/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * rdp2tcp Virtual Channel Extension
 *
 * Copyright 2017 Artur Zaprzala
 *
 * 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 <stdio.h>
#include <assert.h>

#include <winpr/file.h>
#include <winpr/pipe.h>
#include <winpr/thread.h>

#include <freerdp/svc.h>

#define RDP2TCP_CHAN_NAME "rdp2tcp"

static int const debug = 0;

typedef struct
{
	HANDLE hStdOutputRead;
	HANDLE hStdInputWrite;
	HANDLE hProcess;
	HANDLE copyThread;
	HANDLE writeComplete;
	DWORD openHandle;
	void* initHandle;
	CHANNEL_ENTRY_POINTS_FREERDP_EX channelEntryPoints;
	char buffer[16 * 1024];
} Plugin;


static int init_external_addin(Plugin* plugin)
{
	SECURITY_ATTRIBUTES saAttr;
	STARTUPINFO siStartInfo;
	PROCESS_INFORMATION procInfo;
	saAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
	saAttr.bInheritHandle = TRUE;
	saAttr.lpSecurityDescriptor = NULL;
	siStartInfo.cb = sizeof(STARTUPINFO);
	siStartInfo.hStdError = GetStdHandle(STD_ERROR_HANDLE);
	siStartInfo.dwFlags = STARTF_USESTDHANDLES;

	// Create pipes
	if (!CreatePipe(&plugin->hStdOutputRead, &siStartInfo.hStdOutput, &saAttr, 0))
	{
		perror("stdout CreatePipe");
		return -1;
	}

	if (!SetHandleInformation(plugin->hStdOutputRead, HANDLE_FLAG_INHERIT, 0))
	{
		perror("stdout SetHandleInformation");
		return -1;
	}

	if (!CreatePipe(&siStartInfo.hStdInput, &plugin->hStdInputWrite, &saAttr, 0))
	{
		perror("stdin CreatePipe");
		return -1;
	}

	if (!SetHandleInformation(plugin->hStdInputWrite, HANDLE_FLAG_INHERIT, 0))
	{
		perror("stdin SetHandleInformation");
		return -1;
	}

	// Execute plugin
	if (!CreateProcess(NULL,
	                   plugin->channelEntryPoints.pExtendedData,			// command line
	                   NULL,			// process security attributes
	                   NULL,			// primary thread security attributes
	                   TRUE,			// handles are inherited
	                   0,				// creation flags
	                   NULL,			// use parent's environment
	                   NULL,			// use parent's current directory
	                   &siStartInfo,	// STARTUPINFO pointer
	                   &procInfo		// receives PROCESS_INFORMATION
	                  ))
	{
		perror("fork for addin");
		return -1;
	}

	plugin->hProcess = procInfo.hProcess;
	CloseHandle(procInfo.hThread);
	CloseHandle(siStartInfo.hStdOutput);
	CloseHandle(siStartInfo.hStdInput);
	return 0;
}

static void dumpData(char* data, unsigned length)
{
	unsigned const limit = 98;
	unsigned l = length > limit ? limit / 2 : length;
	unsigned i;

	for (i = 0; i < l; ++i)
	{
		printf("%02hhx", data[i]);
	}

	if (length > limit)
	{
		printf("...");

		for (i = length - l; i < length; ++i)
			printf("%02hhx", data[i]);
	}

	puts("");
}

static DWORD WINAPI copyThread(void* data)
{
	Plugin* plugin = (Plugin*)data;
	size_t const bufsize = 16 * 1024;

	while (1)
	{
		DWORD dwRead;
		char* buffer = malloc(bufsize);

		if (!buffer)
		{
			fprintf(stderr, "rdp2tcp copyThread: malloc failed\n");
			return -1;
		}

		//if (!ReadFile(plugin->hStdOutputRead, plugin->buffer, sizeof plugin->buffer, &dwRead, NULL))
		if (!ReadFile(plugin->hStdOutputRead, buffer, bufsize, &dwRead, NULL))
			return -1;

		if (debug > 1)
		{
			printf(">%8u ", (unsigned)dwRead);
			dumpData(buffer, dwRead);
		}

		if (plugin->channelEntryPoints.pVirtualChannelWriteEx(plugin->initHandle, plugin->openHandle,
		        buffer, dwRead, NULL) != CHANNEL_RC_OK)
		{
			fprintf(stderr, "rdp2tcp copyThread failed %i\n", (int)dwRead);
			return -1;
		}

