyIndex = 0;; ++dwDependentsKeyIndex)
		{
			hr = RegKeyEnum(hkDependentsKey, dwDependentsKeyIndex, &sczDependentsKey);

			if (E_NOMOREITEMS == hr)
			{
				hr = S_OK;
				break;
			}

			ExitOnFailure(hr, "Failed to read provider's dependent key.");

			if (CSTR_EQUAL == ::CompareStringW(LOCALE_INVARIANT, 0, sczDependentsKey, -1, sczDependent, -1))
			{
				LogStringLine(REPORT_STANDARD, "  Dependent match found: %ls", sczDependentsKey);

				hr = RegDelete(hkDependentsKey, sczDependent, REG_KEY_DEFAULT, TRUE);
				ExitOnFailure(hr, "Failed to delete dependent \"%ls\"", sczDependent);
				LogStringLine(REPORT_STANDARD, "  Dependent deleted");
				// Reset the index since we're deleting keys while enumerating
				dwDependentsKeyIndex = dwDependentsKeyIndex > 1 ? dwDependentsKeyIndex-- : 0;

				// Check if there are any subkeys remaining under the dependents key. If not, we
				// can uninstall the MSI. We'll recheck the key again in case the MSI fails to clean up the 
				// provider key to make sure we don't have orphaned keys.
				hr = RegQueryKey(hkDependentsKey, &cSubKeys, NULL);
				ExitOnFailure(hr, "Failed to query dependents key.");

				LogStringLine(REPORT_STANDARD, "  Remaining dependents: %i", cSubKeys);

				if (0 == cSubKeys)
				{
					// This was the final dependent, so now we can remove the installation if the provider wasn't corrupted and
					// still contains the product ID.
					hr = RegReadString(hkProviderKey, NULL, &sczProductId);

					if (E_FILENOTFOUND == hr)
					{
						LogStringLine(REPORT_STANDARD, "  No product ID found, provider key: %ls", sczProviderKey);
						hr = S_OK;
						break;
					}
					else
					{
						ExitOnFailure(hr, "Failed to read product ID.");
					}

					// Let's make sure the product is actually installed. The provider key for an MSI typically
					// stores the ProductCode, DisplayName, and Version, but by calling into MsiGetProductInfo,
					// we're doing an implicit detect and getting a property back.
					hr = WiuGetProductInfo(sczProductId, L"ProductName", &sczProductName);
					if (SUCCEEDED(hr))
					{
						// The provider key *should* have the ProductName and ProductVersion properties, but since
						// we know it's installed, we just query the installer service. 
						MsiSetInternalUI(INSTALLUILEVEL_NONE, NULL);
						hr = WiuConfigureProductEx(sczProductId, INSTALLLEVEL_DEFAULT, INSTALLSTATE_ABSENT, L"MSIFASTINSTALL=7 IGNOREDEPENDENCIES=ALL REBOOT=ReallySuppress", &restart);
						LogStringLine(REPORT_STANDARD, "  Uninstall of \"%ls\" (%ls%) exited with 0x%.8x", sczProductName, sczProductId, hr);
						
						// Flag any reboot since we need to return that to the bundle.
						if (WIU_RESTART_INITIATED == restart || WIU_RESTART_REQUIRED == restart)
						{
							LogStringLine(REPORT_STANDARD, "  Reboot requested, deferring.");
							*pbRestartRequired = TRUE;
						}
						
						// Reset potential failures so we can continue to remove as many dependents as possible.
						hr = S_OK;
					}
					else if (HRESULT_FROM_WIN32(ERROR_UNKNOWN_PRODUCT) == hr || HRESULT_FROM_WIN32(ERROR_UNKNOWN_PROPERTY) == hr)
					{
                        // Possibly a corrupted provider key that wasn't cleaned up. We'll just ignore it.
						LogStringLine(REPORT_STANDARD, "  Product is not installed, ProductCode:%ls, result: 0x%.8x", sczProductId, hr);
						hr = S_OK;
					}
				}
			}
		}

		ReleaseRegKey(hkDependentsKey);
		ReleaseRegKey(hkProviderKey);
	}

LExit:
	ReleaseStr(sczProductName);
	ReleaseStr(sczProductId);
	ReleaseStr(sczProviderKey);
	ReleaseStr(sczDependentsKey);
	ReleaseRegKey(hkDependentsKey);
	ReleaseRegKey(hkProviderKey);
	ReleaseRegKey(hkInstallerDependenciesKey);
	return hr;
}

int wmain(int argc, wchar_t* argv[])
{
	HRESULT hr = S_OK;
	DWORD dwExitCode = 0;
	LPWSTR sczDependent = NULL;
	BOOL bRestartRequired = FALSE;

	hr = ::Initialize(argc, argv);
	ExitOnFailure(hr, "Failed to initialize.");

	sczDependent = argv[2];
	hr = ::RemoveDependent(sczDependent, &bRestartRequired);
	ExitOnFailure(hr, "Failed to remove dependent \"%ls\".", sczDependent);

	if (bRestartRequired)
	{
		dwExitCode = ERROR_SUCCESS_REBOOT_REQUIRED;
	}

LExit:
	LogUninitialize(TRUE);
	RegUninitialize();
	WiuUninitialize();
	return FAILED(hr) ? (int)hr : (int)dwExitCode;
}