/*
* High Speed modem to transfer data in a 2,7kHz SSB channel
* =========================================================
* Author: DJ0ABR
*
*   (c) DJ0ABR
*   www.dj0abr.de
*
*   This program is free software; you can redistribute it and/or modify
*   it under the terms of the GNU General Public License as published by
*   the Free Software Foundation; either version 2 of the License, or
*   (at your option) any later version.
*
*   This program is distributed in the hope that it will be useful,
*   but WITHOUT ANY WARRANTY; without even the implied warranty of
*   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
*   GNU General Public License for more details.
*
*   You should have received a copy of the GNU General Public License
*   along with this program; if not, write to the Free Software
*   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
* 
* audio.c ... functions to handle audio in/out via a soundcard
*             uses the "BASS" library
* 
* captures samples from the sound card.
* Samples are 32-bit floats in a range of -1 to +1
* get these samples from the thread safe fifo: cap_read_fifo(&floatvariable)
* 
* plays samples to the sound card
* Samples are 32-bit floats in a range of -1 to +1
* play the samples by calling the thread save function: pb_write_fifo(floatsample)
* 
*/

#include "hsmodem.h"

BOOL CALLBACK RecordingCallback(HRECORD handle, const void *buffer, DWORD length, void *user);
DWORD CALLBACK WriteStream(HSTREAM handle, float *buffer, DWORD length, void *user);
int pb_read_fifo(float *data, int elements);
void close_audio();
void cap_write_fifo(float sample);
int pb_fifo_freespace(int nolock);
void init_pipes();

#define CHANNELS 1      // no of channels used

HRECORD rchan = 0;		// recording channel
BASS_INFO info;
HSTREAM stream = 0;	

/*void showDeviceInfo(BASS_DEVICEINFO info)
{
    if (info.flags & BASS_DEVICE_ENABLED)	printf("%s\n","BASS_DEVICE_ENABLED	");
    if (info.flags & BASS_DEVICE_DEFAULT)	printf("%s\n","BASS_DEVICE_DEFAULT	");
    if (info.flags & BASS_DEVICE_INIT)	printf("%s\n","BASS_DEVICE_INIT	");
    if (info.flags & BASS_DEVICE_LOOPBACK)	printf("%s\n","BASS_DEVICE_LOOPBACK	");
    if (info.flags & BASS_DEVICE_TYPE_DIGITAL)	printf("%s\n","BASS_DEVICE_TYPE_DIGITAL	");
    if (info.flags & BASS_DEVICE_TYPE_DISPLAYPORT)	printf("%s\n","BASS_DEVICE_TYPE_DISPLAYPORT	");
    if (info.flags & BASS_DEVICE_TYPE_HANDSET)	printf("%s\n","BASS_DEVICE_TYPE_HANDSET	");
    if (info.flags & BASS_DEVICE_TYPE_HDMI)	printf("%s\n","BASS_DEVICE_TYPE_HDMI	");
    if (info.flags & BASS_DEVICE_TYPE_HEADPHONES)	printf("%s\n","BASS_DEVICE_TYPE_HEADPHONES	");
    if (info.flags & BASS_DEVICE_TYPE_HEADSET)	printf("%s\n","BASS_DEVICE_TYPE_HEADSET	");
    if (info.flags & BASS_DEVICE_TYPE_LINE)	printf("%s\n","BASS_DEVICE_TYPE_LINE	");
    if (info.flags & BASS_DEVICE_TYPE_MICROPHONE)	printf("%s\n","BASS_DEVICE_TYPE_MICROPHONE	");
    if (info.flags & BASS_DEVICE_TYPE_NETWORK)	printf("%s\n","BASS_DEVICE_TYPE_NETWORK	");
    if (info.flags & BASS_DEVICE_TYPE_SPDIF)	printf("%s\n","BASS_DEVICE_TYPE_SPDIF	");
    if (info.flags & BASS_DEVICE_TYPE_SPEAKERS)	printf("%s\n","BASS_DEVICE_TYPE_SPEAKERS	");

