/**
 * FreeRDP: A Remote Desktop Protocol Implementation
 * Audio Output Virtual Channel
 *
 * Copyright 2013 Dell Software <Mike.McDonald@software.dell.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/wtypes.h>

#include <freerdp/types.h>
#include <freerdp/codec/dsp.h>

#import <AudioToolbox/AudioToolbox.h>

#include "rdpsnd_main.h"
#include "TPCircularBuffer.h"

#define INPUT_BUFFER_SIZE       32768
#define CIRCULAR_BUFFER_SIZE    (INPUT_BUFFER_SIZE * 4)

typedef struct rdpsnd_ios_plugin
{
	rdpsndDevicePlugin device;
	AudioComponentInstance audio_unit;
	TPCircularBuffer buffer;
	BOOL is_opened;
	BOOL is_playing;
} rdpsndIOSPlugin;

#define THIS(__ptr) ((rdpsndIOSPlugin*)__ptr)

static OSStatus rdpsnd_ios_render_cb(
		void *inRefCon,
		AudioUnitRenderActionFlags __unused *ioActionFlags,
		const AudioTimeStamp __unused *inTimeStamp,
		UInt32 inBusNumber,
		UInt32 __unused inNumberFrames,
		AudioBufferList *ioData
)
{
	unsigned int i;

	if (inBusNumber != 0)
	{
		return noErr;
	}

	rdpsndIOSPlugin *p = THIS(inRefCon);

	for (i = 0; i < ioData->mNumberBuffers; i++)
	{
		AudioBuffer* target_buffer = &ioData->mBuffers[i];

		int32_t available_bytes = 0;
		const void *buffer = TPCircularBufferTail(&p->buffer, &available_bytes);
		if (buffer != NULL && available_bytes > 0)
		{
			const int bytes_to_copy = MIN((int32_t)target_buffer->mDataByteSize, available_bytes);

			memcpy(target_buffer->mData, buffer, bytes_to_copy);
			target_buffer->mDataByteSize = bytes_to_copy;

			TPCircularBufferConsume(&p->buffer, bytes_to_copy);
		}
		else
		{
			target_buffer->mDataByteSize = 0;
			AudioOutputUnitStop(p->audio_unit);
			p->is_playing = 0;
		}
	}

	return noErr;
}

static BOOL rdpsnd_ios_format_supported(rdpsndDevicePlugin* __unused device, AUDIO_FORMAT* format)
{
	if (format->wFormatTag == WAVE_FORMAT_PCM)
	{
		return 1;
	}
	return 0;
}

static BOOL rdpsnd_ios_set_format(rdpsndDevicePlugin* __unused device, AUDIO_FORMAT* __unused format, int __unused latency)
{
	return TRUE;
}

static BOOL rdpsnd_ios_set_volume(rdpsndDevicePlugin* __unused device, UINT32 __unused value)
{
	return TRUE;
}

static void rdpsnd_ios_start(rdpsndDevicePlugin* device)
{
	rdpsndIOSPlugin *p = THIS(device);

	/* If this device is not playing... */
	if (!p->is_playing)
	{
		/* Start the device. */
		int32_t available_bytes = 0;
		TPCircularBufferTail(&p->buffer, &available_bytes);
		if (available_bytes > 0)
		{
			p->is_playing = 1;
			AudioOutputUnitStart(p->audio_unit);
		}
	}
}

static void rdpsnd_ios_stop(rdpsndDevicePlugin* __unused device)
{
	rdpsndIOSPlugin *p = THIS(device);

	/* If the device is playing... */
	if (p->is_playing)
	{
		/* Stop the device. */
		AudioOutputUnitStop(p->audio_unit);
		p->is_playing = 0;

		/* Free all buffers. */
		TPCircularBufferClear(&p->buffer);
	}
}

static void rdpsnd_ios_play(rdpsndDevicePlugin* device, BYTE* data, int size)
{
	rdpsndIOSPlugin *p = THIS(device);

	const BOOL ok = TPCircularBufferProduceBytes(&p->buffer, data, size);
	if (!ok)
	{
		return;
	}

	rdpsnd_ios_start(device);
}

static BOOL rdpsnd_ios_open(rdpsndDevicePlugin* device, AUDIO_FORMAT* format, int __unused latency)
{
	rdpsndIOSPlugin *p = THIS(device);

	if (p->is_opened)
		return TRUE;

	/* Find the output audio unit. */
	AudioComponentDescription desc;
	desc.componentManufacturer = kAudioUnitManufacturer_Apple;
	desc.componentType = kAudioUnitType_Output;
	desc.componentSubType = kAudioUnitSubType_RemoteIO;
	desc.componentFlags = 0;
	desc.componentFlagsMask = 0;

	AudioComponent audioComponent = AudioComponentFindNext(NULL, &desc);
	if (audioComponent == NULL)
		return FALSE;

