/*
  * AST muxer
  * Copyright (c) 2012 James Almer
  *
  * 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 "avformat.h"
 #include "avio_internal.h"
 #include "internal.h"
 #include "ast.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 
 typedef struct ASTMuxContext {
     AVClass *class;
     int64_t  size;
     int64_t  samples;
     int64_t  loopstart;
     int64_t  loopend;
     int      fbs;
 } ASTMuxContext;
 
 #define CHECK_LOOP(type) \

     if (ast->loop ## type > 0) { \

         ast->loop ## type = av_rescale_rnd(ast->loop ## type, enc->sample_rate, 1000, AV_ROUND_DOWN); \

         if (ast->loop ## type < 0 || ast->loop ## type > UINT_MAX) { \
             av_log(s, AV_LOG_ERROR, "Invalid loop" #type " value\n"); \
             return AVERROR(EINVAL);  \
         } \
     }
 
 static int ast_write_header(AVFormatContext *s)
 {
     ASTMuxContext *ast = s->priv_data;
     AVIOContext *pb = s->pb;
     AVCodecContext *enc;
     unsigned int codec_tag;
 

     if (s->nb_streams == 1) {

         enc = s->streams[0]->codec;
     } else {
         av_log(s, AV_LOG_ERROR, "only one stream is supported\n");
         return AVERROR(EINVAL);
     }
 
     if (enc->codec_id == AV_CODEC_ID_ADPCM_AFC) {
         av_log(s, AV_LOG_ERROR, "muxing ADPCM AFC is not implemented\n");
         return AVERROR_PATCHWELCOME;
     }
 
     codec_tag = ff_codec_get_tag(ff_codec_ast_tags, enc->codec_id);
     if (!codec_tag) {
         av_log(s, AV_LOG_ERROR, "unsupported codec\n");
         return AVERROR(EINVAL);
     }
 

     if (ast->loopend > 0 && ast->loopstart >= ast->loopend) {

         av_log(s, AV_LOG_ERROR, "loopend can't be less or equal to loopstart\n");
         return AVERROR(EINVAL);
     }
 
     /* Convert milliseconds to samples */
     CHECK_LOOP(start)
     CHECK_LOOP(end)
 
     ffio_wfourcc(pb, "STRM");
 
     ast->size = avio_tell(pb);
     avio_wb32(pb, 0); /* File size minus header */
     avio_wb16(pb, codec_tag);
     avio_wb16(pb, 16); /* Bit depth */
     avio_wb16(pb, enc->channels);

     avio_wb16(pb, 0); /* Loop flag */

     avio_wb32(pb, enc->sample_rate);
 
     ast->samples = avio_tell(pb);
     avio_wb32(pb, 0); /* Number of samples */
     avio_wb32(pb, 0); /* Loopstart */
     avio_wb32(pb, 0); /* Loopend */
     avio_wb32(pb, 0); /* Size of first block */
 
     /* Unknown */
     avio_wb32(pb, 0);
     avio_wl32(pb, 0x7F);
     avio_wb64(pb, 0);
     avio_wb64(pb, 0);
     avio_wb32(pb, 0);
 
     avio_flush(pb);
 
     return 0;
 }
 
 static int ast_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     AVIOContext *pb = s->pb;
     ASTMuxContext *ast = s->priv_data;
     AVCodecContext *enc = s->streams[0]->codec;
     int size = pkt->size / enc->channels;
 
     if (enc->frame_number == 1)
         ast->fbs = size;
 
     ffio_wfourcc(pb, "BLCK");
     avio_wb32(pb, size); /* Block size */
 
     /* padding */
     avio_wb64(pb, 0);
     avio_wb64(pb, 0);
     avio_wb64(pb, 0);
 
     avio_write(pb, pkt->data, pkt->size);
 
     return 0;
 }
 
 static int ast_write_trailer(AVFormatContext *s)
 {
     AVIOContext *pb = s->pb;
     ASTMuxContext *ast = s->priv_data;
     AVCodecContext *enc = s->streams[0]->codec;
     int64_t file_size = avio_tell(pb);
     int64_t samples = (file_size - 64 - (32 * enc->frame_number)) / enc->block_align; /* PCM_S16BE_PLANAR */
 
     av_log(s, AV_LOG_DEBUG, "total samples: %"PRId64"\n", samples);
 
     if (s->pb->seekable) {
         /* Number of samples */
         avio_seek(pb, ast->samples, SEEK_SET);
         avio_wb32(pb, samples);
 
         /* Loopstart if provided */

         if (ast->loopstart > 0) {
         if (ast->loopstart >= samples) {

             av_log(s, AV_LOG_WARNING, "Loopstart value is out of range and will be ignored\n");

             ast->loopstart = -1;
             avio_skip(pb, 4);
         } else

         avio_wb32(pb, ast->loopstart);

         } else
             avio_skip(pb, 4);

 
         /* Loopend if provided. Otherwise number of samples again */

         if (ast->loopend && ast->loopstart >= 0) {

             if (ast->loopend > samples) {
                 av_log(s, AV_LOG_WARNING, "Loopend value is out of range and will be ignored\n");
                 ast->loopend = samples;
             }
             avio_wb32(pb, ast->loopend);
         } else {
             avio_wb32(pb, samples);
         }
 
         /* Size of first block */
         avio_wb32(pb, ast->fbs);

 
         /* File size minus header */
         avio_seek(pb, ast->size, SEEK_SET);
         avio_wb32(pb, file_size - 64);
 
         /* Loop flag */
         if (ast->loopstart >= 0) {
             avio_skip(pb, 6);
             avio_wb16(pb, 0xFFFF);
         }
 
         avio_seek(pb, file_size, SEEK_SET);

         avio_flush(pb);
     }
     return 0;
 }
 
 #define OFFSET(obj) offsetof(ASTMuxContext, obj)
 static const AVOption options[] = {

   { "loopstart", "Loopstart position in milliseconds.", OFFSET(loopstart), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },

   { "loopend",   "Loopend position in milliseconds.",   OFFSET(loopend),   AV_OPT_TYPE_INT64, { .i64 = 0 }, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
   { NULL },
 };
 
 static const AVClass ast_muxer_class = {
     .class_name = "AST muxer",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 AVOutputFormat ff_ast_muxer = {
     .name              = "ast",
     .long_name         = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"),
     .extensions        = "ast",
     .priv_data_size    = sizeof(ASTMuxContext),
     .audio_codec       = AV_CODEC_ID_PCM_S16BE_PLANAR,
     .video_codec       = AV_CODEC_ID_NONE,
     .write_header      = ast_write_header,
     .write_packet      = ast_write_packet,
     .write_trailer     = ast_write_trailer,
     .priv_class        = &ast_muxer_class,
     .codec_tag         = (const AVCodecTag* const []){ff_codec_ast_tags, 0},
 };