/**

 * FreeRDP: A Remote Desktop Protocol Implementation

 * Multiparty Virtual Channel

 *

 * Copyright 2014 Marc-Andre Moreau <marcandre.moreau@gmail.com>

 * Copyright 2015 Thincast Technologies GmbH

 * Copyright 2015 DI (FH) Martin Haimberger <martin.haimberger@thincast.com>

 *

 * 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.

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <winpr/crt.h>

#include <winpr/print.h>

#include <winpr/stream.h>

#include <freerdp/channels/log.h>

#include "encomsp_main.h"

#define TAG CHANNELS_TAG("encomsp.server")

/**

 * Function description

 *

 * @return 0 on success, otherwise a Win32 error code

 */

static UINT encomsp_read_header(wStream* s, ENCOMSP_ORDER_HEADER* header)

{

	if (Stream_GetRemainingLength(s) < ENCOMSP_ORDER_HEADER_SIZE)

		return ERROR_INVALID_DATA;

	Stream_Read_UINT16(s, header->Type);   /* Type (2 bytes) */

	Stream_Read_UINT16(s, header->Length); /* Length (2 bytes) */

	return CHANNEL_RC_OK;

}

#if 0

static int encomsp_write_header(wStream* s, ENCOMSP_ORDER_HEADER* header)

{

	Stream_Write_UINT16(s, header->Type); /* Type (2 bytes) */

	Stream_Write_UINT16(s, header->Length); /* Length (2 bytes) */

	return 1;

}

static int encomsp_read_unicode_string(wStream* s, ENCOMSP_UNICODE_STRING* str)

{

	ZeroMemory(str, sizeof(ENCOMSP_UNICODE_STRING));

	if (Stream_GetRemainingLength(s) < 2)

		return -1;

	Stream_Read_UINT16(s, str->cchString); /* cchString (2 bytes) */

	if (str->cchString > 1024)

		return -1;

	if (Stream_GetRemainingLength(s) < (str->cchString * 2))

		return -1;

	Stream_Read(s, &(str->wString), (str->cchString * 2)); /* String (variable) */

	return 1;

}

#endif

/**

 * Function description

 *

 * @return 0 on success, otherwise a Win32 error code

 */

static UINT encomsp_recv_change_participant_control_level_pdu(EncomspServerContext* context,

                                                              wStream* s,

                                                              ENCOMSP_ORDER_HEADER* header)

{

	int beg, end;

	ENCOMSP_CHANGE_PARTICIPANT_CONTROL_LEVEL_PDU pdu;

	UINT error = CHANNEL_RC_OK;

	beg = ((int)Stream_GetPosition(s)) - ENCOMSP_ORDER_HEADER_SIZE;

	CopyMemory(&pdu, header, sizeof(ENCOMSP_ORDER_HEADER));

	if (Stream_GetRemainingLength(s) < 6)

	{

		WLog_ERR(TAG, "Not enough data!");

		return ERROR_INVALID_DATA;

	}

	Stream_Read_UINT16(s, pdu.Flags);         /* Flags (2 bytes) */

	Stream_Read_UINT32(s, pdu.ParticipantId); /* ParticipantId (4 bytes) */

	end = (int)Stream_GetPosition(s);

	if ((beg + header->Length) < end)

	{

		WLog_ERR(TAG, "Not enough data!");

		return ERROR_INVALID_DATA;

	}

	if ((beg + header->Length) > end)

	{

		if (Stream_GetRemainingLength(s) < (size_t)((beg + header->Length) - end))

		{

			WLog_ERR(TAG, "Not enough data!");

			return ERROR_INVALID_DATA;

		}

		Stream_SetPosition(s, (beg + header->Length));

	}

	IFCALLRET(context->ChangeParticipantControlLevel, error, context, &pdu);

	if (error)

		WLog_ERR(TAG, "context->ChangeParticipantControlLevel failed with error %" PRIu32 "",

		         error);

	return error;

}

/**

 * Function description

 *

 * @return 0 on success, otherwise a Win32 error code

 */

static UINT encomsp_server_receive_pdu(EncomspServerContext* context, wStream* s)

{

	UINT error = CHANNEL_RC_OK;

	ENCOMSP_ORDER_HEADER header;

	while (Stream_GetRemainingLength(s) > 0)

	{

		if ((error = encomsp_read_header(s, &header)))

		{

			WLog_ERR(TAG, "encomsp_read_header failed with error %" PRIu32 "!", error);

			return error;

		}

		WLog_INFO(TAG, "EncomspReceive: Type: %" PRIu16 " Length: %" PRIu16 "", header.Type,

		          header.Length);

		switch (header.Type)

		{

			case ODTYPE_PARTICIPANT_CTRL_CHANGED:

				if ((error =

				         encomsp_recv_change_participant_control_level_pdu(context, s, &header)))

				{

					WLog_ERR(TAG,

					         "encomsp_recv_change_participant_control_level_pdu failed with error "

					         "%" PRIu32 "!",

					         error);

					return error;

				}

				break;

			default:

				WLog_ERR(TAG, "header.Type unknown %" PRIu16 "!", header.Type);

				return ERROR_INVALID_DATA;

				break;

		}

	}

	return error;

}

static DWORD WINAPI encomsp_server_thread(LPVOID arg)

{

	wStream* s;

	DWORD nCount;

	void* buffer;

	HANDLE events[8];

	HANDLE ChannelEvent;

	DWORD BytesReturned;

	ENCOMSP_ORDER_HEADER* header;

	EncomspServerContext* context;

	UINT error = CHANNEL_RC_OK;