	/* Open the audio unit. */
	OSStatus status = AudioComponentInstanceNew(audioComponent, &p->audio_unit);
	if (status != 0)
		return FALSE;

	/* Set the format for the AudioUnit. */
	AudioStreamBasicDescription audioFormat = {0};
	audioFormat.mSampleRate       = format->nSamplesPerSec;
	audioFormat.mFormatID         = kAudioFormatLinearPCM;
	audioFormat.mFormatFlags      = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
	audioFormat.mFramesPerPacket  = 1; /* imminent property of the Linear PCM */
	audioFormat.mChannelsPerFrame = format->nChannels;
	audioFormat.mBitsPerChannel   = format->wBitsPerSample;
	audioFormat.mBytesPerFrame    = (format->wBitsPerSample * format->nChannels) / 8;
	audioFormat.mBytesPerPacket   = audioFormat.mBytesPerFrame * audioFormat.mFramesPerPacket;

	status = AudioUnitSetProperty(
			p->audio_unit,
			kAudioUnitProperty_StreamFormat,
			kAudioUnitScope_Input,
			0,
			&audioFormat,
			sizeof(audioFormat));
	if (status != 0)
	{
		AudioComponentInstanceDispose(p->audio_unit);
		p->audio_unit = NULL;
		return FALSE;
	}

	/* Set up the AudioUnit callback. */
	AURenderCallbackStruct callbackStruct = {0};
	callbackStruct.inputProc = rdpsnd_ios_render_cb;
	callbackStruct.inputProcRefCon = p;
	status = AudioUnitSetProperty(
			p->audio_unit,
			kAudioUnitProperty_SetRenderCallback,
			kAudioUnitScope_Input,
			0,
			&callbackStruct,
			sizeof(callbackStruct));
	if (status != 0)
	{
		AudioComponentInstanceDispose(p->audio_unit);
		p->audio_unit = NULL;
		return FALSE;
	}

	/* Initialize the AudioUnit. */
	status = AudioUnitInitialize(p->audio_unit);
	if (status != 0)
	{
		AudioComponentInstanceDispose(p->audio_unit);
		p->audio_unit = NULL;
		return FALSE;
	}

	/* Allocate the circular buffer. */
	const BOOL ok = TPCircularBufferInit(&p->buffer, CIRCULAR_BUFFER_SIZE);
	if (!ok)
	{
		AudioUnitUninitialize(p->audio_unit);
		AudioComponentInstanceDispose(p->audio_unit);
		p->audio_unit = NULL;
		return FALSE;
	}

	p->is_opened = 1;
	return TRUE;
}

static void rdpsnd_ios_close(rdpsndDevicePlugin* device)
{
	rdpsndIOSPlugin *p = THIS(device);

	/* Make sure the device is stopped. */
	rdpsnd_ios_stop(device);

	/* If the device is open... */
	if (p->is_opened)
	{
		/* Close the device. */
		AudioUnitUninitialize(p->audio_unit);
		AudioComponentInstanceDispose(p->audio_unit);
		p->audio_unit = NULL;
		p->is_opened = 0;

		/* Destroy the circular buffer. */
		TPCircularBufferCleanup(&p->buffer);
	}
}

static void rdpsnd_ios_free(rdpsndDevicePlugin* device)
{
	rdpsndIOSPlugin *p = THIS(device);

	/* Ensure the device is closed. */
	rdpsnd_ios_close(device);

	/* Free memory associated with the device. */
	free(p);
}

#ifdef BUILTIN_CHANNELS
#define freerdp_rdpsnd_client_subsystem_entry	ios_freerdp_rdpsnd_client_subsystem_entry
#else
#define freerdp_rdpsnd_client_subsystem_entry	FREERDP_API freerdp_rdpsnd_client_subsystem_entry
#endif

/**
 * Function description
 *
 * @return 0 on success, otherwise a Win32 error code
 */
UINT freerdp_rdpsnd_client_subsystem_entry(PFREERDP_RDPSND_DEVICE_ENTRY_POINTS pEntryPoints)
{
	rdpsndIOSPlugin* p = (rdpsndIOSPlugin*) calloc(1, sizeof(rdpsndIOSPlugin));

	if (!p)
		return CHANNEL_RC_NO_MEMORY;

	p->device.Open = rdpsnd_ios_open;
	p->device.FormatSupported = rdpsnd_ios_format_supported;
	p->device.SetFormat = rdpsnd_ios_set_format;
	p->device.SetVolume = rdpsnd_ios_set_volume;
	p->device.Play = rdpsnd_ios_play;
	p->device.Start = rdpsnd_ios_start;
	p->device.Close = rdpsnd_ios_close;
	p->device.Free = rdpsnd_ios_free;

	pEntryPoints->pRegisterRdpsndDevice(pEntryPoints->rdpsnd, (rdpsndDevicePlugin*)p);

	return CHANNEL_RC_OK;
}