/* in_flac.c
 * Plugin to read FLAC files as PCM
 *
 * Copyright (c) 2004 Brendan Cully <brendan@xiph.org>
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Id: in_flac.c 7433 2004-07-31 17:49:18Z brendan $
 */

#include "config.h"
#include "in_flac.h"
#include "metadata.h"

#include <FLAC/stream_decoder.h>

/* -- data structures -- */
typedef struct {
  FLAC__StreamDecoder* decoder;
  unsigned char parsed;
  /* read buffer */
  char *buf;
  size_t len;
  /* write buffer */
  int16_t *left;
  int16_t *right;
  size_t olen;
} flac_in_t;

/* -- static prototypes -- */
static int ices_flac_readpcm (input_stream_t* self, size_t len,
			      int16_t* left, int16_t* right);
static int ices_flac_close (input_stream_t* self);

/* -- FLAC callbacks -- */
static FLAC__StreamDecoderReadStatus
flac_read_cb(const FLAC__StreamDecoder* decoder, FLAC__byte buffer[],
	     unsigned* bytes, void* client_data);
static FLAC__StreamDecoderWriteStatus
flac_write_cb(const FLAC__StreamDecoder* decoder, const FLAC__Frame* frame,
	      const FLAC__int32* const buffer[], void* client_data);
static void
flac_metadata_cb(const FLAC__StreamDecoder* decoder,
		 const FLAC__StreamMetadata* metadata, void* client_data);
static void
flac_error_cb(const FLAC__StreamDecoder* decoder,
	      FLAC__StreamDecoderErrorStatus status, void* client_data);

static inline int16_t scale16(int sample, int bps);

/* try to open a FLAC file for decoding. Returns:
 *   0: success
 *   1: not a FLAC file
 *  -1: error opening
 */
int
ices_flac_open (input_stream_t* self, char* buf, size_t len)
{
  flac_in_t* flac_data;
  FLAC__StreamDecoder* decoder;

  if (!(decoder = FLAC__stream_decoder_new())) {
    ices_log_error("ices_flac_open: Error allocating FLAC decoder");
    return -1;
  }

  FLAC__stream_decoder_set_read_callback(decoder, flac_read_cb);
  FLAC__stream_decoder_set_write_callback(decoder, flac_write_cb);
  FLAC__stream_decoder_set_metadata_callback(decoder, flac_metadata_cb);
  FLAC__stream_decoder_set_error_callback(decoder, flac_error_cb);

  FLAC__stream_decoder_set_metadata_respond(decoder, FLAC__METADATA_TYPE_VORBIS_COMMENT);

  if (!(flac_data = (flac_in_t*)malloc (sizeof (flac_in_t)))) {
    ices_log_error ("Malloc failed in ices_flac_open");
    goto errDecoder;
  }
  FLAC__stream_decoder_set_client_data(decoder, self);

  flac_data->decoder = decoder;
  flac_data->parsed = 0;
  flac_data->buf = buf;
  flac_data->len = len;

  self->data = flac_data;

  switch (FLAC__stream_decoder_init(decoder)) {
  case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
    break;
  case FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR:
    ices_log_error("Could not allocate memory during FLAC decoder init");
    goto errData;
  default:
    ices_log_error("Unexpected error during FLAC decoder init");
    goto errData;
  }

  if (!FLAC__stream_decoder_process_single(decoder)) {
    ices_log_error("Could not find FLAC metadata header");
    free(flac_data);
    FLAC__stream_decoder_delete(decoder);
    return 1;
  }
  if (!flac_data->parsed) {
    ices_log_error("Could not find FLAC metadata header in prebuffer");
    free(flac_data);
    FLAC__stream_decoder_delete(decoder);
    return 1;
  }

  self->type = ICES_INPUT_FLAC;

  self->read = NULL;
  self->readpcm = ices_flac_readpcm;
  self->close = ices_flac_close;

  if (!FLAC__stream_decoder_process_until_end_of_metadata(decoder)) {
    ices_log_error("Error seeking past FLAC metadata");
    goto errData;
  }
  
  return 0;

errData:
  free(flac_data);
errDecoder:
  FLAC__stream_decoder_delete(decoder);

  return -1;
}

static int
ices_flac_readpcm (input_stream_t* self, size_t olen, int16_t* left,
		   int16_t* right)
{
  flac_in_t* flac_data = (flac_in_t*)self->data;

  flac_data->left = left;
  flac_data->right = right;
  flac_data->olen = olen;
  if (!FLAC__stream_decoder_process_single(flac_data->decoder)) {
    switch (FLAC__stream_decoder_get_state(flac_data->decoder)) {
    case FLAC__STREAM_DECODER_END_OF_STREAM:
      return 0;
    default:
      ices_log_error("Error reading FLAC stream");
    }
  }
  if (FLAC__stream_decoder_get_state(flac_data->decoder) == FLAC__STREAM_DECODER_END_OF_STREAM)
    return 0;

  return flac_data->olen;
}

static int
ices_flac_close (input_stream_t* self)
{
  flac_in_t* flac_data = (flac_in_t*) self->data;