		WaitForSingleObject(plugin->writeComplete, INFINITE);
		ResetEvent(plugin->writeComplete);
	}

	return 0;
}

static void closeChannel(Plugin* plugin)
{
	if (debug)
		puts("rdp2tcp closing channel");

	plugin->channelEntryPoints.pVirtualChannelCloseEx(plugin->initHandle, plugin->openHandle);
}

static void dataReceived(Plugin* plugin, void* pData, UINT32 dataLength, UINT32 totalLength,
                         UINT32 dataFlags)
{
	DWORD dwWritten;

	if (dataFlags & CHANNEL_FLAG_SUSPEND)
	{
		if (debug)
			puts("rdp2tcp Channel Suspend");

		return;
	}

	if (dataFlags & CHANNEL_FLAG_RESUME)
	{
		if (debug)
			puts("rdp2tcp Channel Resume");

		return;
	}

	if (debug > 1)
	{
		printf("<%c%3u/%3u ", dataFlags & CHANNEL_FLAG_FIRST ? ' ' : '+', totalLength, dataLength);
		dumpData(pData, dataLength);
	}

	if (dataFlags & CHANNEL_FLAG_FIRST)
	{
		if (!WriteFile(plugin->hStdInputWrite, &totalLength, sizeof(totalLength), &dwWritten, NULL))
			closeChannel(plugin);
	}

	if (!WriteFile(plugin->hStdInputWrite, pData, dataLength, &dwWritten, NULL))
		closeChannel(plugin);
}

static void VCAPITYPE VirtualChannelOpenEventEx(LPVOID lpUserParam, DWORD openHandle, UINT event,
        LPVOID pData, UINT32 dataLength, UINT32 totalLength, UINT32 dataFlags)
{
	Plugin* plugin = (Plugin*)lpUserParam;

	switch (event)
	{
		case CHANNEL_EVENT_DATA_RECEIVED:
			;
			dataReceived(plugin, pData, dataLength, totalLength, dataFlags);
			break;

		case CHANNEL_EVENT_WRITE_COMPLETE:
			SetEvent(plugin->writeComplete);
			break;
	}
}

static VOID VCAPITYPE VirtualChannelInitEventEx(LPVOID lpUserParam, LPVOID pInitHandle, UINT event,
        LPVOID pData, UINT dataLength)
{
	Plugin* plugin = (Plugin*)lpUserParam;

	switch (event)
	{
		case CHANNEL_EVENT_CONNECTED:
			if (debug)
				puts("rdp2tcp connected");

			plugin->writeComplete = CreateEvent(NULL, TRUE, FALSE, NULL);
			plugin->copyThread = CreateThread(NULL, 0, copyThread, plugin, 0, NULL);

			if (plugin->channelEntryPoints.pVirtualChannelOpenEx(pInitHandle, &plugin->openHandle,
			        RDP2TCP_CHAN_NAME, VirtualChannelOpenEventEx) != CHANNEL_RC_OK)
				return;

			break;

		case CHANNEL_EVENT_DISCONNECTED:
			if (debug)
				puts("rdp2tcp disconnected");

			break;

		case CHANNEL_EVENT_TERMINATED:
			if (debug)
				puts("rdp2tcp terminated");

			if (plugin->copyThread)
			{
				TerminateThread(plugin->copyThread, 0);
				CloseHandle(plugin->writeComplete);
			}

			CloseHandle(plugin->hStdInputWrite);
			CloseHandle(plugin->hStdOutputRead);
			TerminateProcess(plugin->hProcess, 0);
			CloseHandle(plugin->hProcess);
			free(plugin);
			break;
	}
}

#if 1
#define VirtualChannelEntryEx rdp2tcp_VirtualChannelEntryEx
#else
#define VirtualChannelEntryEx FREERDP_API VirtualChannelEntryEx
#endif
BOOL VCAPITYPE VirtualChannelEntryEx(PCHANNEL_ENTRY_POINTS pEntryPoints, PVOID pInitHandle)
{
	CHANNEL_ENTRY_POINTS_FREERDP_EX* pEntryPointsEx;
	CHANNEL_DEF channelDef;

	Plugin* plugin = (Plugin*)calloc(1, sizeof(Plugin));

	if (!plugin)
		return FALSE;

	pEntryPointsEx = (CHANNEL_ENTRY_POINTS_FREERDP_EX*)pEntryPoints;
	assert(pEntryPointsEx->cbSize >= sizeof(CHANNEL_ENTRY_POINTS_FREERDP_EX) &&
	       pEntryPointsEx->MagicNumber == FREERDP_CHANNEL_MAGIC_NUMBER);
	plugin->initHandle = pInitHandle;
	plugin->channelEntryPoints = *pEntryPointsEx;

	if (init_external_addin(plugin) < 0)
		return FALSE;

	strcpy(channelDef.name, RDP2TCP_CHAN_NAME);
	channelDef.options =
		CHANNEL_OPTION_INITIALIZED |
		CHANNEL_OPTION_ENCRYPT_RDP |
		CHANNEL_OPTION_COMPRESS_RDP;

	if (pEntryPointsEx->pVirtualChannelInitEx(plugin, NULL, pInitHandle, &channelDef, 1,
	        VIRTUAL_CHANNEL_VERSION_WIN2000, VirtualChannelInitEventEx) != CHANNEL_RC_OK)
		return FALSE;

	return TRUE;
}

// vim:ts=4