/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * Server Audio Input Virtual Channel
 *
 * Copyright 2012 Vic Lee
 *
 * 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 <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <winpr/crt.h>
#include <winpr/synch.h>
#include <winpr/thread.h>
#include <winpr/stream.h>

#include <freerdp/codec/dsp.h>
#include <freerdp/codec/audio.h>
#include <freerdp/channels/wtsvc.h>
#include <freerdp/server/audin.h>

#define MSG_SNDIN_VERSION		0x01
#define MSG_SNDIN_FORMATS		0x02
#define MSG_SNDIN_OPEN			0x03
#define MSG_SNDIN_OPEN_REPLY		0x04
#define MSG_SNDIN_DATA_INCOMING		0x05
#define MSG_SNDIN_DATA			0x06
#define MSG_SNDIN_FORMATCHANGE		0x07

typedef struct _audin_server
{
	audin_server_context context;

	BOOL opened;

	HANDLE stopEvent;

	HANDLE thread;
	void* audin_channel;

	DWORD SessionId;

	FREERDP_DSP_CONTEXT* dsp_context;

} audin_server;

static void audin_server_select_format(audin_server_context* context, int client_format_index)
{
	audin_server* audin = (audin_server*) context;

	if (client_format_index >= context->num_client_formats)
		return;

	context->selected_client_format = client_format_index;

	if (audin->opened)
	{
		/* TODO: send MSG_SNDIN_FORMATCHANGE */
	}
}

static void audin_server_send_version(audin_server* audin, wStream* s)
{
	Stream_Write_UINT8(s, MSG_SNDIN_VERSION);
	Stream_Write_UINT32(s, 1); /* Version (4 bytes) */
	WTSVirtualChannelWrite(audin->audin_channel, (PCHAR) Stream_Buffer(s), Stream_GetPosition(s), NULL);
}

static BOOL audin_server_recv_version(audin_server* audin, wStream* s, UINT32 length)
{
	UINT32 Version;

	if (length < 4)
		return FALSE;

	Stream_Read_UINT32(s, Version);

	if (Version < 1)
		return FALSE;

	return TRUE;
}

static void audin_server_send_formats(audin_server* audin, wStream* s)
{
	int i;
	UINT32 nAvgBytesPerSec;

	Stream_SetPosition(s, 0);
	Stream_Write_UINT8(s, MSG_SNDIN_FORMATS);
	Stream_Write_UINT32(s, audin->context.num_server_formats); /* NumFormats (4 bytes) */
	Stream_Write_UINT32(s, 0); /* cbSizeFormatsPacket (4 bytes), client-to-server only */

	for (i = 0; i < audin->context.num_server_formats; i++)
	{
		nAvgBytesPerSec = audin->context.server_formats[i].nSamplesPerSec *
			audin->context.server_formats[i].nChannels *
			audin->context.server_formats[i].wBitsPerSample / 8;

		Stream_EnsureRemainingCapacity(s, 18);

		Stream_Write_UINT16(s, audin->context.server_formats[i].wFormatTag);
		Stream_Write_UINT16(s, audin->context.server_formats[i].nChannels);
		Stream_Write_UINT32(s, audin->context.server_formats[i].nSamplesPerSec);
		Stream_Write_UINT32(s, nAvgBytesPerSec);
		Stream_Write_UINT16(s, audin->context.server_formats[i].nBlockAlign);
		Stream_Write_UINT16(s, audin->context.server_formats[i].wBitsPerSample);
		Stream_Write_UINT16(s, audin->context.server_formats[i].cbSize);

		if (audin->context.server_formats[i].cbSize)
		{
			Stream_EnsureRemainingCapacity(s, audin->context.server_formats[i].cbSize);
			Stream_Write(s, audin->context.server_formats[i].data,
				audin->context.server_formats[i].cbSize);
		}
	}

