/*
  * JACK Audio Connection Kit input device
  * Copyright (c) 2009 Samalyse
  * Author: Olivier Guilyardi <olivier samalyse com>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "config.h"
 #include <semaphore.h>
 #include <jack/jack.h>
 
 #include "libavutil/log.h"
 #include "libavutil/fifo.h"

 #include "libavutil/opt.h"

 #include "libavcodec/avcodec.h"
 #include "libavformat/avformat.h"

 #include "libavformat/internal.h"

 #include "timefilter.h"

 #include "avdevice.h"

 
 /**
  * Size of the internal FIFO buffers as a number of audio packets
  */
 #define FIFO_PACKETS_NUM 16
 
 typedef struct {

     AVClass        *class;

     jack_client_t * client;
     int             activated;
     sem_t           packet_count;
     jack_nframes_t  sample_rate;
     jack_nframes_t  buffer_size;
     jack_port_t **  ports;
     int             nports;
     TimeFilter *    timefilter;
     AVFifoBuffer *  new_pkts;
     AVFifoBuffer *  filled_pkts;
     int             pkt_xrun;
     int             jack_xrun;
 } JackData;
 
 static int process_callback(jack_nframes_t nframes, void *arg)
 {
     /* Warning: this function runs in realtime. One mustn't allocate memory here
      * or do any other thing that could block. */
 
     int i, j;
     JackData *self = arg;
     float * buffer;
     jack_nframes_t latency, cycle_delay;
     AVPacket pkt;
     float *pkt_data;
     double cycle_time;
 
     if (!self->client)
         return 0;
 
     /* The approximate delay since the hardware interrupt as a number of frames */
     cycle_delay = jack_frames_since_cycle_start(self->client);
 
     /* Retrieve filtered cycle time */
     cycle_time = ff_timefilter_update(self->timefilter,
                                       av_gettime() / 1000000.0 - (double) cycle_delay / self->sample_rate,
                                       self->buffer_size);
 
     /* Check if an empty packet is available, and if there's enough space to send it back once filled */
     if ((av_fifo_size(self->new_pkts) < sizeof(pkt)) || (av_fifo_space(self->filled_pkts) < sizeof(pkt))) {
         self->pkt_xrun = 1;
         return 0;
     }
 
     /* Retrieve empty (but allocated) packet */
     av_fifo_generic_read(self->new_pkts, &pkt, sizeof(pkt), NULL);
 
     pkt_data  = (float *) pkt.data;
     latency   = 0;
 
     /* Copy and interleave audio data from the JACK buffer into the packet */
     for (i = 0; i < self->nports; i++) {
         latency += jack_port_get_total_latency(self->client, self->ports[i]);
         buffer = jack_port_get_buffer(self->ports[i], self->buffer_size);
         for (j = 0; j < self->buffer_size; j++)
             pkt_data[j * self->nports + i] = buffer[j];
     }
 
     /* Timestamp the packet with the cycle start time minus the average latency */
     pkt.pts = (cycle_time - (double) latency / (self->nports * self->sample_rate)) * 1000000.0;
 
     /* Send the now filled packet back, and increase packet counter */
     av_fifo_generic_write(self->filled_pkts, &pkt, sizeof(pkt), NULL);
     sem_post(&self->packet_count);
 
     return 0;
 }
 
 static void shutdown_callback(void *arg)
 {
     JackData *self = arg;
     self->client = NULL;
 }
 
 static int xrun_callback(void *arg)
 {
     JackData *self = arg;
     self->jack_xrun = 1;
     ff_timefilter_reset(self->timefilter);
     return 0;
 }
 
 static int supply_new_packets(JackData *self, AVFormatContext *context)
 {
     AVPacket pkt;
     int test, pkt_size = self->buffer_size * self->nports * sizeof(float);
 
     /* Supply the process callback with new empty packets, by filling the new
      * packets FIFO buffer with as many packets as possible. process_callback()
      * can't do this by itself, because it can't allocate memory in realtime. */
     while (av_fifo_space(self->new_pkts) >= sizeof(pkt)) {
         if ((test = av_new_packet(&pkt, pkt_size)) < 0) {
             av_log(context, AV_LOG_ERROR, "Could not create packet of size %d\n", pkt_size);
             return test;
         }
         av_fifo_generic_write(self->new_pkts, &pkt, sizeof(pkt), NULL);
     }
     return 0;
 }
 

 static int start_jack(AVFormatContext *context)

 {
     JackData *self = context->priv_data;
     jack_status_t status;
     int i, test;
     double o, period;
 
     /* Register as a JACK client, using the context filename as client name. */

     self->client = jack_client_open(context->filename, JackNullOption, &status);

     if (!self->client) {
         av_log(context, AV_LOG_ERROR, "Unable to register as a JACK client\n");
         return AVERROR(EIO);
     }
 
     sem_init(&self->packet_count, 0, 0);
 
     self->sample_rate = jack_get_sample_rate(self->client);
     self->ports       = av_malloc(self->nports * sizeof(*self->ports));
     self->buffer_size = jack_get_buffer_size(self->client);
 
     /* Register JACK ports */
     for (i = 0; i < self->nports; i++) {
         char str[16];
         snprintf(str, sizeof(str), "input_%d", i + 1);
         self->ports[i] = jack_port_register(self->client, str,
                                             JACK_DEFAULT_AUDIO_TYPE,
                                             JackPortIsInput, 0);
         if (!self->ports[i]) {
             av_log(context, AV_LOG_ERROR, "Unable to register port %s:%s\n",
                    context->filename, str);
             jack_client_close(self->client);
             return AVERROR(EIO);
         }
     }
 