}*/

#define MAXDEVSTRLEN    2000
uint8_t devstring[MAXDEVSTRLEN +100];
char PBdevs[100][256]; // stores the device names, just for diagnosis, has no real fuction
char CAPdevs[100][256];

// build string of audio devices, to be sent to application as response to Broadcast search
void enumerateAudioDevices()
{
    memset(devstring, 0, sizeof(devstring));
    devstring[0] = 3;   // ID for this UDP message

    // playback devices
    int a;
    int idx = 0;
    BASS_DEVICEINFO info;

    strcat((char*)(devstring + 1), "System Default");
    strcat((char*)(devstring + 1), "~");
    strcpy(PBdevs[idx++], "System Default");

    for (a = 1; BASS_GetDeviceInfo(a, &info); a++)
    {
        printf("PB device:%d = %s\n", a, info.name);
        if (strlen((char*)(devstring+1)) > MAXDEVSTRLEN) break;
        if (info.flags & BASS_DEVICE_ENABLED)
        {
            strncpy(PBdevs[idx], info.name, 255);
            PBdevs[idx][255] = 0;
            idx++;
            strcat((char*)(devstring + 1), info.name);
            strcat((char*)(devstring + 1), "~");    // audio device separator
        }
    }

    strcat((char*)(devstring + 1), "^");    // PB, CAP separator

    // capture devices
    BASS_DEVICEINFO recinfo;
    idx = 0;

    strcat((char*)(devstring + 1), "System Default");
    strcat((char*)(devstring + 1), "~");
    strcpy(CAPdevs[idx++], "System Default");

    for (a = 0; BASS_RecordGetDeviceInfo(a, &recinfo); a++)
    {
        printf("CAP device:%d = %s\n", a, recinfo.name);
        if (strlen((char*)(devstring + 1)) > MAXDEVSTRLEN) break;
        if (recinfo.flags & BASS_DEVICE_ENABLED)
        {
            strncpy(CAPdevs[idx], recinfo.name, 255);
            CAPdevs[idx][255] = 0;
            idx++;
            strcat((char*)(devstring + 1), recinfo.name);
            strcat((char*)(devstring + 1), "~");
        }
    }
}

/*
* Audio Device numbering:
* 
* Playback:
* 0 ... no audio, we use 0 for default, which is -1
* 1 ... audio devices
* 
* Record:
* 0 ... audio devices
* we insert "Default" at position 0, and let the audio devices start with 1, so we are compatible with playback
* but in init_audio() we have to substract 1
*/

uint8_t* getAudioDevicelist(int *len)
{
    *len = strlen((char*)(devstring+1))+1;
    return devstring;
}

// pbdev, capdev: -1=default device
int init_audio(int pbdev, int capdev)
{
    static int f = 1;
    int ocd = capdev;

    // PB devices start with 1 (0 not used, but here used for Default which is -1)
    if (pbdev == 255 || pbdev == 0) pbdev = -1;

    // CAP devices start with 0, but we use 0 for Default (-1)
    // so we have to substract 1 from the real devices
    if (capdev == 255 || capdev == 0 || capdev == -1) capdev = -1;
    else capdev--;

    if (f == 1)
    {
        f = 0;
        enumerateAudioDevices();
        init_pipes();
    }
    
    close_audio();

    printf("init audio, caprate:%d\n",caprate);
    if (pbdev != -1)
        printf("playback device %d: %s\n", pbdev, PBdevs[pbdev]);
    else
        printf("playback device %d: %s\n", pbdev, "Default");

    if (capdev != -1)
        printf("capture device %d: %s\n", capdev, CAPdevs[ocd]);
    else
        printf("capture device %d: %s\n", capdev, "Default");
    
    // check the correct BASS was loaded
	if (HIWORD(BASS_GetVersion()) != BASSVERSION) 
    {
		printf("An incorrect version of BASS was loaded\n");
        return -1;
	}
	