	WTSVirtualChannelWrite(audin->audin_channel, (PCHAR) Stream_Buffer(s), Stream_GetPosition(s), NULL);
}

static BOOL audin_server_recv_formats(audin_server* audin, wStream* s, UINT32 length)
{
	int i;

	if (length < 8)
		return FALSE;

	Stream_Read_UINT32(s, audin->context.num_client_formats); /* NumFormats (4 bytes) */
	Stream_Seek_UINT32(s); /* cbSizeFormatsPacket (4 bytes) */
	length -= 8;

	if (audin->context.num_client_formats <= 0)
		return FALSE;

	audin->context.client_formats = malloc(audin->context.num_client_formats * sizeof(AUDIO_FORMAT));
	ZeroMemory(audin->context.client_formats, audin->context.num_client_formats * sizeof(AUDIO_FORMAT));

	for (i = 0; i < audin->context.num_client_formats; i++)
	{
		if (length < 18)
		{
			free(audin->context.client_formats);
			audin->context.client_formats = NULL;
			return FALSE;
		}

		Stream_Read_UINT16(s, audin->context.client_formats[i].wFormatTag);
		Stream_Read_UINT16(s, audin->context.client_formats[i].nChannels);
		Stream_Read_UINT32(s, audin->context.client_formats[i].nSamplesPerSec);
		Stream_Seek_UINT32(s); /* nAvgBytesPerSec */
		Stream_Read_UINT16(s, audin->context.client_formats[i].nBlockAlign);
		Stream_Read_UINT16(s, audin->context.client_formats[i].wBitsPerSample);
		Stream_Read_UINT16(s, audin->context.client_formats[i].cbSize);

		if (audin->context.client_formats[i].cbSize > 0)
		{
			Stream_Seek(s, audin->context.client_formats[i].cbSize);
		}
	}

	IFCALL(audin->context.Opening, &audin->context);

	return TRUE;
}

static void audin_server_send_open(audin_server* audin, wStream* s)
{
	if (audin->context.selected_client_format < 0)
		return;

	audin->opened = TRUE;

	Stream_SetPosition(s, 0);
	Stream_Write_UINT8(s, MSG_SNDIN_OPEN);
	Stream_Write_UINT32(s, audin->context.frames_per_packet); /* FramesPerPacket (4 bytes) */
	Stream_Write_UINT32(s, audin->context.selected_client_format); /* initialFormat (4 bytes) */
	/*
	 * [MS-RDPEAI] 3.2.5.1.6
	 * The second format specify the format that SHOULD be used to capture data from
	 * the actual audio input device.
	 */
	Stream_Write_UINT16(s, 1); /* wFormatTag = PCM */
	Stream_Write_UINT16(s, 2); /* nChannels */
	Stream_Write_UINT32(s, 44100); /* nSamplesPerSec */
	Stream_Write_UINT32(s, 44100 * 2 * 2); /* nAvgBytesPerSec */
	Stream_Write_UINT16(s, 4); /* nBlockAlign */
	Stream_Write_UINT16(s, 16); /* wBitsPerSample */
	Stream_Write_UINT16(s, 0); /* cbSize */

	WTSVirtualChannelWrite(audin->audin_channel, (PCHAR) Stream_Buffer(s), Stream_GetPosition(s), NULL);
}

static BOOL audin_server_recv_open_reply(audin_server* audin, wStream* s, UINT32 length)
{
	UINT32 Result;

	if (length < 4)
		return FALSE;

	Stream_Read_UINT32(s, Result);