	DWORD status;

	context = (EncomspServerContext*)arg;

	buffer = NULL;

	BytesReturned = 0;

	ChannelEvent = NULL;

	s = Stream_New(NULL, 4096);

	if (!s)

	{

		WLog_ERR(TAG, "Stream_New failed!");

		error = CHANNEL_RC_NO_MEMORY;

		goto out;

	}

	if (WTSVirtualChannelQuery(context->priv->ChannelHandle, WTSVirtualEventHandle, &buffer,

	                           &BytesReturned) == TRUE)

	{

		if (BytesReturned == sizeof(HANDLE))

			CopyMemory(&ChannelEvent, buffer, sizeof(HANDLE));

		WTSFreeMemory(buffer);

	}

	nCount = 0;

	events[nCount++] = ChannelEvent;

	events[nCount++] = context->priv->StopEvent;

	while (1)

	{

		status = WaitForMultipleObjects(nCount, events, FALSE, INFINITE);

		if (status == WAIT_FAILED)

		{

			error = GetLastError();

			WLog_ERR(TAG, "WaitForMultipleObjects failed with error %" PRIu32 "", error);

			break;

		}

		status = WaitForSingleObject(context->priv->StopEvent, 0);

		if (status == WAIT_FAILED)

		{

			error = GetLastError();

			WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "", error);

			break;

		}

		if (status == WAIT_OBJECT_0)

		{

			break;

		}

		WTSVirtualChannelRead(context->priv->ChannelHandle, 0, NULL, 0, &BytesReturned);

		if (BytesReturned < 1)

			continue;

		if (!Stream_EnsureRemainingCapacity(s, BytesReturned))

		{

			WLog_ERR(TAG, "Stream_EnsureRemainingCapacity failed!");

			error = CHANNEL_RC_NO_MEMORY;

			break;

		}

		if (!WTSVirtualChannelRead(context->priv->ChannelHandle, 0, (PCHAR)Stream_Buffer(s),

		                           Stream_Capacity(s), &BytesReturned))

		{

			WLog_ERR(TAG, "WTSVirtualChannelRead failed!");

			error = ERROR_INTERNAL_ERROR;

			break;

		}

		if (Stream_GetPosition(s) >= ENCOMSP_ORDER_HEADER_SIZE)

		{

			header = (ENCOMSP_ORDER_HEADER*)Stream_Buffer(s);

			if (header->Length >= Stream_GetPosition(s))

			{

				Stream_SealLength(s);

				Stream_SetPosition(s, 0);

				if ((error = encomsp_server_receive_pdu(context, s)))

				{

					WLog_ERR(TAG, "encomsp_server_receive_pdu failed with error %" PRIu32 "!",

					         error);

					break;

				}

				Stream_SetPosition(s, 0);

			}

		}

	}

	Stream_Free(s, TRUE);

out:

	if (error && context->rdpcontext)

		setChannelError(context->rdpcontext, error, "encomsp_server_thread reported an error");

	ExitThread(error);

	return error;

}

/**

 * Function description

 *

 * @return 0 on success, otherwise a Win32 error code

 */

static UINT encomsp_server_start(EncomspServerContext* context)

{

	context->priv->ChannelHandle =

	    WTSVirtualChannelOpen(context->vcm, WTS_CURRENT_SESSION, "encomsp");

	if (!context->priv->ChannelHandle)

		return CHANNEL_RC_BAD_CHANNEL;

	if (!(context->priv->StopEvent = CreateEvent(NULL, TRUE, FALSE, NULL)))

	{

		WLog_ERR(TAG, "CreateEvent failed!");

		return ERROR_INTERNAL_ERROR;

	}

	if (!(context->priv->Thread =

	          CreateThread(NULL, 0, encomsp_server_thread, (void*)context, 0, NULL)))

	{

		WLog_ERR(TAG, "CreateThread failed!");

		CloseHandle(context->priv->StopEvent);

		context->priv->StopEvent = NULL;

		return ERROR_INTERNAL_ERROR;

	}

	return CHANNEL_RC_OK;

}

/**

 * Function description

 *

 * @return 0 on success, otherwise a Win32 error code

 */

static UINT encomsp_server_stop(EncomspServerContext* context)

{

	UINT error = CHANNEL_RC_OK;

	SetEvent(context->priv->StopEvent);

	if (WaitForSingleObject(context->priv->Thread, INFINITE) == WAIT_FAILED)

	{

		error = GetLastError();

		WLog_ERR(TAG, "WaitForSingleObject failed with error %" PRIu32 "", error);

		return error;

	}

	CloseHandle(context->priv->Thread);

	CloseHandle(context->priv->StopEvent);

	return error;

}

EncomspServerContext* encomsp_server_context_new(HANDLE vcm)

{

	EncomspServerContext* context;

	context = (EncomspServerContext*)calloc(1, sizeof(EncomspServerContext));

	if (context)

	{

		context->vcm = vcm;

		context->Start = encomsp_server_start;

		context->Stop = encomsp_server_stop;

		context->priv = (EncomspServerPrivate*)calloc(1, sizeof(EncomspServerPrivate));

		if (!context->priv)

		{

			WLog_ERR(TAG, "calloc failed!");

			free(context);

			return NULL;

		}

	}

	return context;

}

void encomsp_server_context_free(EncomspServerContext* context)

{

	if (context)

	{

		if (context->priv->ChannelHandle != INVALID_HANDLE_VALUE)

			WTSVirtualChannelClose(context->priv->ChannelHandle);

		free(context->priv);

		free(context);

	}

}