    // initalize default recording device
    if (!BASS_RecordInit(capdev))
    {
        printf("Can't initialize recording device: %d\n", BASS_ErrorGetCode());
        return -1;
    }
    
	// initialize default output device
	if (!BASS_Init(pbdev, caprate, 0, NULL, NULL)) 
    {
		printf("Can't initialize output device\n");
        return -1;
    }

    // set capture callback
    rchan = BASS_RecordStart(caprate, CHANNELS, BASS_SAMPLE_FLOAT, RecordingCallback, 0);
    if (!rchan) {
        printf("Can't start capturing: %d\n", BASS_ErrorGetCode());
        return -1;
    }
    
	// set play callback
	BASS_GetInfo(&info);
	stream = BASS_StreamCreate(info.freq, CHANNELS, BASS_SAMPLE_FLOAT, (STREAMPROC*)WriteStream, 0); // sample: 32 bit float
	BASS_ChannelSetAttribute(stream, BASS_ATTRIB_BUFFER, 0); // no buffering for minimum latency
	BASS_ChannelPlay(stream, FALSE); // start it

    printf("audio initialized\n");
    
    return 0;
}

void close_audio()
{
    if(stream != 0)
    {
        printf("!close Audio Devices\n");
        BASS_ChannelStop(rchan);
        int rr = BASS_RecordFree();
        if (!rr) printf("Bass_RecordFree error: %d\n", BASS_ErrorGetCode());

        BASS_StreamFree(stream);
        int r = BASS_Free();
        if(!r) printf("Bass_Free error: %d\n", BASS_ErrorGetCode());
        stream = 0;
    }
}

// capture callback
// length: bytes. short=2byte, 2channels, so it requests samples*4
BOOL CALLBACK RecordingCallback(HRECORD handle, const void *buffer, DWORD length, void *user)
{
    //printf("captured %ld samples\n",length/sizeof(float));
    //measure_speed(length/sizeof(float));
    
    float *fbuffer = (float *)buffer;
    //showbytestringf((char*)"cap:", fbuffer, 10);
    //printf("w:%ld ",length/sizeof(float));
    for(unsigned int i=0; i<(length/sizeof(float)); i+=CHANNELS)
    {
        //printf("%f\n",fbuffer[i]);
        cap_write_fifo(fbuffer[i]);
    }

    return TRUE; // continue recording
}

// play callback
// length: bytes. float=4byte, 2channels, so it requests samples*8
DWORD CALLBACK WriteStream(HSTREAM handle, float *buffer, DWORD length, void *user)
{
    //printf("requested %ld samples\n", length / sizeof(float));
    int ret = pb_read_fifo(buffer, length / sizeof(float));
    if(ret == 0)
    {
        // fifo empty, send 00
        memset(buffer,0,length);
    }
	return length;
}

// ================ thread safe fifo for audio callback routines ===============

#ifdef _WIN32_
CRITICAL_SECTION cap_crit_sec;
CRITICAL_SECTION pb_crit_sec;
#define CAP_LOCK	EnterCriticalSection(&cap_crit_sec)
#define PB_LOCK	    EnterCriticalSection(&pb_crit_sec)
void CAP_UNLOCK()
{
    if (&cap_crit_sec != NULL)
        LeaveCriticalSection(&cap_crit_sec);
}
void PB_UNLOCK()
{
    if (&pb_crit_sec != NULL)
        LeaveCriticalSection(&pb_crit_sec);
}
#endif

#ifdef _LINUX_
pthread_mutex_t cap_crit_sec;
pthread_mutex_t pb_crit_sec;
#define CAP_LOCK	pthread_mutex_lock(&cap_crit_sec)
void CAP_UNLOCK() { pthread_mutex_unlock(&cap_crit_sec); }
#define PB_LOCK	pthread_mutex_lock(&pb_crit_sec)
void PB_UNLOCK() { pthread_mutex_unlock(&pb_crit_sec); }
#endif