	IFCALL(audin->context.OpenResult, &audin->context, Result);

	return TRUE;
}

static BOOL audin_server_recv_data(audin_server* audin, wStream* s, UINT32 length)
{
	AUDIO_FORMAT* format;
	int sbytes_per_sample;
	int sbytes_per_frame;
	BYTE* src;
	int size;
	int frames;

	if (audin->context.selected_client_format < 0)
		return FALSE;

	format = &audin->context.client_formats[audin->context.selected_client_format];

	if (format->wFormatTag == WAVE_FORMAT_ADPCM)
	{
		audin->dsp_context->decode_ms_adpcm(audin->dsp_context,
			Stream_Pointer(s), length, format->nChannels, format->nBlockAlign);
		size = audin->dsp_context->adpcm_size;
		src = audin->dsp_context->adpcm_buffer;
		sbytes_per_sample = 2;
		sbytes_per_frame = format->nChannels * 2;
	}
	else if (format->wFormatTag == WAVE_FORMAT_DVI_ADPCM)
	{
		audin->dsp_context->decode_ima_adpcm(audin->dsp_context,
			Stream_Pointer(s), length, format->nChannels, format->nBlockAlign);
		size = audin->dsp_context->adpcm_size;
		src = audin->dsp_context->adpcm_buffer;
		sbytes_per_sample = 2;
		sbytes_per_frame = format->nChannels * 2;
	}
	else
	{
		size = length;
		src = Stream_Pointer(s);
		sbytes_per_sample = format->wBitsPerSample / 8;
		sbytes_per_frame = format->nChannels * sbytes_per_sample;
	}

	if (format->nSamplesPerSec == audin->context.dst_format.nSamplesPerSec && format->nChannels == audin->context.dst_format.nChannels)
	{
		frames = size / sbytes_per_frame;
	}
	else
	{
		audin->dsp_context->resample(audin->dsp_context, src, sbytes_per_sample,
			format->nChannels, format->nSamplesPerSec, size / sbytes_per_frame,
			audin->context.dst_format.nChannels, audin->context.dst_format.nSamplesPerSec);
		frames = audin->dsp_context->resampled_frames;
		src = audin->dsp_context->resampled_buffer;
	}

	IFCALL(audin->context.ReceiveSamples, &audin->context, src, frames);

	return TRUE;
}

static void* audin_server_thread_func(void* arg)
{
	wStream* s;
	void* buffer;
	DWORD nCount;
	BYTE MessageId;
	HANDLE events[8];
	BOOL ready = FALSE;
	HANDLE ChannelEvent;
	DWORD BytesReturned = 0;
	audin_server* audin = (audin_server*) arg;

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

	if (WTSVirtualChannelQuery(audin->audin_channel, WTSVirtualEventHandle, &buffer, &BytesReturned) == TRUE)
	{
		if (BytesReturned == sizeof(HANDLE))
			CopyMemory(&ChannelEvent, buffer, sizeof(HANDLE));

		WTSFreeMemory(buffer);
	}

	nCount = 0;
	events[nCount++] = audin->stopEvent;
	events[nCount++] = ChannelEvent;

	/* Wait for the client to confirm that the Audio Input dynamic channel is ready */

	while (1)
	{
		if (WaitForMultipleObjects(nCount, events, FALSE, 100) == WAIT_OBJECT_0)
			break;

		if (WTSVirtualChannelQuery(audin->audin_channel, WTSVirtualChannelReady, &buffer, &BytesReturned) == FALSE)
			break;

		ready = *((BOOL*) buffer);

		WTSFreeMemory(buffer);

		if (ready)
			break;
	}

	s = Stream_New(NULL, 4096);
	if (!s)
		goto out;

	if (ready)
	{
		audin_server_send_version(audin, s);
	}

	while (ready)
	{
		if (WaitForMultipleObjects(nCount, events, FALSE, INFINITE) == WAIT_OBJECT_0)
			break;

		Stream_SetPosition(s, 0);

		if (WTSVirtualChannelRead(audin->audin_channel, 0, (PCHAR) Stream_Buffer(s),
			Stream_Capacity(s), &BytesReturned) == FALSE)
		{
			if (BytesReturned == 0)
				break;
			
			Stream_EnsureRemainingCapacity(s, BytesReturned);

			if (WTSVirtualChannelRead(audin->audin_channel, 0, (PCHAR) Stream_Buffer(s),
				Stream_Capacity(s), &BytesReturned) == FALSE)
			{
				break;
			}
		}

		if (BytesReturned < 1)
			continue;

