/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 *
 * Copyright 2022 Stefan Koell
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <windows.h>
#include <wincred.h>
#include <stdio.h>
#include <malloc.h>
#include <freerdp/settings.h>

static PCWSTR ValidateString(const BYTE* pb, ULONG cb)
{
	if (!pb || !cb)
		return 0;

	if (cb % sizeof(WCHAR) != 0)
		return 0;

	if (*(WCHAR*)(pb + cb - sizeof(WCHAR)))
		return 0;

	return (PCWSTR)pb;
}

static void AddDefaultSettings_I(rdpSettings* settings, size_t idHostname, size_t idUsername,
                                 size_t idPassword)
{
	static const PSTR TERMSRV = "TERMSRV/%s";

	PSTR TargetName = 0;
	PSTR UserName = 0;
	PSTR Password = 0;
	PWSTR UserNameW = 0;
	PWSTR PasswordW = 0;
	PWSTR TargetNameW = 0;
	PWSTR ServerHostnameW = 0;
	PCREDENTIALW Credential = { 0 };

	PCSTR ServerHostname = freerdp_settings_get_string(settings, idHostname);

	if (!ServerHostname)
		return;

	BOOL bExistUserName = freerdp_settings_get_string(settings, idUsername) != 0;
	BOOL bExistPassword = freerdp_settings_get_string(settings, idPassword) != 0;

	if (bExistUserName && bExistPassword)
		return;

	int len = _snprintf(TargetName, 0, TERMSRV, ServerHostname);
	len++;
	TargetName = (PSTR)malloc(len);

	if (!TargetName)
		goto fail;

	_snprintf(TargetName, len, TERMSRV, ServerHostname);

	TargetName[len - 1] = 0;

	int result = ConvertToUnicode(CP_UTF8, 0, TargetName, -1, &TargetNameW, 0);
	if (result <= 0)
		goto fail;

	if (!CredReadW(TargetNameW, CRED_TYPE_GENERIC, 0, &Credential))
		goto fail;

	if (!bExistPassword)
	{
		PasswordW = ValidateString(Credential->CredentialBlob, Credential->CredentialBlobSize);

		if (PasswordW)
		{
			result = ConvertFromUnicode(CP_UTF8, 0, PasswordW, -1, &Password, 0, NULL, NULL);
			if (result)
				freerdp_settings_set_string(settings, idPassword, Password);
		}
	}

	if (!bExistUserName)
	{
		UserNameW = Credential->UserName;

		if (UserNameW)
		{
			result = ConvertFromUnicode(CP_UTF8, 0, UserNameW, -1, &UserName, 0, NULL, NULL);
			if (result)
				freerdp_settings_set_string(settings, idUsername, UserName);
		}
	}

fail:
	CredFree(Credential);
	free(TargetName);
	free(TargetNameW);
	free(ServerHostnameW);
	free(UserName);
	free(Password);
	return;
}

void WINAPI AddDefaultSettings(rdpSettings* settings)
{
	AddDefaultSettings_I(settings, FreeRDP_ServerHostname, FreeRDP_Username, FreeRDP_Password);
	AddDefaultSettings_I(settings, FreeRDP_GatewayHostname, FreeRDP_GatewayUsername,
	                     FreeRDP_GatewayPassword);
}