/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * Multiparty Virtual Channel
 *
 * Copyright 2014 Marc-Andre Moreau <marcandre.moreau@gmail.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 "encomsp_main.h"

static int encomsp_read_header(wStream* s, ENCOMSP_ORDER_HEADER* header)
{
	if (Stream_GetRemainingLength(s) < ENCOMSP_ORDER_HEADER_SIZE)
		return -1;

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

	return 1;
}

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;
}

static int 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;

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

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

	if (Stream_GetRemainingLength(s) < 6)
		return -1;

	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)
		return -1;

	if ((beg + header->Length) > end)
	{
		if (Stream_GetRemainingLength(s) < ((beg + header->Length) - end))
			return -1;

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

	if (context->ChangeParticipantControlLevel)
	{
		return context->ChangeParticipantControlLevel(context, &pdu);
	}

	return 1;
}

static int encomsp_server_receive_pdu(EncomspServerContext* context, wStream* s)
{
	int status = 1;
	ENCOMSP_ORDER_HEADER header;

	while (Stream_GetRemainingLength(s) > 0)
	{
		if (encomsp_read_header(s, &header) < 0)
			return -1;

		printf("EncomspReceive: Type: %d Length: %d\n", header.Type, header.Length);

		switch (header.Type)
		{
			case ODTYPE_PARTICIPANT_CTRL_CHANGED:
				status = encomsp_recv_change_participant_control_level_pdu(context, s, &header);
				break;

			default:
				status = -1;
				break;
		}

		if (status < 0)
			return -1;
	}

	return status;
}

static void* encomsp_server_thread(void* arg)
{
	wStream* s;
	DWORD status;
	DWORD nCount;
	void* buffer;
	HANDLE events[8];
	HANDLE ChannelEvent;
	DWORD BytesReturned;
	ENCOMSP_ORDER_HEADER* header;
	EncomspServerContext* context;

	context = (EncomspServerContext*) arg;

	buffer = NULL;
	BytesReturned = 0;
	ChannelEvent = NULL;

	s = Stream_New(NULL, 4096);

	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 (WaitForSingleObject(context->priv->StopEvent, 0) == WAIT_OBJECT_0)
		{
			break;
		}

		if (WTSVirtualChannelRead(context->priv->ChannelHandle, 0,
				(PCHAR) Stream_Buffer(s), Stream_Capacity(s), &BytesReturned))
		{
			if (BytesReturned)
				Stream_Seek(s, BytesReturned);
		}
		else
		{
			Stream_EnsureRemainingCapacity(s, BytesReturned);
		}

		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);
				encomsp_server_receive_pdu(context, s);
				Stream_SetPosition(s, 0);
			}
		}
	}

	Stream_Free(s, TRUE);

	return NULL;
}

static int encomsp_server_start(EncomspServerContext* context)
{
	context->priv->ChannelHandle = WTSVirtualChannelOpen(context->vcm, WTS_CURRENT_SESSION, "encomsp");

	if (!context->priv->ChannelHandle)
		return -1;

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

	context->priv->Thread = CreateThread(NULL, 0,
			(LPTHREAD_START_ROUTINE) encomsp_server_thread, (void*) context, 0, NULL);

	return 0;
}

static int encomsp_server_stop(EncomspServerContext* context)
{
	SetEvent(context->priv->StopEvent);

	WaitForSingleObject(context->priv->Thread, INFINITE);
	CloseHandle(context->priv->Thread);

	return 0;
}

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)
		{

		}
	}

	return context;
}

void encomsp_server_context_free(EncomspServerContext* context)
{
	if (context)
	{
		if (context->priv)
		{
			free(context->priv);
		}

		free(context);
	}
}