		Stream_Read_UINT8(s, MessageId);
		BytesReturned--;

		switch (MessageId)
		{
			case MSG_SNDIN_VERSION:
				if (audin_server_recv_version(audin, s, BytesReturned))
					audin_server_send_formats(audin, s);
				break;

			case MSG_SNDIN_FORMATS:
				if (audin_server_recv_formats(audin, s, BytesReturned))
					audin_server_send_open(audin, s);
				break;

			case MSG_SNDIN_OPEN_REPLY:
				audin_server_recv_open_reply(audin, s, BytesReturned);
				break;

			case MSG_SNDIN_DATA_INCOMING:
				break;

			case MSG_SNDIN_DATA:
				audin_server_recv_data(audin, s, BytesReturned);
				break;

			case MSG_SNDIN_FORMATCHANGE:
				break;

			default:
				fprintf(stderr, "audin_server_thread_func: unknown MessageId %d\n", MessageId);
				break;
		}
	}

	Stream_Free(s, TRUE);

out:
	WTSVirtualChannelClose(audin->audin_channel);
	audin->audin_channel = NULL;

	return NULL;
}

static BOOL audin_server_open(audin_server_context* context)
{
	audin_server* audin = (audin_server*) context;

	if (!audin->thread)
	{
		PULONG pSessionId = NULL;
		DWORD BytesReturned = 0;

		audin->SessionId = WTS_CURRENT_SESSION;

		if (WTSQuerySessionInformationA(context->vcm, WTS_CURRENT_SESSION,
				WTSSessionId, (LPSTR*) &pSessionId, &BytesReturned))
		{
			audin->SessionId = (DWORD) *pSessionId;
			WTSFreeMemory(pSessionId);
		}

		audin->audin_channel = WTSVirtualChannelOpenEx(audin->SessionId,
				"AUDIO_INPUT", WTS_CHANNEL_OPTION_DYNAMIC);

		if (!audin->audin_channel)
			return FALSE;

		audin->stopEvent = CreateEvent(NULL, TRUE, FALSE, NULL);

		audin->thread = CreateThread(NULL, 0,
				(LPTHREAD_START_ROUTINE) audin_server_thread_func, (void*) audin, 0, NULL);

		return TRUE;
	}

	return FALSE;
}

static BOOL audin_server_close(audin_server_context* context)
{
	audin_server* audin = (audin_server*) context;

	if (audin->thread)
	{
		SetEvent(audin->stopEvent);
		WaitForSingleObject(audin->thread, INFINITE);
		CloseHandle(audin->thread);
		CloseHandle(audin->stopEvent);
		audin->thread = NULL;
		audin->stopEvent = NULL;
	}

	if (audin->audin_channel)
	{
		WTSVirtualChannelClose(audin->audin_channel);
		audin->audin_channel = NULL;
	}

	audin->context.selected_client_format = -1;

	return TRUE;
}

audin_server_context* audin_server_context_new(HANDLE vcm)
{
	audin_server* audin;

	audin = (audin_server *)calloc(1, sizeof(audin_server));

	audin->context.vcm = vcm;
	audin->context.selected_client_format = -1;
	audin->context.frames_per_packet = 4096;
	audin->context.SelectFormat = audin_server_select_format;
	audin->context.Open = audin_server_open;
	audin->context.Close = audin_server_close;

	audin->dsp_context = freerdp_dsp_context_new();

	return (audin_server_context*) audin;
}

void audin_server_context_free(audin_server_context* context)
{
	audin_server* audin = (audin_server*) context;

	audin_server_close(context);

	if (audin->dsp_context)
		freerdp_dsp_context_free(audin->dsp_context);

	if (audin->context.client_formats)
		free(audin->context.client_formats);

	free(audin);
}