  FLAC__stream_decoder_finish(flac_data->decoder);
  FLAC__stream_decoder_delete(flac_data->decoder);
  free (flac_data);

  return close(self->fd);
}

/* -- callbacks -- */
static FLAC__StreamDecoderReadStatus
flac_read_cb(const FLAC__StreamDecoder* decoder, FLAC__byte buffer[],
	     unsigned* bytes, void* client_data)
{
  input_stream_t* self = (input_stream_t*)client_data;
  flac_in_t* flac_data = (flac_in_t*)self->data;
  ssize_t len;
  char errbuf[128];

  if (!flac_data->len) {
    if (!flac_data->parsed) {
      *bytes = 0;
      return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
    }
    if ((len = read(self->fd, buffer, *bytes)) > 0)
      return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
    if (!len)
      return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
    ices_log_error("Error reading FLAC stream: %s", ices_util_strerror(errno, errbuf, sizeof(errbuf)));
    return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
  }

  if (flac_data->len < *bytes)
    *bytes = flac_data->len;
  memcpy(buffer, flac_data->buf, *bytes);
  flac_data->len -= *bytes;

  return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
}

static FLAC__StreamDecoderWriteStatus
flac_write_cb(const FLAC__StreamDecoder* decoder, const FLAC__Frame* frame,
	      const FLAC__int32* const buffer[], void* client_data)
{
  input_stream_t* self = (input_stream_t*)client_data;
  flac_in_t* flac_data = (flac_in_t*)self->data;
  int i;

  for (i = 0; i < frame->header.blocksize; i++) {
    flac_data->left[i] = scale16(buffer[0][i], frame->header.bits_per_sample);
    if (self->channels > 1) {
      flac_data->right[i] = scale16(buffer[1][i], frame->header.bits_per_sample);
    }
  }
  if (self->channels == 1)
    memcpy(flac_data->right, flac_data->left, frame->header.blocksize << 1);

  flac_data->olen = frame->header.blocksize;

  return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
}

static void
flac_metadata_cb(const FLAC__StreamDecoder* decoder,
		 const FLAC__StreamMetadata* metadata, void* client_data)
{
  input_stream_t* self = (input_stream_t*)client_data;
  flac_in_t* flac_data = (flac_in_t*)self->data;
  FLAC__StreamMetadata_VorbisComment_Entry* comment;
  char *artist = NULL;
  char *title = NULL;
  int i;

  switch(metadata->type) {
  case FLAC__METADATA_TYPE_STREAMINFO:
    self->samplerate = metadata->data.stream_info.sample_rate;
    self->channels = metadata->data.stream_info.channels;
    flac_data->parsed = 1;
    ices_log_debug("Found FLAC file, %d Hz, %d channels, %d bits", self->samplerate, self->channels, metadata->data.stream_info.bits_per_sample);
    break;
  case FLAC__METADATA_TYPE_VORBIS_COMMENT:
    for (i = 0; i < metadata->data.vorbis_comment.num_comments; i++) {
      comment = metadata->data.vorbis_comment.comments + i;

      if (comment->length >= 6 && !strncasecmp("artist", comment->entry, 6)) {
	if ((artist = malloc(comment->length - 6)))
	  snprintf(artist, comment->length - 6, "%s", comment->entry + 7);
      } else if (comment->length >= 5 && !strncasecmp("title", comment->entry, 5)) {
	if ((title = malloc(comment->length - 5)))
	  snprintf(title, comment->length - 5, "%s", comment->entry + 6);
      }
    }
    
    ices_metadata_set(artist, title);
    if (artist)
      free(artist);
    if (title)
      free(title);
    break;
  default:
    ices_log_debug("Ignoring unknown FLAC metadata type");
  }
}

static void
flac_error_cb(const FLAC__StreamDecoder* decoder,
	      FLAC__StreamDecoderErrorStatus status, void* client_data)
{
  switch (status) {
  case FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC:
    ices_log_error("FLAC lost sync");
    break;
  case FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER:
    ices_log_error("Bad header in FLAC stream");
    break;
  case FLAC__STREAM_DECODER_ERROR_STATUS_FRAME_CRC_MISMATCH:
    ices_log_error("Bad CRC for FLAC frame");
    break;
  default:
    ices_log_error("Unspecified error decoding FLAC stream");
  }
}

/* -- utility -- */
static inline int16_t scale16(int sample, int bps) {
  if (bps == 16)
    return sample;
  if (bps < 16)
    return sample << (16 - bps);
  return sample >> (bps - 16);
}