#define AUDIO_BUFFERMAXTIME 2  // fifo can buffer this time in [s]
#define AUDIO_PLAYBACK_BUFLEN (48000 * 10) // space for 10 seconds of samples
#define AUDIO_CAPTURE_BUFLEN  (48000 * 10)

int cap_wridx=0;
int cap_rdidx=0;
float cap_buffer[AUDIO_CAPTURE_BUFLEN];

int pb_wridx=0;
int pb_rdidx=0;
float pb_buffer[AUDIO_PLAYBACK_BUFLEN];

void init_pipes()
{
#ifdef _WIN32_
    if (&cap_crit_sec != NULL) DeleteCriticalSection(&cap_crit_sec);
    InitializeCriticalSection(&cap_crit_sec);

    if (&pb_crit_sec != NULL) DeleteCriticalSection(&pb_crit_sec);
    InitializeCriticalSection(&pb_crit_sec);
#endif
}

// write one sample into the fifo
// overwrite old data if the fifo is full
void cap_write_fifo(float sample)
{
	CAP_LOCK;
    cap_buffer[cap_wridx] = sample;
    if(++cap_wridx >= AUDIO_CAPTURE_BUFLEN) cap_wridx = 0;
	CAP_UNLOCK();
}

int cap_read_fifo(float *data)
{
	CAP_LOCK;

	if (cap_rdidx == cap_wridx)
	{
		// Fifo empty, no data available
		CAP_UNLOCK();
		return 0;
	}
	
	*data = cap_buffer[cap_rdidx];
    if(++cap_rdidx >= AUDIO_CAPTURE_BUFLEN) cap_rdidx = 0;
    CAP_UNLOCK();

	return 1;
}

void pb_write_fifo(float sample)
{
	PB_LOCK;
    
    // check if there is free space in fifo
    if(pb_fifo_freespace(1) == 0)
    {
        PB_UNLOCK();
        printf("************* pb fifo full\n");
        return;
    }
    
    pb_buffer[pb_wridx] = sample;
    if(++pb_wridx >= AUDIO_PLAYBACK_BUFLEN) pb_wridx = 0;
	PB_UNLOCK();
    //printf("write: pbw:%d pbr:%d\n",pb_wridx,pb_rdidx);
}

void pb_write_fifo_clear()
{
    pb_wridx = pb_rdidx = 0;
}

int pb_fifo_freespace(int nolock)
{
int freebuf = 0;

    if(nolock == 0) PB_LOCK;
    
    int elemInFifo = (pb_wridx + AUDIO_PLAYBACK_BUFLEN - pb_rdidx) % AUDIO_PLAYBACK_BUFLEN;
    freebuf = AUDIO_PLAYBACK_BUFLEN - elemInFifo;
    
	if(nolock == 0) PB_UNLOCK();
    
    //printf("fifolen:%d check: pbw:%d pbr:%d freebuf:%d\n",AUDIO_PLAYBACK_BUFLEN,pb_wridx,pb_rdidx,freebuf);
    
    return freebuf;
}

// read elements floats from fifo or return 0 if not enough floats are available
int pb_read_fifo(float *data, int elements)
{
    //printf("pb read fifo: %d\n",elements);
    PB_LOCK;
    
    int e = AUDIO_PLAYBACK_BUFLEN - pb_fifo_freespace(1);
    if(e < elements)
	{
		// Fifo empty, no data available
		PB_UNLOCK();
        //printf("pb fifo empty, need:%d have:%d size:%d\n",elements,e,AUDIO_PLAYBACK_BUFLEN);
		return 0;
	}
	
    for(int i=0; i<elements; i++)
    {
        data[i] = pb_buffer[pb_rdidx];
        if(++pb_rdidx >= AUDIO_PLAYBACK_BUFLEN) pb_rdidx = 0;
    }
    //printf("read %d floats\n",elements);
    
    PB_UNLOCK();
    return 1;
}