     /* Register JACK callbacks */
     jack_set_process_callback(self->client, process_callback, self);
     jack_on_shutdown(self->client, shutdown_callback, self);
     jack_set_xrun_callback(self->client, xrun_callback, self);
 
     /* Create time filter */
     period            = (double) self->buffer_size / self->sample_rate;
     o                 = 2 * M_PI * 1.5 * period; /// bandwidth: 1.5Hz
     self->timefilter  = ff_timefilter_new (1.0 / self->sample_rate, sqrt(2 * o), o * o);
 
     /* Create FIFO buffers */
     self->filled_pkts = av_fifo_alloc(FIFO_PACKETS_NUM * sizeof(AVPacket));
     /* New packets FIFO with one extra packet for safety against underruns */
     self->new_pkts    = av_fifo_alloc((FIFO_PACKETS_NUM + 1) * sizeof(AVPacket));
     if ((test = supply_new_packets(self, context))) {
         jack_client_close(self->client);
         return test;
     }
 
     return 0;
 
 }
 
 static void free_pkt_fifo(AVFifoBuffer *fifo)
 {
     AVPacket pkt;
     while (av_fifo_size(fifo)) {
         av_fifo_generic_read(fifo, &pkt, sizeof(pkt), NULL);
         av_free_packet(&pkt);
     }
     av_fifo_free(fifo);
 }
 
 static void stop_jack(JackData *self)
 {
     if (self->client) {
         if (self->activated)
             jack_deactivate(self->client);
         jack_client_close(self->client);
     }
     sem_destroy(&self->packet_count);
     free_pkt_fifo(self->new_pkts);
     free_pkt_fifo(self->filled_pkts);
     av_freep(&self->ports);
     ff_timefilter_destroy(self->timefilter);
 }
 
 static int audio_read_header(AVFormatContext *context, AVFormatParameters *params)
 {
     JackData *self = context->priv_data;
     AVStream *stream;
     int test;
 

     if ((test = start_jack(context)))

         return test;
 

     stream = avformat_new_stream(context, NULL);

     if (!stream) {
         stop_jack(self);
         return AVERROR(ENOMEM);
     }
 

     stream->codec->codec_type   = AVMEDIA_TYPE_AUDIO;

 #if HAVE_BIGENDIAN

     stream->codec->codec_id     = CODEC_ID_PCM_F32BE;
 #else
     stream->codec->codec_id     = CODEC_ID_PCM_F32LE;
 #endif
     stream->codec->sample_rate  = self->sample_rate;
     stream->codec->channels     = self->nports;
 

     avpriv_set_pts_info(stream, 64, 1, 1000000);  /* 64 bits pts in us */

     return 0;
 }
 
 static int audio_read_packet(AVFormatContext *context, AVPacket *pkt)
 {
     JackData *self = context->priv_data;
     struct timespec timeout = {0, 0};
     int test;
 
     /* Activate the JACK client on first packet read. Activating the JACK client
      * means that process_callback() starts to get called at regular interval.
      * If we activate it in audio_read_header(), we're actually reading audio data
      * from the device before instructed to, and that may result in an overrun. */
     if (!self->activated) {
         if (!jack_activate(self->client)) {
             self->activated = 1;
             av_log(context, AV_LOG_INFO,
                    "JACK client registered and activated (rate=%dHz, buffer_size=%d frames)\n",
                    self->sample_rate, self->buffer_size);
         } else {
             av_log(context, AV_LOG_ERROR, "Unable to activate JACK client\n");
             return AVERROR(EIO);
         }
     }
 

     /* Wait for a packet coming back from process_callback(), if one isn't available yet */

     timeout.tv_sec = av_gettime() / 1000000 + 2;
     if (sem_timedwait(&self->packet_count, &timeout)) {
         if (errno == ETIMEDOUT) {
             av_log(context, AV_LOG_ERROR,
                    "Input error: timed out when waiting for JACK process callback output\n");
         } else {
             av_log(context, AV_LOG_ERROR, "Error while waiting for audio packet: %s\n",
                    strerror(errno));
         }
         if (!self->client)
             av_log(context, AV_LOG_ERROR, "Input error: JACK server is gone\n");
 
         return AVERROR(EIO);
     }
 
     if (self->pkt_xrun) {
         av_log(context, AV_LOG_WARNING, "Audio packet xrun\n");
         self->pkt_xrun = 0;
     }
 
     if (self->jack_xrun) {
         av_log(context, AV_LOG_WARNING, "JACK xrun\n");
         self->jack_xrun = 0;
     }
 
     /* Retrieve the packet filled with audio data by process_callback() */
     av_fifo_generic_read(self->filled_pkts, pkt, sizeof(*pkt), NULL);
 
     if ((test = supply_new_packets(self, context)))
         return test;
 
     return 0;
 }
 
 static int audio_read_close(AVFormatContext *context)
 {
     JackData *self = context->priv_data;
     stop_jack(self);
     return 0;
 }
 

 #define OFFSET(x) offsetof(JackData, x)
 static const AVOption options[] = {

     { "channels", "Number of audio channels.", OFFSET(nports), AV_OPT_TYPE_INT, { 2 }, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },

     { NULL },
 };
 
 static const AVClass jack_indev_class = {
     .class_name     = "JACK indev",
     .item_name      = av_default_item_name,
     .option         = options,
     .version        = LIBAVUTIL_VERSION_INT,
 };
 

 AVInputFormat ff_jack_demuxer = {

     .name           = "jack",
     .long_name      = NULL_IF_CONFIG_SMALL("JACK Audio Connection Kit"),
     .priv_data_size = sizeof(JackData),
     .read_header    = audio_read_header,
     .read_packet    = audio_read_packet,
     .read_close     = audio_read_close,
     .flags          = AVFMT_NOFILE,
     .priv_class     = &jack_indev_class,

 };